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Sample records for viciifolia forage tested

  1. Potential to reduce Escherichia coli shedding in cattle feces by using sainfoin (Onobrychis viciifolia) forage, tested in vitro and in vivo.

    Science.gov (United States)

    Berard, Natalie C; Holley, Richard A; McAllister, Tim A; Ominski, Kim H; Wittenberg, Karin M; Bouchard, Kristen S; Bouchard, Jenelle J; Krause, Denis O

    2009-02-01

    There is a growing concern about the presence of pathogens in cattle manure and its implications on human and environmental health. The phytochemical-rich forage sainfoin (Onobrychis viciifolia) and purified phenolics (trans-cinnamic acid, p-coumaric acid, and ferulic acid) were evaluated for their ability to reduce the viability of pathogenic Escherichia coli strains, including E. coli O157:H7. MICs were determined using purified phenolics and acetone extracts of sainfoin and alfalfa (Medicago sativa), a non-tannin-containing legume. Ground sainfoin or pure phenolics were mixed with fresh cattle feces and inoculated with a ciprofloxacin-resistant strain of E. coli, O157:H7, to assess its viability at -20 degrees C, 5 degrees C, or 37 degrees C over 14 days. Forty steers were fed either a sainfoin (hay or silage) or alfalfa (hay or silage) diet over a 9-week period. In the in vitro study, the MICs for coumaric (1.2 mg/ml) and cinnamic (1.4 mg/ml) acids were 10- to 20-fold lower than the MICs for sainfoin and alfalfa extracts. In the inoculated feces, the -20 degrees C treatment had death rates which were at least twice as high as those of the 5 degrees C treatment, irrespective of the additive used. Sainfoin was less effective than coumaric acid in reducing E. coli O157:H7 Cip(r) in the inoculated feces. During the animal trial, fecal E. coli numbers declined marginally in the presence of sainfoin (silage and hay) and alfalfa silage but not in the presence of hay, indicating the presence of other phenolics in alfalfa. In conclusion, phenolic-containing forages can be used as a means of minimally reducing E. coli shedding in cattle without affecting animal production.

  2. Potential To Reduce Escherichia coli Shedding in Cattle Feces by Using Sainfoin (Onobrychis viciifolia) Forage, Tested In Vitro and In Vivo▿

    Science.gov (United States)

    Berard, Natalie C.; Holley, Richard A.; McAllister, Tim A.; Ominski, Kim H.; Wittenberg, Karin M.; Bouchard, Kristen S.; Bouchard, Jenelle J.; Krause, Denis O.

    2009-01-01

    There is a growing concern about the presence of pathogens in cattle manure and its implications on human and environmental health. The phytochemical-rich forage sainfoin (Onobrychis viciifolia) and purified phenolics (trans-cinnamic acid, p-coumaric acid, and ferulic acid) were evaluated for their ability to reduce the viability of pathogenic Escherichia coli strains, including E. coli O157:H7. MICs were determined using purified phenolics and acetone extracts of sainfoin and alfalfa (Medicago sativa), a non-tannin-containing legume. Ground sainfoin or pure phenolics were mixed with fresh cattle feces and inoculated with a ciprofloxacin-resistant strain of E. coli, O157:H7, to assess its viability at −20°C, 5°C, or 37°C over 14 days. Forty steers were fed either a sainfoin (hay or silage) or alfalfa (hay or silage) diet over a 9-week period. In the in vitro study, the MICs for coumaric (1.2 mg/ml) and cinnamic (1.4 mg/ml) acids were 10- to 20-fold lower than the MICs for sainfoin and alfalfa extracts. In the inoculated feces, the −20°C treatment had death rates which were at least twice as high as those of the 5°C treatment, irrespective of the additive used. Sainfoin was less effective than coumaric acid in reducing E. coli O157:H7 Cipr in the inoculated feces. During the animal trial, fecal E. coli numbers declined marginally in the presence of sainfoin (silage and hay) and alfalfa silage but not in the presence of hay, indicating the presence of other phenolics in alfalfa. In conclusion, phenolic-containing forages can be used as a means of minimally reducing E. coli shedding in cattle without affecting animal production. PMID:19098216

  3. Acylated flavonol glycosides from the forage legume, Onobrychis viciifolia (sainfoin).

    Science.gov (United States)

    Veitch, Nigel C; Regos, Ionela; Kite, Geoffrey C; Treutter, Dieter

    2011-04-01

    Ten acylated flavonol glycosides were isolated from aqueous acetone extracts of the aerial parts of the forage legume, Onobrychis viciifolia, and their structures determined using spectroscopic methods. Among these were eight previously unreported examples which comprised either feruloylated or sinapoylated derivatives of 3-O-di- and 3-O-triglycosides of kaempferol (3,5,7,4'-tetrahydroxyflavone) or quercetin (3,5,7,3',4'-pentahydroxyflavone). The diglycosides were acylated at the primary Glc residue of O-α-Rhap(1→6)-β-Glcp (rutinose), whereas the triglycosides were acylated at the terminal Rha residues of the branched trisaccharides, O-α-Rhap(1→2)[α-Rhap(1→6)]-β-Galp or O-α-Rhap(1→2)[α-Rhap(1→6)]-β-Glcp. Identification of the primary 3-O-linked hexose residues as either Gal or Glc was carried out by negative ion electrospray and serial MS, and cryoprobe NMR spectroscopy. Analysis of UV and MS spectra of the acylated flavonol glycosides provided additional diagnostic features relevant to direct characterisation of these compounds in hyphenated analyses. Quantitative analysis of the acylated flavonol glycosides present in different aerial parts of sainfoin revealed that the highest concentrations were in mature leaflets. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Evidence and consequences of self-fertilisation in the predominantly outbreeding forage legume Onobrychis viciifolia.

    Science.gov (United States)

    Kempf, Katharina; Grieder, Christoph; Walter, Achim; Widmer, Franco; Reinhard, Sonja; Kölliker, Roland

    2015-10-07

    Sainfoin (Onobrychis viciifolia) is a promising alternative forage plant of good quality, moderate nutrient demand and a high content of polyphenolic compounds. Its poor adoption is caused by the limited availability of well performing varieties. Sainfoin is characterised as tetraploid and mainly outcrossing, but the extent of self-fertilisation and its consequences was not investigated so far. This study aimed at assessing the rate of self-fertilisation in sainfoin under different pollination regimes and at analysing the consequences on plant performance in order to assist future breeding efforts. The self-fertilisation rate was assessed in three sainfoin populations with artificially directed pollination (ADP) and in three populations with non-directed pollination (NDP). Dominant SRAP (sequence-related amplified polymorphism) and codominant SSR (simple sequence repeats) markers were used to detect self-fertilisation in sainfoin for the first time based on molecular marker data. High rates of self-fertilisation of up to 64.8% were observed for ADP populations in contrast to only up to 3.9% for NDP populations. Self-fertilisation in ADP populations led to a reduction in plant height, plant vigour and, most severely, for seed yield. Although sainfoin is predominantly outcrossing, self-fertilisation can occur to a high degree under conditions of limited pollen availability. These results will influence future breeding efforts because precautions have to be taken when crossing breeding material. The resulting inbreeding depression can lead to reduced performance in self-fertilised offspring. Nevertheless the possibility of self-fertilisation also offers new ways for hybrid breeding based on the development of homogenous inbred lines.

  5. Identification and quantification of phenolic compounds from the forage legume sainfoin ( Onobrychis viciifolia ).

    Science.gov (United States)

    Regos, Ionela; Urbanella, Andrea; Treutter, Dieter

    2009-07-08

    Phenolic compounds of sainfoin ( Onobrychis viciifolia ) variety Cotswold Common are assumed to contribute to its nutritive value and bioactive properties. A purified acetone/water extract was separated by Sephadex LH-20 gel chromatography. Sixty-three phenolic and other aromatic compounds were identified by means of chemical, chromatographic, and spectroscopic methods. Reverse phase HPLC with diode array and chemical reaction detection was used to investigate the phenolic composition of different plant organs. All plant parts showed specific phenolic profiles. Moreover, there were considerable variations in the phenolic content among individual plants of the same variety. The three most abundant phenolic compounds were found to be arbutin [predominant in petiols, 17.7 mg/g of dry weight (DW)], rutin (predominant in leaves, 19.9 mg/g of DW), and catechin (predominant flavanol in petiols, 3.5 mg/g of DW). The present study reveals that the phenolic profile of sainfoin is even more complex than hitherto assumed.

  6. Tanniferous forage plants with anthelmintic properties: the example of sainfoin (Onobrychis viciifolia)

    OpenAIRE

    Heckendorn, Felix; Maurer, Veronika; Häring, Dieter; Langhans, Wolfgang; Hertzberg, Hubertus

    2007-01-01

    Introduction: Sainfoin is a high-quality condensed tannin containing forage plant. The knowledge about anthelmintic effects against sheep nematodes and about the influence of plant preservation (e.g. ensiling) on the anthelmintic activity is limited. Method: 36 parasite naïve lambs (6 groups of 6 animals each) were infected with H. contortus (7,000 L3) and C. curticei (15,000 L3). From day 28 until day 44 p.i., groups A1, B1 and C1 received fresh, dried or ensiled sainfoin. Groups A2, B2 a...

  7. Natural glyphosate tolerance in sainfoin (onybrychis viciifolia)

    Science.gov (United States)

    Sainfoin (Onybrychis viciifolia Scop.), a non-bloating forage legume, is purported to have tolerance to glyphosate [N-(phosphonomethyl) glycine]. The effect on biomass yield (BMY) and survival of eight rates of glyphosate on seedlings and mature plants were determined. Treatment rates were 0.0, 0....

  8. Testing for direct anthelmintic effects of bioactive forages against Trichostrongylus colubriformis in grazing sheep.

    Science.gov (United States)

    Athanasiadou, S; Tzamaloukas, O; Kyriazakis, I; Jackson, F; Coop, R L

    2005-02-28

    The aim of the present study was to investigate potential direct anthelmintic effects of forages that contain plant secondary metabolites (PSM) towards the intestinal nematode Trichostrongylus colubriformis. For this purpose, we introduced an experimental design, which enabled us to investigate the direct anthelmintic effects of PSM-rich forages, without significant interference of possible indirect immunological effects of PSM. Sixty parasite naive sheep were infected with 8000 T. colubriformis L(3) on day 1 of the experiment. On day 28, sheep entered one of the experimental plots, which consisted of four PSM-rich forages and one control: Lotus pedunculatus (lotus), Hedysarium coronarium (sulla), Onobrychis viciifolia (sainfoin), Cichorium intybus (chicory) and Lolium perenne/Trifolium repens (grass/clover). On day 35 of the experiment, all sheep were re-infected with 8000 T. colubriformis L(3) and were killed on day 42. By day 42, all parasites of the primary infection would have been recovered as adults, whereas those of the secondary challenge would have only developed to the fourth stage larvae within a week (i.e. days 35-42). The first batch of larvae would enable us to investigate possible direct anthelmintic effects of PSM-rich forages against adult T. colubriformis, whereas the second one whether grazing on the PSM-rich forages could affect the establishment of the incoming infective larvae. Sheep grazing on lotus tended to have a lower FEC compared to sheep grazing on grass/clover (P = 0.06), whereas daily faecal output was higher in sheep grazing lotus compared to those grazing on the other forages (P forages for a period of 2 weeks did not affect the immature and adult parasite populations. Although the present experimental design enabled us to test the experimental hypothesis, the lack of evidence on a direct anthelmintic effect of PSM-rich forages can not be considered conclusive, as the composition of PSM-rich forages is variable within and across

  9. Anti-parasitic activity of pelleted sainfoin (Onobrychis viciifolia) against Ostertagia ostertagi and Cooperia oncophora in calves

    DEFF Research Database (Denmark)

    Desrues, O.; Pena-Espinoza, Miguel Angel; Hansen, T. V.

    2016-01-01

    BACKGROUND: Increasing anthelmintic-resistance in nematodes of ruminants emphasises the need for sustainable parasite control. Condensed tannin-containing legume forages such as sainfoin (Onobrychis viciifolia) have shown promising anthelmintic properties in small ruminants but this has never been...

  10. Sainfoin (Onobrychis viciifolia)

    NARCIS (Netherlands)

    Huyen, Nguyen Thi

    2016-01-01

    Sainfoin (Onobrychis viciifolia): a forgotten crop for dairy cows with future potential SUMMARY The world population growth and rising incomes are expected to increase the consumption of animal-derived foods such as meat, eggs and milk. However, livestock production

  11. Sainfoin (Onobrychis viciifolia)

    OpenAIRE

    Huyen, Nguyen Thi

    2016-01-01

    Sainfoin (Onobrychis viciifolia): a forgotten crop for dairy cows with future potential SUMMARY The world population growth and rising incomes are expected to increase the consumption of animal-derived foods such as meat, eggs and milk. However, livestock production should not only be directed towards increasing productivity but should also incorporate environmental, food safety and animal welfare aspects. Therefore, farm businesses have to respond to the high environment impact of their acti...

  12. Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions

    NARCIS (Netherlands)

    Huyen, N. T.; Desrues, O.; Alferink, S. J. J.; Zandstra, T.; Verstegen, M. W. A.; Hendriks, W. H.; Pellikaan, W. F.

    Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow

  13. Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions

    NARCIS (Netherlands)

    Huyen, N.T.; Desrues, O.; Alferink, S.J.J.; Zandstra, T.; Verstegen, M.W.A.; Hendriks, W.H.; Pellikaan, W.F.

    2016-01-01

    Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy

  14. Asymmetric somatic hybrid plants between Medicago sativa L. (alfalfa, lucerne) and Onobrychis viciifolia Scop. (sainfoin).

    Science.gov (United States)

    Li, Y G; Tanner, G J; Delves, A C; Larkin, P J

    1993-12-01

    This paper reports on the production of intergeneric somatic hybrid plants between two sexually incompatible legume species. Medicago sativa (alfalfa, lucerne) leaf protoplasts were inactivated by lethal doses of iodoacetamide. Onobrychis viciifolia (sainfoin) suspension-cell protoplasts were gamma-irradiated at lethal doses. Following electrofusion under optimized conditions about 50,000 viable heterokaryons were produced in each test. The fusion products were cultured with the help of alfalfa nurse protoplasts. Functional complementation permitted only the heterokaryons to survive. A total of 706 putative heterokaryon-derived plantlets were regenerated and 570 survived transplantation to soil. Experimentation was aimed at the introduction of proanthocyanidins (condensed tannins) from sainfoin, a bloat-safe plant, to alfalfa, a bloat-causing forage crop; however, no tannin-positive regenerant plants were detected. Most regenerant plants have shown morphological differences from the fusion parents, although, as expected, all resembled the "recipient" parent, alfalfa. Southern analysis using an improved total-genomic probing technique has shown low levels of sainfoin-specific DNA in 43 out of 158 tested regenerants. Cytogenetic analysis of these asymmetric hybrids has confirmed the existence of euploid (2n=32; 17%) as well as aneuploid (2n=30, 33-78; 83%) plants. Pollen germination tests have indicated that the majority of the hybrids were fertile, while 35% had either reduced fertility or were completely sterile.

  15. In vivo and in vitro efficacy of sainfoin (Onobrychis viciifolia) against Eimeria spp in lambs.

    Science.gov (United States)

    Saratsis, Anastasios; Regos, Ionela; Tzanidakis, Nikolaos; Voutzourakis, Nikolaos; Stefanakis, Alexandros; Treuter, Dieter; Joachim, Anja; Sotiraki, Smaragda

    2012-08-13

    The effect of sainfoin (Onobrychis viciifolia) against ovine coccidia was evaluated in vivo and in vitro. In 3 in vivo trials weaned lambs were allocated into two treatment groups receiving diets with either lucerne (Medicago sativa) or sainfoin. During the trials, which lasted for 7 (trial 1) or 8 weeks (trials 2 and 3), oocysts per gram of faeces (OPGs), faecal scores and weight gain were recorded. In two of the experiments (trials 1 and 3) a reduction in the mean oocyst excretion rates was observed, starting three to four weeks after sainfoin hay feeding. This reduction ranged between 21.3% (trial 1) and 61.7% (trial 3) compared to the control values. As a result, a decrease in the total number of oocysts excreted (expressed as the mean area under the curve of the OPG) was observed from week 4 to the end of the two trials, respectively (trial 1: 42.6% reduction, p=0.05; trial 3: 52.4% reduction, p=0.06). The results did not show any significant diet effect on lamb growth rates and faecal scores. In the in vitro experiments the effect of 39 sainfoin extracts were tested in an oocyst sporulation inhibition assay. The Eimeria oocysts sporulation inhibition throughout the experiments did not exceed 10.7%, showing that extracts of this forages do not have a significant inhibitory effect on Eimeria oocyst sporulation. This was an initial attempt to investigate a possible anticoccidial effect of sainfoin and further studies are needed in order to better understand its mode of action against Eimeria. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Geographic profiling applied to testing models of bumble-bee foraging

    Science.gov (United States)

    Raine, Nigel E.; Rossmo, D. Kim; Le Comber, Steven C.

    2008-01-01

    Geographic profiling (GP) was originally developed as a statistical tool to help police forces prioritize lists of suspects in investigations of serial crimes. GP uses the location of related crime sites to make inferences about where the offender is most likely to live, and has been extremely successful in criminology. Here, we show how GP is applicable to experimental studies of animal foraging, using the bumble-bee Bombus terrestris. GP techniques enable us to simplify complex patterns of spatial data down to a small number of parameters (2–3) for rigorous hypothesis testing. Combining computer model simulations and experimental observation of foraging bumble-bees, we demonstrate that GP can be used to discriminate between foraging patterns resulting from (i) different hypothetical foraging algorithms and (ii) different food item (flower) densities. We also demonstrate that combining experimental and simulated data can be used to elucidate animal foraging strategies: specifically that the foraging patterns of real bumble-bees can be reliably discriminated from three out of nine hypothetical foraging algorithms. We suggest that experimental systems, like foraging bees, could be used to test and refine GP model predictions, and that GP offers a useful technique to analyse spatial animal behaviour data in both the laboratory and field. PMID:18664426

  17. Drought Effects on Proanthocyanidins in Sainfoin (Onobrychis viciifolia Scop.) Are Dependent on the Plant's Ontogenetic Stage.

    Science.gov (United States)

    Malisch, Carsten S; Salminen, Juha-Pekka; Kölliker, Roland; Engström, Marica T; Suter, Daniel; Studer, Bruno; Lüscher, Andreas

    2016-12-14

    Sainfoin (Onobrychis viciifolia Scop.) is a forage legume, which improves animal health and the environmental impact of livestock farming due to its proanthocyanidin content. To identify the impact of drought on acetone/water-extractable proanthocyanidin (PA) concentration and composition in the generative and vegetative stages, a rain exclosure experiment was established. Leaves of 120 plants from 5 different sainfoin accessions were sampled repeatedly and analyzed by UPLC-ESI-MS/MS. The results showed distinct differences in response to drought between vegetative and generative plants. Whereas vegetative plants showed a strong response to drought in growth (-56%) and leaf PA concentration (+46%), generative plants showed no response in growth (-2%) or PA concentration (-9%). The PA composition was stable across environments. The five accessions varied in PA concentrations and composition but showed the same pattern of response to the experimental treatments. These results show that the ontogenetic stage at which drought occurs significantly affects the plant's response.

  18. A framework for testing assumptions about foraging scales, body mass, and niche separation using telemetry data.

    Science.gov (United States)

    Cumming, Graeme S; Henry, Dominic A W; Reynolds, Chevonne

    2017-07-01

    Ecological theory predicts that if animals with very similar dietary requirements inhabit the same landscape, then they should avoid niche overlap by either exploiting food resources at different times or foraging at different spatial scales. Similarly, it is often assumed that animals that fall in different body mass modes and share the same body plan will use landscapes at different spatial scales. We developed a new methodological framework for understanding the scaling of foraging (i.e. the range and distribution of scales at which animals use their landscapes) by applying a combination of three well-established methods to satellite telemetry data to quantify foraging patch size distributions: (1) first-passage time analysis; (2) a movement-based kernel density estimator; and (3) statistical comparison of resulting histograms and tests for multimodality. We demonstrate our approach using two sympatric, ecologically similar species of African ducks with quite different body masses: Egyptian Geese (actually a shelduck), and Red-billed Teal. Contrary to theoretical predictions, the two species, which are sympatric throughout the year, foraged at almost identical spatial scales. Our results show how ecologists can use GPS tracking data to explicitly quantify and compare the scales of foraging by different organisms within an animal community. Our analysis demonstrates both a novel approach to foraging data analysis and the need for caution when making assumptions about the relationships among niche separation, diet, and foraging scale.

  19. Testing optimal foraging theory in a penguin-krill system.

    Science.gov (United States)

    Watanabe, Yuuki Y; Ito, Motohiro; Takahashi, Akinori

    2014-03-22

    Food is heterogeneously distributed in nature, and understanding how animals search for and exploit food patches is a fundamental challenge in ecology. The classic marginal value theorem (MVT) formulates optimal patch residence time in response to patch quality. The MVT was generally proved in controlled animal experiments; however, owing to the technical difficulties in recording foraging behaviour in the wild, it has been inadequately examined in natural predator-prey systems, especially those in the three-dimensional marine environment. Using animal-borne accelerometers and video cameras, we collected a rare dataset in which the behaviour of a marine predator (penguin) was recorded simultaneously with the capture timings of mobile, patchily distributed prey (krill). We provide qualitative support for the MVT by showing that (i) krill capture rate diminished with time in each dive, as assumed in the MVT, and (ii) dive duration (or patch residence time, controlled for dive depth) increased with short-term, dive-scale krill capture rate, but decreased with long-term, bout-scale krill capture rate, as predicted from the MVT. Our results demonstrate that a single environmental factor (i.e. patch quality) can have opposite effects on animal behaviour depending on the time scale, emphasizing the importance of multi-scale approaches in understanding complex foraging strategies.

  20. Antioxidant activity and chemical constituents of edible flower of Sophora viciifolia.

    Science.gov (United States)

    Tai, Zhigang; Cai, Le; Dai, Lin; Dong, Liuhong; Wang, Mingfeng; Yang, Yabin; Cao, Qiue; Ding, Zhongtao

    2011-06-15

    The antioxidant activities of crude extract and its derived soluble fractions from the flower of Sophora viciifolia were evaluated in five different test systems (DPPH, ABTS, FRAP, reducing power and inhibition of lipid peroxidant models) for the first time. The ethylacetate soluble fraction exhibited the highest antioxidant effect. Correlation analysis suggested that the flavonoids might be the major contributors for the high antioxidant activity of this flower. In addition, 11 compounds were isolated from this flower, and the antioxidant capacities of 5 flavonoids were evaluated by DPPH assay. Compound 3 (luteolin) had a significant DPPH radical-scavenging activity, and was also present at the highest concentration (5.56mg/gdrysample), implying an important role of 3 for the antioxidant activity of this flower. The study suggests that the flower of S. viciifolia can provide valuable functional ingredients and can be used for the prevention of diseases related to various oxidant by-products of human metabolism. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Marker-trait association analysis for agronomic and compositional traits in sainfoin (Onobrychis viciifolia).

    Science.gov (United States)

    Kempf, K; Malisch, C S; Grieder, C; Widmer, F; Kölliker, R

    2017-01-23

    Sainfoin (Onobrychis viciifolia) is a perennial forage legume with great potential for use in sustainable agriculture due to its low input requirements, good drought tolerance, and production of forage rich in polyphenolic compounds, which are beneficial for animal health. However, its distribution and cultivation are limited due to its moderate agronomic performance and a general lack of well adapted, highly yielding cultivars. Faster progress in breeding is imperative, but is often hampered by the complex inheritance of traits and limited knowledge on the genetic composition of this tetraploid, outbreeding species. Molecular genetic tools might aid phenotypic selection; however, to date no information on marker-trait associations is available for sainfoin. Hence, the goal of the present study was to detect marker-trait associations in a biparental F 1 population. Single plants were screened for recently developed genetic markers and phenotyped for important agronomic traits and concentrations of different polyphenolic compounds. Significant trait-associated markers (TAM) were detected for plant height (11), plant vigor (1), and seed yield (7). These three traits were positively correlated with each other and shared some TAMs. Correlations among markers suggested that two independent loci control these three vigor-related traits. One additional, independent TAM was detected for the share of prodelphinidins in total condensed tannins. Our results provide insight into the genetic control of important traits of sainfoin, and the TAMs reported here could assist selection in combination with phenotypic assessment.

  2. Genetic Diversity of Iranian and Exotic Sainfoin Accessions (Onobrychis viciifolia Scop Based on Morphological Traits

    Directory of Open Access Journals (Sweden)

    M. Zarabiyan

    2016-12-01

    Full Text Available Sainfoin (Onobrychis viciifolia Scop. is widely grown as forage and pasture legume in Iran and is tolerant to environmental stresses. To investigate the genetic diversity among 56 accessions of sainfoin germplasm (including 46 Iranian and 10 foreign based on morphological and agronomic characteristics, present experiment was conducted as randomized complete block design with three replications in Isfahan University of Technology Research Farm during 2010-2011. The results of analysis of variance indicated considerable variation between studied germplasm for all traits and the better performance for Iranian accessions. The estimation of broad sense heritability for plant height, number of stems per plant, number of stems per meter square and number of nods per stem was high suggesting contribution of the major genes for controlling these traits. On the basis of means comparison, the forage yield was greatest for the first cutting as compared to the second cutting. Also the highest yield obtained from second year. Regarding the palatability (based on leaf to stem ratio the exotic accessions had higher values. Developing of superior cultivars may be possible through combining high yield and palatability in breeding programs.

  3. Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting

    OpenAIRE

    Hopper, Lydia M.; Kurtycz, Laura M.; Ross, Stephen R.; Bonnie, Kristin E.

    2015-01-01

    In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for foo...

  4. Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions

    DEFF Research Database (Denmark)

    Huyen, N.T.; Desrues, O; Alferink, S.J.J

    2016-01-01

    cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight...... were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin silage in dairy cow rations reduces CH4 per kilogram of DM intake and nutrient digestibility. Moreover, sainfoin......Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy...

  5. Large Variability of Proanthocyanidin Content and Composition in Sainfoin (Onobrychis viciifolia).

    Science.gov (United States)

    Malisch, Carsten S; Lüscher, Andreas; Baert, Nicolas; Engström, Marica T; Studer, Bruno; Fryganas, Christos; Suter, Daniel; Mueller-Harvey, Irene; Salminen, Juha-Pekka

    2015-12-02

    Proanthocyanidins (PAs) in sainfoin (Onobrychis viciifolia Scop.) are of interest to ameliorate the sustainability of livestock production. However, sainfoin forage yield and PA concentrations, as well as their composition, require optimization. Individual plants of 27 sainfoin accessions from four continents were analyzed with LC-ESI-QqQ-MS/MS for PA concentrations and simple phenolic compounds. Large variability existed in PA concentrations (23.0-47.5 mg g(-1) leaf dry matter (DM)), share of prodelphinidins (79-96%), and mean degree of polymerization (11-14) among, but also within, accessions. PAs were mainly located in leaves (26.8 mg g(-1) DM), whereas stems had less PAs (7.8 mg g(-1) DM). Overall, high-yielding plants had lower PA leaf concentrations (R(2) = 0.16, P < 0.001) and fewer leaves (R(2) = 0.66, P < 0.001). However, the results show that these two trade-offs between yield and bioactive PAs can be overcome.

  6. In vivo effects of Sainfoin (Onobrychis viciifolia) on parasitic nematodes in calves

    DEFF Research Database (Denmark)

    Desrues, Oliver; Pena-Espinoza, Miguel Angel; Hansen, T.V.A.

    Sainfoin (Onobrychis viciifolia) is a fodder legume containing condensed tannins known to improve protein self-sufficiency, animal health and environment. In addition, anthelmintic effects have been demonstrated in vitro against cattle nematodes, and in vivo against nematodes of small ruminants......, but in vivo effects against gastro-intestinal parasites (GIN) of cattle still remains to be proven. Thus, the aim of the present investigation was to determine the in vivo effects of sainfoin against the most important trichostrongylids of cattle the brown stomach worm Ostertagia ostertagi...... , and the intestinal worm Cooperia oncophora. Jersey male calves (2-4 months) reared indoor and GIN naive, were stratified for live weight and randomly allocated into a test group (SF; n=9) which was fed 80% sainfoin (cv. Perly) pellets and hay, and a control group (CO; n=6) fed hay and compound feed. Daily intake...

  7. Individual administration of three tanniferous forage plants to lambs artificially infected with Haemonchus contortus and Cooperia curticei.

    Science.gov (United States)

    Heckendorn, Felix; Häring, Dieter Adrian; Maurer, Veronika; Senn, Markus; Hertzberg, Hubertus

    2007-05-15

    We investigated direct anthelmintic effects associated with the feeding of fresh tanniferous forages against established populations of Haemonchus contortus and Cooperia curticei in lambs. Twenty-four parasite naive lambs were inoculated with a single dose of infective larvae of these two parasites 27 days prior to the start of the feeding experiment. Lambs were individually fed with either chicory (Cichorium intybus), birdsfoot trefoil (Lotus corniculatus), sainfoin (Onobrychis viciifolia) or a ryegrass/lucerne mixture (control) for 17 days. Animals where then united to one flock and subjected to control feeding for another 11 days to test the sustainability of potentially lowered egg excretion generated by tanniferous forage feeding. When compared to the control, administration of all tanniferous forages was associated with significant reductions of total daily faecal egg output specific to H. contortus (chicory: 89%; birdsfoot trefoil: 63%; sainfoin: 63%; all tests P<0.05) and a tendency of reduced H. contortus worm burden (chicory: 15%; birdsfoot trefoil: 49% and sainfoin: 35% reduction). Irrespective of the condensed tannin (CT) containing fodder, no anthelmintic effects were found against C. curticei. Cessation of CT-feeding followed by non-CT control feeding did not result in a re-emergence of faecal egg counts based on faecal dry matter (FECDM) in any group, suggesting that egg output reductions are sustainable. The moderate to high concentrations of CTs in birdsfoot trefoil (15.2 g CTs kg(-1) dry matter (DM)) and sainfoin (26.1 g CTs kg(-1) DM) were compatible with the hypothesis that the antiparasitic effect of these forages is caused by their content of CTs. For chicory (3 g CTs kg(-1) DM), however, other secondary metabolites need to be considered. Overall, birdsfoot trefoil and in particular sainfoin seem promising candidates in contributing to an integrated control strategy against H. contortus not only by mitigating parasite related health

  8. The glycosyl moiety of lectin from sainfoin (Onobrychis viciifolia, Scop.).

    Science.gov (United States)

    Namen, A E; Hapner, K D

    1979-09-29

    A lectin isolated from the seeds of sainfoin (Onobrychis viciifolia, Scop. var Eski) has been shown to be a glycoprotein containing 2.6% (w/w) neutral carbohydrate and 1.6% (w/w) glucosamine (Hapner, K.D. and Robbins, J.E. (1979) Biochim. Biophys. Acta 580, 186--197) A homogeneous glycopeptide accounting for 70% of the original glycoprotein carbohydrate was isolated from pronase digests of the lectin by gel filtration chromatography. Gas-liquid chromatographic and amino acid analyses showed the glycosyl portion to contain glucosamine, mannose, xylose and fucose in molar ratio to glycopeptide of 1.8 : 1.8 : 0.7 : 0.9. The amino acid sequence was determined as H2N-Ser-Asn(glycosyl)-glu-Thr-COOH. The glycosyl moiety was attached to the peptide through N-glycosidic linkage between asparagine and glucosamine.

  9. Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting

    Science.gov (United States)

    Kurtycz, Laura M.; Ross, Stephen R.; Bonnie, Kristin E.

    2015-01-01

    In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they

  10. Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting.

    Science.gov (United States)

    Hopper, Lydia M; Kurtycz, Laura M; Ross, Stephen R; Bonnie, Kristin E

    2015-01-01

    In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they

  11. Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting

    Directory of Open Access Journals (Sweden)

    Lydia M. Hopper

    2015-03-01

    Full Text Available In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes. The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3. However, when travel was required for both rewards (phase 2, the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more

  12. Stimulatory Effects of Gamma Irradiation on Phytochemical Properties, Mitotic Behaviour, and Nutritional Composition of Sainfoin (Onobrychis viciifolia Scop.

    Directory of Open Access Journals (Sweden)

    Sadegh Mohajer

    2014-01-01

    Full Text Available Sainfoin (Onobrychis viciifolia Scop. Syn. Onobrychis sativa L. is a bloat-safe forage crop with high levels of tannins, which is renowned for its medicinal qualities in grazing animals. Mutagenesis technique was applied to investigate the influence of gamma irradiation at 30, 60, 90, and 120 Gy on mitotic behavior, in vitro growth factors, phytochemical and nutritional constituents of sainfoin. Although a percentage of plant necrosis and non-growing seed were enhanced by irradiation increment, the germination speed was significantly decreased. It was observed that gamma irradiated seeds had higher value of crude protein and dry matter digestibility compared to control seeds. Toxicity of copper was reduced in sainfoin irradiated seeds at different doses of gamma rays. Anthocyanin content also decreased in inverse proportion to irradiation intensity. Accumulation of phenolic and flavonoid compounds was enhanced by gamma irradiation exposure in leaf cells. HPLC profiles differed in peak areas of the two important alkaloids, Berberine and Sanguinarine, in 120 Gy irradiated seeds compared to control seeds. There were positive correlations between irradiation dose and some abnormality divisions such as laggard chromosome, micronucleus, binucleated cells, chromosome bridge, and cytomixis. In reality, radiocytological evaluation was proven to be essential in deducing the effectiveness of gamma irradiation to induce somaclonal variation in sainfoin.

  13. Stimulatory effects of gamma irradiation on phytochemical properties, mitotic behaviour, and nutritional composition of sainfoin (Onobrychis viciifolia Scop.).

    Science.gov (United States)

    Mohajer, Sadegh; Taha, Rosna Mat; Lay, Ma Ma; Esmaeili, Arash Khorasani; Khalili, Mahsa

    2014-01-01

    Sainfoin (Onobrychis viciifolia Scop. Syn. Onobrychis sativa L.) is a bloat-safe forage crop with high levels of tannins, which is renowned for its medicinal qualities in grazing animals. Mutagenesis technique was applied to investigate the influence of gamma irradiation at 30, 60, 90, and 120 Gy on mitotic behavior, in vitro growth factors, phytochemical and nutritional constituents of sainfoin. Although a percentage of plant necrosis and non-growing seed were enhanced by irradiation increment, the germination speed was significantly decreased. It was observed that gamma irradiated seeds had higher value of crude protein and dry matter digestibility compared to control seeds. Toxicity of copper was reduced in sainfoin irradiated seeds at different doses of gamma rays. Anthocyanin content also decreased in inverse proportion to irradiation intensity. Accumulation of phenolic and flavonoid compounds was enhanced by gamma irradiation exposure in leaf cells. HPLC profiles differed in peak areas of the two important alkaloids, Berberine and Sanguinarine, in 120 Gy irradiated seeds compared to control seeds. There were positive correlations between irradiation dose and some abnormality divisions such as laggard chromosome, micronucleus, binucleated cells, chromosome bridge, and cytomixis. In reality, radiocytological evaluation was proven to be essential in deducing the effectiveness of gamma irradiation to induce somaclonal variation in sainfoin.

  14. Condensed tannins in the tissue culture of sainfoin (Onobrychis viciifolia Scop.) and birdsfoot trefoil (Lotus corniculatus L.).

    Science.gov (United States)

    Lees, G L

    1986-08-01

    Two forage legumes, birdsfoot trefoil (Lotus corniculatus L.) and sainfoin (Onobrychis viciifolia Scop.), containing condensed tannins in their leaves and stems were used as source material to study condensed tannins in tissue culture. More protoplasts were isolated from mesophyll tissue of a low tannin-containing strain of birdsfoot trefoil than from a high tannin-containing strain, but more tannin-filled protoplasts were observed in the latter. Growth rates of leaf explant-derived callus tissue were greater for the high-tannin than for the low-tannin strain. In sainfoin, callus cultures from leaf explants produced numerous tannin-filled cells by 21 days. Explants from sainfoin cotyledons and roots, tissues which normally do not contain tannins, also formed callus with tannin-filled cells in 21 days but in almost every case, a cytokinin was required for tannin formation to occur. The occurrence of tannin-filled cells in callus from root and cotyledon explants was variable and genotype specific. These results show that endogenous tannins can affect protoplast isolation and possibly callus growth in birds-foot trefoil, and that the formation of condensed tannins in sainfoin callus culture can be influenced by a growth regulator.

  15. Social foraging and individual consistency in following behaviour: testing the information centre hypothesis in free-ranging vultures.

    Science.gov (United States)

    Harel, Roi; Spiegel, Orr; Getz, Wayne M; Nathan, Ran

    2017-04-12

    Uncertainties regarding food location and quality are among the greatest challenges faced by foragers and communal roosting may facilitate success through social foraging. The information centre hypothesis (ICH) suggests that uninformed individuals at shared roosts benefit from following informed individuals to previously visited resources. We tested several key prerequisites of the ICH in a social obligate scavenger, the Eurasian griffon vulture (Gyps fulvus), by tracking movements and behaviour of sympatric individuals over extended periods and across relatively large spatial scales, thereby precluding alternative explanations such as local enhancement. In agreement with the ICH, we found that 'informed' individuals returning to previously visited carcasses were followed by 'uninformed' vultures that consequently got access to these resources. When a dyad (two individuals that depart from the same roost within 2 min of each other) included an informed individual, they spent a higher proportion of the flight time close to each other at a shorter distance between them than otherwise. Although all individuals occasionally profited from following others, they differed in their tendencies to be informed or uninformed. This study provides evidence for 'following behaviour' in natural conditions and demonstrates differential roles and information states among foragers within a population. Moreover, demonstrating the possible reliance of vultures on following behaviour emphasizes that individuals in declining populations may suffer from reduced foraging efficiency. © 2017 The Author(s).

  16. Optimization of a high-performance liquid chromatography method for the analysis of complex polyphenol mixtures and application for sainfoin extracts (Onobrychis viciifolia).

    Science.gov (United States)

    Regos, Ionela; Treutter, Dieter

    2010-10-01

    A pentafluorophenylpropyl (PFP) stationary phase was tested for the simultaneous determination of several classes of phenolic compounds. The chromatographic results were compared with those obtained by using a bifunctional phase constituted of octadecyl and phenylpropyl bonded silica and three conventional C18 columns. The elution gradient was optimized with 5% formic acid and sodium acetate in combination with acetic acid as additives and methanol as solvents. For these evaluations, a complex phenolic extract of Onobrychis viciifolia (sainfoin) and test mixtures containing 54 standard substances including 2 simple phenolic compounds, 1 amino acid, 4 hydroxybenzoic acids (HBA), 6 hydroxycinnamic acids (HCA), 3 flavan-3-ols, 9 anthocyanins, 2 dihydroflavonols, 1 chalcone, 4 flavones, 1 isoflavone and 21 flavonols have been assayed. The perfluorinated column showed good resolution for the studied phenolic compounds which have the following elution order: HBA, HCA, flavan-3-ols, anthocyanins, dihydroflavonols, flavones, flavonols and isoflavones. Compared with other columns, it provides longer elution ranges for HBA, HCA and flavan-3-ols and increased retention times for all compound classes except anthocyanins which were similarly retained on a C18 column. Its selectivity is different from C18 and bifunctional phases. A high-performance liquid chromatography (HPLC) method with diode array detection (DAD) and post-column derivatization with p-dimethyl-aminocinnamic aldehyde (DMACA) has been validated for the analysis of individual phenolic compounds from a sainfoin plant extract (O. viciifolia). Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Lectin from sainfoin (Onobrychis viciifolia scop.). Complete amino acid sequence.

    Science.gov (United States)

    Kouchalakos, R N; Bates, O J; Bradshaw, R A; Hapner, K D

    1984-04-10

    The complete amino acid sequence of a lectin from sainfoin ( Onobrychis viciifolia Scop . var. Eski ) has been determined by sequential Edman analyses of the intact protein and peptides derived from digests with trypsin and thermolysin. Peptides were purified by pH fractionation, by gel filtration, and by cation-exchange and reverse-phase high-performance liquid chromatography. Seven segments of continuous sequence, accounting for the entire protein, were aligned through sequence comparison with several homologous leguminous lectins to give the final structure. Sainfoin lectin monomer, a glycoprotein which contains a single polypeptide chain of 236 amino acid residues with a molecular weight of 26 509, has amino- and carboxyl-terminal residues of alanine and threonine, respectively. A single residue of cysteine, located at position 33, is the only sulfur-containing amino acid present. Asparagine-118 is the single oligosaccharide attachment site. At least two apparent allelomorphic forms of the protein, having valine or isoleucine at position 49 in equal amounts, were detected. The amino acid sequence of sainfoin lectin exhibits circular permutation relative to that of the homologous protein concanavalin A.

  18. Effect of bioactive compounds from Sainfoin ( Onobrychis viciifolia Scop.) on the in vitro larval migration of Haemonchus contortus: role of tannins and flavonol glycosides.

    Science.gov (United States)

    Barrau, E; Fabre, N; Fouraste, I; Hoste, H

    2005-10-01

    Anthelmintic bioactivity against gastrointestinal nematodes has been associated with leguminous forages supporting the hypothesis of a role of condensed tannins. However, the possibility that other compounds might also been involved has received less consideration. Using bio-guided fractionation, the current study aimed at characterizing the biochemical nature of the active compounds present in sainfoin (Onobrychis viciifolia ), previously identified as an anthelmintic leguminous forage. The effects of sainfoin extracts were evaluated on 3rd-stage larvae (L3) of Haemonchus contortus by using a larval migration inhibition (LMI) assay. Comparison of extracts obtained with several solvent systems showed that the bioactivity was associated with the 70ratio30 acetone/water extract. Further fractionation of the later allowed the separation of phenolic compounds. By use of a dialysis method, compounds were separated with a molecular weight cut-off of 2000 Da. The in vitro anthelmintic effect of the fraction with condensed tannins was confirmed. In the fraction containing molecules of MW <2000 Da, 3 flavonol glycosides were identified as rutin, nicotiflorin and narcissin. At 1200 mug/ml, each inhibited significantly the migration of larvae. Addition of polyvinyl pyrrolidone (PVPP) to both fractions before incubation restored larval migration. These results confirmed the role of both tannins and flavonol glycosides in the anthelmintic properties of sainfoin.

  19. Protoplast-derived streptomycin resistant plants of the forage legume Onobrychis viciifolia Scop. (sainfoin).

    Science.gov (United States)

    Hamill, J D; Ahuja, P S; Davey, M R; Cocking, E C

    1986-12-01

    Approximately 10(6) protoplast-derived cell colonies of sainfoin were stressed with streptomycin and two resistant colonies were recovered. Plants regenerated from these colonies could be recallused on streptomycin-containing medium three years after growth in the absence of the antibiotic.Ultrastructural studies showed cells of resistant callus grown in the presence of streptomycin to contain chloroplasts with internal thykaloids and grana. Such mutant plants should be useful in designing biochemical selection schemes to recover somatic hybrids and cybrids.

  20. In vitro effects of extracts and purified tannins of sainfoin (Onobrychis viciifolia) against two cattle nematodes.

    Science.gov (United States)

    Novobilský, A; Stringano, E; Hayot Carbonero, C; Smith, L M J; Enemark, H L; Mueller-Harvey, I; Thamsborg, S M

    2013-09-23

    Sainfoin (Onobrychis viciifolia) is a condensed tannin (CT)-containing legume and has anthelmintic potential against gastrointestinal nematodes of ruminants. This study investigated in vitro effects of acetone/water extracts and derived CT fractions from different types of sainfoin (i.e. accessions) against larvae of Cooperia oncophora and Ostertagia ostertagi by applying the larval feeding inhibition assay (LFIA). Seven sainfoin accessions were extracted and tested with L1 larvae at 10 and 40 μg extract/ml. In addition, CT in extracts from 4 accessions were fractionated according to polymer size and tested by LFIA at two concentrations (2 and 10 μg CT fraction/ml). All sainfoin extracts caused significant inhibition of L1-feeding of both C. oncophora and O. ostertagi with varying intensity compared to the control (phosphate buffered saline). For both nematode species the in vitro effect was positively correlated with CT content in the extracts, but not with any of the structural CT parameters. In contrast, the 16 CT fractions revealed significant correlations between in vitro effect and CT content, polymer size (mean degree of polymerisation, mDP) and monomeric composition (prodelphinidin percentage, % PD). These differences between crude extracts and purified fractions may stem from the fact that extracts contain complex CT mixtures, which may mask and thus suppress CT structural effects. This study provides the first indication that, apart from CT and % PD content, polymer size also contributes to anthelmintic activity of CTs. The results, therefore, suggest that the inter-accession variability in CT content and composition needs to be taken into account in future plant breeding programmes which seek to enhance the anthelmintic properties of sainfoin. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Anti-parasitic activity of pelleted sainfoin (Onobrychis viciifolia) against Ostertagia ostertagi and Cooperia oncophora in calves.

    Science.gov (United States)

    Desrues, Olivier; Peña-Espinoza, Miguel; Hansen, Tina V A; Enemark, Heidi L; Thamsborg, Stig M

    2016-06-10

    Increasing anthelmintic-resistance in nematodes of ruminants emphasises the need for sustainable parasite control. Condensed tannin-containing legume forages such as sainfoin (Onobrychis viciifolia) have shown promising anthelmintic properties in small ruminants but this has never been explored in cattle. Therefore, our aim was to examine the efficacy of sainfoin against cattle nematodes in vivo. Fifteen Jersey male calves (2-4 month-old) were allocated into two groups and fed isoproteic and isoenergetic diets mainly composed of sainfoin pellets (Group SF; n = 9, three pens) or concentrate and grass-clover hay (Group CO; n = 6, two pens). After 16 days of adaptation, all animals were experimentally infected with 10,000 and 66,000 third-stage larvae of Ostertagia ostertagi and Cooperia oncophora, respectively. Egg excretion, blood parameters and bodyweights were recorded throughout the study. Worms were harvested by sieving for quantification and scanning electron microscopy (SEM) 42 days post-infection (dpi) when the calves were necropsied. The number of O. ostertagi adults in the abomasum was reduced by 50 % in Group SF compared with Group CO (P  0.05). Likewise, no statistical difference in total worm burdens of C. oncophora was found between the groups. Weight gains were lower for Group SF (P < 0.05), which may reflect lower digestibility and phosphorus levels in the SF diet, despite similar feed intake at pen-level. Overall, the effect of sainfoin on abomasal nematodes corroborates results from studies with small ruminants and encourages further investigations of the use of this crop for control of cattle nematodes.

  2. Polyphenols, condensed tannins, and other natural products in Onobrychis viciifolia (Sainfoin).

    Science.gov (United States)

    Marais, J P; Mueller-Harvey, I; Brandt, E V; Ferreira, D

    2000-08-01

    An acetone/water extract of the fodder legume Onobrychis viciifolia afforded arbutin, kaempferol, quercetin, rutin, afzelin, the branched quercetin-3-(2(G)-rhamnosylrutinoside), the amino acid L-tryptophan, the inositol (+)-pinitol, and relatively high concentrations of sucrose (ca. 35% of extractable material). Acid-catalyzed cleavage of the condensed tannins with phloroglucinol afforded catechin, epicatechin and gallocatechin as the terminal and extender units, but epigallocatechin was only present in extender units. The condensed tannins in O. viciifolia presumably consist of hetero- and homopolymers containing both procyanidin and prodelphinidin units. Comparison of data from the present study and the literature suggests that sainfoin tannins have a highly variable composition with cis:trans ratios ranging from 47:53 to 90:10 and delphinidin:cyanidin ratios from 36:64 to 93:7. The composition of terminal and extender units in sainfoin tannins seems to be cultivar specific.

  3. Polyphenol metabolism provides a screening tool for beneficial effects of Onobrychis viciifolia (sainfoin).

    Science.gov (United States)

    Thill, Jana; Regos, Ionela; Farag, Mohamed A; Ahmad, Asma F; Kusek, Justyna; Castro, Ana; Schlangen, Karin; Carbonero, Christine Hayot; Gadjev, Ilya Z; Smith, Lydia M J; Halbwirth, Heidi; Treutter, Dieter; Stich, Karl

    2012-10-01

    Onobrychis viciifolia (sainfoin) is a traditional fodder legume showing multiple benefits for the environment, animal health and productivity but weaker agronomic performance in comparison to other legumes. Benefits can be mainly ascribed to the presence of polyphenols. The polyphenol metabolism in O. viciifolia was studied at the level of gene expression, enzyme activity, polyphenol accumulation and antioxidant activity. A screening of 37 accessions regarding each of these characters showed a huge variability between individual samples. Principal component analysis revealed that flavonols and flavan 3-ols are the most relevant variables for discrimination of the accessions. The determination of the activities of dihydroflavonol 4-reductase and flavonol synthase provides a suitable screening tool for the estimation of the ratio of flavonols to flavan 3-ols and can be used for the selection of samples from those varieties that have a specific optimal ratio of these compounds for further breeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. The response of various ecotypes of common sainfoin (Onobrychis viciifolia L. to the foliar application of nitrogen, iron and zinc in a cold climate of

    Directory of Open Access Journals (Sweden)

    ali tadayon

    2009-06-01

    Full Text Available Common sainfoin (Onobrychis viciifolia L. is a forage crop belonging to the legume family. The crop is characterized by numerous favorable criteria such as the capability to fix atmospheric nitrogen symbiotically. In order to study the response of various ecotypes of common sainfoin to the foliar application of nitrogen and micronutrients, such as iron and zinc, two separate field experiments were conducted using a spilt-plot design with completely randomized block replicated three times. In the first experiment, the main plots included five different ecotypes of common sainfoin, and the sub-plots included four rates of urea application (0, 15, 30 and 45 kg N/ha. In the second experiment, the main plots included seven different ecotypes of common sainfoin, and the sub-plots included four rates of micronutrients (0, 0.04 % Fe, 0.04 % Zn and 0.04 % Fe + 0.04 % Zn. The foliar application of urea, Fe and Zn with increasing nutrient concentrations had a statistically significant (p

  5. Do leaf cutting ants cut undetected? Testing the effect of ant-induced plant defences on foraging decisions in Atta colombica.

    Science.gov (United States)

    Kost, Christian; Tremmel, Martin; Wirth, Rainer

    2011-01-01

    Leaf-cutting ants (LCAs) are polyphagous, yet highly selective herbivores. The factors that govern their selection of food plants, however, remain poorly understood. We hypothesized that the induction of anti-herbivore defences by attacked food plants, which are toxic to either ants or their mutualistic fungus, should significantly affect the ants' foraging behaviour. To test this "induced defence hypothesis," we used lima bean (Phaseolus lunatus), a plant that emits many volatile organic compounds (VOCs) upon herbivore attack with known anti-fungal or ant-repellent effects. Our results provide three important insights into the foraging ecology of LCAs. First, leaf-cutting by Atta ants can induce plant defences: Lima bean plants that were repeatedly exposed to foraging workers of Atta colombica over a period of three days emitted significantly more VOCs than undamaged control plants. Second, the level to which a plant has induced its anti-herbivore defences can affect the LCAs' foraging behaviour: In dual choice bioassays, foragers discriminated control plants from plants that have been damaged mechanically or by LCAs 24 h ago. In contrast, strong induction levels of plants after treatment with the plant hormone jasmonic acid or three days of LCA feeding strongly repelled LCA foragers relative to undamaged control plants. Third, the LCA-specific mode of damaging leaves allows them to remove larger quantities of leaf material before being recognized by the plant: While leaf loss of approximately 15% due to a chewing herbivore (coccinelid beetle) was sufficient to significantly increase VOC emission levels after 24 h, the removal of even 20% of a plant's leaf area within 20 min by LCAs did not affect its VOC emission rate after 24 h. Taken together, our results support the "induced defence hypothesis" and provide first empirical evidence that the foraging behaviour of LCAs is affected by the induction of plant defence responses.

  6. Brain morphology of the threespine stickleback (Gasterosteus aculeatus) varies inconsistently with respect to habitat complexity: A test of the Clever Foraging Hypothesis.

    Science.gov (United States)

    Ahmed, Newaz I; Thompson, Cole; Bolnick, Daniel I; Stuart, Yoel E

    2017-05-01

    The Clever Foraging Hypothesis asserts that organisms living in a more spatially complex environment will have a greater neurological capacity for cognitive processes related to spatial memory, navigation, and foraging. Because the telencephalon is often associated with spatial memory and navigation tasks, this hypothesis predicts a positive association between telencephalon size and environmental complexity. The association between habitat complexity and brain size has been supported by comparative studies across multiple species but has not been widely studied at the within-species level. We tested for covariation between environmental complexity and neuroanatomy of threespine stickleback (Gasterosteus aculeatus) collected from 15 pairs of lakes and their parapatric streams on Vancouver Island. In most pairs, neuroanatomy differed between the adjoining lake and stream populations. However, the magnitude and direction of this difference were inconsistent between watersheds and did not covary strongly with measures of within-site environmental heterogeneity. Overall, we find weak support for the Clever Foraging Hypothesis in our study.

  7. Beneficial Effects of Temperate Forage Legumes that Contain Condensed Tannins

    Directory of Open Access Journals (Sweden)

    Jennifer W. MacAdam

    2015-07-01

    Full Text Available The two temperate forage legumes containing condensed tannins (CT that promote ruminant production are birdsfoot trefoil (Lotus corniculatus L.; BFT and sainfoin (Onobrychis viciifolia Scop.; SF. Both are well-adapted to the cool-temperate climate and alkaline soils of the Mountain West USA. Condensed tannins comprise a diverse family of bioactive chemicals with multiple beneficial functions for ruminants, including suppression of internal parasites and enteric methane. Birdsfoot trefoil contains 10 to 40 g·CT·kg−1 dry matter (DM, while SF contains 30 to 80 g·CT·kg−1 DM. Our studies have focused on these two plant species and have demonstrated consistently elevated rates of gain for beef calves grazing both BFT and SF. Novel results from our BFT research include carcass dressing percentages and consumer sensory evaluations equivalent to feedlot-finished steers and significantly greater than grass-finished steers, but with omega-3 fatty acid concentrations equal to grass-finished beef. We have further demonstrated that ruminants fed BFT or SF will consume more endophyte-infected tall fescue (Schedonorus arundinaceus (Schreb. Dumort. forage or seed than ruminants fed a non-CT forage legume. There is great potential value for sustainable livestock production in the use of highly digestible, nitrogen-fixing legumes containing tannins demonstrated to improve ruminant productivity.

  8. Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions.

    Science.gov (United States)

    Huyen, N T; Desrues, O; Alferink, S J J; Zandstra, T; Verstegen, M W A; Hendriks, W H; Pellikaan, W F

    2016-05-01

    Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight (BW(0.75)) of 132.5±3.6kg were randomly assigned to either a control (CON) or a sainfoin (SAIN)-based diet over 2 experimental periods of 25 d each in a crossover design. The CON diet was a mixture of grass silage, corn silage, concentrate, and linseed. In the SAIN diet, 50% of grass silage dry matter (DM) of the CON diet was exchanged for sainfoin silage. The cows were adapted to 95% of ad libitum feed intake for a 21-d period before being housed in climate-controlled respiration chambers for 4 d, during which time feed intake, apparent total-tract digestibility, N and energy balance, and CH4 production was determined. Data were analyzed using a mixed model procedure. Total daily DM, organic matter, and neutral detergent fiber intake did not differ between the 2 diets. The apparent digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber were, respectively, 5.7, 4.0, 15.7, and 14.8% lower for the SAIN diet. Methane production per kilogram of DM intake was lowest for the SAIN diet, CH4 production as a percentage of gross energy intake tended to be lower, and milk yield was greater for the SAIN diet. Nitrogen intake, N retention, and energy retained in body protein were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin

  9. Effect of Weeds and Some Methods for their Control in Seed Production Stands of Sainfoin (Onobrychis viciifolia Scop.

    Directory of Open Access Journals (Sweden)

    Tsvetanka Dimitrova

    2010-01-01

    Full Text Available During the 2007-2009 period in the experimental field of the Institute of Forage Cropsa study was conducted with the purpose of investigating the effect of weeds and somemethods for their control in seed production stands of sainfoin (Onobrychis viciifolia Scop..The trial was carried out on a slightly leached chernozem on an area with a natural backgroundof weed infestation. As a result of the study it was found:Establishment of very uniform and productive seed production stands of sainfoinrequired effective weed control concentrated mainly in the first year when the degree ofweed infestation was the highest and reached to a number of 245 plants/m2 and the freshweed biomass to 1311 g/m2.The chemical control method showed the highest efficacy had the highest efficiencywhen, in the year of stand establishment at the stage of second-fourth true leaf of sainfoin,the treatment was conducted with imazamox 40g/l (Pulsar 40 at the dose of 48 g a.i./haor with the system of Bentazon 600 g/l (Basagran 600 SL – 900 g a.i./ha – fluazifop-P-butylg/l (Fusilad Forte – 120 g a.i./ha. In the years of seed production in spring at the beginningof vegetation, the treatment was conducted with imazamox 40 g/l (Pulsar 40 at the doseof 20 g a.i./ha + adjuvant DESH at the dose of 1000 ml/ha.An alternative to the chemical method is to sow sainfoin under cover of spring barleyachieving more complete use of the area in the first year, a weed suppressive and ecologicaleffect, but some negative residual effect on the crop was also observed;The pure stands of sainfoin with chemical control of weeds had the highest seed productivity,exceeding the zero check by 24 to 28%, followed by the stands with spring barleyas a cover crop with an increase of 12% and the mixed stands of sainfoin with crestedwheatgrass had the lowest productivity.

  10. Risky business for a juvenile marine predator? Testing the influence of foraging strategies on size and growth rate under natural conditions.

    Science.gov (United States)

    Hussey, Nigel E; DiBattista, Joseph D; Moore, Jonathan W; Ward, Eric J; Fisk, Aaron T; Kessel, Steven; Guttridge, Tristan L; Feldheim, Kevin A; Franks, Bryan R; Gruber, Samuel H; Weideli, Ornella C; Chapman, Demian D

    2017-04-12

    Mechanisms driving selection of body size and growth rate in wild marine vertebrates are poorly understood, thus limiting knowledge of their fitness costs at ecological, physiological and genetic scales. Here, we indirectly tested whether selection for size-related traits of juvenile sharks that inhabit a nursery hosting two dichotomous habitats, protected mangroves (low predation risk) and exposed seagrass beds (high predation risk), is influenced by their foraging behaviour. Juvenile sharks displayed a continuum of foraging strategies between mangrove and seagrass areas, with some individuals preferentially feeding in one habitat over another. Foraging habitat was correlated with growth rate, whereby slower growing, smaller individuals fed predominantly in sheltered mangroves, whereas larger, faster growing animals fed over exposed seagrass. Concomitantly, tracked juveniles undertook variable movement behaviours across both the low and high predation risk habitat. These data provide supporting evidence for the hypothesis that directional selection favouring smaller size and slower growth rate, both heritable traits in this shark population, may be driven by variability in foraging behaviour and predation risk. Such evolutionary pathways may be critical to adaptation within predator-driven marine ecosystems. © 2017 The Author(s).

  11. Micropropagation of Bioencapsulation and Ultrastructural Features of Sainfoin (Onobrychis viciifolia Grown In Vivo and In Vitro

    Directory of Open Access Journals (Sweden)

    Sadegh Mohajer

    2014-01-01

    Full Text Available To explore the potential of in vitro rapid regeneration, three varieties (Golpaygan-181, Orumieh-1763, and Gorgan-1601 of sainfoin (Onobrychis viciifolia Scop. syn. Onobrychis sativa L. were evaluated. For the first time, an encapsulation protocol was established from somatic embryogenic callus in torpedo and cotyledonary stages to create artificial seeds. Callus derived from different concentrations of Kinetin (0–2.0 mg L−1 and Indole-3-acetic acid (0–2.0 mg L−1 was coated with sodium alginate and subsequently cultured either in Murashige and Skoog (MS medium or in soil substrate. Adventitious shoots from synthetic beads developed into rooting in full and half strength MS medium supplemented with various concentrations of auxin and cytokinin. Prolonged water conservation of black and red soils (1 : 1 had the highest rate of survival plantlets in the acclimatization process. Diverse resistance techniques in Onobrychis viciifolia were evaluated when the plants were subjected to water deficiency. Higher frequency of epicuticular waxes was observed in in vivo leaves compared to in vitro leaves. Jagged trichomes nonsecreting glands covered by spines were only observed in the lower leaf side. Ultimately, stomata indices were 0.127 (abaxial, 0.188 (adaxial in in vivo and 0.121 (abaxial, 0.201 (adaxial in in vitro leaves.

  12. Micropropagation of bioencapsulation and ultrastructural features of sainfoin (Onobrychis viciifolia) grown in vivo and in vitro.

    Science.gov (United States)

    Mohajer, Sadegh; Mat Taha, Rosna; Mohajer, Minoo; Khorasani Esmaeili, Arash

    2014-01-01

    To explore the potential of in vitro rapid regeneration, three varieties (Golpaygan-181, Orumieh-1763, and Gorgan-1601) of sainfoin (Onobrychis viciifolia Scop. syn. Onobrychis sativa L.) were evaluated. For the first time, an encapsulation protocol was established from somatic embryogenic callus in torpedo and cotyledonary stages to create artificial seeds. Callus derived from different concentrations of Kinetin (0-2.0 mg L(-1)) and Indole-3-acetic acid (0-2.0 mg L(-1)) was coated with sodium alginate and subsequently cultured either in Murashige and Skoog (MS) medium or in soil substrate. Adventitious shoots from synthetic beads developed into rooting in full and half strength MS medium supplemented with various concentrations of auxin and cytokinin. Prolonged water conservation of black and red soils (1:1) had the highest rate of survival plantlets in the acclimatization process. Diverse resistance techniques in Onobrychis viciifolia were evaluated when the plants were subjected to water deficiency. Higher frequency of epicuticular waxes was observed in in vivo leaves compared to in vitro leaves. Jagged trichomes nonsecreting glands covered by spines were only observed in the lower leaf side. Ultimately, stomata indices were 0.127 (abaxial), 0.188 (adaxial) in in vivo and 0.121 (abaxial), 0.201 (adaxial) in in vitro leaves.

  13. Optimal Foraging by Birds: Experiments for Secondary & Postsecondary Students

    Science.gov (United States)

    Pecor, Keith W.; Lake, Ellen C.; Wund, Matthew A.

    2015-01-01

    Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. We describe three experiments designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These experiments can be used alone or in combination and can…

  14. The effect of dietary sainfoin ( Onobrychis viciifolia) on local cellular responses to Trichostrongylus colubriformis in sheep.

    Science.gov (United States)

    Ríos-de Alvarez, L; Greer, A W; Jackson, F; Athanasiadou, S; Kyriazakis, I; Huntley, J F

    2008-08-01

    The effect of sainfoin (Onobrychis viciifolia) hay consumption on the pathophysiology and local cellular responses of growing lambs during infection with Trichostrongylus colubriformis was investigated. Thirty-two lambs, 16 weeks of age, were allocated to 1 of 4 treatment groups (n=8) that were offered either grass (G) or sainfoin (S) hay while concurrently either infected (+), or not (-) with 12,000 L3 T. colubriformis larvae per week for 6 weeks. Liveweight gains were affected by diet (P=0.002) and reduced by infection (P0.05).Feeding sainfoin appeared to enhance immune cell development with tissue eosinophils, mast cells and pan T cells present in greater concentrations in S+ than in G+ animals. However, further studies are required to determine if the enhanced immune cell development is a consequence of a greater nutrient supply or a direct influence of sainfoin metabolites on local inflammatory responses to the gastrointestinal nematode T. colubriformis.

  15. Test of a foraging-bioenergetics model to evaluate growth dynamics of endangered pallid sturgeon (Scaphirhynchus albus)

    Science.gov (United States)

    Deslauriers, David; Heironimus, Laura B.; Chipps, Steven R.

    2016-01-01

    Factors affecting feeding and growth of early life stages of the federally endangered pallid sturgeon (Scaphirhynchus albus) are not fully understood, owing to their scarcity in the wild. In this study was we evaluated the performance of a combined foraging-bioenergetics model as a tool for assessing growth of age-0 pallid sturgeon in the Missouri River. In the laboratory, three size classes of sturgeon larvae (18–44 mm; 0.027–0.329 g) were grown for 7 to 14 days under differing temperature (14–24 °C) and prey density (0–9 Chironomidae larvae/d) regimes. After accounting for effects of water temperature and prey density on fish activity, we compared observed final weight, final length, and number of prey consumed to values generated from the foraging-bioenergetics model. When confronted with an independent dataset, the combined model provided reliable estimates (within 13% of observations) of fish growth and prey consumption, underscoring the usefulness of the modeling approach for evaluating growth dynamics of larval fish when empirical data are lacking.

  16. Effect of sainfoin (Onobrychis viciifolia) silage and hay on established populations of Haemonchus contortus and Cooperia curticei in lambs.

    Science.gov (United States)

    Heckendorn, Felix; Häring, Dieter Adrian; Maurer, Veronika; Zinsstag, Jakob; Langhans, Wolfgang; Hertzberg, Hubertus

    2006-12-20

    The objective of the study was to examine the effect of dried and ensiled sainfoin (Onobrychis viciifolia) on established populations of Haemonchus contortus (abomasum) and Cooperia curticei (small intestine) in lambs under controlled conditions. Twenty-four parasite naïve lambs were inoculated with a single dose of infective larvae of these parasites 28 days prior to the start of the feeding experiment. Twenty-four days post-infection, 4 days prior to the start of the feeding experiment, animals were allocated to four groups according to egg excretion, live weight and sex. Groups A and B received sainfoin hay and control hay, respectively, for 16 days. Groups C and D were fed on sainfoin silage or control silage for the same period. Feeds were offered ad libitum and on the basis of daily refusals were supplemented with concentrate in order to make them isoproteic and isoenergetic. Individual faecal egg counts on a dry matter basis (FECDM) were performed every 3-4 days and faecal cultures and packed cell volume (PCV) measurements were done weekly. After 16 days of experimental feeding, all animals were slaughtered and adult worm populations were determined. The consumption of conserved sainfoin was associated with a reduction of adult H. contortus (47% in the case of hay, P<0.05; 49% in the case of silage, P=0.075) but had little effect on adult C. curticei. Compared to the controls, H. contortus specific FECDM was reduced by 58% (P<0.01) in the sainfoin hay group and by 48% (P=0.075) in the sainfoin silage group. For both sainfoin feeds FECDM specific to C. curticei were significantly decreased when compared to the control feeds (hay 81% and silage 74%, both tests P<0.001). Our data suggest that different mechanisms were responsible for the reduction in FECDM in response to feeding tanniferous fodder. For H. contortus, the decrease seemed to be due to a nematocidal effect towards adult H. contortus. In contrast for C. curticei, the reduction in FECDM appeared to

  17. Effects of condensed tannins in wrapped silage bales of sainfoin (Onobrychis viciifolia) on in vivo and in situ digestion in sheep.

    Science.gov (United States)

    Theodoridou, K; Aufrère, J; Andueza, D; Le Morvan, A; Picard, F; Pourrat, J; Baumont, R

    2012-02-01

    The objective of this study was to characterize the condensed tannins (CTs) in wrapped silage bales of sainfoin (Onobrychis viciifolia) and examine their potential action on in vivo and in situ digestive characteristics in sheep. Silage was made from sainfoin, cut at two phenological stages. The first phenological stage, at which silage was made, was from the first vegetation cycle at the end of flowering and the second stage silage was made from regrowth, 5 weeks after the first cut, but before flowering. The silages made from the two phenological stages were fed to 12 rumen-fistulated sheep in a crossover design. Of the 12 sheep, six received polyethylene glycol (PEG) to bind with and remove the effects of CT, whereas the other six were dosed with water. Organic matter digestibility, total-tract N digestibility and N (N) balance were measured over 6 days. Kinetic studies were performed on total N, ammonia N (NH3-N) and volatile fatty acids (VFAs) in rumen fluid before and 1.5, 3 and 6 h after feeding. The kinetics of degradation of dry matter and N from Dacron bags suspended in the rumen were also determined. Biological activity of CT (protein-binding capacity) and CT concentration were greater for the silage made from sainfoin at the early flowering stage. Total-tract N digestibility was increased by the addition of PEG (P < 0.001) to the sainfoin silage before flowering (P < 0.001). CTs decreased N excretion in urine (P < 0.05) and increased faecal N excretion (P < 0.001), but had no effect on body N retention, which is beneficial for the animal. Ruminal N degradability was smaller in the presence of active CT (P < 0.001) at both phenological stages; however, soluble N (P = 0.2060) and NH3-N (P = 0.5225) concentrations in rumen fluid remained unchanged. The results of this experiment indicate that CT in the sainfoin retain their ability to affect the nutritive value of preserved forage legumes.

  18. Proanthocyanidin diversity in the EU 'HealthyHay' sainfoin (Onobrychis viciifolia) germplasm collection.

    Science.gov (United States)

    Stringano, Elisabetta; Hayot Carbonero, Christine; Smith, Lydia M J; Brown, Ronald H; Mueller-Harvey, Irene

    2012-05-01

    This study investigated 37 diverse sainfoin (Onobrychis viciifolia Scop.) accessions from the EU 'HealthyHay' germplasm collection for proanthocyanidin (PA) content and composition. Accessions displayed a wide range of differences: PA contents varied from 0.57 to 2.80 g/100 g sainfoin; the mean degree of polymerisation from 12 to 84; the proportion of prodelphinidin tannins from 53% to 95%, and the proportion of trans-flavanol units from 12% to 34%. A positive correlation was found between PA contents (thiolytic versus acid-butanol degradation; P<0.001; R(2)=0.49). A negative correlation existed between PA content (thiolysis) and mDP (P<0.05; R(2)=-0.30), which suggested that accessions with high PA contents had smaller PA polymers. Cluster analysis revealed that European accessions clustered into two main groups: Western Europe and Eastern Europe/Asia. In addition, accessions from USA, Canada and Armenia tended to cluster together. Overall, there was broad agreement between tannin clusters and clusters that were based on morphological and agronomic characteristics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Isolation and properties of a lectin from sainfoin (Onobrychis viciifolia, Scop.).

    Science.gov (United States)

    Hapner, K D; Robbins, J E

    1979-09-29

    A glycoprotein capable of binding simple carbohydrates and causing hemagglutination has been isolated from seeds of the legume plant sainfoin (Onobrychis viciifolia, Scop. var Eski). The phytolectin was prepared by affinity chromatography of pH 7.0 sodium phosphate extracts on columns of Sepharose-4B containing covalently attached D-mannose. Molecular weight determinations showed the lectin to be a dimer consisting of 26 000 dalton, non-covalently associated monomers. Amino acid analyses indicated high amounts of aspartate, glutamate, threonine and serine which accounted for 41% of all amino acids. One residue of cysteine was present and methionine was totally absent. The lectin contained 2.6% (w/w) neutral carbohydrate and two residues of N-acetylglucosamine/monomer. Carbohydrate-binding specificity was directed toward D-mannose and D-glucose and their alpha-glycosidic derivatives. The purified protein agglutinated cat erythrocytes at 5 micrograms/ml. Antiserum to seed lectin showed a single common immunoprecipitation line in Ouchterlony double diffusion against both the seed and root antigen. Lectin isolated from sainfoin seedling roots showed molecular weight, amino acid and carbohydrate values similar to that of the seed lectin.

  20. Nitrogen transfer between herbivores and their forage species

    NARCIS (Netherlands)

    Sjögersten, S.; Kuijper, D.; Van der Wal, R.; Loonen, M.J.J.E.; Huiskes, A.H.L.; Woodin, S.J.

    2010-01-01

    Herbivores may increase the productivity of forage plants; however, this depends on the return of nutrients from faeces to the forage plants. The aim of this study was to test if nitrogen (N) from faeces is available to forage plants and whether the return of nutrients differs between plant species

  1. Nitrogen transfer between herbivores and their forage species

    NARCIS (Netherlands)

    Sjogersten, Sofie; Kuijper, Dries P. J.; van der Wal, Rene; Loonen, Maarten J. J. E.; Huiskes, Ad H. L.; Woodin, Sarah J.

    Herbivores may increase the productivity of forage plants; however, this depends on the return of nutrients from faeces to the forage plants. The aim of this study was to test if nitrogen (N) from faeces is available to forage plants and whether the return of nutrients differs between plant species

  2. Optimally Frugal Foraging

    OpenAIRE

    Benichou, O.; Bhat, U.; Krapivsky, P. L.; Redner, S.

    2017-01-01

    We introduce the \\emph{frugal foraging} model in which a forager performs a discrete-time random walk on a lattice, where each site initially contains $\\mathcal{S}$ food units. The forager metabolizes one unit of food at each step and starves to death when it last ate $\\mathcal{S}$ steps in the past. Whenever the forager decides to eat, it consumes all food at its current site and this site remains empty (no food replenishment). The crucial property of the forager is that it is \\emph{frugal} ...

  3. Testing Convergent Evolution in Auditory Processing Genes between Echolocating Mammals and the Aye-Aye, a Percussive-Foraging Primate.

    Science.gov (United States)

    Bankoff, Richard J; Jerjos, Michael; Hohman, Baily; Lauterbur, M Elise; Kistler, Logan; Perry, George H

    2017-07-01

    Several taxonomically distinct mammalian groups-certain microbats and cetaceans (e.g., dolphins)-share both morphological adaptations related to echolocation behavior and strong signatures of convergent evolution at the amino acid level across seven genes related to auditory processing. Aye-ayes (Daubentonia madagascariensis) are nocturnal lemurs with a specialized auditory processing system. Aye-ayes tap rapidly along the surfaces of trees, listening to reverberations to identify the mines of wood-boring insect larvae; this behavior has been hypothesized to functionally mimic echolocation. Here we investigated whether there are signals of convergence in auditory processing genes between aye-ayes and known mammalian echolocators. We developed a computational pipeline (Basic Exon Assembly Tool) that produces consensus sequences for regions of interest from shotgun genomic sequencing data for nonmodel organisms without requiring de novo genome assembly. We reconstructed complete coding region sequences for the seven convergent echolocating bat-dolphin genes for aye-ayes and another lemur. We compared sequences from these two lemurs in a phylogenetic framework with those of bat and dolphin echolocators and appropriate nonecholocating outgroups. Our analysis reaffirms the existence of amino acid convergence at these loci among echolocating bats and dolphins; some methods also detected signals of convergence between echolocating bats and both mice and elephants. However, we observed no significant signal of amino acid convergence between aye-ayes and echolocating bats and dolphins, suggesting that aye-aye tap-foraging auditory adaptations represent distinct evolutionary innovations. These results are also consistent with a developing consensus that convergent behavioral ecology does not reliably predict convergent molecular evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Effects of a tannin-rich legume (Onobrychis viciifolia) on in vitro ruminal biohydrogenation and fermentation

    Energy Technology Data Exchange (ETDEWEB)

    González, M.A.; Peláez, F.R.; Martínez, A.L.; Avilés, C.; Peña, F.

    2016-11-01

    There is still controversy surrounding the ability of tannins to modulate the ruminal biohydrogenation (BH) of fatty acids (FA) and improve the lipid profile of milk or meat without conferring a negative response in the digestive utilization of the diet. Based on this, an in vitro trial using batch cultures of rumen microorganisms was performed to compare the effects of two legume hays with similar chemical composition but different tannin content, alfalfa and sainfoin (Onobrychis viciifolia), on the BH of dietary unsaturated FA and on the ruminal fermentation. The first incubation substrate, alfalfa, was practically free of tannins, while the second, sainfoin, contained 3.5% (expressed as tannic acid equivalents). Both hays were enriched with sunflower oil as a source of unsaturated FA. Most results of the lipid composition analysis (e.g., greater concentrations of 18:2n-6, cis-9 18:1 or total polyunsaturated FA in sainfoin incubations) showed the ability of this tannin-containing legume to inhibit the BH process. However, no significant differences were detected in the accumulation of cis-9 trans-11 conjugated linoleic acid, and variations in trans-11 18:1 and trans-11 cis-15 18:2 did not follow a regular pattern. Regarding the rumen fermentation, gas production, ammonia concentration and volatile FA production were lower in the incubations with sainfoin (‒17, ‒23 and ‒11%, respectively). Thus, although this legume was able to modify the ruminal BH, which might result in improvements in the meat or milk lipid profile, the present results were not as promising as expected or as obtained before with other nutritional strategies. (Author)

  5. Effects of a tannin-rich legume (Onobrychis viciifolia on in vitro ruminal biohydrogenation and fermentation

    Directory of Open Access Journals (Sweden)

    Gonzalo Hervás

    2016-03-01

    Full Text Available There is still controversy surrounding the ability of tannins to modulate the ruminal biohydrogenation (BH of fatty acids (FA and improve the lipid profile of milk or meat without conferring a negative response in the digestive utilization of the diet. Based on this, an in vitro trial using batch cultures of rumen microorganisms was performed to compare the effects of two legume hays with similar chemical composition but different tannin content, alfalfa and sainfoin (Onobrychis viciifolia, on the BH of dietary unsaturated FA and on the ruminal fermentation. The first incubation substrate, alfalfa, was practically free of tannins, while the second, sainfoin, contained 3.5% (expressed as tannic acid equivalents. Both hays were enriched with sunflower oil as a source of unsaturated FA. Most results of the lipid composition analysis (e.g., greater concentrations of 18:2n-6, cis-9 18:1 or total polyunsaturated FA in sainfoin incubations showed the ability of this tannin-containing legume to inhibit the BH process. However, no significant differences were detected in the accumulation of cis-9 trans-11 conjugated linoleic acid, and variations in trans-11 18:1 and trans-11 cis-15 18:2 did not follow a regular pattern. Regarding the rumen fermentation, gas production, ammonia concentration and volatile FA production were lower in the incubations with sainfoin (-17, -23 and -11%, respectively. Thus, although this legume was able to modify the ruminal BH, which might result in improvements in the meat or milk lipid profile, the present results were not as promising as expected or as obtained before with other nutritional strategies.

  6. Optimal foraging by birds: feeder-based experiments for secondary and post-secondary students

    Science.gov (United States)

    Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. Here, we describe three exercises designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These e...

  7. An assessment of the cultural capabilities of Trifolium repens L. (white clover) and Onobrychis viciifolia Scop. (sainfoin) mesophyll protoplasts.

    Science.gov (United States)

    Ahuja, P S; Lu, D Y; Cocking, E C; Davey, M R

    1983-10-01

    Mesophyll protoplasts isolated from white clover and sainfoin divided to form callus under similar cultural conditions. White clover protoplasts showed varietal differences in their plating efficiency. Sainfoin tissues regenerated readily by forming shoots, but induction of morphogenesis in white clover was only achieved after testing several media and culture sequences. Many of the white clover shoots were abnormal in being fused together to form green plate-like structures, but the latter still developed into plantlets while attached to the parent callus. The ability to isolate, culture, and regenerate mesophyll protoplasts of these two forage legumes is discussed in relation to future attempts to produce somatic hybrids between high tannin containing bloat-safe sainfoin and other major forage legumes such as alfalfa, white clover, and red clover.

  8. Characterization of novel SSR markers in diverse sainfoin (Onobrychis viciifolia) germplasm.

    Science.gov (United States)

    Kempf, Katharina; Mora-Ortiz, Marina; Smith, Lydia M J; Kölliker, Roland; Skøt, Leif

    2016-08-30

    Sainfoin is a perennial forage legume with beneficial properties for animal husbandry due to the presence of secondary metabolites. However, worldwide cultivation of sainfoin is marginal due to the lack of varieties with good agronomic performance, adapted to a broad range of environmental conditions. Little is known about the genetics of sainfoin and only few genetic markers are available to assist breeding and genetic investigations. The objective of this study was to develop a set of SSR markers useful for genetic studies in sainfoin and their characterization in diverse germplasm. A set of 400 SSR primer combinations were tested for amplification and their ability to detect polymorphisms in a set of 32 sainfoin individuals, representing distinct varieties or landraces. Alleles were scored for presence or absence and polymorphism information content of each SSR locus was calculated with an adapted formula taking into account the tetraploid character of sainfoin. Relationships among individuals were visualized using cluster and principle components analysis. Of the 400 primer combinations tested, 101 reliably detected polymorphisms among the 32 sainfoin individuals. Among the 1154 alleles amplified 250 private alleles were observed. The number of alleles per locus ranged from 2 to 24 with an average of 11.4 alleles. The average polymorphism information content reached values of 0.14 to 0.36. The clustering of the 32 individuals suggested a separation into two groups depending on the origin of the accessions. The SSR markers characterized and tested in this study provide a valuable tool to detect polymorphisms in sainfoin for future genetic studies and breeding programs. As a proof of concept, we showed that these markers can be used to separate sainfoin individuals based on their origin.

  9. Winter foraging behavior of elk in the shrub-steppe of Washington

    Energy Technology Data Exchange (ETDEWEB)

    McCorquodale, S.M. (Pacific Northwest Lab., Richland, WA (United States))

    1993-01-01

    Numerous models of ungulate foraging behavior have been published, but data on foraging behavior for wild North American ungulates relevant to model testing are scarce. I studied the detailed foraging behavior of elk from autumn through early spring in Washington's shrub-steppe using focal animal sampling and collected corollary data on elk diets, forage quality, and home ranges. I tested the hypotheses that foraging effort is proportional to energetic payoffs determined by the quality and abundance of various forages, and elk home-range size reflects relative foraging movements (i.e., macro and micro movements are related). Elk were mobile foragers during autumn and spring and were relatively sedentary during mid-winter. High mobility was associated with low diet diversity and generally with reduced forage harvesting rates. This mobile foraging occurred during periods of higher quality forage availability. Thus, mobile foraging appeared to reflect increased effort when energetic payoffs of selective foraging were enhanced. Degree of dietary specialization was limited by the relative abundance of preferred forages, being greater when grass quality was high, and less when forb quality was high. Indices of elk movement while foraging were also positively related to home-range size and distance between relocations of radio-collared elk. These data are generally consistent with ungulate foraging model predictions. 34 refs., 4 figs., 2 tabs.

  10. The hidden cost of information in collective foraging.

    Science.gov (United States)

    Dechaume-Moncharmont, François-Xavier; Dornhaus, Anna; Houston, Alasdair I; McNamara, John M; Collins, Edmund J; Franks, Nigel R

    2005-08-22

    Many animals nest or roost colonially. At the start of a potential foraging period, they may set out independently or await information from returning foragers. When should such individuals act independently and when should they wait for information? In a social insect colony, for example, information transfer may greatly increase a recruit's probability of finding food, and it is commonly assumed that this will always increase the colony's net energy gain. We test this assumption with a mathematical model. Energy gain by a colony is a function both of the probability of finding food sources and of the duration of their availability. A key factor is the ratio of pro-active foragers to re-active foragers. When leaving the nest, pro-active foragers search for food independently, whereas re-active foragers rely on information from successful foragers to find food. Under certain conditions, the optimum strategy is totally independent (pro-active) foraging because potentially valuable information that re-active foragers may gain from successful foragers is not worth waiting for. This counter-intuitive outcome is remarkably robust over a wide range of parameters. It occurs because food sources are only available for a limited period. Our study emphasizes the importance of time constraints and the analysis of dynamics, not just steady states, to understand social insect foraging.

  11. Information Foraging for Perceptual Decisions

    OpenAIRE

    Ludwig, Casimir J.H.; Evens, David R

    2016-01-01

    We tested an information foraging framework to characterize the mechanisms that drive active (visual) sampling behavior in decision problems that involve multiple sources of information. Experiments 1 through 3 involved participants making an absolute judgment about the direction of motion of a single random dot motion pattern. In Experiment 4, participants made a relative comparison between 2 motion patterns that could only be sampled sequentially. Our results show that: (a) Information (abo...

  12. Macronutrient modifications of optimal foraging theory: an approach using indifference curves applied to some modern foragers

    Energy Technology Data Exchange (ETDEWEB)

    Hill, K.

    1988-06-01

    The use of energy (calories) as the currency to be maximized per unit time in Optimal Foraging Models is considered in light of data on several foraging groups. Observations on the Ache, Cuiva, and Yora foragers suggest men do not attempt to maximize energetic return rates, but instead often concentration on acquiring meat resources which provide lower energetic returns. The possibility that this preference is due to the macronutrient composition of hunted and gathered foods is explored. Indifference curves are introduced as a means of modeling the tradeoff between two desirable commodities, meat (protein-lipid) and carbohydrate, and a specific indifference curve is derived using observed choices in five foraging situations. This curve is used to predict the amount of meat that Mbuti foragers will trade for carbohydrate, in an attempt to test the utility of the approach.

  13. How universal is the Big Five? Testing the five-factor model of personality variation among forager-farmers in the Bolivian Amazon.

    Science.gov (United States)

    Gurven, Michael; von Rueden, Christopher; Massenkoff, Maxim; Kaplan, Hillard; Lero Vie, Marino

    2013-02-01

    The five-factor model (FFM) of personality variation has been replicated across a range of human societies, suggesting the FFM is a human universal. However, most studies of the FFM have been restricted to literate, urban populations, which are uncharacteristic of the majority of human evolutionary history. We present the first test of the FFM in a largely illiterate, indigenous society. Tsimane forager-horticulturalist men and women of Bolivia (n = 632) completed a translation of the 44-item Big Five Inventory (Benet-Martínez & John, 1998), a widely used metric of the FFM. We failed to find robust support for the FFM, based on tests of (a) internal consistency of items expected to segregate into the Big Five factors, (b) response stability of the Big Five, (c) external validity of the Big Five with respect to observed behavior, (d) factor structure according to exploratory and confirmatory factor analysis, and (e) similarity with a U.S. target structure based on Procrustes rotation analysis. Replication of the FFM was not improved in a separate sample of Tsimane adults (n = 430), who evaluated their spouses on the Big Five Inventory. Removal of reverse-scored items that may have elicited response biases produced factors suggestive of Extraversion, Agreeableness, and Conscientiousness, but fit to the FFM remained poor. Response styles may covary with exposure to education, but we found no better fit to the FFM among Tsimane who speak Spanish or have attended school. We argue that Tsimane personality variation displays 2 principal factors that may reflect socioecological characteristics common to small-scale societies. We offer evolutionary perspectives on why the structure of personality variation may not be invariant across human societies. (c) 2013 APA, all rights reserved.

  14. Does market integration buffer risk, erode traditional sharing practices and increase inequality? A test among Bolivian forager-farmers

    Science.gov (United States)

    Gurven, Michael; Jaeggi, Adrian V.; von Rueden, Chris; Hooper, Paul L.; Kaplan, Hillard

    2015-01-01

    Sharing and exchange are common practices for minimizing food insecurity in rural populations. The advent of markets and monetization in egalitarian indigenous populations presents an alternative means of managing risk, with the potential impact of eroding traditional networks. We test whether market involvement buffers several types of risk and reduces traditional sharing behavior among Tsimane Amerindians of the Bolivian Amazon. Results vary based on type of market integration and scale of analysis (household vs. village), consistent with the notion that local culture and ecology shape risk management strategies. Greater wealth and income were unassociated with the reliance on others for food, or on reciprocity, but wealth was associated with a greater proportion of food given to others (i.e., giving intensity) and a greater number of sharing partners (i.e., sharing breadth). Across villages, greater mean income was negatively associated with reciprocity, but economic inequality was positively associated with giving intensity and sharing breadth. Incipient market integration does not necessarily replace traditional buffering strategies but instead can often enhance social capital. PMID:26526638

  15. Does market integration buffer risk, erode traditional sharing practices and increase inequality? A test among Bolivian forager-farmers.

    Science.gov (United States)

    Gurven, Michael; Jaeggi, Adrian V; von Rueden, Chris; Hooper, Paul L; Kaplan, Hillard

    2015-08-01

    Sharing and exchange are common practices for minimizing food insecurity in rural populations. The advent of markets and monetization in egalitarian indigenous populations presents an alternative means of managing risk, with the potential impact of eroding traditional networks. We test whether market involvement buffers several types of risk and reduces traditional sharing behavior among Tsimane Amerindians of the Bolivian Amazon. Results vary based on type of market integration and scale of analysis (household vs. village), consistent with the notion that local culture and ecology shape risk management strategies. Greater wealth and income were unassociated with the reliance on others for food, or on reciprocity, but wealth was associated with a greater proportion of food given to others (i.e., giving intensity) and a greater number of sharing partners (i.e., sharing breadth). Across villages, greater mean income was negatively associated with reciprocity, but economic inequality was positively associated with giving intensity and sharing breadth. Incipient market integration does not necessarily replace traditional buffering strategies but instead can often enhance social capital.

  16. Bumblebee vibration activated foraging

    OpenAIRE

    Su, Dan Kuan-Nien

    2009-01-01

    The ability use vibrational signals to activate nestmate foraging is found in the highly social bees, stingless bees and honey bees, and has been hypothesized to exist in the closely related, primitively eusocial bumble bees. We provide the first strong and direct evidence that this is correct. Inside the nest, bumble bee foragers produce brief bursts of vibration (foraging activation pulses) at 594.5 Hz for 63±26 ms (velocityRMS=0.46±0.02mm/s, forceRMS=0.8±0.2 mN. Production of these vibrati...

  17. Diversity of condensed tannin structures affects rumen in vitro methane production in sainfoin (Onobrychis viciifolia) accessions

    NARCIS (Netherlands)

    Hatew, B.; Hayot Carbonero, C.; Stringano, E.; Sales, L.F.; Smith, L.M.J.; Mueller-Harvey, I.; Hendriks, W.H.; Pellikaan, W.F.

    2015-01-01

    Sainfoin is a non-bloating temperate forage legume with a moderate-to-high condensed tannin (CT) content. This study investigated whether the diversity of sainfoin accessions in terms of CT structures and contents could be related to rumen in vitro gas and methane (CH4) production and fermentation

  18. Adaptive Bacterial Foraging Optimization

    OpenAIRE

    Hanning Chen; Yunlong Zhu; Kunyuan Hu

    2011-01-01

    Bacterial Foraging Optimization (BFO) is a recently developed nature-inspired optimization algorithm, which is based on the foraging behavior of E. coli bacteria. Up to now, BFO has been applied successfully to some engineering problems due to its simplicity and ease of implementation. However, BFO possesses a poor convergence behavior over complex optimization problems as compared to other nature-inspired optimization techniques. This paper first analyzes how ...

  19. Specialization on pollen or nectar in bumblebee foragers is not associated with ovary size, lipid reserves or sensory tuning

    Directory of Open Access Journals (Sweden)

    Adam R. Smith

    2016-10-01

    Full Text Available Foraging specialization allows social insects to more efficiently exploit resources in their environment. Recent research on honeybees suggests that specialization on pollen or nectar among foragers is linked to reproductive physiology and sensory tuning (the Reproductive Ground-Plan Hypothesis; RGPH. However, our understanding of the underlying physiological relationships in non-Apis bees is still limited. Here we show that the bumblebee Bombus terrestris has specialist pollen and nectar foragers, and test whether foraging specialization in B. terrestris is linked to reproductive physiology, measured as ovarian activation. We show that neither ovary size, sensory sensitivity, measured through proboscis extension response (PER, or whole-body lipid stores differed between pollen foragers, nectar foragers, or generalist foragers. Body size also did not differ between any of these three forager groups. Non-foragers had significantly larger ovaries than foragers. This suggests that potentially reproductive individuals avoid foraging.

  20. Effect of feeding bioactive forages on infection and subsequent development of Haemonchus contortus in lamb faeces.

    Science.gov (United States)

    Valderrábano, J; Calvete, C; Uriarte, J

    2010-08-27

    Contrasting dried herbage diets were offered to lambs to evaluate their effects on Haemonchus contortus infection and on subsequent development of larvae in faeces. Artificially infected lambs (n=24, 4 months old) were allocated to one of four treatment groups (n=6) and fed on hay of lucerne (Medicago sativa; Lu), sulla (Hedysarum coronarium; Su), sainfoin (Onobrychis viciifolia; Sa) or wormwood (Artemisia absinthium; Wo) included as 20% in ground lucerne pellets. While voluntary intake was similar, lamb growth rates were notably affected by diet. Additionally, necropsies carried out 30 days post-infection showed that worm burden was reduced by 8 (Su), 13 (Sa) and 49% (Wo) with respect to that found in lambs fed on lucerne, though only the difference with wormwood was significant. Faecal egg excretion expressed on a dry matter basis was also reduced by 22 (Su), 54 (Sa) and 73% (Wo), but differences were significant only for wormwood and sainfoin, which was associated with a decrease in female fecundity. Sulla and sainfoin diets significantly reduced egg hatching rates but increased the percentage of L(3) in the faeces of the host animal, particularly in the case of sulla hay compared to other forages. Consequently, the potential risk of infection derived from faecal excretion could be notably altered. Further work is needed to validate these findings and their implications in an applied farming system. (c) 2010 Elsevier B.V. All rights reserved.

  1. Adaptive Bacterial Foraging Optimization

    Directory of Open Access Journals (Sweden)

    Hanning Chen

    2011-01-01

    Full Text Available Bacterial Foraging Optimization (BFO is a recently developed nature-inspired optimization algorithm, which is based on the foraging behavior of E. coli bacteria. Up to now, BFO has been applied successfully to some engineering problems due to its simplicity and ease of implementation. However, BFO possesses a poor convergence behavior over complex optimization problems as compared to other nature-inspired optimization techniques. This paper first analyzes how the run-length unit parameter of BFO controls the exploration of the whole search space and the exploitation of the promising areas. Then it presents a variation on the original BFO, called the adaptive bacterial foraging optimization (ABFO, employing the adaptive foraging strategies to improve the performance of the original BFO. This improvement is achieved by enabling the bacterial foraging algorithm to adjust the run-length unit parameter dynamically during algorithm execution in order to balance the exploration/exploitation tradeoff. The experiments compare the performance of two versions of ABFO with the original BFO, the standard particle swarm optimization (PSO and a real-coded genetic algorithm (GA on four widely-used benchmark functions. The proposed ABFO shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

  2. Sexually distinct foraging strategies in an omnivorous seabird

    NARCIS (Netherlands)

    Camphuysen, K.C.J.; Shamoun-Baranes, J.; van Loon, E.E.; Bouten, W.

    2015-01-01

    Intra-specific differences in foraging behaviour can have fitness consequences, especially during breeding. We combined GPS tracking data from 34 lesser black-backed gulls (Larus fuscus) encompassing 2029 foraging trips with dietary information and morphometric measurements to test the effect of

  3. Foraging effort and prey choice in cape gannets | Adams | African ...

    African Journals Online (AJOL)

    In order to test the hypothesis that sardine Sardinops sagax are the preferred prey of Cape gannets Morus capensis, the link between foraging effort and prey choice was evaluated by simultaneously monitoring the activity and the diet of adult birds attending chicks at Bird Island, Algoa Bay, South Africa. Foraging trip ...

  4. An Optimal Foraging Approach to Information Seeking and Use.

    Science.gov (United States)

    Sandstrom, Pamela Effrein

    1994-01-01

    Explores optimal foraging theory, derived from evolutionary ecology, for its potential to clarify and operationalize studies of scholarly communication. Metaphorical parallels between subsistence foragers and scholarly information seekers are drawn. Hypotheses to test the models are recommended. The place of ethnographic and bibliometric…

  5. Interactions with combined chemical cues inform harvester ant foragers' decisions to leave the nest in search of food.

    Directory of Open Access Journals (Sweden)

    Michael J Greene

    Full Text Available Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food.

  6. Cooperative Bacterial Foraging Optimization

    Directory of Open Access Journals (Sweden)

    Hanning Chen

    2009-01-01

    Full Text Available Bacterial Foraging Optimization (BFO is a novel optimization algorithm based on the social foraging behavior of E. coli bacteria. This paper presents a variation on the original BFO algorithm, namely, the Cooperative Bacterial Foraging Optimization (CBFO, which significantly improve the original BFO in solving complex optimization problems. This significant improvement is achieved by applying two cooperative approaches to the original BFO, namely, the serial heterogeneous cooperation on the implicit space decomposition level and the serial heterogeneous cooperation on the hybrid space decomposition level. The experiments compare the performance of two CBFO variants with the original BFO, the standard PSO and a real-coded GA on four widely used benchmark functions. The new method shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

  7. Comparative Effect of Sole Forage and Mixed Concentrate-Forage ...

    African Journals Online (AJOL)

    The response of weaner rabbits to two dietary treatments, sole forage and mixed concentrate-forage was evaluated in a completely randomized design (CRD) for a trial period of 10 weeks. The concentrate used was poultry growers mash while the forage was Tridax procumbens.Thirty two (32) New Zealand White ...

  8. Redesigning forages with condensed tannins

    Science.gov (United States)

    Maximizing protein content in forages and minimizing protein loss during silage fermentation and rumen digestion are concerns for livestock and dairy producers. Substantial amounts of forage protein undergo proteolysis (breakdown) during the ensiling process and during rumen fermentation, transforme...

  9. Resiliency in forage and grazinglands

    Science.gov (United States)

    This manuscript is a combined effort of the speakers at the 2017 C6 Forage and Grazinglands Division Symposia which was titled “Resiliency in Forage and Grazinglands.” Developing more resilient agroecosystems, including those that produce forage and livestock, will become necessary to maintain agric...

  10. Optimal Foraging in Semantic Memory

    Science.gov (United States)

    Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

    2012-01-01

    Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

  11. In situ analysis and structural elucidation of sainfoin (Onobrychis viciifolia) tannins for high-throughput germplasm screening.

    Science.gov (United States)

    Gea, An; Stringano, Elisabetta; Brown, Ron H; Mueller-Harvey, Irene

    2011-01-26

    A rapid thiolytic degradation and cleanup procedure was developed for analyzing tannins directly in chlorophyll-containing sainfoin ( Onobrychis viciifolia ) plants. The technique proved suitable for complex tannin mixtures containing catechin, epicatechin, gallocatechin, and epigallocatechin flavan-3-ol units. The reaction time was standardized at 60 min to minimize the loss of structural information as a result of epimerization and degradation of terminal flavan-3-ol units. The results were evaluated by separate analysis of extractable and unextractable tannins, which accounted for 63.6-113.7% of the in situ plant tannins. It is of note that 70% aqueous acetone extracted tannins with a lower mean degree of polymerization (mDP) than was found for tannins analyzed in situ. Extractable tannins had between 4 and 29 lower mDP values. The method was validated by comparing results from individual and mixed sample sets. The tannin composition of different sainfoin accessions covered a range of mDP values from 16 to 83, procyanidin/prodelphinidin (PC/PD) ratios from 19.2/80.8 to 45.6/54.4, and cis/trans ratios from 74.1/25.9 to 88.0/12.0. This is the first high-throughput screening method that is suitable for analyzing condensed tannin contents and structural composition directly in green plant tissue.

  12. Evolution of foraging behavior in Drosophilid larvae

    Science.gov (United States)

    Rivera-Alba, Marta; Kabra, Mayank; Branson, Kristin; Mirth, Christen

    2015-03-01

    Drosophilids, like other insects, go through a larval phase before metamorphosing into adults. Larvae increase their body weight by several orders of magnitude in a few days. We therefore hypothesized that foraging behavior is under strong evolutionary pressure to best fit the larval environment. To test our hypothesis we used a multidisciplinary approach to analyze foraging behavior across species and larval stages. First, we recorded several videos of larvae foraging for each of 47 Drosophilid species. Then, using a supervised machine learning approach, we automatically annotated the video collection for the foraging sub-behaviors, including crawling, turning, head casting or burrowing. We also computed over 100 features to describe the posture and dynamics of each animal in each video frame. From these data, we fit models to the behavior of each species. The models each had the same parametric form, but differed in the exact parameters. By simulating larva behavior in virtual arenas we can infer which properties of the environments are better for each species. Comparisons between these inferred environments and the actual environments where these animals live will give us a deeper understanding about the evolution of foraging behavior in Drosophilid larvae.

  13. Relationships between food resources, foraging patterns, and reproductive success in the water pipit, Anthus sp. spinoletta

    OpenAIRE

    Frey-Roos, F; Brodmann, P A.; Reyer, H U.

    1995-01-01

    A basic but rarely tested assumption in optimal foraging theory is that positive relationships exist between the foraging pattern of an animal, its short-term benefits in feeding, and its long-term fitness. We present evidence for these relationships for a central place foraging situation. We studied the foraging behavior of adult water pipits (Anthus sp. spinoletta) feeding nestlings in an Alpine habitat near Davos, Switzerland, with the following results: (1) searching effort decreases with...

  14. Nutrient balance affects foraging behaviour of a trap-building predator

    DEFF Research Database (Denmark)

    Mayntz, David; Toft, Søren; Vollrath, Fritz

    2009-01-01

    Predator foraging may be affected by previous prey capture, but it is unknown how nutrient balance affects foraging behaviour. Here, we use a trap-building predator to test whether nutrients from previous prey captures affect foraging behaviour. We fed orb-weaving spiders (Zygiella x-notata) prey...... composition while prey availability affected capture area and mesh height. Our results show that both the balance of nutrients in captured prey and the previous capture rate may affect future foraging behaviour of predators....

  15. Comparative Sucrose Responsiveness in Apis mellifera and A. cerana Foragers

    Science.gov (United States)

    Yang, Wenchao; Kuang, Haiou; Wang, Shanshan; Wang, Jie; Liu, Wei; Wu, Zhenhong; Tian, Yuanyuan; Huang, Zachary Y.; Miao, Xiaoqing

    2013-01-01

    In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources. PMID:24194958

  16. Near-Infrared Spectroscopy Calibrations Performed on Oven-Dried Green Forages for the Prediction of Chemical Composition and Nutritive Value of Preserved Forage for Ruminants.

    Science.gov (United States)

    Andueza, Donato; Picard, Fabienne; Martin-Rosset, William; Aufrère, Jocelyne

    2016-08-01

    Predicting forage feed value is a vital part of estimating ruminant performances. Most near-infrared (NIR) reflectance calibration models have been developed on oven-dried green forages, but preserved forages such as hays or silages are a significant part of real-world farm practice. Fresh and preserved forages give largely similar fodder, but drying or ensiling processes could modify preserved forage spectra which would make the oven-dried green forage model unsuitable to use on preserved forage samples. The aim of this study was to monitor the performance of oven-dried green forage calibration models on a set of hay and silage to predict their nutritive value. Local and global approaches were tested and 1025 green permanent grassland forages, 46 types of hay, and 27 types of silage were used. The samples were scanned by NIR spectroscopy and analyzed for nitrogen, neutral detergent fiber, acid detergent fiber, and pepsin-cellulase dry matter digestibility (PCDMD). Local and global calibrations were developed on 975 oven-dried green forage spectra and tested on 50 samples of oven-dried green forages, 46 samples of hay, and 27 samples of silage. For oven-dried green forage and hay validation sets, Mahalanobis distance (H) between these samples and the calibration population center was lower than 3. No significant standard error of prediction differences was obtained when calibration models were applied to oven-dried green forage and hay validation sets. For silage, the H-distance was higher than 3, meaning that calibration models built from oven-dried green forages cannot be applied to silage samples. We conclude that local calibration outperforms global strategy on predicting the PCDMD of oven-dried green forages and hay. © The Author(s) 2016.

  17. The impact of weather on kingbird foraging behavior

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.T. (Museum of Natural History, The University of Kansas, Lawrence, KS 66045)

    1987-01-01

    Foraging data on Eastern Kingbirds (Tyrannus tyrannus) were collected during the early breeding season in eastern Kansas to test the hypothesis that foraging rate and other aspects of foraging behavior vary with weather. Foraging characteristics of five additional kingbird species were also examined to assess Fitzpatrick's 1980 generalization that kingbirds (Tyrannus spp.) are aerial hawking specialists. In Eastern Kingbirds, total foraging rate was independent of air temperature, cloud cover, wind speed, and time of day, but the rate of aerial hawking varied directly with air temperature and inversely with cloud cover (both P < 0.05). Effects of the two variables were additive. The percentage of foraging movements that were aerial hawks also increased with temperature and declined with cloud cover, and hover-gleaning and perch-to-ground sallying were observed mainly during cloudy weather. Sally (i.e., foraging flight) distance correlated directly with perch height and air temperature, and large insects were captured almost exclusively in long upward or horizontal flights. I interpret these data to indicate that foraging behavior and the capture of large, flying insects depends on weather because of how it affects the activity of insect prey. Foraging data on kingbirds support Fitzpatrick's generalization, but the relative use of aerial hawking varies considerably among species. Resident Tropical Kingbirds (T. melancholicus) are the most specialized foragers, whereas the migrant and widely distributed Eastern Kingbird appears to be the most generalized. Certain habitats also appear to favor the use of particular foraging methods (e.g., outward striking in grasslands, and perch-to-ground sallying in drier, open habitats).

  18. Organic forage seed production

    OpenAIRE

    BOELT, B.; Deleuran, L.C.

    2000-01-01

    From January 2004 only organically produced seed can be used in organic farming systems within the EU. Danish seed producers and seed companies are establishing an organic forage seed production in order to supply organic growers within the EU with high quality seed of recognised varieties. This brief paper outlines a project investigating improved cultivation and management techniques to ensure such a supply is met.

  19. Effect of forage quality in faeces from different ruminant species fed high and low quality forage

    DEFF Research Database (Denmark)

    Jalali, A R; Nørgaard, P; Nielsen, M O

    2010-01-01

    Effect of forage quality in faeces from different ruminant species fed high and low quality forage......Effect of forage quality in faeces from different ruminant species fed high and low quality forage...

  20. The effect of sainfoin (Onobrychis viciifolia) and carob pods (Ceratonia siliqua) feeding regimes on the control of lamb coccidiosis.

    Science.gov (United States)

    Saratsis, A; Voutzourakis, N; Theodosiou, T; Stefanakis, A; Sotiraki, S

    2016-06-01

    Recent research has suggested that plants containing condensed tannins may offer a promising alternative approach for the control of coccidiosis in lambs and goat kids. The present study aimed to examine the potential effect of condensed tannins in sainfoin (Onobrychis viciifolia) and carob pods (Ceratonia siliqua) incorporated in sheep rations against lamb coccidiosis. The above tannin-rich sources were studied in three independent feeding trials in which the animals (naturally infected by Eimeria spp. ewes and their lambs) were allocated (i) in the control group and received a tannin-free diet (lucerne hay), or (ii) in the treatment groups and received a tannin-rich diet based on sainfoin hay (in trials 1 and 2), or in carob pod meal and a combination of carob pod meal and sainfoin hay (in trial 3). In total, 95 newborn lambs (and their 73 ewes) were enrolled in all trials which started a month before lambing and ended 8-10 weeks after lambs were born (at weaning). The course of coccidial infection was monitored in lambs by faecal oocyst counts and consistencies which were recorded at weekly intervals. Moreover, lambs total weight gain was evaluated at the end of each trial. During all trials, 100 % of the animals got naturally infected by Eimeria species and the infection burden was higher in trials 2 and 3 compared to trial 1 but in all cases, severe signs of diarrhoea were not observed. Tannin-rich diets were well accepted by the animals not affecting their feed intake and body weight gain when compared to the controls. The results suggest that incorporation of both tannin-rich resources (especially sainfoin) in sheep rations can reduce Eimeria oocyst excretion rates by the lambs, which can decrease subsequently the contamination of the farm environment with the parasite. However, the high variability noted on the results is not allowing us to draw any definite conclusions at least until the potential of those plants is further investigated.

  1. The Dynamics of Foraging Ants

    Science.gov (United States)

    Baxter, G. William

    2009-03-01

    We experimentally study the foraging of small black ants, Formicinae lasius flavus, in order to describe their foraging behavior mathematically. Individual ants are allowed to forage on a two-dimensional surface in the absence of any food sources. The position of the ant as a function of time is determined using a high-resolution digital camera. Analysis of the average square displacements of many ants suggests that the foraging strategy is a non-reversing random walk. Moreover, the ants do not retrace their steps to return home but instead continue the random walk until it brings them back near their starting point.

  2. Learning foraging thresholds for lizards

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, L.A. [Univ. of Warwick, Coventry (United Kingdom). Dept. of Computer Science; Hart, W.E. [Sandia National Labs., Albuquerque, NM (United States); Wilson, D.B. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1996-01-12

    This work gives a proof of convergence for a randomized learning algorithm that describes how anoles (lizards found in the Carribean) learn a foraging threshold distance. This model assumes that an anole will pursue a prey if and only if it is within this threshold of the anole`s perch. This learning algorithm was proposed by the biologist Roughgarden and his colleagues. They experimentally confirmed that this algorithm quickly converges to the foraging threshold that is predicted by optimal foraging theory our analysis provides an analytic confirmation that the learning algorithm converses to this optimal foraging threshold with high probability.

  3. Direct and Indirect Selection for Forage Yield and Its Components in Sainfoin under Normal and Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    M. M. Majidi

    2014-08-01

    Full Text Available Selection based on indices is an effective method for breeding complex traits. To assess the efficiency of different selection methods, twenty one accessions of Sainfoin (Onobrychis viciifolia were evaluated in two environments including drought stress and non-stress conditions according to a randomized complete block design with three replications in 2010. In this study, the selection indices of Smith-Hazel and Pesek-Baker were determined based on the percentage of dry matter yield, stem percent, plant height and number of stem per plant under both conditions. Also response to selection and relative selection efficiency were estimated for studied traits and dry matter yield. The highest estimated selection efficiency for genetically improvement of dry matter yield was obtained via selection for stem percent and number of stem per plant. Therefore, these traits can be used as an appropriate selection criterion for improvement of forage yield. In Smith-Hazel indices under normal environment plant height and under stress environment stem percent had the highest gain, while in Pesek-Baker index, under both moisture conditions percentage of dry matter yield had the highest gain. The results indicated that Smith-Hazel index 1 had the most selection efficiency and could be used in sainfoin breeding programs.

  4. Choice and foraging

    OpenAIRE

    Abarca, Nureya; Fantino, Edmund

    1982-01-01

    In Experiment 1, six naive pigeons were trained on a foraging schedule characterized by different states beginning with a search state in which completion of a fixed-interval on a white key led to a choice state. In the choice state the subject could, by appropriate responding on a fixed ratio of three, either accept or reject the schedule of reinforcement that was offered (either a variable-interval five-second or a variable-interval 20-second). If the subject accepted the schedule, it enter...

  5. Foraging Online Social Networks

    OpenAIRE

    Koot, Gijs; Huis in ’t Veld, Mirjam; Hendricksen, Joost; Kaptein, Rianne; Vries, Arnout; van den Broek, Egon; den Hengst, M; Israël, M; Zeng, D.; Veenman, C.; Wang, A.

    2014-01-01

    A concise and practical introduction is given on Online Social Networks (OSN) and their application in law enforcement, including a brief survey of related work. Subsequently, a tool is introduced that can be used to search OSN in order to generate user profiles. Both its architecture and processing pipeline are described. This tool is meant as a flexible framework that supports manual foraging (and not replaces it). As such, we aim to bridge science’s state-of-the-art and current security of...

  6. Info-gap robust-satisficing model of foraging behavior: do foragers optimize or satisfice?

    Science.gov (United States)

    Carmel, Yohay; Ben-Haim, Yakov

    2005-11-01

    In this note we compare two mathematical models of foraging that reflect two competing theories of animal behavior: optimizing and robust satisficing. The optimal-foraging model is based on the marginal value theorem (MVT). The robust-satisficing model developed here is an application of info-gap decision theory. The info-gap robust-satisficing model relates to the same circumstances described by the MVT. We show how these two alternatives translate into specific predictions that at some points are quite disparate. We test these alternative predictions against available data collected in numerous field studies with a large number of species from diverse taxonomic groups. We show that a large majority of studies appear to support the robust-satisficing model and reject the optimal-foraging model.

  7. Thermal constraints on foraging of tropical canopy ants.

    Science.gov (United States)

    Spicer, Michelle Elise; Stark, Alyssa Y; Adams, Benjamin J; Kneale, Riley; Kaspari, Michael; Yanoviak, Stephen P

    2017-04-01

    Small cursorial ectotherms risk overheating when foraging in the tropical forest canopy, where the surfaces of unshaded tree branches commonly exceed 50 °C. We quantified the heating and subsequent cooling rates of 11 common canopy ant species from Panama and tested the hypothesis that ant workers stop foraging at temperatures consistent with the prevention of overheating. We created hot experimental "sunflecks" on existing foraging trails of four ant species from different clades and spanning a broad range of body size, heating rate, and critical thermal maxima (CTmax). Different ant species exhibited very different heating rates in the lab, and these differences did not follow trends predicted by body size alone. Experiments with ant models showed that heating rates are strongly affected by color in addition to body size. Foraging workers of all species showed strong responses to heating and consistently abandoned focal sites between 36 and 44 °C. Atta colombica and Azteca trigona workers resumed foraging shortly after heat was removed, but Cephalotes atratus and Dolichoderus bispinosus workers continued to avoid the heated patch even after >5 min of cooling. Large foraging ants (C. atratus) responded slowly to developing thermal extremes, whereas small ants (A. trigona) evacuated sunflecks relatively quickly, and at lower estimated body temperatures than when revisiting previously heated patches. The results of this study provide the first field-based insight into how foraging ants respond behaviorally to the heterogeneous thermal landscape of the tropical forest canopy.

  8. Forage kochia: Friend or foe

    Science.gov (United States)

    Blair L. Waldron; R. Deane Harrison; N. Jerry Chatterton; Burke W. Davenport

    2001-01-01

    Perennial forage kochia (Kochia prostrata) is a halfshrub valuable for reclamation, fire breaks, and livestock and wildlife forage on semiarid and saline rangelands. Interest is mounting about this species, but some are concerned that it will become an invader of perennial communities. Only one cultivar (Immigrant) has been released in the United States. Eighty-one...

  9. In vivo and in situ measurements of the digestive characteristics of sainfoin in comparison with lucerne fed to sheep as fresh forages at two growth stages and as hay.

    Science.gov (United States)

    Aufrère, J; Dudilieu, M; Poncet, C

    2008-09-01

    In vivo and in situ digestive characteristics of sainfoin (Onobrychis viciifolia L., a tannin-rich forage) and lucerne (Medicago sativa L., a tannin-free forage) were compared to evaluate the effects of condensed tannins (CT) and growth stage (vegetative v. early flowering) in experiment 1. In experiment 2, the hays of the two forages, harvested at early flowering, were compared. Ingestibility, organic matter digestibility (OMD) and nitrogen (N) retention were measured in sheep fed sainfoin and lucerne fresh forages and hays. The loss of dry matter (DM) and N from polyester bags suspended in the rumen, abomasum and small intestine was also measured using rumen fistulated sheep and other intestine fistulated sheep. Nitrogen content was lower in sainfoin than in lucerne. Content of CT in sainfoin decreased with growth stage (3.5 to 2.5 g CT/kg DM) and was lower for sainfoin hay (0.6 g CT/kg DM). Ingestibility and OMD did not differ between fresh-fed forage species. Total N tract digestibility in vivo was much lower for sainfoin than for lucerne fresh forages (mean value 0.540 v. 0.721, P < 0.001) and for sainfoin hay than lucerne hay (0.464 v. 0.683, P < 0.001). In both species, N digestibility was not altered by growth stage. The rumen degradation of N was lower in sainfoin than in lucerne, resulting in a lower proportion of N intake excreted in urine. The intestinal digestibility of sainfoin was also lower than that of lucerne, resulting in a higher N excretion in faeces. Hence the efficiency of N utilisation by sheep (ENr) was similar (mean value 0.205 and 0.199 g N retained/g N intake for fresh sainfoin and lucerne, respectively). The coefficient of N retention by the animal was higher for sainfoin at the vegetative stage than for all the other forages. Nitrogen degradability in the rumen determined by the nylon bag technique (DegN) was lower for sainfoin than for lucerne when forages were studied both fresh (mean value 0.608 and 0.818, respectively) and as hays

  10. Foraging strategy quick response to temperature of Messor barbarus (Hymenoptera: Formicidae) in Mediterranean environments.

    Science.gov (United States)

    Doblas-Miranda, Enrique; Reyes-López, Joaquín

    2008-08-01

    Animals principally forage to try to maximize energy intake per unit of feeding time, developing different foraging strategies. Temperature effects on foraging have been observed in diverse ant species; these effects are limited to the duration of foraging or the number of foragers involved. The harvester ant Messor barbarus L. 1767 has a specialized foraging strategy that consists in the formation of worker trails. Because of the high permeability of their body integument, we presume that the length, shape, and type of foraging trails of M. barbarus must be affected by temperature conditions. From mid-June to mid-August 1999, we tested the effect on these trail characteristics in a Mediterranean forest. We found that thermal stress force ants to use a foraging pattern based on the variation of the workers trail structure. Ants exploit earlier well-known sources using long physical trails, but as temperatures increases throughout the morning, foragers reduce the length of the foraging column gradually, looking for alternative food sources in nonphysical trails. This study shows that animal forage can be highly adaptable and versatile in environments with high daily variations.

  11. Deciphering the complexity of sainfoin (Onobrychis viciifolia) proanthocyanidins by MALDI-TOF mass spectrometry with a judicious choice of isotope patterns and matrixes.

    Science.gov (United States)

    Stringano, Elisabetta; Cramer, Rainer; Hayes, Wayne; Smith, Celia; Gibson, Trevor; Mueller-Harvey, Irene

    2011-06-01

    Use of superdihydroxybenzoic acid as the matrix enabled the analysis of highly complex mixtures of proanthocyanidins from sainfoin (Onobrychis viciifolia) by MALDI-TOF mass spectrometry. Proanthocyanidins contained predominantly B-type homopolymers and heteropolymers up to 12-mers (3400 Da). Use of another matrix, 2,6-dihydroxyacetophenone, revealed the presence of A-type glycosylated dimers. In addition, we report here how a comparison of the isotopic adduct patterns, which resulted from Li and Na salts as MALDI matrix additives, could be used to confirm the presence of A-type linkages in complex proanthocyanidin mixtures. Preliminary evidence suggested the presence of A-type dimers in glycosylated prodelphinidins and in tetrameric procyanidins and prodelphinidins.

  12. Attention in Urban Foraging

    Directory of Open Access Journals (Sweden)

    Malcolm McCullough

    2013-05-01

    Full Text Available This position paper argues how there has to be much more to smart city learning than just wayshowing, and something better as augmented reality than covering the world with instructions. Attention has become something for many people to know better in an age of information superabundance. Embodied cognition explains how the work-ings of attention are not solely a foreground task, as if attention is something to pay. As digital media appear in ever more formats and contexts, their hybrids with physical form increasing influence how habitual engagement with persistent situations creates learning. Ambient information can just add to the distraction by multitasking, or it can support more favorable processes of shifting among different kinds of information with a particular intent. As one word for this latter process, foraging deserves more consideration in smart city learning

  13. Allometry and spatial scales of foraging in mammalian herbivores.

    Science.gov (United States)

    Laca, Emilio A; Sokolow, Susanne; Galli, Julio R; Cangiano, Carlos A

    2010-03-01

    Herbivores forage in spatially complex habitats. Due to allometry and scale-dependent foraging, herbivores are hypothesized to perceive and respond to heterogeneity of resources at scales relative to their body sizes. This hypothesis has not been manipulatively tested for animals with only moderate differences in body size and similar food niches. We compared short-term spatial foraging behavior of two herbivores (sheep and cattle) with similar dietary niche but differing body size. Although intake rates scaled allometrically with body mass (mass(0.75)), spatial foraging strategies substantially differed, with cattle exhibiting a coarser-grained use of the 'foodscape.' Selectivity by cattle (and not sheep) for their preferred food was more restricted when patches were smaller (< 10 m(2)). We conclude that differences in spatial scales of selection offers a plausible mechanism by which species can coexist on shared resources that exhibit multiple scales of spatial heterogeneity.

  14. A Novel Plant Root Foraging Algorithm for Image Segmentation Problems

    Directory of Open Access Journals (Sweden)

    Lianbo Ma

    2014-01-01

    Full Text Available This paper presents a new type of biologically-inspired global optimization methodology for image segmentation based on plant root foraging behavior, namely, artificial root foraging algorithm (ARFO. The essential motive of ARFO is to imitate the significant characteristics of plant root foraging behavior including branching, regrowing, and tropisms for constructing a heuristic algorithm for multidimensional and multimodal problems. A mathematical model is firstly designed to abstract various plant root foraging patterns. Then, the basic process of ARFO algorithm derived in the model is described in details. When tested against ten benchmark functions, ARFO shows the superiority to other state-of-the-art algorithms on several benchmark functions. Further, we employed the ARFO algorithm to deal with multilevel threshold image segmentation problem. Experimental results of the new algorithm on a variety of images demonstrated the suitability of the proposed method for solving such problem.

  15. Foraging decisions, patch use, and seasonality in egrets (Aves: ciconiiformes)

    Science.gov (United States)

    Erwin, R.M.

    1985-01-01

    Feeding snowy (Egretta thula) and great (Casmerodius albus) egrets were observed during 2 breeding seasons in coastal New Jersey and 2 brief winter periods in northeast Florida (USA). A number of tests based on assumptions of foraging models, predictions from foraging theory, and earlier empirical tests concerning time allocation and movement in foraging patches was made. Few of the expectations based on foraging theory and/or assumptions were supported by the empirical evidence. Snowy egrets fed with greater intensity and efficiency during the breeding season (when young were being fed) than during winter. They also showed some tendency to leave patches when their capture rate declined, and they spent more time foraging in patches when other birds were present nearby. Great egrets showed few of these tendencies, although they did leave patches when their intercapture intervals increased. Satiation differences had some influence on feeding rates in snowy egrets, but only at the end of feeding bouts. Some individuals of both species revisited areas in patches that had recently been exploited, and success rates were usually higher after the 2nd visit. Apparently, for predators of active prey, short-term changes in resource availability ('resource depression') may be more important than resource depletion, a common assumption in most optimal foraging theory models.

  16. Root foraging influences plant growth responses to earthworm foraging.

    Directory of Open Access Journals (Sweden)

    Erin K Cameron

    Full Text Available Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L. impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants.

  17. Root foraging influences plant growth responses to earthworm foraging.

    Science.gov (United States)

    Cameron, Erin K; Cahill, James F; Bayne, Erin M

    2014-01-01

    Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L.) impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants.

  18. Behavioural environments and niche construction: the evolution of dim-light foraging in bees.

    Science.gov (United States)

    Wcislo, William T; Tierney, Simon M

    2009-02-01

    Most bees forage for floral resources during the day, but temporal patterns of foraging activity vary extensively, and foraging in dim-light environments has evolved repeatedly. Facultative dim-light foraging behaviour is known in five of nine families of bees, while obligate behaviour is known in four families and evolved independently at least 19 times. The light intensity under which bees forage varies by a factor of 10(8), and therefore the evolution of dim-light foraging represents the invasion of a new, extreme niche. The repeated evolution of dim-light foraging behaviour in bees allows tests of the hypothesis that behaviour acts as an evolutionary pacemaker. With the exception of one species of Apis, facultative dim-light foragers show no external structural traits that are thought to enable visually mediated flight behaviour in low-light environments. By contrast, most obligate dim-light foragers show a suite of convergent optical traits such as enlarged ocelli and compound eyes. In one intensively studied species (Megalopta genalis) these optical changes are associated with neurobiological changes to enhance photon capture. The available ecological evidence suggests that an escape from competition for pollen and nectar resources and avoidance of natural enemies are driving factors in the evolution of obligate dim-light foraging.

  19. The forager oral tradition and the evolution of prolonged juvenility.

    Science.gov (United States)

    Scalise Sugiyama, Michelle

    2011-01-01

    The foraging niche is characterized by the exploitation of nutrient-rich resources using complex extraction techniques that take a long time to acquire. This costly period of development is supported by intensive parental investment. Although human life history theory tends to characterize this investment in terms of food and care, ethnographic research on foraging skill transmission suggests that the flow of resources from old-to-young also includes knowledge. Given the adaptive value of information, parents may have been under selection pressure to invest knowledge - e.g., warnings, advice - in children: proactive provisioning of reliable information would have increased offspring survival rates and, hence, parental fitness. One way that foragers acquire subsistence knowledge is through symbolic communication, including narrative. Tellingly, oral traditions are characterized by an old-to-young transmission pattern, which suggests that, in forager groups, storytelling might be an important means by which adults transfer knowledge to juveniles. In particular, by providing juveniles with vicarious experience, storytelling may expand episodic memory, which is believed to be integral to the generation of possible future scenarios (i.e., planning). In support of this hypothesis, this essay reviews evidence that: mastery of foraging knowledge and skill sets takes a long time to acquire; foraging knowledge is transmitted from parent to child; the human mind contains adaptations specific to social learning; full assembly of learning mechanisms is not complete in early childhood; and forager oral traditions contain a wide range of information integral to occupation of the foraging niche. It concludes with suggestions for tests of the proposed hypothesis.

  20. The forager oral tradition and the evolution of prolonged juvenility

    Directory of Open Access Journals (Sweden)

    Michelle Scalise Sugiyama

    2011-08-01

    Full Text Available The foraging niche is characterized by the exploitation of nutrient-rich resources using complex extraction techniques that take a long time to acquire. This costly period of development is supported by intensive parental investment. Although human life history theory tends to characterize this investment in terms of food and care, ethnographic research on foraging skill transmission suggests that the flow of resources from old to young also includes knowledge. Given the adaptive value of information, parents may have been under selection pressure to invest knowledge—e.g., warnings, advice--in children: proactive provisioning of reliable information would have increased offspring survival rates and, hence, parental fitness. One way that foragers acquire subsistence knowledge is through symbolic communication, including narrative. Tellingly, oral traditions are characterized by an old-to-young transmission pattern, which suggests that, in forager groups, storytelling might be an important means by which adults transfer knowledge to juveniles. In particular, by providing juveniles with vicarious experience, storytelling may expand episodic memory, which is believed to be integral to the generation of possible future scenarios (i.e., planning. In support of this hypothesis, this essay reviews evidence that: mastery of foraging knowledge and skill sets takes a long time to acquire; foraging knowledge is transmitted from parent to child; the human mind contains adaptations specific to social learning; full assembly of learning mechanisms is not complete in early childhood; and forager oral traditions contain a wide range of information integral to occupation of the foraging niche. It concludes with suggestions for tests of the proposed hypothesis.

  1. Information foraging for perceptual decisions.

    Science.gov (United States)

    Ludwig, Casimir J H; Evens, David R

    2017-02-01

    We tested an information foraging framework to characterize the mechanisms that drive active (visual) sampling behavior in decision problems that involve multiple sources of information. Experiments 1 through 3 involved participants making an absolute judgment about the direction of motion of a single random dot motion pattern. In Experiment 4, participants made a relative comparison between 2 motion patterns that could only be sampled sequentially. Our results show that: (a) Information (about noisy motion information) grows to an asymptotic level that depends on the quality of the information source; (b) The limited growth is attributable to unequal weighting of the incoming sensory evidence, with early samples being weighted more heavily; (c) Little information is lost once a new source of information is being sampled; and (d) The point at which the observer switches from 1 source to another is governed by online monitoring of his or her degree of (un)certainty about the sampled source. These findings demonstrate that the sampling strategy in perceptual decision-making is under some direct control by ongoing cognitive processing. More specifically, participants are able to track a measure of (un)certainty and use this information to guide their sampling behavior. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Palatability in sheep and in vitro nutritional value of dried and ensiled sainfoin (Onobrychis viciifolia) birdsfoot trefoil (Lotus corniculatus), and chicory (Cichorium intybus).

    Science.gov (United States)

    Scharenberg, Anna; Arrigo, Yves; Gutzwiller, Andreas; Soliva, Carla R; Wyss, Ueli; Kreuzer, Michael; Dohme, Frigga

    2007-12-01

    Three temperate forages, sainfoin, birdsfoot trefoil, and chicory, characterized by elevated contents of plant secondary compounds, were compared to a ryegrass-clover mixture (control) in dried (Experiment 1) and ensiled form (Experiment 2) in their palatability and nutritional value. Palatability was measured in adult wethers (n = 6) allowed to choose between the familiar control forage and one of the three test plants. Palatability index was calculated from differences in intake of control and test plants measured after given times. Generally at first contact, palatability of the unfamiliar plants was low. Lag time until palatability index approached or exceeded a value of 100 was 2-5 d, but could not be related to the content of condensed tannins. Sainfoin had a high palatability, the highest content of condensed tannins (77.4 +/- 10.23 g/kg DM), a high content of duodenally utilisable crude protein (94.7 +/- 16.87 g/100 g CP), and a high content of metabolizable energy (9.5 +/- 0.38 MJ ME/kg DM), making this plant most promising for various purposes including anthelmintic action.

  3. Does greed help a forager survive?

    Science.gov (United States)

    Bhat, U.; Redner, S.; Bénichou, O.

    2017-06-01

    We investigate the role of greed on the lifetime of a random-walking forager on an initially resource-rich lattice. Whenever the forager lands on a food-containing site, all the food there is eaten and the forager can hop S more steps without food before starving. Upon reaching an empty site, the forager comes one time unit closer to starvation. The forager is also greedy—given a choice to move to an empty or to a food-containing site in its local neighborhood, the forager moves preferentially toward food. Surprisingly, the forager lifetime varies nonmonotonically with greed, with different senses of the nonmonotonicity in one and two dimensions. Also unexpectedly, the forager lifetime in one dimension has a huge peak for very negative greed where the forager is food averse.

  4. [Application and prospect of near infrared reflectance spectroscopy in forage analysis].

    Science.gov (United States)

    Ren, Xiu-Zhen; Guo, Hong-Ru; Jia, Yu-Shan; Ge, Gen-Tu; Wang, Kun

    2009-03-01

    Forage was the material basis of animal husbandry production, and its quality is directly related to the quality of animal products. It was very important to control the forage quality and detect the composition of forage raw materials in forage production. Predication of forage quality was often completed by the traditional and classical methods in the past, which were complex, time consuming and expensive, and could not acquire the nutritional value of forage timely. Near infrared reflectance spectroscopy was a highly efficient and rapid modern analysis technique developed in 1970's. It comprehensively applied the latest research results of computer technique, spectroscopy and chemometrics, and has been widely used in various fields owing to its unique advantages such as being timely, less expensive, non-destructive, and so on. Near infrared reflectance spectroscopy has gained more and more importance though its application to forage analysis was very late. Presently, not only conventional composition (such as moisture, dry matter, crude protein, crude fiber, crude fat, crude ash neutral detergent fiber, acid detergent fiber, etc.), but also non-conventional composition (including minerals, trace elements, enzyme and anti-nutritional factors etc. ) and anti-nutritional factors in forage were determined by means of near infrared reflectance spectroscopy. Testing and analyzing the conventional composition in forage was the traditional applied field of near infrared reflectance spectroscopy, a lot of studies of which were done and it has already been one of the standard methods of testing the conventional composition. Forage bioavaibility was also evaluated by near infrared reflectance spectroscopy, so as to assess the utilization rate and nutritional value of forage. Moreover, near infrared spectroscopy could be used successfully to predict the botanical composition in grassland and leaf/stem ratios. Near infrared spectroscopy technique and its application and

  5. Investigation of sainfoin (Onobrychis viciifolia) cultivar differences on nitrogen balance and fecal egg count in artificially infected lambs.

    Science.gov (United States)

    Azuhnwi, B N; Hertzberg, H; Arrigo, Y; Gutzwiller, A; Hess, H D; Mueller-Harvey, I; Torgerson, P R; Kreuzer, M; Dohme-Meier, F

    2013-05-01

    Research in ruminant nutrition and helminth control with forages, which contain condensed tannins (CT), suggests that varying responses may depend not only on CT concentration but also on CT composition. An experiment was designed to test this by feeding 2 dried sainfoin cultivars (Visnovsky and Perly), which differed in CT properties, to lambs that were artificially infected with the abomasal blood-sucking nematode Haemonchus contortus. Twenty-four infected lambs received 1 of these 2 cultivars; the feeds were either untreated or treated with the CT-binding polyethylene glycol over 4 wk (n = 6). The 2 cultivars were also fed to 2 × 6 uninfected lambs. Nutrient digestibility, N balance, ADG, plasma urea, together with indicators of infection [fecal egg count (FEC), abomasal worm count, per capita female fecundity, erythrocytic indices, and serum protein], were determined. The specific effects of sainfoin cultivar, CT, and infection were evaluated by contrast analysis. Digestibility of both NDF and ADF were less (P < 0.001) with Perly compared with Visnovsky. The apparent nutrient digestibility was reduced (P < 0.001) by CT. However, no clear cultivar effects were evident on N excretion and retention. Condensed tannins reduced (P = 0.05) body N retention and shifted (P < 0.001) N excretion from urine to feces. Unlike cultivar and CT, infection decreased (P = 0.002) ADG. Plasma urea concentration was decreased (P = 0.007) in Perly- compared with Visnovsky-fed lambs and was decreased (P < 0.001) by CT. Plasma concentrations of essential and semiessential AA were increased (P < 0.001) by CT. The groups of infected lambs did not clearly differ in abomasal worm counts and erythrocytic indicators. In the last 2 to 3 wk of the experiment, FEC was decreased (P ≤ 0.01) when feeding CT. The lack of substantial cultivar effects suggests that the differences in CT properties may have been too small to result in nutritional and anthelmintic effects. The present results

  6. In vivo effects of Sainfoin (Onobrychis viciifolia) on parasitic nematodes in calves

    DEFF Research Database (Denmark)

    Desrues, Olivier; Peña-Espinoza, Miguel; Hansen, Tina Vicky Alstrup

    2014-01-01

    Sainfoin is a fodder legume containing condensed tannins known to improve protein self-sufficiency, animal health and environment. In addition, anthelmintic effects have been demonstrated in vitro against cattle nematodes, and in vivo against nematodes of small ruminants, but in vivo effects...... against gastro-intestinal parasites (GIN) of cattle still remains to be proven. Thus, the aim of the present investigation was to determine the in vivo effects of sainfoin against the most important trichostrongylids of cattle the brown stomach worm Ostertagia ostertagi, and the intestinal worm Cooperia...... oncophora. Jersey male calves (2-4 months) reared indoor and GIN naive, were stratified for live weight and randomly allocated into a test group (SF; n=9) which was fed 80% sainfoin (cv. Perly) pellets and hay, and a control group (CO; n=6) fed hay and compound feed. Daily intake was monitored and protein...

  7. Forage crops as substrate for animal feed and ethanol production in ...

    African Journals Online (AJOL)

    Five forage crops, namely ruzi (Brachiaria ruziziensis), purple guinea (Panicum maximum), atratum (Paspalum atratum), plicatulum (Paspalum plicatulum), and rhodes grass (Chloris gayana), were experimented for their possibility of ethanol and animal feed utilization. All tested forage crops were harvested 45 and 75 days ...

  8. Foraging site choice and diet selection of Meadow Pipits Anthus pratensis breeding on grazed salt marshes

    NARCIS (Netherlands)

    van Klink, Roel; Mandema, Freek S.; Bakker, Jan P.; Tinbergen, Joost M.

    2014-01-01

    Capsule Breeding Meadow Pipits foraged for caterpillars and large spiders in vegetation that was less heterogeneous than vegetation at random locations.Aims To gain a better understanding of the foraging ecology of breeding Meadow Pipits on grazed coastal salt marshes, we tested three hypotheses:

  9. Foraging and public information use in common pipistrelle bats (Pipistrellus pipistrellus): a field experiment

    NARCIS (Netherlands)

    Jonker, M.N.; Boer, de W.F.; Kurvers, R.H.J.M.; Dekker, J.J.A.

    2010-01-01

    Decision making by animals is likely to be influenced strongly by the behaviour of conspecifics. In this study we tested whether public information affected the foraging behaviour of common pipistrelles (Pipistrellus pipistrellus) by manipulating public information about the quality of foraging

  10. Green manure and forage potential of lablab in the U.S. southern plains

    Science.gov (United States)

    Current perennial summer forages available to support grazing by yearling cattle in the U.S. southern Great Plains have mid-July through September quality gaps. This study tested the function of the tropical/subtropical legume lablab [Lablab purpureus (L.)Sweet]as green manure or forage in central O...

  11. To walk or to fly? How birds choose among foraging modes

    NARCIS (Netherlands)

    Bautista, LM; Tinbergen, J; Kacelnik, A; Bautista, Luis M.; Southwood, Richard

    2001-01-01

    We test the predictive value of the main energetic currencies used in foraging theory using starlings that choose between two foraging modes (walking versus flying). Walking is low-cost, low-yield, whereas flying is the opposite. We fixed experimentally, at 11 different values, the amount of flight

  12. Foraging behavior and physiological changes in precocial quail chicks in response to low temperatures

    NARCIS (Netherlands)

    Krijgsveld, KL; Visser, GH; Daan, S

    We examined whether low ambient temperatures influence foraging behavior of precocial Japanese quail chicks and alter the balance between investment in growth and thermogenic function. To test this, one group of chicks was exposed to 7 degreesC and one group to 24 degreesC during foraging throughout

  13. Physiological responses of the M1sainfoin (Onobrychis viciifolia Scop) plants to gamma radiation.

    Science.gov (United States)

    Beyaz, Ramazan; Sancak, Cengiz; Yildiz, Çiğdem; Kuşvuran, Şebnem; Yildiz, Mustafa

    2016-12-01

    Effects of gamma radiation on physiological responses of the M 1 sainfoin plants were investigated. Seeds of sainfoin ecotype 'Koçaş' were exposed to 0, 400, 500 and 600Gy from a 6 0 Co source at a dose rate of 0.483 kGyh -1 . Irradiated and unirradiated seeds were sown into culture vessels containing MS-basal medium to be cultured for 30 days under in vitro conditions. At the end of this period, seedlings, which germinated from the radiated and unirradiated seeds, were transferred into pots in a growth chamber for 30 days more. Chlorophyll contents, activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as contents of monodehydroascorbate reductase (MDA) and proline were examined in unirradiated and irradiated 60-day-old seedlings. Overall, the activities of the antioxidant enzymes (SOD, CAT and GR) and contents of chlorophyll and proline in the leaves tended to increase after irradiation in a dose-dependent manner. By contrast, the activity of APX decreased. The lipid peroxidation characterized by the MDA content remained unchanged, except after irradiation to 500Gy. The highest CAT activity and the highest proline content were observed after irradiation to the highest dose of 600Gy. The highest SOD and GR activities were observed after irradiation to the lowest tested dose of 400Gy. This is the first study that provided basic information on the impact of gamma radiation on physiological responses of sainfoin and its radiosensitivity. These findings will be useful in development of a mutation breeding program of sainfoin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Foraging task specialisation and foraging labour allocation in stingless bees

    NARCIS (Netherlands)

    Hofstede, Frouke Elisabeth

    2006-01-01

    Social bees collect nectar and pollen from flowering plants for energy of the adult bees and for feeding the larvae in the colony. The flowering patterns of plants imply that periods of high food availability are often followed by periods of meagre foraging conditions. Being dependent on such a

  15. Bumblebee foraging rhythms under the midnight sun measured with radiofrequency identification

    Directory of Open Access Journals (Sweden)

    Chittka Lars

    2010-06-01

    Full Text Available Abstract Background In the permanent daylight conditions north of the Arctic circle, there is a unique opportunity for bumblebee foragers to maximise intake, and therefore colony growth, by remaining active during the entire available 24-h period. We tested the foraging rhythms of bumblebee (Bombus terrestris and B. pascuorum colonies in northern Finland during the summer, when the sun stays above the horizon for weeks. We used fully automatic radio-frequency identification to monitor the foraging activity of more than 1,000 workers and analysed their circadian foraging rhythms. Results Foragers did not use the available 24-h foraging period but exhibited robust diurnal rhythms instead. A mean of 95.2% of the tested B. terrestris workers showed robust diurnal rhythms with a mean period of 23.8 h. Foraging activity took place mainly between 08:00 and 23:00, with only low or almost no activity during the rest of the day. Activity levels increased steadily during the morning, reached a maximum around midday and decreased again during late afternoon and early evening. Foraging patterns of native B. pascuorum followed the same temporal organisation, with the foraging activity being restricted to the period between 06:00 and 22:00. Conclusions The results of the present study indicate that the circadian clock of the foragers must have been entrained by some external cue, the most prominent being daily cycles in light intensity and temperature. Daily fluctuations in the spectral composition of light, especially in the UV range, could also be responsible for synchronising the circadian clock of the foragers under continuous daylight conditions.

  16. Forage evaluation by analysis after

    African Journals Online (AJOL)

    by forages, can be estimated by amino acid analysis of the products of fermentation in vitro. Typical results of such analyses are presented in Table 1. These results indicate that .... Figure 1 The correlation between digestion of dry matter in vitro and in vitro yield of VFA from six grass species, different extents of digestion.

  17. SOCIAL COMPLEXITY AND LEARNING FORAGING TASKS IN BEES

    Directory of Open Access Journals (Sweden)

    AMAYA-MÁRQUEZ MARISOL

    2008-12-01

    Full Text Available Social complexity and models concerning central place foraging were tested with respect to learning predictions using the social honey bee (Apis mellifera and solitary blue orchard bee (Osmia lignaria when given foraging problems. Both species were presented the same foraging problems, where 1 only reward molarity varied between flower morphs, and 2 only reward volume varied between flower morphs. Experiments utilized blue vs. white flower patches to standardize rewards in each experimental situation. Although honey bees learned faster than blue orchard bees when given a molarity difference reward problem, there was no significant difference in learning rate when presented a volume difference reward problem. Further, the rate at which blue orchard bees learned the volume difference problem was not significantly different from that with which honey bees learned about reward molarity differences. The results do not support the predictions of the social complexity theory, but do support those of the central place model

  18. Complex scaling behavior in animal foraging patterns

    Science.gov (United States)

    Premachandra, Prabhavi Kaushalya

    This dissertation attempts to answer questions from two different areas of biology, ecology and neuroscience, using physics-based techniques. In Section 2, suitability of three competing random walk models is tested to describe the emergent movement patterns of two species of primates. The truncated power law (power law with exponential cut off) is the most suitable random walk model that characterizes the emergent movement patterns of these primates. In Section 3, an agent-based model is used to simulate search behavior in different environments (landscapes) to investigate the impact of the resource landscape on the optimal foraging movement patterns of deterministic foragers. It should be noted that this model goes beyond previous work in that it includes parameters such as spatial memory and satiation, which have received little consideration to date in the field of movement ecology. When the food availability is scarce in a tropical forest-like environment with feeding trees distributed in a clumped fashion and the size of those trees are distributed according to a lognormal distribution, the optimal foraging pattern of a generalist who can consume various and abundant food types indeed reaches the Levy range, and hence, show evidence for Levy-flight-like (power law distribution with exponent between 1 and 3) behavior. Section 4 of the dissertation presents an investigation of phase transition behavior in a network of locally coupled self-sustained oscillators as the system passes through various bursting states. The results suggest that a phase transition does not occur for this locally coupled neuronal network. The data analysis in the dissertation adopts a model selection approach and relies on methods based on information theory and maximum likelihood.

  19. Multimodal Floral Signals and Moth Foraging Decisions

    Science.gov (United States)

    Riffell, Jeffrey A.; Alarcón, Ruben

    2013-01-01

    Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as

  20. The Role of Semantic Clustering in Optimal Memory Foraging

    Science.gov (United States)

    Montez, Priscilla; Thompson, Graham; Kello, Christopher T.

    2015-01-01

    Recent studies of semantic memory have investigated two theories of optimal search adopted from the animal foraging literature: Lévy flights and marginal value theorem. Each theory makes different simplifying assumptions and addresses different findings in search behaviors. In this study, an experiment is conducted to test whether clustering in…

  1. the chentical composition and in vitro digestibility of forage samples ...

    African Journals Online (AJOL)

    determined in conventional digestion trials. However, di- gestion trials with animals are laborious and time con- suming. The in vitro fermentation technique introduced by. Tilley & Terry (1963), showed much promise for the pre- diction of the actual digestibility of forages. This tech- nique was tested with 59 South African ...

  2. Root foraging theory put to the test

    NARCIS (Netherlands)

    Kroon, de H.; Mommer, L.

    2006-01-01

    Roots have a tremendous plasticity that has long fascinated plant scientists. Root proliferation into enriched soil patches is commonly considered as a way for plants to acquire patchily distributed soil resources. In a recent synthetic study involving the responses of over 100 species, Kembel and

  3. Corn in consortium with forages

    Directory of Open Access Journals (Sweden)

    Cássia Maria de Paula Garcia

    2013-12-01

    Full Text Available The basic premises for sustainable agricultural development with focus on rural producers are reducing the costs of production and aggregation of values through the use crop-livestock system (CLS throughout the year. The CLS is based on the consortium of grain crops, especially corn with tropical forages, mainly of the genus Panicum and Urochloa. The study aimed to evaluate the grain yield of irrigated corn crop intercropped with forage of the genus Panicum and Urochloa. The experiment was conducted at the Fazenda de Ensino, Pesquisa e Extensão – FEPE  of the Faculdade de Engenharia - UNESP, Ilha Solteira in an Oxisol in savannah conditions and in the autumn winter of 2009. The experimental area was irrigated by a center pivot and had a history of no-tillage system for 8 years. The corn hybrid used was simple DKB 390 YG at distances of 0.90 m. The seeds of grasses were sown in 0.34 m spacing in the amount of 5 kg ha-1, they were mixed with fertilizer minutes before sowing  and placed in a compartment fertilizer seeder and fertilizers were mechanically deposited in the soil at a depth of 0.03 m. The experimental design used was a randomized block with four replications and five treatments: Panicum maximum cv. Tanzania sown during the nitrogen fertilization (CTD of the corn; Panicum maximum cv. Mombaça sown during the nitrogen fertilization (CMD of the corn; Urochloa brizantha cv. Xaraés sown during the occasion of nitrogen fertilization (CBD of the corn; Urochloa ruziziensis cv. Comumsown during the nitrogen fertilization (CRD of the corn and single corn (control. The production components of corn: plant population per hectare (PlPo, number of ears per hectare (NE ha-1, number of rows per ear (NRE, number of kernels per row on the cob (NKR, number of grain in the ear (NGE and mass of 100 grains (M100G were not influenced by consortium with forage. Comparing grain yield (GY single corn and maize intercropped with forage of the genus Panicum

  4. Effect of forage type with or without corn supplementation on animal performance, beef fatty acid composition, and palatability.

    Science.gov (United States)

    Wright, A M; Andrae, J G; Rosso, C Fernandez; Miller, M C; Pavan, E; Bridges, W; Duckett, S K

    2015-10-01

    Thirty-two steers were used to examine forage type (legumes [ and ] vs. grasses [ and ]) with or without individual corn grain supplementation (0 vs. 0.75% of live weight [LW]/d) on beef fatty acid composition and palatability. In each year, steers ( = 16/yr) were randomly assigned to forage type ( = 8/forage type per yr) and to supplementation treatments within forage type ( = 4/supplementation treatment/forage type per yr). Forage types (grasses vs. legumes) were replicated in 2 paddocks of perennial and annual forage type pastures. A mixed model was developed with forage type, corn grain supplementation, and the 2-way interaction as fixed effects and 2 different error terms, one for testing forage and another for testing grain supplement and grain supplement × forage interaction. Corn grain supplementation increased ( = 0.01) ADG by 0.29 kg/d and final LW by 13 kg. Hot carcass weight, dressing percentage (DP), and KPH were greater ( forage types; however, the magnitude of this reduction was greater for legumes than for grasses. The ratio of -6 to -3 PUFA was greater ( = 0.03) in the LM of corn grain-supplemented steers than in the LM of nonsupplemented steers. Supplementation of corn grain decreased ( 0.05) by forage type, supplementation, or the 2-way interaction. Beef finished on legumes had greater concentrations of -3 PUFA, whereas beef supplemented with corn grain had a greater ratio of -6 to -3 fatty acids. On a gravimetric basis (mg/100 g LM), -3 PUFA and CLA contents were not altered with supplementation, indicating that corn grain can be supplemented at this level in a forage-finishing beef system without negative consequences on perceived beneficial fatty acids.

  5. To walk or to fly? How birds choose among foraging modes.

    Science.gov (United States)

    Bautista, L M; Tinbergen, J; Kacelnik, A

    2001-01-30

    We test the predictive value of the main energetic currencies used in foraging theory using starlings that choose between two foraging modes (walking versus flying). Walking is low-cost, low-yield, whereas flying is the opposite. We fixed experimentally, at 11 different values, the amount of flight required to get one food reward, and for each flight cost value, we titrated the amount of walking until the birds showed indifference between foraging modes. We then compared the indifference points to those predicted by gross rate of gain over time, net rate of gain over time, and the ratio of gain to expenditure (efficiency). The results for the choice between modes show strong qualitative and quantitative support for net rate of gain over time over the alternatives. However, the birds foraged for only a fraction of the available time, indicating that the choice between foraging and resting could not be explained by any of these currencies. We suggest that this discrepancy could be accounted for functionally because nonenergetic factors such as predation risk may differ between resting and foraging in any mode but may not differ much between foraging modes, hence releasing the choice between foraging modes from the influence of such factors. Alternatively, the discrepancy may be attributable to the use of predictable (rather than stochastic) ratios of effort per prey in our experiment, and it may thus be better understood with mechanistic rather than functional arguments.

  6. Foraging decisions in wild versus domestic Mus musculus: What does life in the lab select for?

    Science.gov (United States)

    Troxell-Smith, Sandra M; Tutka, Michal J; Albergo, Jessica M; Balu, Deebika; Brown, Joel S; Leonard, John P

    2016-01-01

    What does domestication select for in terms of foraging and anti-predator behaviors? We applied principles of patch use and foraging theory to test foraging strategies and fear responses of three strains of Mus musculus: wild-caught, control laboratory, and genetically modified strains. Foraging choices were quantified using giving-up densities (GUDs) under three foraging scenarios: (1) patches varying in microhabitat (covered versus open), and initial resource density (low versus high); (2) daily variation in auditory cues (aerial predators and control calls); (3) patches with varying seed aggregations. Overall, both domestic strains harvested significantly more food than wild mice. Each strain revealed a significant preference for foraging under cover compared to the open, and predator calls had no detectable effects on foraging. Both domestic strains biased their harvest toward high quality patches; wild mice did not. In terms of exploiting favorable and avoiding unfavorable distributions of seeds within patches, the lab strain performed best, the wild strain worst, and the mutant strain in between. Our study provides support for hypothesis that domestic animals have more energy-efficient foraging strategies than their wild counterparts, but retain residual fear responses. Furthermore, patch-use studies can reveal the aptitudes and priorities of both domestic and wild animals. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Fast learning in free-foraging bumble bees is negatively correlated with lifetime resource collection.

    Science.gov (United States)

    Evans, Lisa J; Smith, Karen E; Raine, Nigel E

    2017-03-29

    Despite widespread interest in the potential adaptive value of individual differences in cognition, few studies have attempted to address the question of how variation in learning and memory impacts their performance in natural environments. Using a novel split-colony experimental design we evaluated visual learning performance of foraging naïve bumble bees (Bombus terrestris) in an ecologically relevant associative learning task under controlled laboratory conditions, before monitoring the lifetime foraging performance of the same individual bees in the field. We found appreciable variation among the 85 workers tested in both their learning and foraging performance, which was not predicted by colony membership. However, rather than finding that foragers benefited from enhanced learning performance, we found that fast and slow learners collected food at comparable rates and completed a similar number of foraging bouts per day in the field. Furthermore, bees with better learning abilities foraged for fewer days; suggesting a cost of enhanced learning performance in the wild. As a result, slower learning individuals collected more resources for their colony over the course of their foraging career. These results demonstrate that enhanced cognitive traits are not necessarily beneficial to the foraging performance of individuals or colonies in all environments.

  8. Winter active bumblebees (Bombus terrestris achieve high foraging rates in urban Britain.

    Directory of Open Access Journals (Sweden)

    Ralph J Stelzer

    Full Text Available BACKGROUND: Foraging bumblebees are normally associated with spring and summer in northern Europe. However, there have been sightings of the bumblebee Bombus terrestris during the warmer winters in recent years in southern England. But what floral resources are they relying upon during winter and how much winter forage can they collect? METHODOLOGY/PRINCIPAL FINDINGS: To test if urban areas in the UK provide a rich foraging niche for bees we set up colonies of B. terrestris in the field during two late winter periods (2005/6 & 2006/7 in London, UK, and measured their foraging performance. Fully automatic radio-frequency identification (RFID technology was used in 2006/7 to enable us to record the complete foraging activity of individually tagged bees. The number of bumblebees present during winter (October 2007 to March 2008 and the main plants they visited were also recorded during transect walks. Queens and workers were observed throughout the winter, suggesting a second generation of bee colonies active during the winter months. Mass flowering shrubs such as Mahonia spp. were identified as important food resources. The foraging experiments showed that bees active during the winter can attain nectar and pollen foraging rates that match, and even surpass, those recorded during summer. CONCLUSIONS/SIGNIFICANCE: B. terrestris in the UK are now able to utilise a rich winter foraging resource in urban parks and gardens that might at present still be under-exploited, opening up the possibility of further changes in pollinator phenology.

  9. Winter active bumblebees (Bombus terrestris) achieve high foraging rates in urban Britain.

    Science.gov (United States)

    Stelzer, Ralph J; Chittka, Lars; Carlton, Marc; Ings, Thomas C

    2010-03-05

    Foraging bumblebees are normally associated with spring and summer in northern Europe. However, there have been sightings of the bumblebee Bombus terrestris during the warmer winters in recent years in southern England. But what floral resources are they relying upon during winter and how much winter forage can they collect? To test if urban areas in the UK provide a rich foraging niche for bees we set up colonies of B. terrestris in the field during two late winter periods (2005/6 & 2006/7) in London, UK, and measured their foraging performance. Fully automatic radio-frequency identification (RFID) technology was used in 2006/7 to enable us to record the complete foraging activity of individually tagged bees. The number of bumblebees present during winter (October 2007 to March 2008) and the main plants they visited were also recorded during transect walks. Queens and workers were observed throughout the winter, suggesting a second generation of bee colonies active during the winter months. Mass flowering shrubs such as Mahonia spp. were identified as important food resources. The foraging experiments showed that bees active during the winter can attain nectar and pollen foraging rates that match, and even surpass, those recorded during summer. B. terrestris in the UK are now able to utilise a rich winter foraging resource in urban parks and gardens that might at present still be under-exploited, opening up the possibility of further changes in pollinator phenology.

  10. Food availability and foraging near human developments by black bears

    Science.gov (United States)

    Merkle, Jerod A.; Robinson, Hugh S.; Krausman, Paul R.; Alaback, Paul B.

    2013-01-01

    Understanding the relationship between foraging ecology and the presence of human-dominated landscapes is important, particularly for American black bears (Ursus americanus), which sometimes move between wildlands and urban areas to forage. The food-related factors influencing this movement have not been explored, but can be important for understanding the benefits and costs to black bear foraging behavior and the fundamental origins of bear conflicts. We tested whether the scarcity of wildland foods or the availability of urban foods can explain when black bears forage near houses, examined the extent to which male bears use urban areas in comparison to females, and identified the most important food items influencing bear movement into urban areas. We monitored 16 collared black bears in and around Missoula, Montana, during 2009 and 2010, while quantifying the rate of change in green vegetation and the availability of 5 native berry-producing species outside the urban area, the rate of change in green vegetation, and the availability of apples and garbage inside the urban area. We used parametric time-to-event models in which an event was a bear location collected within 100 m of a house. We also visited feeding sites located near houses and quantified food items bears had eaten. The probability of a bear being located near a house was 1.6 times higher for males, and increased during apple season and the urban green-up. Fruit trees accounted for most of the forage items at urban feeding sites (49%), whereas wildland foods composed garbage in influencing when bears forage near houses.

  11. Adapting forage to changing needs

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, N.

    1978-09-01

    The Comarca Lagunera in northern Mexico is the principal center of milk production in that country. Water shortages are becoming more critical each year. A main research effort is directed toward increasing the efficiency of use of the available water. Considerable success has been achieved with the introduction of a winter-growing annual, Italian ryegrass (Lolium multiflorum). Its potential yield reaches three-quarters that of alfalfa, but it requires only a quarter to a third of the water. This species has the added advantage that it leaves the land and the water free for summer-growing annuals that are more efficient in their water use than alfalfa. The net result is a forage production sequence that provides more feed at a lower water cost per unit of forage produced.

  12. Starvation dynamics of a greedy forager

    Science.gov (United States)

    Bhat, U.; Redner, S.; Bénichou, O.

    2017-07-01

    We investigate the dynamics of a greedy forager that moves by random walking in an environment where each site initially contains one unit of food. Upon encountering a food-containing site, the forager eats all the food there and can subsequently hop an additional S steps without food before starving to death. Upon encountering an empty site, the forager goes hungry and comes one time unit closer to starvation. We investigate the new feature of forager greed; if the forager has a choice between hopping to an empty site or to a food-containing site in its nearest neighborhood, it hops preferentially towards food. If the neighboring sites all contain food or are all empty, the forager hops equiprobably to one of these neighbors. Paradoxically, the lifetime of the forager can depend non-monotonically on greed, and the sense of the non-monotonicity is opposite in one and two dimensions. Even more unexpectedly, the forager lifetime in one dimension is substantially enhanced when the greed is negative; here the forager tends to avoid food in its local neighborhood. We also determine the average amount of food consumed at the instant when the forager starves. We present analytic, heuristic, and numerical results to elucidate these intriguing phenomena.

  13. Geographic profiling and animal foraging.

    Science.gov (United States)

    Le Comber, Steven C; Nicholls, Barry; Rossmo, D Kim; Racey, Paul A

    2006-05-21

    Geographic profiling was originally developed as a statistical tool for use in criminal cases, particularly those involving serial killers and rapists. It is designed to help police forces prioritize lists of suspects by using the location of crime scenes to identify the areas in which the criminal is most likely to live. Two important concepts are the buffer zone (criminals are less likely to commit crimes in the immediate vicinity of their home) and distance decay (criminals commit fewer crimes as the distance from their home increases). In this study, we show how the techniques of geographic profiling may be applied to animal data, using as an example foraging patterns in two sympatric colonies of pipistrelle bats, Pipistrellus pipistrellus and P. pygmaeus, in the northeast of Scotland. We show that if model variables are fitted to known roost locations, these variables may be used as numerical descriptors of foraging patterns. We go on to show that these variables can be used to differentiate patterns of foraging in these two species.

  14. Foraging patterns in online searches

    Science.gov (United States)

    Wang, Xiangwen; Pleimling, Michel

    2017-03-01

    Nowadays online searches are undeniably the most common form of information gathering, as witnessed by billions of clicks generated each day on search engines. In this work we describe online searches as foraging processes that take place on the semi-infinite line. Using a variety of quantities like probability distributions and complementary cumulative distribution functions of step length and waiting time as well as mean square displacements and entropies, we analyze three different click-through logs that contain the detailed information of millions of queries submitted to search engines. Notable differences between the different logs reveal an increased efficiency of the search engines. In the language of foraging, the newer logs indicate that online searches overwhelmingly yield local searches (i.e., on one page of links provided by the search engines), whereas for the older logs the foraging processes are a combination of local searches and relocation phases that are power law distributed. Our investigation of click logs of search engines therefore highlights the presence of intermittent search processes (where phases of local explorations are separated by power law distributed relocation jumps) in online searches. It follows that good search engines enable the users to find the information they are looking for through a local exploration of a single page with search results, whereas for poor search engine users are often forced to do a broader exploration of different pages.

  15. Foraging pattern, colony distribution, and foraging range of the Florida harvester ant, Pogonomyrmex badius

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.S. (Savannah River Ecology Laboratory); Gentry, J.B.; Aiken, S.C.

    1981-12-01

    This report describes the foraging pattern of the Florida harvester ant Pogonomyrmex badius in a high-density population of colonies. The foraging pattern has both promoted and been influenced by the colony distribution. Pogonomyrmex badius forages from short trails which extend into a surrounding foraging range. Direction of foraging trails is influenced by the location of a colony's near neighbors. Seasonal nest relocations always occur along a foraging trail, usually the main trail. Foraging ranges are not actively defended, but are used almost exclusively by foragers from a single colony. Foraging ranges will be extended into an area abandoned by neighboring foragers, indicating that forager presence may define each colony's range. Colony distribution has remained essentially the same for several years, despite seasonal nest relocations and addition of new colonies. Establishment of trails and exclusive foraging ranges by each colony minimizes encounters with neighboring foragers and guarantees access to available resources; this pattern also promotes maintenance of the existing colony distribution and partitioning of resources.

  16. Foraging pattern, colony distribution, and foraging range of the Florida harvester ant Pogonomyrmex badius

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.S.; Gentry, J.B.

    1981-12-01

    This report describes the foraging pattern of the Florida harvester ant Pogonomyrmex badius in a high-density population of colonies. The foraging pattern has both promoted and been influenced by the colony distribution. Pogonomyrmex badius forages from short trails which extend into a surrounding foraging range. Direction of foraging trails is influenced by the location of a colony's near neighbors. Seasonal nest relocations always occur along a foraging trail, usually the main trail. Foraging ranges are not actively defended, but are used almost exclusively by foragers from a single colony. Foraging ranges will be extended into an area abondoned by neighboring foragers, indicating that forager presence may define each colony's range. Colony distribution has remained essentially the same for several years, despite seasonal nest relocations and addition of new colonies. Establishment of trails and exclusive foraging ranges by each colony minimizes encounters with neighboring foragers and guarantees access to available resources; this pattern also pomotes maintenance of the existing colony distribution and partitioning of resources.

  17. Horse owners to learn about forage and grazing management during 2008 forage conference

    OpenAIRE

    Greiner, Lori A.

    2007-01-01

    Virginia Cooperative Extension and the Virginia Forage and Grassland Council will explore how horse owners can maintain a healthy animal, pasture, and environment at this year's equine forage conference, Feb. 11-13.

  18. The function of roll in foraging behaviour of sperm whales

    OpenAIRE

    Hartvig, Eva Christel

    2011-01-01

    Though direct experiments to test echolocation in sperm whales (Physeter macrocephalus) remain impossible, the indirect evidence is overwhelming that one function of their clicks is echolocation used during foraging, as has been shown for other toothed whales. In this thesis, the aim was to test: 1) the hypothesis by Fristrup and Harbison (2002) that the sperm whale might be using downwelling light during the day to spot prey or prey patches as silhouettes against the lighter s...

  19. Flexible foraging tactics by a large opportunistic seabird preying on forage- and large pelagic fishes

    OpenAIRE

    Montevecchi, W. A.; Benvenuti, S.; Garthe, Stefan; Davoren, G. K.; Fifield, D.

    2009-01-01

    Generalist and opportunistic marine predators use flexible foraging behaviour to exploit prey bases that change in diversity and spatial and temporal distributions, Behavioural flexibility is constrained by characteristics Such as individual cognitive and physical capabilities, age, reproductive condition and central place foraging. To assess flexibility in the foraging tactics of a marine bird, we investigated the diets and foraging behaviour of the largest seabird predator in the North Atla...

  20. Developing Cyber Foraging Applications for Portable Devices

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Bouvin, Niels Olof

    2008-01-01

    This paper presents the Locusts cyber foraging framework. Cyber foraging is the opportunistic use of computing resources available in the nearby environment, and using such resources thus fall into the category of distributed computing. Furthermore, for the resources to be used efficiently......, parallel computing techniques must also be employed. Distributed and parallel computing are two concepts that are both notoriously known for being very hard for developers to grasp. Because of this one might think that techniques such as cyber foraging would have a hard time surviving outside of research...... environments. In this paper a framework is presented that has special focus on making cyber foraging accessible for all developers....

  1. Social foraging with partial (public) information.

    Science.gov (United States)

    Mann, Ofri; Kiflawi, Moshe

    2014-10-21

    Group foragers can utilize public information to better estimate patch quality and arrive at more efficient patch-departure rules. However, acquiring such information may come at a cost; e.g. reduced search efficiency. We present a Bayesian group-foraging model in which social foragers do not require full awareness of their companions' foraging success; only of their number. In our model, patch departure is based on direct estimates of the number of remaining items. This is achieved by considering all likely combinations of initial patch-quality and group foraging-success; given the individual forager's experience within the patch. Slower rates of information-acquisition by our 'partially-aware' foragers lead them to over-utilize poor patches; more than fully-aware foragers. However, our model suggests that the ensuing loss in long-term intake-rates can be matched by a relatively low cost to the acquisition of full public information. In other words, we suggest that group-size offers sufficient information for optimal patch utilization by social foragers. We suggest, also, that our model is applicable to other situations where resources undergo 'background depletion', which is coincident but independent of the consumer's own utilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. U.S. DAIRY FORAGE RESEARCH CENTER

    Data.gov (United States)

    Federal Laboratory Consortium — Vision: Leading the world in integrated dairy forage systems research. Mission: Providing dairy industry solutions for food security, environmental sustainability,...

  3. U.S. Dairy Forage Research Center

    Data.gov (United States)

    Federal Laboratory Consortium — Vision: Leading the world in integrated dairy forage systems research. Mission: Providing dairy industry solutions for food security, environmental sustainability,...

  4. A neural coding scheme reproducing foraging trajectories

    Science.gov (United States)

    Gutiérrez, Esther D.; Cabrera, Juan Luis

    2015-12-01

    The movement of many animals may follow Lévy patterns. The underlying generating neuronal dynamics of such a behavior is unknown. In this paper we show that a novel discovery of multifractality in winnerless competition (WLC) systems reveals a potential encoding mechanism that is translatable into two dimensional superdiffusive Lévy movements. The validity of our approach is tested on a conductance based neuronal model showing WLC and through the extraction of Lévy flights inducing fractals from recordings of rat hippocampus during open field foraging. Further insights are gained analyzing mice motor cortex neurons and non motor cell signals. The proposed mechanism provides a plausible explanation for the neuro-dynamical fundamentals of spatial searching patterns observed in animals (including humans) and illustrates an until now unknown way to encode information in neuronal temporal series.

  5. Spatial organization and interactions of harvester ants during foraging activity.

    Science.gov (United States)

    Davidson, Jacob D; Gordon, Deborah M

    2017-10-01

    Local interactions, when individuals meet, can regulate collective behaviour. In a system without any central control, the rate of interaction may depend simply on how the individuals move around. But interactions could in turn influence movement; individuals might seek out interactions, or their movement in response to interaction could influence further interaction rates. We develop a general framework to address these questions, using collision theory to establish a baseline expected rate of interaction based on proximity. We test the models using data from harvester ant colonies. A colony uses feedback from interactions inside the nest to regulate foraging activity. Potential foragers leave the nest in response to interactions with returning foragers with food. The time series of interactions and local density of ants show how density hotspots lead to interactions that are clustered in time. A correlated random walk null model describes the mixing of potential and returning foragers. A model from collision theory relates walking speed and spatial proximity with the probability of interaction. The results demonstrate that although ants do not mix homogeneously, trends in interaction patterns can be explained simply by the walking speed and local density of surrounding ants. © 2017 The Author(s).

  6. Optimal foraging, not biogenetic law, predicts spider orb web allometry

    Science.gov (United States)

    Gregorič, Matjaž; Kiesbüy, Heine C.; Quiñones Lebrón, Shakira G.; Rozman, Alenka; Agnarsson, Ingi; Kuntner, Matjaž

    2013-03-01

    The biogenetic law posits that the ontogeny of an organism recapitulates the pattern of evolutionary changes. Morphological evidence has offered some support for, but also considerable evidence against, the hypothesis. However, biogenetic law in behavior remains underexplored. As physical manifestation of behavior, spider webs offer an interesting model for the study of ontogenetic behavioral changes. In orb-weaving spiders, web symmetry often gets distorted through ontogeny, and these changes have been interpreted to reflect the biogenetic law. Here, we test the biogenetic law hypothesis against the alternative, the optimal foraging hypothesis, by studying the allometry in Leucauge venusta orb webs. These webs range in inclination from vertical through tilted to horizontal; biogenetic law predicts that allometry relates to ontogenetic stage, whereas optimal foraging predicts that allometry relates to gravity. Specifically, pronounced asymmetry should only be seen in vertical webs under optimal foraging theory. We show that, through ontogeny, vertical webs in L. venusta become more asymmetrical in contrast to tilted and horizontal webs. Biogenetic law thus cannot explain L. venusta web allometry, but our results instead support optimization of foraging area in response to spider size.

  7. Foraging behavior and virulence of some entomopathogenic nematodes

    Directory of Open Access Journals (Sweden)

    Manana A. Lortkipanidze

    2016-06-01

    Full Text Available At present the biological control as a pest control technology is becoming more desirable. Biological formulations on basis of entomopathogenic nematodes are one of the effective means for the protection of agricultural and forest plants from harmful insects. Nowadays, the use of entomopathogenic nematodes as biological control agents is a key component in IPM system. The foraging strategies of entomopathogenic nematodes (EPNs vary between species. This variation is consistent with use of different foraging strategies between ambush, cruise and intermediate to find their host insects. In order to ambush prey, some species of EPNs nictate, or raise their bodies of the soil surface so they are better poised to attach passing insects, other species adopt a cruising strategy and rarely nictate. Some species adopt an intermediate strategy between ambush and cruise. We compared in laboratory the foraging strategies of the entomopathogenic nematode species: Steinernema carpocapsae, Heterorhabditis bacteriophora and the recently described species Steinernema tbilisiensis and assessed their virulence against mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae. The tests showed that S. tbilisiensis adopts both foraging strategies.

  8. Artificial root foraging optimizer algorithm with hybrid strategies

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2017-02-01

    Full Text Available In this work, a new plant-inspired optimization algorithm namely the hybrid artificial root foraging optimizion (HARFO is proposed, which mimics the iterative root foraging behaviors for complex optimization. In HARFO model, two innovative strategies were developed: one is the root-to-root communication strategy, which enables the individual exchange information with each other in different efficient topologies that can essentially improve the exploration ability; the other is co-evolution strategy, which can structure the hierarchical spatial population driven by evolutionary pressure of multiple sub-populations that ensure the diversity of root population to be well maintained. The proposed algorithm is benchmarked against four classical evolutionary algorithms on well-designed test function suites including both classical and composition test functions. Through the rigorous performance analysis that of all these tests highlight the significant performance improvement, and the comparative results show the superiority of the proposed algorithm.

  9. Costs associated with tail autotomy in an ambush foraging lizard ...

    African Journals Online (AJOL)

    . Most studies on the effects of tail loss have focused on active foraging lizards, but few data exist for ambush foraging lizards. We investigated potential costs associated with tail autotomy in an extreme ambush foraging cordylid lizard, ...

  10. Foraging behaviour of the Tawny-flanked Prinia Prinia subflava ...

    African Journals Online (AJOL)

    ) was studied at Morogoro, eastern Tanzania during the late winter, 2016. TFP foraged mostly in dense subcanopy or weedy vegetation. They foraged alone or in loosely constructed groups, and stayed in contact using calling. Foraging ...

  11. Interactions between shoal size and conformity in guppy social foraging

    NARCIS (Netherlands)

    Day, R.L.; Macdonald, T.; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1

  12. Sexual segregation of forage patch use: Support for the social-factors and predation hypotheses.

    Science.gov (United States)

    Biggerstaff, Michael T; Lashley, Marcus A; Chitwood, M Colter; Moorman, Christopher E; DePerno, Christopher S

    2017-03-01

    Nearly all species of sexually dimorphic ungulates sexually segregate. Several hypotheses have been proposed to explain this phenomenon, including the social-factors hypothesis (SFH) and the predation hypothesis (PH). Interestingly, previous studies have accepted and rejected each hypothesis within and across species but few studies have simultaneously tested both hypotheses in the same population. In August 2011 and 2012 using 7680 photographs taken with camera traps in standardized forage patches, we tested two predictions of the SFH: 1) foraging efficiency of both sexes would decrease when foraging rate in mixed-sex groups relative to single-sex groups, and 2) activity patterns (i.e., the pattern of temporal use of forage patches on a diel scale) of the sexes would decrease in temporal overlap at the forage patch level (i.e., social segregation) compared to the overall temporal overlap of activity patterns of the population. Also, we tested two predictions of the +PH : 1) the relationship between feeding rates of each sex, and 2) temporal activity overlap would change with changing risk level of forage patches as a result of differing risk perception between sexes. In support of the SFH for temporal segregation, when in mixed-sex groups, mature males and all females decreased feeding rate 30% and 10%, respectively; further, the sexes had similar activity patterns overall (94-95% overlap), though temporal overlap was lower in individual forage patches (68-74% overlap). In multi-male mixed sex groups, at least one male exhibited aggressive posture toward females during all foraging bouts suggesting intersex aggression was the cause of the observed decrease in foraging rates. In support of the PH , the sexes adjusted feeding rate differently in response to changing risk level of a forage patch, encouraging spatial segregation; however, the PH was not supported for temporal segregation because temporal activity pattern overlap did not vary as a function of predation

  13. Risk of predation makes foragers less choosy about their food.

    Science.gov (United States)

    Charalabidis, Alice; Dechaume-Moncharmont, François-Xavier; Petit, Sandrine; Bohan, David A

    2017-01-01

    Animals foraging in the wild have to balance speed of decision making and accuracy of assessment of a food item's quality. If resource quality is important for maximizing fitness, then the duration of decision making may be in conflict with other crucial and time consuming tasks, such as anti-predator behaviours or competition monitoring. Individuals facing the risk of predation and/or competition should adjust the duration of decision making and, as a consequence, their level of choosiness for resources. When exposed to predation, the forager could either maintain its level of choosiness for food items but accept a reduction in the amount of food items consumed or it could reduce its level of choosiness and accept all prey items encountered. Under competition risk, individuals are expected to reduce their level of choosiness as slow decision making exposes individuals to a higher risk of opportunity costs. To test these predictions, the level of choosiness of a seed-eating carabid beetle, Harpalus affinis, was examined under 4 different experimental conditions of risk: i) predation risk; ii) intraspecific competition; iii) interspecific competition; and, iv) control. All the risks were simulated using chemical cues from individual conspecifics or beetles of different species that are predatory or granivorous. Our results show that when foraging under the risk of predation, H. affinis individuals significantly reduce their level of choosiness for seeds. Reductions in level of choosiness for food items might serve as a sensible strategy to reduce both the total duration of a foraging task and the cognitive load of the food quality assessment. No significant differences were observed when individuals were exposed to competition cues. Competition, (i.e opportunity cost) may not be perceived as risk high enough to induce changes in the level of choosiness. Our results suggest that considering the amount of items consumed, alone, would be a misleading metric when

  14. Competition in a group of equal foragers.

    Science.gov (United States)

    Rita, H; Ranta, E

    1998-07-01

    Using techniques from renewal process theory, we build a stochastic model for gain accumulation in a group of equal competitors foraging in a patchy environment. The model for gain of the individuals is based on the waiting times between subsequent prey encounters by the group. These waiting times depend on the number of foragers in the group. A single parameter of this dependency encompasses a variety of foraging scenarios, from co-operation to scramble. With constant patch size, correlations between gains of any pair of foragers are negative. This dependency is most intense in small groups. Increased variation in patch size makes correlations in gains between group members positive irrespective of the group size. For a solitary forager, variance in gain approaches zero with increasing time in the patch. For an individual member in a group, variance grows monotonically. Thus, depending on the patch departure rule controlling the time to be spent in the patch, solitary foragers may have a smaller variance in gain than members in a group. As solitary foragers also potentially harvest all prey in the patch, it is hard to believe that grouping behavior would evolve solely on the basis of foraging.

  15. Unidirectional prey–predator facilitation: apparent prey enhance predators' foraging success on cryptic prey

    OpenAIRE

    Zhang, Yixin; Richardson, John S

    2007-01-01

    Food availability can strongly affect predator–prey dynamics. When change in habitat condition reduces the availability of one prey type, predators often search for other prey, perhaps in a different habitat. Interactions between behavioural and morphological traits of different prey may influence foraging success of visual predators through trait-mediated indirect interactions (TMIIs), such as prey activity and body coloration. We tested the hypothesis that foraging success of stream-dwellin...

  16. Does similarity in call structure or foraging ecology explain interspecific information transfer in wild Myotis bats?

    Science.gov (United States)

    Hügel, Theresa; van Meir, Vincent; Muñoz-Meneses, Amanda; Clarin, B-Markus; Siemers, Björn M; Goerlitz, Holger R

    2017-01-01

    Animals can gain important information by attending to the signals and cues of other animals in their environment, with acoustic information playing a major role in many taxa. Echolocation call sequences of bats contain information about the identity and behaviour of the sender which is perceptible to close-by receivers. Increasing evidence supports the communicative function of echolocation within species, yet data about its role for interspecific information transfer is scarce. Here, we asked which information bats extract from heterospecific echolocation calls during foraging. In three linked playback experiments, we tested in the flight room and field if foraging Myotis bats approached the foraging call sequences of conspecifics and four heterospecifics that were similar in acoustic call structure only (acoustic similarity hypothesis), in foraging ecology only (foraging similarity hypothesis), both, or none. Compared to the natural prey capture rate of 1.3 buzzes per minute of bat activity, our playbacks of foraging sequences with 23-40 buzzes/min simulated foraging patches with significantly higher profitability. In the flight room, M. capaccinii only approached call sequences of conspecifics and of the heterospecific M. daubentonii with similar acoustics and foraging ecology. In the field, M. capaccinii and M. daubentonii only showed a weak positive response to those two species. Our results confirm information transfer across species boundaries and highlight the importance of context on the studied behaviour, but cannot resolve whether information transfer in trawling Myotis is based on acoustic similarity only or on a combination of similarity in acoustics and foraging ecology. Animals transfer information, both voluntarily and inadvertently, and within and across species boundaries. In echolocating bats, acoustic call structure and foraging ecology are linked, making echolocation calls a rich source of information about species identity, ecology and

  17. Fearful foragers: honey bees tune colony and individual foraging to multi-predator presence and food quality.

    Directory of Open Access Journals (Sweden)

    Ken Tan

    Full Text Available Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller and V. tropica (bigger preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w, colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55-79% and residence times by 17-33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose, colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger, colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees.

  18. Fearful foragers: honey bees tune colony and individual foraging to multi-predator presence and food quality.

    Science.gov (United States)

    Tan, Ken; Hu, Zongwen; Chen, Weiwen; Wang, Zhengwei; Wang, Yuchong; Nieh, James C

    2013-01-01

    Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller) and V. tropica (bigger) preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive) as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w), colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55-79% and residence times by 17-33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose), colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger), colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees.

  19. Foraging in space and time structure an African small mammal community.

    Science.gov (United States)

    Abu Baker, Mohammad A; Brown, Joel S

    2014-06-01

    We used live-trapping and foraging to test for the effect of habitat selection and diet on structuring a community of six small mammals and one bird within the Soutpansberg, South Africa. We established grids that straddled adjacent habitats: woodland, rocky hillside, and grassland. Trapping and foraging were used to estimate abundance, habitat use, and species-specific foraging costs. The species with the highest abundance and foraging activity in a habitat, activity time, or food was considered the most efficient and presumed to have a competitive advantage. All species exhibited distinct patterns of spatial and temporal habitat preference which provided the main mechanism of coexistence, followed by diet selection. The study species were organized into three assemblages (α diversity): grassland, Rhabdomys pumilio, Dendromus melanotis, and Mus minutoides.; woodland, Aethomys ineptus and Micaelamys namaquensis; and rock-dwelling, M. namaquensis and Elephantulus myurus. Francolinus natalensis foraged in open rocky areas and under wooded islands within the grassland. Species organization across the habitats suggested that feeding opportunities are available within all habitats; however, distinct habitat preferences resulted from differing foraging aptitudes and efficiencies of the competing species. At Lajuma, species distribution and coexistence are promoted through distinct habitat preferences that were shaped by competition and species-specific foraging costs. The combination of trapping and foraging provided a mechanistic approach that integrates behavior into community ecology by 'asking' the animal to reveal its perspective of the environment. Using spatial and temporal foraging decisions-as behavioral indicators-enables us to guide our understanding for across-taxa species coexistence.

  20. Forage selection by Royle's pika (Ochotona roylei) in the western Himalaya, India.

    Science.gov (United States)

    Bhattacharyya, Sabuj; Adhikari, Bhupendra S; Rawat, Gopal S

    2013-10-01

    Forage selection decisions of herbivores are often complex and dynamic; they are modulated by multiple cues, such as quality, accessibility and abundance of forage plants. To advance the understanding of plant-herbivore interactions, we explored foraging behavior of the alpine lagomorph Royle's pika (Ochotona roylei) in Kedarnath Wildlife Sanctuary, India. Pika bite counts on food plants were recorded through focal sampling in three permanently marked plots. Food plant abundance was recorded by traditional quadrat procedures; forage selection was estimated with Jacob's selection index. Multiple food-choice experiments were conducted to determine whether forage selection criteria would change with variation in food plant composition. We also analyzed leaf morphology and nutrient content in both major food plants and abundantly available non-food plants. Linear regression models were used to test competing hypotheses in order to identify factors governing forage selection. Royle's pika fed primarily on 17 plant species and each forage selection decision was positively modulated by leaf area and negatively modulated by contents of avoided substances (neutral detergent fiber, acid detergent fiber, acid detergent lignin and tannin) in food plants. Furthermore, significance of the interaction term "leaf size × avoided substance" indicates that plants with large leaves were selected only when they had low avoided substance content. The forage selection criteria did not differ between field and laboratory experiments. The parameter estimates of best fit models indicate that the influence of leaf size or amount of avoided substance on pika forage selection was modulated by the magnitude of predation risk. Copyright © 2013 Elsevier GmbH. All rights reserved.

  1. Sexual segregation in foraging giraffe

    Science.gov (United States)

    Mramba, Rosemary Peter; Mahenya, Obeid; Siyaya, Annetjie; Mathisen, Karen Marie; Andreassen, Harry Peter; Skarpe, Christina

    2017-02-01

    Sexual segregation in giraffe is known to vary between savannas. In this study, we compared sexual segregation in giraffe in one nutrient-rich savanna, the Serengeti National Park, one nutrient-poor, Mikumi National Park, and one medium rich savanna, Arusha National Park, (from here on referred to just by name) based on effects of sexual size dimorphism and related hypotheses. Data were collected in the wet and dry seasons, by driving road transects and making visual observations of browsing giraffe. Additional data were collected from literature (plant chemistry; mammal communities). There was a noticeable difference in browsing by females and males and in browsing between the three savannas. Females browsed a higher diversity of tree species in Serengeti whereas males browsed a higher diversity in Arusha, while the diversity of species browsed in Mikumi was high and about the same in both sexes. Females selected for high concentrations of nitrogen and low concentrations of tannins and phenolics compared to males in Serengeti but selection in Mikumi was more complex. Males browsed higher in the canopy than females in all sites, but the browsing height was generally higher in Serengeti than Mikumi and Arusha. Season had an effect on the browsing height independent of sex in Mikumi, where giraffes browsed higher in the dry season compared to the wet season. Males spent more time browsing per tree compared to females in all three sites; however, browsing time in Mikumi was also affected by season, where giraffes had longer browsing bouts in the wet season compared to the dry season. We suggest that sexual differences in forage requirement and in foraging interacts with differences in tree chemistry and in competing herbivore communities between nutrient rich and nutrient poor savanna in shaping the sexual segregation.

  2. Perennial forages as second generation bioenergy crops.

    Science.gov (United States)

    Sanderson, Matt A; Adler, Paul R

    2008-05-01

    The lignocellulose in forage crops represents a second generation of biomass feedstock for conversion into energy-related end products. Some of the most extensively studied species for cellulosic feedstock production include forages such as switchgrass (Panicum virgatum L.), reed canarygrass (Phalaris arundinacea L.), and alfalfa (Medicago sativa L.). An advantage of using forages as bioenergy crops is that farmers are familiar with their management and already have the capacity to grow, harvest, store, and transport them. Forage crops offer additional flexibility in management because they can be used for biomass or forage and the land can be returned to other uses or put into crop rotation. Estimates indicate about 22.3 million ha of cropland, idle cropland, and cropland pasture will be needed for biomass production in 2030. Converting these lands to large scale cellulosic energy farming could push the traditional forage-livestock industry to ever more marginal lands. Furthermore, encouraging bioenergy production from marginal lands could directly compete with forage-livestock production.

  3. Experimental warming alters migratory caribou forage quality.

    Science.gov (United States)

    Zamin, Tara J; Côté, Steeve D; Tremblay, Jean-Pierre; Grogan, Paul

    2017-10-01

    Global declines in caribou and reindeer (Rangifer) populations have drawn attention to the myriad of stressors that these Arctic and boreal forest herbivores currently face. Arctic warming has resulted in increased tundra shrub growth and therefore Rangifer forage quantity. However, its effects on forage quality have not yet been addressed although they may be critical to Rangifer body condition and fecundity. We investigated the impact of 8 yrs of summer warming on the quality of forage available to the Bathurst caribou herd using experimental greenhouses (n = 5) located in mesic birch hummock tundra in the central Canadian Low Arctic. Leaf forage quality and digestibility characteristics associated with nutrients (nitrogen and phosphorus), phenolics, and fiber were measured on the deciduous shrub Betula glandulosa (an important Rangifer diet component) at six time points through the growing season, and on five other very common vascular plant and lichen species in late summer. Experimental warming reduced B. glandulosa leaf nitrogen concentrations by ~10% in both late June and mid-July, but not afterwards. It also reduced late summer forage quality of the graminoid Eriophorum vaginatum by increasing phenolic concentrations 38%. Warming had mixed effects on forage quality of the lichen Cetraria cucullata in that it increased nutrient concentrations and tended to decrease fiber contents, but it also increased phenolics. Altogether, these warming-induced changes in forage quality over the growing season, and response differences among species, highlight the importance of Rangifer adaptability in diet selection. Furthermore, the early season reduction in B. glandulosa nitrogen content is a particular concern given the importance of this time for calf growth. Overall, our demonstration of the potential for significant warming impacts on forage quality at critical times for these animals underscores the importance of effective Rangifer range conservation to ensure

  4. Do bigger bats need more time to forage?

    Directory of Open Access Journals (Sweden)

    CEL. Esbérard

    Full Text Available We test the hypothesis is that bats using the same area and at the same time would be using similar preys, but they would have different foraging times due to specific differences in biomass. A total of 730 captures was analyzed 13 species of Vespertilionidae and Molossidae bats netted over a small dam in southeastern Brazil from 1993 and 1999. The relationship between the average time of captures and the biomass of the species of Vespertilinidae and Molossidae most frequent (captures > 4 was positive and significant (r = 0.83, p = 0.022, N = 7. Two lines are discussed to answer the longer foraging time for bigger bats: 1 larger insectivorous bats don't consume proportionally larger preys and 2 larger insects are less available.

  5. Physical barrier to reduce WP mortalities of foraging waterfowl

    Energy Technology Data Exchange (ETDEWEB)

    Pochop, P.A.; Cummings, J.L.; Yoder, C.A.; Gossweiler, W.A.

    2000-02-01

    White phosphorus (WP) has been identified as the cause of mortality to certain species of water-fowl at Eagle River Flats, a tidal marsh in Alaska, used as an ordinance impact area by the US Army. A blend of calcium bentonite/organo clays, gravel, and binding polymers was tested for effectiveness as a barrier to reduce duck foraging and mortality. Following the application of the barrier to one of two contaminated ponds, the authors observed greater duck foraging and higher mortality in the untreated pond and no mortality in the treated pond after a year of tidal inundations and ice effects. Emergent vegetation recovered within a year of treatment. WP levels in the barrier were less than the method limit of detection, indicating no migration of WP into the materials. Barrier thickness remained relatively stable over a period of 4 years, and vegetation was found to be important in stabilizing the barrier material.

  6. New Inoculants Containing Lactic Bacteria Applied in Forage Ensiling

    Directory of Open Access Journals (Sweden)

    Teodor Vintila

    2010-05-01

    Full Text Available In a first study, the capacity of lactic bacteria to accumulate biomass in different culture media and temperatures was tested and the biosynthesis parameters were established. In the second study, the strains producing the highest quantity of biomass and determining the most rapid pH drop in culture medium were conditioned in solid supports. The obtained solid products containing lactic bacteria were used to inoculate different types of forages. Ensilage was carried out in laboratory silos made from O2-impermeable plastic flasks, vacuumed using a vacuum pump. The experiment was 2 x 2 factorial with two types of forage (alfalfa and sorghum, each of them inoculated and not inoculated with lactic bacteria. The evolution of lactic bacteria, pH value, and the concentration in volatile acids was verified. In the third experiment, lactic bacteria were used to inoculate silages in farm conditions. The obtained results recommend the tested strain for the improvement of preserving conditions and nutritive value in ensiled forages.

  7. Economic emission load dispatch through fuzzy based bacterial foraging algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Hota, P.K.; Barisal, A.K. [Department of Electrical Engineering, UCE, Burla, Orissa (India); Chakrabarti, R. [Department of Electrical Engineering, Jadavpur University, Kolkata (India)

    2010-09-15

    This paper presents a newly developed optimization approach involving a modified bacterial foraging algorithm (MBFA) applied for the solution of the economic and emission load dispatch (EELD) problem. The approach utilizes the natural selection of global optimum bacterium having successful foraging strategies in the fitness function. The bacterial foraging algorithm (BFA) appears to be a robust and reliable optimization algorithm for the solution of the EELD problems. To obtain the best compromising solution a fuzzy decision making approach using MBFA is applied to the standard IEEE 30-bus six generator test system and a Taiwan power system of 40 generating units with valve point loading effects. The results confirm the potential and effectiveness of the proposed algorithm compared to various methods such as, linear programming (LP), multi-objective stochastic search technique (MOSST), differential evolution (DE), non-dominated sorting genetic algorithm (NSGA), niched pareto genetic algorithm (NPGA), strength pareto evolutionary algorithm (SPEA) and fuzzy clustering based particle swarm optimization (FCPSO) performed in different central load dispatch centers to solve EELD problems. The quality and usefulness of the proposed algorithm is demonstrated through its application to two standard test systems in comparison with the other existing techniques. The current proposal was found to be better than, or at least comparable to, them, considering the quality of the solutions obtained. (author)

  8. Determination of Tropical Forage Preferences Using Two Offering Methods in Rabbits

    Directory of Open Access Journals (Sweden)

    A. M. Safwat

    2014-04-01

    Full Text Available Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group; for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%, which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1st method (34.28%, which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use.

  9. Trade-offs between predation risk and forage differ between migrant strategies in a migratory ungulate.

    Science.gov (United States)

    Hebblewhite, Mark; Merrill, Evelyn H

    2009-12-01

    Trade-offs between predation risk and forage fundamentally drive resource selection by animals. Among migratory ungulates, trade-offs can occur at large spatial scales through migration, which allows an "escape" from predation, but trade-offs can also occur at finer spatial scales. Previous authors suggest that ungulates will avoid predation risk at the largest scale, although few studies have examined multi-scale trade-offs to test for the relative benefits of risk avoidance across scales. Building on previously developed spatial models of forage and wolf predation risk, we tested for trade-offs at the broad landscape scale and at a finer, within-home-range scale for migratory and non-migratory resident elk (Cervus elaphus) during summer in the Canadian Rockies in Banff National Park (BNP) and adjacent Alberta, Canada. Migration reduced exposure to wolf predation risk by 70% relative to residents at the landscape scale; at the fine scale, migrants used areas that were, on average, 6% higher in forage digestibility. In contrast, by forgoing migration, resident elk were exposed to higher predation risk, but they reduced predation risk at fine scales to only 15% higher than migrants by using areas close to human activity, which wolves avoided. Thus, residents paid for trying to avoid predation risk with lower forage quality. Residents may have been able to compensate, however, by using areas of abundant forage close to human activity where they may have been able to forage more selectively while avoiding predation risk. Human activity effectively decoupled the positive correlation between high forage quality and wolf predation, providing an effective alternate strategy for residents, similar to recent findings in other systems. Although ungulates appear capable of balancing risk and forage at different spatial scales, risk avoidance at large landscape scales may be more effective in the absence of human-caused refugia from predation.

  10. Contrasting responses of male and female foraging effort to year-round wind conditions.

    Science.gov (United States)

    Lewis, Sue; Phillips, Richard A; Burthe, Sarah J; Wanless, Sarah; Daunt, Francis

    2015-11-01

    There is growing interest in the effects of wind on wild animals, given evidence that wind speeds are increasing and becoming more variable in some regions, particularly at temperate latitudes. Wind may alter movement patterns or foraging ability, with consequences for energy budgets and, ultimately, demographic rates. These effects are expected to vary among individuals due to intrinsic factors such as sex, age or feeding proficiency. Furthermore, this variation is predicted to become more marked as wind conditions deteriorate, which may have profound consequences for population dynamics as the climate changes. However, the interaction between wind and intrinsic effects has not been comprehensively tested. In many species, in particular those showing sexual size dimorphism, males and females vary in foraging performance. Here, we undertook year-round deployments of data loggers to test for interactions between sex and wind speed and direction on foraging effort in adult European shags Phalacrocorax aristotelis, a pursuit-diving seabird in which males are c. 18% heavier. We found that foraging time was lower at high wind speeds but higher during easterly (onshore) winds. Furthermore, there was an interaction between sex and wind conditions on foraging effort, such that females foraged for longer than males when winds were of greater strength (9% difference at high wind speeds vs. 1% at low wind speeds) and when winds were easterly compared with westerly (7% and 4% difference, respectively). The results supported our prediction that sex-specific differences in foraging effort would become more marked as wind conditions worsen. Since foraging time is linked to demographic rates in this species, our findings are likely to have important consequences for population dynamics by amplifying sex-specific differences in survival rates. © 2015 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of the British Ecological Society.

  11. Determination of Tropical Forage Preferences Using Two Offering Methods in Rabbits

    Science.gov (United States)

    Safwat, A. M.; Sarmiento-Franco, L.; Santos-Ricalde, R. H.; Nieves, D.

    2014-01-01

    Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group); for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%), which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1st method (34.28%), which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use. PMID:25049983

  12. Sympatric cattle grazing and desert bighorn sheep foraging

    Science.gov (United States)

    Garrison, Kyle R.; Cain, James W.; Rominger, Eric M.; Goldstein, Elise J.

    2015-01-01

    Foraging behavior affects animal fitness and is largely dictated by the resources available to an animal. Understanding factors that affect forage resources is important for conservation and management of wildlife. Cattle sympatry is proposed to limit desert bighorn population performance, but few studies have quantified the effect of cattle foraging on bighorn forage resources or foraging behavior by desert bighorn. We estimated forage biomass for desert bighorn sheep in 2 mountain ranges: the cattle-grazed Caballo Mountains and the ungrazed San Andres Mountains, New Mexico. We recorded foraging bout efficiency of adult females by recording feeding time/step while foraging, and activity budgets of 3 age-sex classes (i.e., adult males, adult females, yearlings). We also estimated forage biomass at sites where bighorn were observed foraging. We expected lower forage biomass in the cattle-grazed Caballo range than in the ungrazed San Andres range and lower biomass at cattle-accessible versus inaccessible areas within the Caballo range. We predicted bighorn would be less efficient foragers in the Caballo range. Groundcover forage biomass was low in both ranges throughout the study (Jun 2012–Nov 2013). Browse biomass, however, was 4.7 times lower in the Caballo range versus the San Andres range. Bighorn in the Caballo range exhibited greater overall daily travel time, presumably to locate areas of higher forage abundance. By selecting areas with greater forage abundance, adult females in the Caballo range exhibited foraging bout efficiency similar to their San Andres counterparts but lower overall daily browsing time. We did not find a significant reduction in forage biomass at cattle-accessible areas in the Caballo range. Only the most rugged areas in the Caballo range had abundant forage, potentially a result of intensive historical livestock use in less rugged areas. Forage conditions in the Caballo range apparently force bighorn to increase foraging effort by

  13. QTL mapping of forage yield and forage yield component traits in Sorghum bicolor x S. sudanense.

    Science.gov (United States)

    Liu, Y L; Wang, L H; Li, J Q; Zhan, Q W; Zhang, Q; Li, J F; Fan, F F

    2015-04-22

    The sorghum-sudangrass hybrid (Sorghum bicolor x S. sudanense) is an important forage crop. However, little is known about the genetic mechanisms related to forage yield and the 4 forage yield component traits in this forage crop. In this study, a linkage map was constructed with 124 assigned SSR markers using an F2 mapping population derived from the crossing of sorghum Tx623A and sudangrass Sa. Nine quantitative trait loci (QTLs) were detected for forage yield and the 4 forage yield component traits using inclusive composite interval mapping. Five fresh weight QTLs were identified and contributed >50% of the total phenotypic variance. Of these QTLs, all showed additive and dominant effects, but most exhibited mainly dominant effects. These results will provide useful information for improvements in sorghum-sudangrass hybrid breeding.

  14. Experimental Wing Damage Affects Foraging Effort and Foraging Distance in Honeybees Apis mellifera

    Directory of Open Access Journals (Sweden)

    Andrew D. Higginson

    2011-01-01

    Full Text Available Bees acquire wing damage as they age, and loss of wing area affects longevity and behaviour. This may influence colony performance via effects on worker behaviour. The effects of experimental wing damage were studied in worker honeybees in observation hives by recording survivorship, how often and for how long bees foraged, and by decoding waggle dances. Mortality rate increased with both age and wing damage. Damaged bees carried out shorter and/or less frequent foraging trips, foraged closer to the hive, and reported the profitability of flower patches to be lower than did controls. These results suggest that wing damage caused a reduction in foraging ability, and that damaged bees adjusted their foraging behaviour accordingly. Furthermore, the results suggest that wing damage affects the profitability of nectar sources. These results have implications for the colony dynamics and foraging efficiency in honeybees.

  15. Group foraging increases foraging efficiency in a piscivorous diver, the African penguin

    Science.gov (United States)

    McGeorge, Cuan; Ginsberg, Samuel; Pichegru, Lorien; Pistorius, Pierre A.

    2017-01-01

    Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change. PMID:28989785

  16. Forage polyphenol oxidase and ruminant livestock nutrition

    OpenAIRE

    Michael Richard F. Lee

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to r...

  17. Diet and foraging behaviour of oystercatchers ( Haematopus ...

    African Journals Online (AJOL)

    The two bird species differed in their success rate and foraging rate but not in their foraging efficiency. Oystercatchers spent 70.2 % of time for handling mussels and 28.6 % for worms whereas grey plovers spent 93.3 % of the time for handling worms. During the whole period of observation, 75.5% and 42.5% of prey were ...

  18. Interactions Increase Forager Availability and Activity in Harvester Ants.

    Directory of Open Access Journals (Sweden)

    Evlyn Pless

    Full Text Available Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

  19. Interactions Increase Forager Availability and Activity in Harvester Ants.

    Science.gov (United States)

    Pless, Evlyn; Queirolo, Jovel; Pinter-Wollman, Noa; Crow, Sam; Allen, Kelsey; Mathur, Maya B; Gordon, Deborah M

    2015-01-01

    Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

  20. Inferring foraging areas of nesting loggerhead turtles using satellite telemetry and stable isotopes.

    Directory of Open Access Journals (Sweden)

    Simona A Ceriani

    Full Text Available In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i identify key foraging grounds used by female loggerheads nesting in Florida and (ii examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1 a seasonal continental shelf-constrained migratory pattern along the northeast U.S. coastline, (2 a non-breeding residency in southern foraging areas and (3 a residency in the waters adjacent to the breeding area. Isotopic variability in both δ(13C and δ(15N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well δ(13C and δ(15N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61% of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level.

  1. Associative effects between forages on feed intake and digestion in ruminants.

    Science.gov (United States)

    Niderkorn, V; Baumont, R

    2009-07-01

    The feeding value of forage mixtures from permanent and temporary multi-species grasslands cannot always be precisely defined. Indeed, the digestibility and feed intake of a combination of forages can differ from the balanced median values calculated from forages considered separately. In order to present an overview of the associative effects between forages on digestion and intake, a literature study was carried out. The associative effects can be studied in a complementary way in vitro to test digestive interactions of a large number of mixtures and to carry out explanatory experiments, and in vivo to investigate intake and digestion at the whole animal scale. We identified three main situations in which interactions between forages can lead to associative effects on intake and digestion: (i) increased intake that can be observed with grass and legume association can be explained by fast digestion of the soluble fraction of legumes, and a higher rate of particle breakdown and passage through the rumen, (ii) increased digestion when a poor forage is supplemented by a high nitrogen content plant can be explained by stimulation of the microbial activity and (iii) modification of digestive processes in the rumen, including proteolysis and methane production when certain bioactive secondary metabolites such as tannins, saponins or polyphenol oxidase are present. According to the type and concentration of these compounds in the diet, the effects can be favourable or unfavourable on intake and digestive parameters. Reported associative effects between forages show a large variability among studies. This reflects the complexity and multiplicity of nutritional situations affecting intake and the rumen function in a given animal. In order to provide more reliable information, further accumulation of data combining in vitro and in vivo studies is required. A better understanding of the associative effects between forages could help to optimise feed use efficiency

  2. Ecological risk aversion and juvenile ring-tailed lemur feeding and foraging.

    Science.gov (United States)

    O'Mara, M Teague

    2015-01-01

    The extended primate juvenile period has been linked to interactions between feeding ecology and sociality. However, accumulating field data on juvenile primates suggest variation in the linkages between foraging efficiency, group foraging and social behaviour. In many non-human primates, juvenile ability (strength, coordination and motor skills) does not limit foraging success. If predicted limitations in feeding are not found in juvenile monkeys, it is possible that the gregarious strepsirrhines may show foraging patterns similar to those implicated in the evolution of a life history where long juvenile periods are advantageous. To test these behavioural predictions, I present a mixed longitudinal sample of observations on feeding and foraging behaviour from ring-tailed lemurs (Lemur catta) at the Bezà Mahafaly Special Reserve, Madagascar. Like several platyrrhine species, close proximity during foraging, low feeding efficiency and low dietary diversity are not typical of ring-tailed lemurs. The lack of ecological trade-offs in these species may indicate stronger common roles of sociality and social complexity in structuring the elongation of the primate juvenile period. © 2015 S. Karger AG, Basel.

  3. The effects of chlorpyrifos on cholinesterase activity and foraging behavior in the dragonfly, Anax junius (Odonata)

    Science.gov (United States)

    Brewer, S.K.; Atchison, G.J.

    1999-01-01

    We examined head capsule cholinesterase (ChE) and foraging behavior in nymphs of the dragonfly, Anax junius, exposed for 24 h to 0.2, 0.6 and 1.0 ??g l-1 of the organophosphorus (OP) insecticide, chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate]. The invertebrate community is an important component of the structure and function of wetland ecosystems, yet the potential effects of insecticides on wetland ecosystems are largely unknown. Our objectives were to determine if exposure to environmentally realistic concentrations of chlorpyrifos affected foraging behavior and ChE activity in head capsules of dragonfly nymphs. Nymphs were exposed to different concentrations of chlorpyrifos and different prey densities in a factorial design. ChE activities and foraging behaviors of treated nymphs were not statistically different (p ??? 0.05) from control groups. Prey density effects exerted a greater effect on dragonfly foraging than toxicant exposures. Nymphs offered higher prey densities exhibited more foraging behaviors but also missed their prey more often. High variability in ChE activities within the control group and across treated groups precluded determination of relationships between ChE and foraging behaviors. It appears that A. junius is relatively tolerant of chlorpyrifos, although the concentrations we tested have been shown in other work to adversely affect the prey base; therefore the introduction of this insecticide may have indirect adverse affects on top invertebrate predators such as Odonata.

  4. Older and wiser? Age differences in foraging and learning by an endangered passerine.

    Science.gov (United States)

    Franks, Victoria R; Thorogood, Rose

    2017-12-19

    Birds use cues when foraging to help relocate food resources, but natural environments provide many potential cues and choosing which to use may depend on previous experience. Young animals have less experience of their environment compared to adults, so may be slower to learn cues or may need to sample the environment more. Whether age influences cue use and learning has, however, received little experimental testing in wild animals. Here we investigate effects of age in a wild population of hihi (Notiomystis cincta), a threatened New Zealand passerine. We manipulated bird feeders using a novel colour cue to indicate a food reward; once hihi learned its location, we rotated the feeder to determine whether the birds followed the colour or returned to the previous location. Both age groups made fewer errors over trials and learned the location of the food reward, but juveniles continued to sample unrewarding locations more than adults. Following a second rotation, more adults preferred to forage from the hole indicated by the colour cue than juveniles, despite this no longer being rewarding. Overall, juveniles spent longer in the feeder arena to reach the same proportion of foraging time as adults. Combined, these results suggest that juveniles and adults may use an "explore and exploit" foraging strategy differently, and this affects how efficiently they forage. Further work is needed to understand how juveniles may compensate for their inexperience in learning and foraging strategies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Fishing amplifies forage fish population collapses.

    Science.gov (United States)

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

    2015-05-26

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  6. Aggressive and foraging behavioral interactions among ruffe

    Science.gov (United States)

    Savino, Jacqueline F.; Kostich, Melissa J.

    2000-01-01

    The ruffe, Gymnocephalus cernuus, is a nonindigenous percid in the Great Lakes. Ruffe are aggressive benthivores and forage over soft substrates. Laboratory studies in pools (100 cm in diameter, 15 cm water depth) were conducted to determine whether fish density (low = 2, medium = 4, high = 6 ruffe per pool) changed foraging and aggressive behaviors with a limited food supply of chironomid larvae. All fish densities demonstrated a hierarchy based on aggressive interactions, but ruffe were most aggressive at low and high fish densities. Time spent in foraging was lowest at the low fish density. The best forager at the low fish density was the most aggressive individual, but the second most aggressive fish at the medium and high fish density was the best forager and also the one chased most frequently. A medium fish density offered the best energetic benefits to ruffe by providing the lowest ratio of time spent in aggression to that spent foraging. Based on our results, ruffe should grow best at an intermediate density. With high ruffe densities, we would also expect disparity in size as the more aggressive fish are able to garner a disproportionate amount of the resources. Alternatively, as the Great Lakes are a fairly open system, ruffe could migrate out of one area to colonize another as populations exceed optimal densities.

  7. Exotic invaders gain foraging benefits by shoaling with native fish.

    Science.gov (United States)

    Camacho-Cervantes, Morelia; Garcia, Constantino Macías; Ojanguren, Alfredo F; Magurran, Anne E

    2014-11-01

    Freshwater habitats are under increasing threat due to invasions of exotic fish. These invasions typically begin with the introduction of small numbers of individuals unfamiliar with the new habitat. One way in which the invaders might overcome this disadvantage is by associating with native taxa occupying a similar ecological niche. Here we used guppies (Poecilia reticulata) from a feral population in Mexico to test the prediction that exotic shoaling fish can associate with heterospecifics, and that they improve their foraging efficiency by doing so. Guppies have invaded the Mexican High Plateau and are implicated in the declines of many native topminnow (Goodeinae) species. We show that heterospecific associations between guppies and topminnows can deliver the same foraging benefits as conspecific shoals, and that variation in foraging gains is linked to differences in association tendency. These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well in every continent except Antarctica.

  8. Bust economics: foragers choose high quality habitats in lean times

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    Sonny S. Bleicher

    2016-01-01

    Full Text Available In environments where food resources are spatially variable and temporarily impoverished, consumers that encounter habitat patches with different food density should focus their foraging initially where food density is highest before they move to patches where food density is lower. Increasing missed opportunity costs should drive individuals progressively to patches with lower food density as resources in the initially high food density patches deplete. To test these expectations, we assessed the foraging decisions of two species of dasyurid marsupials (dunnarts: Sminthopsis hirtipes and S. youngsoni during a deep drought, or bust period, in the Simpson Desert of central Australia. Dunnarts were allowed access to three patches containing different food densities using an interview chamber experiment. Both species exhibited clear preference for the high density over the lower food density patches as measured in total harvested resources. Similarly, when measuring the proportion of resources harvested within the patches, we observed a marginal preference for patches with initially high densities. Models analyzing behavioral choices at the population level found no differences in behavior between the two species, but models analyzing choices at the individual level uncovered some variation. We conclude that dunnarts can distinguish between habitat patches with different densities of food and preferentially exploit the most valuable. As our observations were made during bust conditions, experiments should be repeated during boom times to assess the foraging economics of dunnarts when environmental resources are high.

  9. THE INFLUENCE OF PRECIPITATION ON FORAGE PEA SEED YIELDS

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    Svetislav Popović

    2015-12-01

    Full Text Available Field pea (Pisum arvense L., also known as Austrian winter pea, is increasingly being planted in Croatia and its surrounding to produce high-quality roughage. The main characteristics of the variety are short vegetation, high forage yields and excellent forage quality that is reflected in the high protein production. Seed production of peas is a very complex process. In agricultural production the yield is under the influence of plant genetic potential and environmental factors, especially of the precipitation amount during the growing season. Seed production of forage pea variety 'Osječki zeleni' along with the climatic conditions for a nine-year period (2004-2012 were analysed. The analyses showed large variability in yields, germination and 1000 grain weight as well as oscillations in the amounts of precipitation during the growing period of winter peas in the analysed years. Pearson's correlation coefficient analysis showed a lack of relation between yield, germination and 1000 grain weight. There was no correlation observed between the tested parameters and the total amount of precipitation during the growing period. Thus it can be concluded that the observed parameters were substantially influenced by other environmental factors.

  10. Foraging behavior by Daphnia in stoichiometric gradients of food quality.

    Science.gov (United States)

    Schatz, Greg S; McCauley, Edward

    2007-10-01

    Mismatches in the elemental composition of herbivores and their resources can impact herbivore growth and reproduction. In aquatic systems, the ratio of elements, such as C, P, and N, is used to characterize the food quality of algal prey. For example, large increases in the C:P ratio of edible algae can decrease rates of growth and reproduction in Daphnia. Current theory emphasizes that Daphnia utilize only assimilation and respiration processes to maintain an optimal elemental composition, yet studies of terrestrial herbivores implicate behavioral processes in coping with local variation in food quality. We tested the ability of juvenile and adult Daphnia to locate regions of high-quality food within a spatial gradient of algal prey differing in C:P ratio, while holding food density constant over space. Both juveniles and adults demonstrated similar behavior by quickly locating (i.e., high food quality. Foraging paths were centred on regions of high food quality and these differed significantly from paths of individuals exposed to a homogeneous environment of both food density and food quality. Ingestion rate experiments on algal prey of differing stoichiometric ratio show that individuals can adjust their intake rate over fast behavioral time-scales, and we use these data to examine how individuals choose foraging locations when presented with a spatial gradient that trades off food quality and food quantity. Daphnia reared under low food quality conditions chose to forage in regions of high food quality even though they could attain the same C ingestion rate elsewhere along a spatial gradient. We argue that these aspects of foraging behavior by Daphnia have important implications for how these herbivores manage their elemental composition and our understanding of the dynamics of these herbivore-plant systems in lakes and ponds where spatial variation in food quality is present.

  11. Simultaneous brightness contrast of foraging Papilio butterflies

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    Kinoshita, Michiyo; Takahashi, Yuki; Arikawa, Kentaro

    2012-01-01

    This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to perceive brightness in two different protocols: (i) two orange discs of different intensity presented on the same intensity grey background and (ii) two orange discs of the same intensity separately presented on a grey background that was either higher or lower in intensity than the training background. The butterflies trained to high intensity red selected the orange disc of high intensity in protocol 1, and the disc on the background of low intensity grey in protocol 2. We obtained similar results in another set of experiments with purple discs instead of orange discs. The choices of the butterflies trained to low intensity red were opposite to those just described. Taken together, we conclude that Papilio has the ability to learn brightness and darkness of targets independent of colour, and that they have the so-called simultaneous brightness contrast. PMID:22179808

  12. Intercropping of Cereals and Legumes for Forage Production

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    Hamdollah ESKANDARI

    2009-12-01

    Full Text Available Cereals are high important in feeding ruminant animals for their high dry matter production and low cost. However, cereals forage is poor in protein content which shows their low quality and nutritive value. Regarding to high feed costs of protein supplementations, legumes can be used in livestock nutrition for their high protein content and, thus, providing cost saving. Since legumes have low dry matter yield, acceptable forage yield and quality can obtained from intercropping of cereals and legumes compared with their sole crops. In this paper, forage quality indicators and different factors affecting forage quality are discussed. Forage production and quality of different cereals-legumes intercropping are also reviewed, where; different legumes had different effect on forage quality when intercropped with specific cereal. Regarding to forage quality and quantity, different cereals also led to different production of forage. A number of factors which must be noticified in selecting cereal-legume intercropping compositions, especially for forage production, were considered.

  13. Good days, bad days: wind as a driver of foraging success in a flightless seabird, the southern rockhopper penguin.

    Science.gov (United States)

    Dehnhard, Nina; Ludynia, Katrin; Poisbleau, Maud; Demongin, Laurent; Quillfeldt, Petra

    2013-01-01

    Due to their restricted foraging range, flightless seabirds are ideal models to study the short-term variability in foraging success in response to environmentally driven food availability. Wind can be a driver of upwelling and food abundance in marine ecosystems such as the Southern Ocean, where wind regime changes due to global warming may have important ecological consequences. Southern rockhopper penguins (Eudyptes chrysocome) have undergone a dramatic population decline in the past decades, potentially due to changing environmental conditions. We used a weighbridge system to record daily foraging mass gain (the difference in mean mass of adults leaving the colony in the morning and returning to the colony in the evening) of adult penguins during the chick rearing in two breeding seasons. We related the day-to-day variability in foraging mass gain to ocean wind conditions (wind direction and wind speed) and tested for a relationship between wind speed and sea surface temperature anomaly (SSTA). Foraging mass gain was highly variable among days, but did not differ between breeding seasons, chick rearing stages (guard and crèche) and sexes. It was strongly correlated between males and females, indicating synchronous changes among days. There was a significant interaction of wind direction and wind speed on daily foraging mass gain. Foraging mass gain was highest under moderate to strong winds from westerly directions and under weak winds from easterly directions, while decreasing under stronger easterly winds and storm conditions. Ocean wind speed showed a negative correlation with daily SSTA, suggesting that winds particularly from westerly directions might enhance upwelling and consequently the prey availability in the penguins' foraging areas. Our data emphasize the importance of small-scale, wind-induced patterns in prey availability on foraging success, a widely neglected aspect in seabird foraging studies, which might become more important with increasing

  14. Good days, bad days: wind as a driver of foraging success in a flightless seabird, the southern rockhopper penguin.

    Directory of Open Access Journals (Sweden)

    Nina Dehnhard

    Full Text Available Due to their restricted foraging range, flightless seabirds are ideal models to study the short-term variability in foraging success in response to environmentally driven food availability. Wind can be a driver of upwelling and food abundance in marine ecosystems such as the Southern Ocean, where wind regime changes due to global warming may have important ecological consequences. Southern rockhopper penguins (Eudyptes chrysocome have undergone a dramatic population decline in the past decades, potentially due to changing environmental conditions. We used a weighbridge system to record daily foraging mass gain (the difference in mean mass of adults leaving the colony in the morning and returning to the colony in the evening of adult penguins during the chick rearing in two breeding seasons. We related the day-to-day variability in foraging mass gain to ocean wind conditions (wind direction and wind speed and tested for a relationship between wind speed and sea surface temperature anomaly (SSTA. Foraging mass gain was highly variable among days, but did not differ between breeding seasons, chick rearing stages (guard and crèche and sexes. It was strongly correlated between males and females, indicating synchronous changes among days. There was a significant interaction of wind direction and wind speed on daily foraging mass gain. Foraging mass gain was highest under moderate to strong winds from westerly directions and under weak winds from easterly directions, while decreasing under stronger easterly winds and storm conditions. Ocean wind speed showed a negative correlation with daily SSTA, suggesting that winds particularly from westerly directions might enhance upwelling and consequently the prey availability in the penguins' foraging areas. Our data emphasize the importance of small-scale, wind-induced patterns in prey availability on foraging success, a widely neglected aspect in seabird foraging studies, which might become more important

  15. Central-place foraging and ecological effects of an invasive predator across multiple habitats.

    Science.gov (United States)

    Benkwitt, Cassandra E

    2016-10-01

    Cross-habitat foraging movements of predators can have widespread implications for predator and prey populations, community structure, nutrient transfer, and ecosystem function. Although central-place foraging models and other aspects of optimal foraging theory focus on individual predator behavior, they also provide useful frameworks for understanding the effects of predators on prey populations across multiple habitats. However, few studies have examined both the foraging behavior and ecological effects of nonnative predators across multiple habitats, and none has tested whether nonnative predators deplete prey in a manner predicted by these foraging models. I conducted behavioral observations of invasive lionfish (Pterois volitans) to determine whether they exhibit foraging movements similar to other central-place consumers. Then, I used a manipulative field experiment to test whether their effects on prey populations are consistent with three qualitative predictions from optimal foraging models. Specifically, I predicted that the effects of invasive lionfish on native prey will (1) occur at central sites first and then in surrounding habitats, (2) decrease with increasing distance away from their shelter site, and (3) extend to greater distances when prey patches are spaced closer together. Approximately 40% of lionfish exhibited short-term crepuscular foraging movements into surrounding habitats from the coral patch reefs where they shelter during daylight hours. Over the course of 7 weeks, lionfish depleted native fish populations on the coral patch reefs where they reside, and subsequently on small structures in the surrounding habitat. However, their effects did not decrease with increasing distance from the central shelter site and the influence of patch spacing was opposite the prediction. Instead, lionfish always had the greatest effects in areas with the highest prey densities. The differences between the predicted and observed effects of lionfish

  16. In vitro effects of extracts and purified tannins of sainfoin (Onobrychis viciifolia) against two cattle nematodes

    DEFF Research Database (Denmark)

    Novobilský, A.; Stringano, E.; Hayot Carbonero, C.

    2013-01-01

    .e. accessions) against larvae of Cooperia oncophora and Ostertagia ostertagi by applying the larval feeding inhibition assay (LFIA). Seven sainfoin accessions were extracted and tested with L1 larvae at 10 and 40 μg extract/ml. In addition, CT in extracts from 4 accessions were fractionated according to polymer...... size and tested by LFIA at two concentrations (2 and 10 μg CT fraction/ml). All sainfoin extracts caused significant inhibition of L1-feeding of both C. oncophora and O. ostertagi with varying intensity compared to the control (phosphate buffered saline). For both nematode species the in vitro effect...

  17. Characterization of winter foraging locations of Adélie penguins along the Western Antarctic Peninsula, 2001–2002

    Science.gov (United States)

    Erdmann, Eric S.; Ribic, Christine; Patterson-Fraser, Donna L.; Fraser, William R.

    2011-01-01

    In accord with the hypotheses driving the Southern Ocean Global Ocean Ecosystems Dynamics (SO GLOBEC) program, we tested the hypothesis that the winter foraging ecology of a major top predator in waters off the Western Antarctic Peninsula (WAP), the Adélie penguin (Pygoscelis adeliae), is constrained by oceanographic features related to the physiography of the region. This hypothesis grew from the supposition that breeding colonies in the WAP during summer are located adjacent to areas of complex bathymetry where circulation and upwelling processes appear to ensure predictable food resources. Therefore, we tested the additional hypothesis that these areas continue to contribute to the foraging strategy of this species throughout the non-breeding winter season. We used satellite telemetry data collected as part of the SO GLOBEC program during the austral winters of 2001 and 2002 to characterize individual penguin foraging locations in relation to bathymetry, sea ice variability within the pack ice, and wind velocity and divergence (as a proxy for potential areas with cracks and leads). We also explored differences between males and females in core foraging area overlap. Ocean depth was the most influential variable in the determination of foraging location, with most birds focusing their effort on shallow (penguin's foraging, the analysis of sea ice data of a higher resolution than was available for this study may help elucidate the role of sea ice in affecting Adélie penguin winter foraging behavior within the pack ice.

  18. Cholecystokinin-33 acutely attenuates food foraging, hoarding and intake in Siberian hamsters.

    Science.gov (United States)

    Teubner, Brett J W; Bartness, Timothy J

    2010-04-01

    Neurochemicals that stimulate food foraging and hoarding in Siberian hamsters are becoming more apparent, but we do not know if cessation of these behaviors is due to waning of excitatory stimuli and/or the advent of inhibitory factors. Cholecystokinin (CCK) may be such an inhibitory factor as it is the prototypic gastrointestinal satiety peptide and is physiologically important in decreasing food intake in several species including Siberian hamsters. Systemic injection of CCK-33 in laboratory rats decreases food intake, doing so to a greater extent than CCK-8. We found minimal effects of CCK-8 on food foraging and hoarding previously in Siberian hamsters, but have not tested CCK-33. Therefore, we asked: Does CCK-33 decrease normal levels or food deprivation-induced increases in food foraging, hoarding and intake? Hamsters were housed in a wheel running-based foraging system with simulated burrows to test the effects of peripheral injections of CCK-33 (13.2, 26.4, or 52.8 microg/kg body mass), with or without a preceding 56 h food deprivation. The highest dose of CCK-33 caused large baseline reductions in all three behaviors for the 1st hour post-injection compared with saline; in addition, the intermediate CCK-33 dose was sufficient to curtail food intake and foraging during the 1st hour. In food-deprived hamsters, we used a 52.8 microg/kg body mass dose of CCK-33 which decreased food intake, hoarding, and foraging almost completely compared with saline controls for 1h. Therefore, CCK-33 appears to be a potent inhibitor of food intake, hoarding, and foraging in Siberian hamsters. Copyright (c) 2009 Elsevier Inc. All rights reserved.

  19. In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies.

    Science.gov (United States)

    Thums, Michele; Bradshaw, Corey J A; Hindelli, Mark A

    2011-06-01

    Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed "area-restricted search." However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity could also be spatially aware of suitable feeding areas based on prior experience; changes in movement patterns might therefore arise from the anticipation of higher prey density. We tested the hypothesis that regions of area-restricted search were associated with a higher number of daily speed spikes (a proxy for potential prey encounter rate) and foraging success in southern elephant seals (Mirounga leonina), a species exhibiting both area-restricted searches and high interannual foraging site fidelity. We used onshore morphological measurements and diving data from archival tags deployed during winter foraging trips. Foraging success was inferred from in situ changes in relative lipid content derived from measured changes in buoyancy, and first-passage time analysis was used to identify area-restricted search behavior. Seals exhibited relatively direct southerly movement on average, with intensive search behavior predominantly located at the distal end of tracks. The probability of being in search mode was positively related to changes in relative lipid content; thus, intensively searched areas were associated with the highest foraging success. However, there was high foraging success during the outward transit even though seals moved through quickly without slowing down and increasing turning rate to exploit these areas. In addition, the probability of being in search mode was negatively related to the number of daily speed spikes. These results suggest that movement patterns represent a response to prior expectation of the location of predictable and profitable resources. Shelf habitat was 4-9 times more profitable than the other habitats, emphasizing the importance

  20. Anthelmintic Treatment Does Not Change Foraging Strategies of Female Eastern Grey Kangaroos, Macropus giganteus.

    Science.gov (United States)

    Cripps, Jemma K; Martin, Jennifer K; Coulson, Graeme

    2016-01-01

    Large mammalian herbivores are commonly infected with gastrointestinal helminths. Heavily parasitised hosts are likely to have increased nutritional requirements and would be predicted to increase their food intake to compensate for costs of being parasitised, but experimental tests of the impacts of these parasites on the foraging efficiency of hosts are lacking, particularly in free-ranging wildlife. We conducted a field experiment on a population of free-ranging eastern grey kangaroos (Macropus giganteus) to test this prediction, removing nematodes from one group of adult females using an anthelmintic treatment. We then carried out observations before and following treatment to assess the influence of parasites on foraging behaviour. Contrary to our predictions, the manipulation of parasite burdens did not result in changes in any of the key foraging variables we measured. Our results suggest that despite carrying large burdens of gastrointestinal parasites, the foraging strategy of female kangaroos is likely be driven by factors unrelated to parasitism, and that kangaroos in high nutritional environments may be able acquire sufficient nutrients to offset the costs of parasitism. We conclude that the drivers of forage intake likely differ between domesticated and free-ranging herbivores, and that free-ranging hosts are likely more resilient to parasitism.

  1. Anthelmintic Treatment Does Not Change Foraging Strategies of Female Eastern Grey Kangaroos, Macropus giganteus.

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    Jemma K Cripps

    Full Text Available Large mammalian herbivores are commonly infected with gastrointestinal helminths. Heavily parasitised hosts are likely to have increased nutritional requirements and would be predicted to increase their food intake to compensate for costs of being parasitised, but experimental tests of the impacts of these parasites on the foraging efficiency of hosts are lacking, particularly in free-ranging wildlife. We conducted a field experiment on a population of free-ranging eastern grey kangaroos (Macropus giganteus to test this prediction, removing nematodes from one group of adult females using an anthelmintic treatment. We then carried out observations before and following treatment to assess the influence of parasites on foraging behaviour. Contrary to our predictions, the manipulation of parasite burdens did not result in changes in any of the key foraging variables we measured. Our results suggest that despite carrying large burdens of gastrointestinal parasites, the foraging strategy of female kangaroos is likely be driven by factors unrelated to parasitism, and that kangaroos in high nutritional environments may be able acquire sufficient nutrients to offset the costs of parasitism. We conclude that the drivers of forage intake likely differ between domesticated and free-ranging herbivores, and that free-ranging hosts are likely more resilient to parasitism.

  2. The effect of olfactory exposure to non-insecticidal agrochemicals on bumblebee foraging behavior.

    Directory of Open Access Journals (Sweden)

    Jordanna D H Sprayberry

    Full Text Available Declines in bumblebee populations have led to investigations into potential causes - including agrochemical effects on bumblebee physiology. The indirect effects of agrochemicals (i.e. behavior modulation have been postulated, but rarely directly tested. Olfactory information is critical in mediating bumblebee-floral interactions. As agrochemicals emit volatiles, they may indirectly modify foraging behavior. We tested the effects of olfactory contamination of floral odor by agrochemical scent on foraging activity of Bombus impatiens using two behavioral paradigms: localization of food within a maze and forced-choice preference. The presence of a fungicide decreased bumblebees' ability to locate food within a maze. Additionally, bumblebees preferred to forage in non-contaminated feeding chambers when offered a choice between control and either fertilizer- or fungicide-scented chambers.

  3. Determinants of tree species preference for foraging by insectivorous birds in a novel Prosopis - Leucaena woodland in Puerto Rico: the role of foliage palatability

    Science.gov (United States)

    W. Beltran; J.M. Wunderle Jr.

    2013-01-01

    The foliage palatability hypothesis predicts that avian insectivores will preferentially forage in tree species with the greatest abundance of their arthropod prey, which in turn are associated with the tree’s foliage nutrition and palatability. We tested this hypothesis in a novel Prosopis–Leucaena woodland in Puerto Rico by determining foraging preferences of five...

  4. Spatiotemporal chemotactic model for ant foraging

    Science.gov (United States)

    Ramakrishnan, Subramanian; Laurent, Thomas; Kumar, Manish; Bertozzi, Andrea L.

    2014-12-01

    In this paper, we present a generic theoretical chemotactic model that accounts for certain emergent behaviors observed in ant foraging. The model does not have many of the constraints and limitations of existing models for ants colony dynamics and takes into account the distinctly different behaviors exhibited in nature by ant foragers in search of food and food ferrying ants. Numerical simulations based on the model show trail formation in foraging ant colonies to be an emergent phenomenon and, in particular, replicate behavior observed in experiments involving the species P. megacephala. The results have broader implications for the study of randomness in chemotactic models. Potential applications include the developments of novel algorithms for stochastic search in engineered complex systems such as robotic swarms.

  5. Forage diversity and nutrition supply of reindeer

    Directory of Open Access Journals (Sweden)

    Hans Staaland

    1993-12-01

    Full Text Available This study describes the mineral and nitrogen concentrations of reindeer forage plants from the Elgå reindeer herding district of south-eastern Norway. The data are compared with results from 5 other areas in Norway. Emphasis is put on the importance of environmental diversity. Different plant species accumulate Ca, Mg, P, S, Na, K, CI and K to a varying degree but reindeer can meet their nutritional requirements by eating different types of forage. Examples are sodium from aquatic herbs, sulphur and sodium from horsetails etc. Of further importance are variations in soil type, phenological development of plants in relation to differences in time for snowmelting, as well as different levels of nutrients in forage from different geographical.

  6. Ambient Air Temperature Does Not Predict whether Small or Large Workers Forage in Bumble Bees (Bombus impatiens

    Directory of Open Access Journals (Sweden)

    Margaret J. Couvillon

    2010-01-01

    Full Text Available Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature. We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16∘C and 36∘C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperatures.

  7. The impact of using alternative forages on the nutrient value within slurry and its implications for forage productivity in agricultural systems.

    Directory of Open Access Journals (Sweden)

    Felicity V Crotty

    Full Text Available Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense, lucerne (Medicago sativa or kale (Brassica oleracea would improve the yield of hybrid ryegrass (Lolium hybridicum, compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha⁻¹ with 100 kg N ha⁻¹ inorganic fertiliser; dry matter (DM yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha⁻¹ year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (Pred clover (81 kg >kale (44 kg >ryegrass (26 kg ha⁻¹ yr⁻¹. These FNE values represent relative efficiencies of 22% (ryegrass, 52% (kale, 47% (red clover and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005. Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001. Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks.

  8. Reproductive success is energetically linked to foraging efficiency in Antarctic fur seals.

    Science.gov (United States)

    Jeanniard-du-Dot, Tiphaine; Trites, Andrew W; Arnould, John P Y; Guinet, Christophe

    2017-01-01

    The efficiency with which individuals extract energy from their environment defines their survival and reproductive success, and thus their selective contribution to the population. Individuals that forage more efficiently (i.e., when energy gained exceeds energy expended) are likely to be more successful at raising viable offspring than individuals that forage less efficiently. Our goal was to test this prediction in large long-lived mammals under free-ranging conditions. To do so, we equipped 20 lactating Antarctic fur seals (Arctocephalus gazella) breeding on Kerguelen Island in the Southern Ocean with tags that recorded GPS locations, depth and tri-axial acceleration to determine at-sea behaviours and detailed time-activity budgets during their foraging trips. We also simultaneously measured energy spent at sea using the doubly-labeled water (DLW) method, and estimated the energy acquired while foraging from 1) type and energy content of prey species present in scat remains, and 2) numbers of prey capture attempts determined from head acceleration. Finally, we followed the growth of 36 pups from birth until weaning (of which 20 were the offspring of our 20 tracked mothers), and used the relative differences in body mass of pups at weaning as an index of first year survival and thus the reproductive success of their mothers. Our results show that females with greater foraging efficiencies produced relatively bigger pups at weaning. These mothers achieved greater foraging efficiency by extracting more energy per minute of diving rather than by reducing energy expenditure. This strategy also resulted in the females spending less time diving and less time overall at sea, which allowed them to deliver higher quality milk to their pups, or allowed their pups to suckle more frequently, or both. The linkage we demonstrate between reproductive success and the quality of individuals as foragers provides an individual-based quantitative framework to investigate how

  9. Is genetic engineering ever going to take off in forage, turf and bioenergy crop breeding?

    Science.gov (United States)

    Wang, Zeng-Yu; Brummer, E. Charles

    2012-01-01

    Background Genetic engineering offers the opportunity to generate unique genetic variation that is either absent in the sexually compatible gene pool or has very low heritability. The generation of transgenic plants, coupled with breeding, has led to the production of widely used transgenic cultivars in several major cash crops, such as maize, soybean, cotton and canola. The process for regulatory approval of genetically engineered crops is slow and subject to extensive political interference. The situation in forage grasses and legumes is more complicated. Scope Most widely grown forage, turf and bioenergy species (e.g. tall fescue, perennial ryegrass, switchgrass, alfalfa, white clover) are highly self-incompatible and outcrossing. Compared with inbreeding species, they have a high potential to pass their genes to adjacent plants. A major biosafety concern in these species is pollen-mediated transgene flow. Because human consumption is indirect, risk assessment of transgenic forage, turf and bioenergy species has focused on their environmental or ecological impacts. Although significant progress has been made in genetic modification of these species, commercialization of transgenic cultivars is very limited because of the stringent and costly regulatory requirements. To date, the only transgenic forage crop deregulated in the US is ‘Roundup Ready’ (RR) alfalfa. The approval process for RR alfalfa was complicated, involving several rounds of regulation, deregulation and re-regulation. Nevertheless, commercialization of RR alfalfa is an important step forward in regulatory approval of a perennial outcrossing forage crop. As additional transgenic forage, turf and bioenergy crops are generated and tested, different strategies have been developed to meet regulatory requirements. Recent progress in risk assessment and deregulation of transgenic forage and turf species is summarized and discussed. PMID:22378838

  10. Dairy cows fed on tropical legume forages: effects on milk yield, nutrients use efficiency and profitability.

    Science.gov (United States)

    Castro-Montoya, J M; García, R A; Ramos, R A; Flores, J M; Alas, E A; Corea, E E

    2018-01-02

    Two trials with multiparous dairy cows were conducted. Experiment 1 tested the effects of increasing forage proportion in the diet (500, 600, and 700 g/kg DM) when a mixed sorghum (Sorghum bicolor) and jackbean (Cannavalia ensiformis) silage was used as forage. Experiment 2 studied the substitution of sorghum silage and soybean meal by jackbean silage or fresh cowpea (Vigna unguiculata) forage in the diet. All diets were iso-energetic and iso-proteic. In each experiment, 30 cows were used and separated into three groups. In experiment 1, there were no differences in dry matter intake (DMI), milk yield (MY), or apparent total tract digestibility (aTTd) among the three diets, but milk fat content increased with increasing forage proportion, even though the similar neutral detergent fiber of all diets. Nitrogen use efficiency was highest in the diet containing 600 g forage/kg DM, and some evidence was observed for a better profitability with this forage proportion. In experiment 2, feeding legumes increased DMI despite no effects on aTTd. Milk yield increased in line with DMI, with a larger increase for the fresh cowpea. Nitrogen use efficiency and milk composition were not affected by the diets. The increased MY and lower feed costs increased the economic benefits when feeding legumes, particularly when feeding fresh cowpea. Feeding fresh cowpea or jackbean silage to dairy cows appears to be an alternative to soybean as protein source, ideally at a forage proportions of 600 g/kg DM, without altering milk yield and quality and increasing the farm profitability.

  11. Tandem Recruitment and Foraging in the Ponerine Ant Pachycondyla harpax (Fabricius).

    Science.gov (United States)

    Grüter, C; Wüst, M; Cipriano, A P; Nascimento, F S

    2018-01-10

    Tandem running is a common recruitment strategy in ant species with small colony sizes. During a tandem run, an informed leader guides a usually naïve nestmate to a food source or a nest site. Some species perform tandem runs only during house hunting, suggesting that tandem running does not always improve foraging success in species known to use tandem running as a recruitment strategy, but more natural history information on tandem running under natural conditions is needed to better understand the adaptive significance of tandem recruitment in foraging. Studying wild colonies in Brazil, we for the first time describe tandem running in the ponerine ant Pachycondyla harpax (Fabricius). We asked if foragers perform tandem runs to carbohydrate- (honey) and protein-rich (cheese) food items. Furthermore, we tested whether the speed and success rate of tandem runs depend on the foraging distance. Foragers performed tandem runs to both carbohydrate food sources and protein-rich food items that exceed a certain size. The probability to perform a tandem run and the travelling speed increase with increasing foraging distances, which could help colonies monopolize more distant food sources in a competitive environment. Guiding a recruit to a food source is costly for leaders as ants are ~66% faster when travelling alone. If tandem runs break up (~23% of all tandem runs), followers do not usually discover the food source on their own but return to the nest. Our results show that tandem running to food sources is common in P. harpax, but that foragers modify their behaviour according to the type of food and its distance from the nest. Competition with other ants was intense and we discuss how tandem running in P. harpax might help colonies to build-up a critical number of ants at large food items that can then defend the food source against competitors.

  12. RFID tracking of sublethal effects of two neonicotinoid insecticides on the foraging behavior of Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Christof W Schneider

    Full Text Available The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee and clothianidin (0.05-2 ng/bee under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of ≥0.5 ng/bee (clothianidin and ≥1.5 ng/bee (imidacloprid during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further

  13. Does information sharing promote group foraging?

    OpenAIRE

    Sernland, Emma; Olsson, Ola; Holmgren, NMA

    2003-01-01

    Individuals may join groups for several reasons, one of which is the possibility of sharing information about the quality of a foraging area. Sharing information in a patch-foraging scenario gives each group member an opportunity to make a more accurate estimate of the quality of the patch. In this paper we present a mathematical model in which we study the effect of group size on patch-leaving policy and per capita intake rate. In the model, group members share information equally in a rando...

  14. A properly adjusted forage harvester can save time and money

    Science.gov (United States)

    A properly adjusted forage harvester can save fuel and increase the realizable milk per ton of your silage. This article details the adjustments necessary to minimize energy while maximizing productivity and forage quality....

  15. [Application of near infrared spectroscopy technology (NIRS) in forage field].

    Science.gov (United States)

    Yan, Xu; Bai, Shi-Qie; Yan, Jia-Jun; Gan, You-Min; Dao, Zhi-Xue

    2012-07-01

    The majority of nutrients in ruminants and other herbivores come from forages. Forage quality not only affects the growth and production efficiency of livestock, but also determines the final output and quality of livestock products. Forage quality mainly depends on nutrient concentrations and their digestibility, palatability and the level of presence of antiquality factors and mycotoxins in forage. Near infrared reflectance spectroscopy (NIRS) has been widely used in many research areas because it is a inexpensive, rapid, simple and nondestructive technique offering the potential for qualitative and quantitative analysis. The present paper briefly introduces the principle and characteristics of NIRS, detailedly expounds the application of NIRS in forage quality. In addition, other applications of near infrared spectroscopy technique in forage are also discussed, including forage breeding, identification of variety and classification by kind. This paper comprehensively reviews the status quo of application of NIRS in forage filed, in order to contribute to promoting development of NIRS in this field in China.

  16. Information Foraging Theory: A Framework for Intelligence Analysis

    Science.gov (United States)

    2014-11-01

    oceanographic information, human intelligence (HUMINT), open-source intelligence ( OSINT ), and information provided by other governmental departments [1][5...Human Intelligence IFT Information Foraging Theory LSA Latent Semantic Similarity MVT Marginal Value Theorem OFT Optimal Foraging Theory OSINT

  17. Multiobjective bacteria foraging algorithm for electrical load dispatch problem

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, B.K., E-mail: bkpanigrahi@ee.iitd.ac.i [Department of Electrical Engineering, IIT, Delhi (India); Pandi, V. Ravikumar [Department of Electrical Engineering, IIT, Delhi (India); Sharma, Renu [Department of Electrical and Electronics Engg, ITER, SOA University, Bhubaneswar, Orissa (India); Das, Swagatam [Department of Electronics and Communication Engineering, Jadavpur University, Kolkata (India); Das, Sanjoy [Department of Electrical and Computer Engineering, Kansas State University (United States)

    2011-02-15

    In this paper the bacteria foraging meta-heuristic is extended into the domain of multiobjective optimization. In this multiobjective bacteria foraging (MOBF) optimization technique, during chemotaxis a set of intermediate bacteria positions are generated. Next, we use pareto non-dominance criterion to determine final set of bacteria positions, which constitute the superior solutions among current and intermediate solutions. To test the efficacy of our proposed algorithm we have chosen a highly constrained optimization problem namely economic/emission dispatch. Economic dispatch is a constrained optimization problem in power system to distribute the load demand among the committed generators economically. Now-a-days environmental concern that arises due to the operation of fossil fuel fired electric generators and global warming, transforms the classical economic load dispatch problem into multiobjective environmental/economic dispatch (EED). In the proposed work, we have considered the standard IEEE 30-bus six-generator test system on which several other multiobjective evolutionary algorithms are tested. We have also made a comparative study of the proposed algorithm with that of reported in the literature. Results show that the proposed algorithm is a capable candidate in solving the multiobjective economic emission load dispatch problem.

  18. Foraging Behavior of Odontomachus bauri on Barro Colorado Island, Panama

    Directory of Open Access Journals (Sweden)

    Birgit Ehmer

    1995-01-01

    Full Text Available Foraging behavior and partitioning of foraging areas of Odonomachus bauri were investigated on Barro Colorado Island in Panama. The activity of the ants did not show any daily pattern; foragers were active day and night. The type of prey captured by O. bauri supports the idea that in higher Odontomachus and Anochetus species, the high speed of mandible closure serves more for generating power than capturing elusive prey. Polydomous nests may enable O. bauri colonies to enlarge their foraging areas.

  19. Effects of seasonal advancement on the forage availability, quality ...

    African Journals Online (AJOL)

    Fourteen Sokoto Gudali cattle weighing 82 ± 11 kg were used to investigate the effect of season on the availability, quality and acceptability of forage. The animals were allowed free grazing for six hours daily and every bite of forages was collected to assess their availability and nutritive value. The forages collected were ...

  20. 7 CFR 407.13 - Group risk plan for forage.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows: 1...

  1. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Forage seeding crop insurance provisions. 457.151... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE COMMON CROP INSURANCE REGULATIONS § 457.151 Forage seeding crop insurance provisions. The Forage Seeding Crop Insurance Provisions for 2003 and succeeding crop...

  2. Comparison of nectar foraging efficiency in the Cape honeybee ...

    African Journals Online (AJOL)

    Colonies of African honeybees have significantly (p < 0,05) more unsuccessful foragers than colonies of Cape honeybees, while Cape colonies have significantly (p < 0,02) more foragers returning with nectar. No significant difference was observed in the numbers of returning pollen gatherers or foragers carrying both ...

  3. Foraging behaviour of Apis mellifera adansonii and its impact on ...

    African Journals Online (AJOL)

    A. m. adansonii primarily foraged for nectar on C. lanatus throughout the whole blooming period of each plant and pollen collection was low. The mean maximum number of workers foraging at the same time was 331 ± 173 (n= 41) per 1000 flowers. The mean foraging speed was 10.20 ± 2.75 (n = 154) flowers per minute.

  4. Scheduling and development support in the Scavenger cyber foraging system

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Bouvin, Niels Olof

    2010-01-01

    Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity. One of the main challenges within cyber foraging is that it is very difficult to develop cyber foraging enabled applications. An applicati...

  5. 7 CFR 457.117 - Forage production crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Forage production crop insurance provisions. 457.117... production crop insurance provisions. The Forage Production Crop Insurance Provisions for the 2001 and... Forage Production Crop Insurance Provisions If a conflict exists among the policy provisions, the order...

  6. Determinants of forage adoption and production niches among ...

    African Journals Online (AJOL)

    In contrast, distance to market, farm and household size negatively influenced the adoption of forages. Gender, age, off/non-farm income and number of livestock did not influence adoption of forages. Farm size, agro-ecological zone and type of livestock management system influenced the choice of niches for forage ...

  7. The role of seed attributes in eastern gray squirrel foraging

    OpenAIRE

    Sundaram, Mekala

    2016-01-01

    Seed attributes are important predictors of rodent foraging behaviors. I examined the role of seed attributes in eastern gray squirrel (Sciurus carolinensis) foraging behavior from an evolutionary, economic, ecological and biochemical perspective. From an evolutionary perspective (chapter 2), I found that squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and evolutionarily labile seed traits, which supports a diffuse coevolutionary relationship between ...

  8. Predicting of maximum forage intake capacity in cattle from ...

    African Journals Online (AJOL)

    Predicting of maximum forage intake capacity in cattle from degradability characteristics, passage rate and rumen pool size of NDF. ... It was concluded that a system of describing the physical fill of NDF in tropical forages could be used to predict VFI in cattle. Keywords: Prediction of intake, tropical forages, NDF kinetics

  9. Foraging modes of cordyliform lizards | Cooper | African Zoology

    African Journals Online (AJOL)

    The first quantitative data on foraging mode in the cordyliform lizards reveal different foraging behaviours between and within families. All species of cordylids studied (four Cordylus, two Pseudocordylus and one Platysaurus) are ambush foragers. However, the species of Cordylus and Pseudocordylus microlepidotus are ...

  10. Effects of environmental complexity and temporary captivity on foraging behavior of wild-caught meadow voles.

    Science.gov (United States)

    Kozuch, Amaranta E; McPhee, M Elsbeth

    2014-01-01

    Increased housing of wild nonhuman animals in captivity for conservation, research, and rehabilitation has revealed the importance of systematically analyzing effects of the captive environment on behavior. This study focused on the effects of complexity and time held in captivity on foraging behaviors of wild-caught, adult meadow voles (Microtus pennsylvanicus). Forty-six individuals captured from a meadow outside Oshkosh, WI, were assigned to 1 of 4 captive treatment groups: simple/50 days, complex/50 days. Number of dish visits, proportion foraging, and frequency of nonforaging behaviors recorded during a 15-min foraging trial were measured for all subjects. Kruskal-Wallis and Mann-Whitney U Tests were conducted to analyze 4 different comparisons within this behavioral data. Overall, neither time in captivity or environmental complexity affected nonforaging behaviors. In contrast, foraging behaviors did change with treatment: Voles were less active at food dishes and visited control dishes more in treatment group SS than in the other treatment groups. In addition, sex-related differences in foraging behaviors were maintained when voles were exposed to environmental complexity. This article includes options for wildlife managers to adapt captive environments to meet the welfare and behavioral needs of translocated wild nonhuman mammals.

  11. Foraging Behaviour in Magellanic Woodpeckers Is Consistent with a Multi-Scale Assessment of Tree Quality.

    Directory of Open Access Journals (Sweden)

    Pablo M Vergara

    Full Text Available Theoretical models predict that animals should make foraging decisions after assessing the quality of available habitat, but most models fail to consider the spatio-temporal scales at which animals perceive habitat availability. We tested three foraging strategies that explain how Magellanic woodpeckers (Campephilus magellanicus assess the relative quality of trees: 1 Woodpeckers with local knowledge select trees based on the available trees in the immediate vicinity. 2 Woodpeckers lacking local knowledge select trees based on their availability at previously visited locations. 3 Woodpeckers using information from long-term memory select trees based on knowledge about trees available within the entire landscape. We observed foraging woodpeckers and used a Brownian Bridge Movement Model to identify trees available to woodpeckers along foraging routes. Woodpeckers selected trees with a later decay stage than available trees. Selection models indicated that preferences of Magellanic woodpeckers were based on clusters of trees near the most recently visited trees, thus suggesting that woodpeckers use visual cues from neighboring trees. In a second analysis, Cox's proportional hazards models showed that woodpeckers used information consolidated across broader spatial scales to adjust tree residence times. Specifically, woodpeckers spent more time at trees with larger diameters and in a more advanced stage of decay than trees available along their routes. These results suggest that Magellanic woodpeckers make foraging decisions based on the relative quality of trees that they perceive and memorize information at different spatio-temporal scales.

  12. Personality-dependent differences in problem-solving performance in a social context reflect foraging strategies.

    Science.gov (United States)

    Zandberg, Lies; Quinn, John L; Naguib, Marc; van Oers, Kees

    2017-01-01

    Individuals develop innovative behaviours to solve foraging challenges in the face of changing environmental conditions. Little is known about how individuals differ in their tendency to solve problems and in their subsequent use of this solving behaviour in social contexts. Here we investigated whether individual variation in problem-solving performance could be explained by differences in the likelihood of solving the task, or if they reflect differences in foraging strategy. We tested this by studying the use of a novel foraging skill in groups of great tits (Parus major), consisting of three naive individuals with different personality, and one knowledgeable tutor. We presented them with multiple, identical foraging devices over eight trials. Though birds of different personality type did not differ in solving latency; fast and slow explorers showed a steeper increase over time in their solving rate, compared to intermediate explorers. Despite equal solving potential, personality influenced the subsequent use of the skill, as well as the pay-off received from solving. Thus, variation in the tendency to solve the task reflected differences in foraging strategy among individuals linked to their personality. These results emphasize the importance of considering the social context to fully understand the implications of learning novel skills. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Fermentation of six different forages in the semi-continuous fermentation technique Caesitec.

    Science.gov (United States)

    Vosmer, J; Liesegang, A; Wanner, M; Zeyner, A; Suter, D; Hoelzle, L; Wichert, B

    2012-10-01

    The aim of the present study was to compare carbohydrate degradation of forages which store carbohydrates either predominantly as fructan or starch, in horses' hindgut. The effects of an abrupt change from hay-based feeding to green fodder-based feeding on the caecal flora were tested with the in vitro hindgut simulation technique 'Caesitec'. Six trials with different forages (English ryegrass, tall fescue, grass mixture-horses, grass mixture-cows, lucerne, white clover) were conducted. During a 4-day stabilisation period, samples were taken once a day before loading the fermenters with hay. After diet-change to forage-based feeding, samples were taken four times a day. Ammonia and pH-value were measured before and 1, 2 and 6 h after loading the 'Caesitec'. Gas formation was measured daily. Bacterial numbers, lactate and short chain fatty acids were detected at four time-points of each trial. The grass mixtures contained the highest amounts of fructan. The pH-values were in the physiological range from pH 6 up to 7 (6.58-6.83) by feeding all forages. Gas formation, anaerobic and aerobic bacterial numbers increased after diet change from hay to any forage. The maximum amount of fructan (3.75 g/kg) in swiss pasture did not cause a permanent pathological change in the hindgut-flora. © 2012 Blackwell Verlag GmbH.

  14. Characterization of Cyber-foraging Usage Contexts

    NARCIS (Netherlands)

    Lewis, G.A.; Lago, P.

    2015-01-01

    Cyber-foraging is a technique to enable mobile devices to extend their computing power and storage by offloading computation or data to more powerful servers located in the cloud or in single-hop proximity. There are many domains and applications that can benefit from the longer battery life and

  15. Field and Forage Crop Pests. MEP 310.

    Science.gov (United States)

    Morgan, Omar, D.; And Others

    As part of a cooperative extension service series by the University of Maryland, this publication introduces the identification and control of common agricultural pests that can be found in field and forage crops. The first of the five sections defines "pest" and "weed" and generally introduces different kinds of pests in the…

  16. Alternatives for forage evaluation in ruminants

    NARCIS (Netherlands)

    Gosselink, J.M.J.

    2004-01-01

    The objective of this thesis was to validate and to compare in situ and in vitro techniques with in vivo data. These techniques were also evaluated for future and practical use in feed evaluation for ruminants. The techniques were compared using the digestion data of 98 forages and the energy

  17. Foraging guilds of North American birds

    Science.gov (United States)

    Richard M. DeGraaf; Nancy G. Tilghman; Stanley H. Anderson

    1985-01-01

    Many approaches have been taken to describe bird feeding behavior. Comparisons between different studies, however, have been difficult because of differences in terminology. We propose to establish a classification scheme for North American birds by using common terminology based on major food type, substrate, and technique, using foraging guilds.

  18. Foraging behaviour of Apis mellifera adansonii Latreille ...

    African Journals Online (AJOL)

    At Dang, flowers of each plant species were prospected at least four days per month, between 07.00 and 18.00 h, for recording of the nectar and/or pollen foraging behaviour of A. m. adansonii workers. Results showed that A. m. adansonii harvested nectar and pollen of each plant species. The greatest number of workers ...

  19. The Kanizsa triangle illusion in foraging ants.

    Science.gov (United States)

    Sakiyama, Tomoko; Gunji, Yukio-Pegio

    2016-01-01

    The Kanizsa triangle, wherein three Pac-Man configurations symmetrically face inwards, is a well-known illusion. By exposing foraging ants (Lasius niger) to Kanizsa-shaped honeydew solutions, we studied the origin of this illusion. More specifically, we examined whether foraging ants showed different movement reactions to local honeydew patterns formed by nestmates. This novel phenomenon could serve as an abstract model of the Kanizsa triangle illusion under the assumption that such an illusion could arise through the sum of each agent's limited global cognitions, because each agent could not perceive the entire subjective contours. Even a subjective consciousness consists of some parts which have no identical perception and could be an illusion. We succeeded in inducing foragers to move along the sides of a Kanizsa triangle when Pac-Man-shaped inducers were introduced. Furthermore, foragers appeared to form Y-shaped trajectories when dot-shaped or inverse Kanizsa inducers were used. Based on our findings, we propose an agent-based ant model that compares modelled behaviour with experimental phenomena. Our abstract model could be used to explain such cognitive phenomena for bottom-up processes, because ants cannot perceive the given subjective contours, instead simply move along the edges. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. African Journal of Range and Forage Science

    African Journals Online (AJOL)

    The African Journal of Range & Forage Science (previously known as Proceedings of the Grassland Society of Southern Africa and Journal of the Grassland Society of Southern Africa) is the leading rangeland and pastoral journal in Africa, and serves as an important reference for anyone interested in the management and ...

  1. Optimal search behavior and classic foraging theory

    Energy Technology Data Exchange (ETDEWEB)

    Bartumeus, F [Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ (United States); Catalan, J [Centre d' Estudis Avancats de Blanes CEAB-CSIC, C/Acces a la Cala Sant Francesc 14, 17300 Blanes, Catalonia (Spain)

    2009-10-30

    Random walk methods and diffusion theory pervaded ecological sciences as methods to analyze and describe animal movement. Consequently, statistical physics was mostly seen as a toolbox rather than as a conceptual framework that could contribute to theory on evolutionary biology and ecology. However, the existence of mechanistic relationships and feedbacks between behavioral processes and statistical patterns of movement suggests that, beyond movement quantification, statistical physics may prove to be an adequate framework to understand animal behavior across scales from an ecological and evolutionary perspective. Recently developed random search theory has served to critically re-evaluate classic ecological questions on animal foraging. For instance, during the last few years, there has been a growing debate on whether search behavior can include traits that improve success by optimizing random (stochastic) searches. Here, we stress the need to bring together the general encounter problem within foraging theory, as a mean for making progress in the biological understanding of random searching. By sketching the assumptions of optimal foraging theory (OFT) and by summarizing recent results on random search strategies, we pinpoint ways to extend classic OFT, and integrate the study of search strategies and its main results into the more general theory of optimal foraging.

  2. Skill ontogeny among Tsimane forager-horticulturalists.

    Science.gov (United States)

    Schniter, Eric; Gurven, Michael; Kaplan, Hillard S; Wilcox, Nathaniel T; Hooper, Paul L

    2015-09-01

    We investigate whether age profiles of Tsimane forager-horticulturalists' reported skill development are consistent with predictions derived from life history theory about the timing of productivity and reproduction. Previous studies of forager skill development have often focused on a few abilities (e.g. hunting), and neglected the broad range of skills and services typical of forager economies (e.g. childcare, craft production, music performance, story-telling). By systematically examining age patterns in reported acquisition, proficiency, and expertise across a broad range of activities including food production, childcare, and other services, we provide the most complete skill development study of a traditional subsistence society to date. Our results show that: (1) most essential skills are acquired prior to first reproduction, then developed further so that their productive returns meet the increasing demands of dependent offspring during adulthood; (2) as postreproductive adults age beyond earlier years of peak performance, they report developing additional conceptual and procedural proficiency, and despite greater physical frailty than younger adults, are consensually regarded as the most expert (especially in music and storytelling), consistent with their roles as providers and educators. We find that adults have accurate understandings of their skillsets and skill levels -an important awareness for social exchange, comparison, learning, and pedagogy. These findings extend our understanding of the evolved human life history by illustrating how changes in embodied capital and the needs of dependent offspring predict the development of complementary skills and services in a forager-horticulturalist economy. © 2015 Wiley Periodicals, Inc.

  3. Foraging behavior analysis of swarm robotics system

    Directory of Open Access Journals (Sweden)

    Sakthivelmurugan E.

    2018-01-01

    Full Text Available Swarm robotics is a number of small robots that are synchronically works together to accomplish a given task. Swarm robotics faces many problems in performing a given task. The problems are pattern formation, aggregation, Chain formation, self-assembly, coordinated movement, hole avoidance, foraging and self-deployment. Foraging is most essential part in swarm robotics. Foraging is the task to discover the item and get back into the shell. The researchers conducted foraging experiments with random-movement of robots and they have end up with unique solutions. Most of the researchers have conducted experiments using the circular arena. The shell is placed at the centre of the arena and environment boundary is well known. In this study, an attempt is made to different strategic movements like straight line approach, parallel line approach, divider approach, expanding square approach, and parallel sweep approach. All these approaches are to be simulated by using player/stage open-source simulation software based on C and C++ programming language in Linux operating system. Finally statistical comparison will be done with task completion time of all these strategies using ANOVA to identify the significant searching strategy.

  4. Investigating Optimal Foraging Theory in the Laboratory

    Science.gov (United States)

    Harden, Siegfried; Grilliot, Matthew E.

    2014-01-01

    Optimal foraging theory is a principle that is often presented in the community ecology section of biology textbooks, but also can be demonstrated in the laboratory. We introduce a lab activity that uses an interactive strategy to teach high school and/or college students about this ecological concept. The activity is ideal because it engages…

  5. Balancing organization and flexibility in foraging dynamics.

    Science.gov (United States)

    Tabone, Michaelangelo; Ermentrout, Bard; Doiron, Brent

    2010-10-07

    Proper pattern organization and reorganization are central problems facing many biological networks which thrive in fluctuating environments. However, in many cases the mechanisms that organize system activity oppose those that support behavioral flexibility. Thus, a balance between pattern organization and pattern flexibility is critically important for overall biological fitness. We study this balance in the foraging strategies of ant colonies exploiting food in dynamic environments. We present discrete time and space simulations of colony activity that uses a pheromone-based recruitment strategy biasing foraging towards a food source. After food relocation, the pheromone must evaporate sufficiently before foraging can shift colony attention to a new food source. The amount of food consumed within the dynamic environment depends non-monotonically on the pheromone evaporation time constant-with maximal consumption occurring at a time constant which balances trail formation and trail flexibility. A deterministic, 'mean field' model of pheromone and foragers on trails mimics our colony simulations. This reduced framework captures the essence of the flexibility-organization balance, and relates optimal pheromone evaporation to the timescale of the dynamic environment. We expect that the principles exposed in our study will generalize and motivate novel analysis across a broad range systems biology. 2010 Elsevier Ltd. All rights reserved.

  6. Scholarly Foraging and Network Discovery Tools.

    Science.gov (United States)

    Cronin, Blaise; Hert, Carol A.

    1995-01-01

    Parallels between subsistence foraging and scholarly information seeking are described in the context of the World Wide Web. Suggests that the prevailing information retrieval paradigm does not capture the complex of behavior and stimuli that drives scholars' quests for new ideas and insights. Research questions are suggested by extended use of…

  7. Rumen degradation characteristics of two tropical forages ...

    African Journals Online (AJOL)

    Rumen degradation characteristics of Panicum maximum and Gmelina arborea forages in response to monensin supplementation were studied in a 2 x 4 factorial experiment using an N'dama fistulated steer. Monensin had no significant effect (P>0.05) on the soluble fraction 'a' of nutrients but showed reductions (P<0.05) ...

  8. Varroa destructor Mites Can Nimbly Climb from Flowers onto Foraging Honey Bees.

    Science.gov (United States)

    Peck, David T; Smith, Michael L; Seeley, Thomas D

    2016-01-01

    Varroa destructor, the introduced parasite of European honey bees associated with massive colony deaths, spreads readily through populations of honey bee colonies, both managed colonies living crowded together in apiaries and wild colonies living widely dispersed in natural settings. Mites are hypothesized to spread between most managed colonies via phoretically riding forager bees when they engage in robbing colonies or they drift between hives. However, widely spaced wild colonies show Varroa infestation despite limited opportunities for robbing and little or no drifting of bees between colonies. Both wild and managed colonies may also exchange mites via another mechanism that has received remarkably little attention or study: floral transmission. The present study tested the ability of mites to infest foragers at feeders or flowers. We show that Varroa destructor mites are highly capable of phoretically infesting foraging honey bees, detail the mechanisms and maneuvers by which they do so, and describe mite behaviors post-infestation.

  9. Anterior cingulate engagement in a foraging context reflects choice difficulty, not foraging value.

    Science.gov (United States)

    Shenhav, Amitai; Straccia, Mark A; Cohen, Jonathan D; Botvinick, Matthew M

    2014-09-01

    Previous theories predict that human dorsal anterior cingulate (dACC) should respond to decision difficulty. An alternative theory has been recently advanced that proposes that dACC evolved to represent the value of 'non-default', foraging behavior, calling into question its role in choice difficulty. However, this new theory does not take into account that choosing whether or not to pursue foraging-like behavior can also be more difficult than simply resorting to a default. The results of two neuroimaging experiments show that dACC is only associated with foraging value when foraging value is confounded with choice difficulty; when the two are dissociated, dACC engagement is only explained by choice difficulty, and not the value of foraging. In addition to refuting this new theory, our studies help to formalize a fundamental connection between choice difficulty and foraging-like decisions, while also prescribing a solution for a common pitfall in studies of reward-based decision making.

  10. Attention as foraging for information and reward

    Directory of Open Access Journals (Sweden)

    Sanjay G Manohar

    2013-11-01

    Full Text Available What is the purpose of attention? One avenue of research has led to the proposal that attention might be crucial for gathering information about the environment, while other lines of study have demonstrated attention's role in guiding behavior to rewarded options. Many experiments to study attention require participants to make a decision based on information acquired discretely at one point in time. In real-world situations, however, we are usually not presented with information about which option to select in such a manner. Rather we must initially search for information, weighing up reward values of options before we commit to a decision.Here, we propose that attention plays a role in both foraging for information and foraging for value.When foraging for information, attention is guided towards the unknown. When foraging for reward, attention is guided towards high reward values, allowing decision-making to proceed by accept-or-reject decisions on the currently attended option. According to this account, attention can be regarded as a low-cost alternative to moving around and engaging with the environment—teleforaging—before a decision is made to interact physically with the world.To track the timecourse of attention, we asked participants to seek out and acquire information about two gambles by directing their gaze, before choosing one of them. Participants often made multiple refixations on items before making a decision. Their eye movements revealed that early in the trial, attention was guided towards information, i.e. towards locations that reduced uncertainty about value. In contrast, late in the trial, attention was guided by expected value of the options. At the end of the decision period, participants were generally attending to the item they eventually chose. We suggest that attentional foraging shifts from an uncertainty-driven to a reward-driven mode during the evolution of a decision, allowing choices to be made by an engage

  11. Attention as foraging for information and value.

    Science.gov (United States)

    Manohar, Sanjay G; Husain, Masud

    2013-01-01

    What is the purpose of attention? One avenue of research has led to the proposal that attention might be crucial for gathering information about the environment, while other lines of study have demonstrated how attention may play a role in guiding behavior to rewarded options. Many experiments that study attention require participants to make a decision based on information acquired discretely at one point in time. In real-world situations, however, we are usually not presented with information about which option to select in such a manner. Rather we must initially search for information, weighing up reward values of options before we commit to a decision. Here, we propose that attention plays a role in both foraging for information and foraging for value. When foraging for information, attention is guided toward the unknown. When foraging for reward, attention is guided toward high reward values, allowing decision-making to proceed by accept-or-reject decisions on the currently attended option. According to this account, attention can be regarded as a low-cost alternative to moving around and physically interacting with the environment-"teleforaging"-before a decision is made to interact physically with the world. To track the timecourse of attention, we asked participants to seek out and acquire information about two gambles by directing their gaze, before choosing one of them. Participants often made multiple refixations on items before making a decision. Their eye movements revealed that early in the trial, attention was guided toward information, i.e., toward locations that reduced uncertainty about value. In contrast, late in the trial, attention was guided by expected value of the options. At the end of the decision period, participants were generally attending to the item they eventually chose. We suggest that attentional foraging shifts from an uncertainty-driven to a reward-driven mode during the evolution of a decision, permitting decisions to be made by

  12. Can video playback provide social information for foraging blue tits?

    Science.gov (United States)

    Hämäläinen, Liisa; Rowland, Hannah M; Mappes, Johanna; Thorogood, Rose

    2017-01-01

    Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits (Cyanistes caeruleus) videos of demonstrators discovering palatable or aversive prey (injected with bitter-tasting Bitrex) from coloured feeding cups. First we quantify variation in demonstrators' responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show that focal blue tits respond differently to the presence of a demonstrator on a video screen, depending on whether demonstrators discover palatable or aversive prey. Focal birds faced the video screen more during aversive prey presentations, and made more head turns. Regardless of prey type, focal birds also hopped more frequently during the presence of a demonstrator (compared to a control video of a different coloured feeding cup in an empty cage). Finally, we tested if demonstrators' behaviour affected focal birds' food preferences by giving individuals a choice to forage from the same cup as a demonstrator, or from the cup in the control video. We found that only half of the individuals made their choice in accordance to social information in the videos, i.e., their foraging choices were not different from random. Individuals that chose in accordance with a demonstrator, however, made their choice faster than individuals that chose an alternative cup. Together, our results suggest that video playback can provide social cues to blue tits, but individuals vary greatly in how they use this information in their foraging decisions.

  13. Can video playback provide social information for foraging blue tits?

    Directory of Open Access Journals (Sweden)

    Liisa Hämäläinen

    2017-03-01

    Full Text Available Video playback is becoming a common method for manipulating social stimuli in experiments. Parid tits are one of the most commonly studied groups of wild birds. However, it is not yet clear if tits respond to video playback or how their behavioural responses should be measured. Behaviours may also differ depending on what they observe demonstrators encountering. Here we present blue tits (Cyanistes caeruleus videos of demonstrators discovering palatable or aversive prey (injected with bitter-tasting Bitrex from coloured feeding cups. First we quantify variation in demonstrators’ responses to the prey items: aversive prey provoked high rates of beak wiping and head shaking. We then show that focal blue tits respond differently to the presence of a demonstrator on a video screen, depending on whether demonstrators discover palatable or aversive prey. Focal birds faced the video screen more during aversive prey presentations, and made more head turns. Regardless of prey type, focal birds also hopped more frequently during the presence of a demonstrator (compared to a control video of a different coloured feeding cup in an empty cage. Finally, we tested if demonstrators’ behaviour affected focal birds’ food preferences by giving individuals a choice to forage from the same cup as a demonstrator, or from the cup in the control video. We found that only half of the individuals made their choice in accordance to social information in the videos, i.e., their foraging choices were not different from random. Individuals that chose in accordance with a demonstrator, however, made their choice faster than individuals that chose an alternative cup. Together, our results suggest that video playback can provide social cues to blue tits, but individuals vary greatly in how they use this information in their foraging decisions.

  14. Comparative Foraging Efficiency of Two Sympatric Jackals, Silver-Backed Jackals (Canis mesomelas and Golden Jackals (Canis aureus, in the Ngorongoro Crater, Tanzania

    Directory of Open Access Journals (Sweden)

    S. E. Temu

    2016-01-01

    Full Text Available The foraging efficiency of two sympatric species of jackals, silver-backed jackals (Canis mesomelas and golden jackals (Canis aureus, was studied in the Ngorongoro crater from July 2014 through May 2015. The focal animal observation method was used and individuals of both species were followed as they foraged from morning to evening. Observations of individuals of both jackal species were made from a vehicle using binoculars and a spotting scope. Three major parameters were used for determination of foraging efficiency: distance travelled while foraging, time spent foraging, and amount of food secured in foraging period. The Mann–Whitney U test showed no significant difference (P>0.05 in distance travelled per unit time of foraging between the two species in the dry and wet seasons, respectively. Golden jackals secured a significantly higher amount of food than the silver-backed jackals in the wet season (Mann–Whitney U test, P<0.05, U=1035.4. Hunting of prey larger than Thomson’s gazelle (Eudorcas thomsonii fawns was not common. Both species mainly fed on smaller prey such as invertebrates and rodents and scavenged opportunistically. Efficient foraging is crucial for both jackal species especially during their breeding season when they are provisioning dependent pups.

  15. GRASS SPECIES FROM C-4 CARBON FIXATION GROUP: POLISH EXPERIMENT WITH A NOVEL ENERGY AND FORAGE PURPOSES CROP

    Directory of Open Access Journals (Sweden)

    Włodzimierz Majtkowski

    2010-02-01

    Full Text Available Experiment was conducted during four years 2003-2006. Materials used were three genus grass species of C-4 photosynthesis: Andropogon gerardi Vitman, Panicum virgatum L. and Miscanthus sacchariflorus (Maxim. Hack. Plants were planted at spring 1998. Agrotechnical part of experiment was conducted in Botanical Garden of Plant Breeding Acclimatization Institute in Bydgoszcz and analytical part in Department of Animal Nutrition and Feed Management, Faculty of Animal Breeding and Biology of University of Technology and Life Science in Bydgoszcz. Forage from grass C-4 photosynthesis were material of good ensilage suitability. High structural carbohydrates (NDF, ADF contents in tested forage dry matter suggest ensilage at early phases of plant development. Above results suggest to possibility of usage of forage from grass C-4 carbon fixation group for animal feeding purposes. C-4 grass forage should be recognized as a supplementary source of green matter in periods of insufficient access to traditional silage sources.

  16. Intraspecific Variation among Social Insect Colonies: Persistent Regional and Colony-Level Differences in Fire Ant Foraging Behavior.

    Directory of Open Access Journals (Sweden)

    Alison A Bockoven

    Full Text Available Individuals vary within a species in many ecologically important ways, but the causes and consequences of such variation are often poorly understood. Foraging behavior is among the most profitable and risky activities in which organisms engage and is expected to be under strong selection. Among social insects there is evidence that within-colony variation in traits such as foraging behavior can increase colony fitness, but variation between colonies and the potential consequences of such variation are poorly documented. In this study, we tested natural populations of the red imported fire ant, Solenopsis invicta, for the existence of colony and regional variation in foraging behavior and tested the persistence of this variation over time and across foraging habitats. We also reared single-lineage colonies in standardized environments to explore the contribution of colony lineage. Fire ants from natural populations exhibited significant and persistent colony and regional-level variation in foraging behaviors such as extra-nest activity, exploration, and discovery of and recruitment to resources. Moreover, colony-level variation in extra-nest activity was significantly correlated with colony growth, suggesting that this variation has fitness consequences. Lineage of the colony had a significant effect on extra-nest activity and exploratory activity and explained approximately half of the variation observed in foraging behaviors, suggesting a heritable component to colony-level variation in behavior.

  17. Experience matters: context-dependent decisions explain spatial foraging patterns in the deposit-feeding crab Scopimera intermedia.

    Science.gov (United States)

    Hui, T Y; Williams, Gray A

    2017-08-30

    Behavioural decisions are often context-dependent, where information from immediate experience is incorporated into an individual's decision-making, particularly in complex environments. To test whether such mechanism is adopted by foragers in heterogeneous environments, we investigated the foraging behaviour of the deposit-feeding sand-bubbler crab, Scopimera intermedia An individual-based model was constructed, based on an optimal-patch selection criterion, which implicitly assumed that individuals adjust foraging decisions based on immediate past experience. The model's predictions were tested on the shore by manipulating the location of food patches, where the crab showed a strong context-dependent foraging pattern. When resources were randomly distributed, the crab responded by spending 56% of time in enriched patches compared with only 28% in the same area when patches were composed of natural sediments. Shore manipulations varying resource distribution supported the underlying principles of the model mechanism, and highlighted the benefits of such a strategy in heterogeneous environments such as intertidal sediments where food resources vary at different spatial and temporal scales. The proposed model therefore provides a mechanistic process, based on optimal foraging, to predict foraging decisions and movement patterns of animals feeding in heterogeneous landscapes. © 2017 The Author(s).

  18. Posterior Cingulate Neurons Dynamically Signal Decisions to Disengage during Foraging.

    Science.gov (United States)

    Barack, David L; Chang, Steve W C; Platt, Michael L

    2017-10-11

    Foraging for resources is a fundamental behavior balancing systematic search and strategic disengagement. The foraging behavior of primates is especially complex and requires long-term memory, value comparison, strategic planning, and decision-making. Here we provide evidence from two different foraging tasks that neurons in primate posterior cingulate cortex (PCC) signal decision salience during foraging to motivate disengagement from the current strategy. In our foraging tasks, salience refers to the difference between decision thresholds and the net harvested reward. Salience signals were stronger in poor foraging contexts than rich ones, suggesting low harvest rates recruit mechanisms in PCC that regulate strategic disengagement and exploration during foraging. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Scavenger: Transparent Development of Efficient Cyber Foraging Applications

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø

    2010-01-01

    Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity. This paper presents Scavenger-a new cyber foraging system supporting easy development of mobile cyber foraging applications, while still...... delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new dual-profiling scheduler. One of the main difficulties within cyber foraging is that it is very challenging for application programmers to develop cyber foraging...... enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science known to be hard for programmers to grasp. In this paper it is shown by example, how a highly distributed, parallel, cyber foraging enabled...

  20. Comparative digestibility by cattle versus sheep: effect of forage quality.

    Science.gov (United States)

    Soto-Navarro, S A; Lopez, R; Sankey, C; Capitan, B M; Holland, B P; Balstad, L A; Krehbiel, C R

    2014-04-01

    The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned to 1 of 3 forage sources within ruminant specie, and the study was conducted over 3 periods. For forage source, both animal and period served as the blocking factor with all forage sources represented once within each animal and all forage sources represented at least once within each period. The treatment structure was arranged in a 2 × 3 factorial with ruminant species (2) and forage source (3) as the factors. Forage sources were 1) alfalfa hay (Medicago sativa; 17.5% CP and 34.1% NDF, DM basis), 2) warm-season grass hay mix (Bothriochloa ischaemum and Cynodon dactylon; 7.3% CP and 74.7% NDF, DM basis), and 3) lovegrass hay (Eragrostis curvula; 2.5% CP and 81.9% NDF, DM basis). As a percent of BW, steers and wethers consumed similar (P ≤ 0.06) amounts of forage, and intake was more influenced by forage quality (P forage than by ruminant species (P = 0.07). Steers and wethers had greater (P forages are evaluated. However, sheep are not an adequate model for cattle when low-quality forages are compared because cattle digest low-quality forages to a greater extent than sheep. Expressing digestibility as digestible intake per unit of BW allows for a wider range of forage qualities to be compared when substituting sheep for cattle.

  1. The regulation of ant colony foraging activity without spatial information.

    Science.gov (United States)

    Prabhakar, Balaji; Dektar, Katherine N; Gordon, Deborah M

    2012-01-01

    Many dynamical networks, such as the ones that produce the collective behavior of social insects, operate without any central control, instead arising from local interactions among individuals. A well-studied example is the formation of recruitment trails in ant colonies, but many ant species do not use pheromone trails. We present a model of the regulation of foraging by harvester ant (Pogonomyrmex barbatus) colonies. This species forages for scattered seeds that one ant can retrieve on its own, so there is no need for spatial information such as pheromone trails that lead ants to specific locations. Previous work shows that colony foraging activity, the rate at which ants go out to search individually for seeds, is regulated in response to current food availability throughout the colony's foraging area. Ants use the rate of brief antennal contacts inside the nest between foragers returning with food and outgoing foragers available to leave the nest on the next foraging trip. Here we present a feedback-based algorithm that captures the main features of data from field experiments in which the rate of returning foragers was manipulated. The algorithm draws on our finding that the distribution of intervals between successive ants returning to the nest is a Poisson process. We fitted the parameter that estimates the effect of each returning forager on the rate at which outgoing foragers leave the nest. We found that correlations between observed rates of returning foragers and simulated rates of outgoing foragers, using our model, were similar to those in the data. Our simple stochastic model shows how the regulation of ant colony foraging can operate without spatial information, describing a process at the level of individual ants that predicts the overall foraging activity of the colony.

  2. The regulation of ant colony foraging activity without spatial information.

    Directory of Open Access Journals (Sweden)

    Balaji Prabhakar

    Full Text Available Many dynamical networks, such as the ones that produce the collective behavior of social insects, operate without any central control, instead arising from local interactions among individuals. A well-studied example is the formation of recruitment trails in ant colonies, but many ant species do not use pheromone trails. We present a model of the regulation of foraging by harvester ant (Pogonomyrmex barbatus colonies. This species forages for scattered seeds that one ant can retrieve on its own, so there is no need for spatial information such as pheromone trails that lead ants to specific locations. Previous work shows that colony foraging activity, the rate at which ants go out to search individually for seeds, is regulated in response to current food availability throughout the colony's foraging area. Ants use the rate of brief antennal contacts inside the nest between foragers returning with food and outgoing foragers available to leave the nest on the next foraging trip. Here we present a feedback-based algorithm that captures the main features of data from field experiments in which the rate of returning foragers was manipulated. The algorithm draws on our finding that the distribution of intervals between successive ants returning to the nest is a Poisson process. We fitted the parameter that estimates the effect of each returning forager on the rate at which outgoing foragers leave the nest. We found that correlations between observed rates of returning foragers and simulated rates of outgoing foragers, using our model, were similar to those in the data. Our simple stochastic model shows how the regulation of ant colony foraging can operate without spatial information, describing a process at the level of individual ants that predicts the overall foraging activity of the colony.

  3. Insect odour perception: recognition of odour components by flower foraging moths.

    Science.gov (United States)

    Cunningham, John Paul; Moore, Chris J; Zalucki, Myron P; Cribb, Bronwen W

    2006-08-22

    Odours emitted by flowers are complex blends of volatile compounds. These odours are learnt by flower-visiting insect species, improving their recognition of rewarding flowers and thus foraging efficiency. We investigated the flexibility of floral odour learning by testing whether adult moths recognize single compounds common to flowers on which they forage. Dual choice preference tests on Helicoverpa armigera moths allowed free flying moths to forage on one of three flower species; Argyranthemum frutescens (federation daisy), Cajanus cajan (pigeonpea) or Nicotiana tabacum (tobacco). Results showed that, (i) a benzenoid (phenylacetaldehyde) and a monoterpene (linalool) were subsequently recognized after visits to flowers that emitted these volatile constituents, (ii) in a preference test, other monoterpenes in the flowers' odour did not affect the moths' ability to recognize the monoterpene linalool and (iii) relative preferences for two volatiles changed after foraging experience on a single flower species that emitted both volatiles. The importance of using free flying insects and real flowers to understand the mechanisms involved in floral odour learning in nature are discussed in the context of our findings.

  4. Effects of forage species and poultry litter application timing on forage preference by horses.

    Science.gov (United States)

    Clark, J K; Shanks, B C; Jogan, K S; Philipp, D; Coffey, K P; Jack, N E; Caldwell, J D; Rhein, R T

    2016-12-01

    Bermudagrass ( L.) is a familiar forage in the equine industry and teff () is gaining popularity as well. However, it is unclear if the application of poultry litter as a fertilizer affects palatability of these forages in horses. Therefore, the objective of this study was to determine if forage species and timing of litter application as a fertilizer has an effect on preference by horses. Hay treatments were arranged in a 2 × 3 factorial treatment arrangement consisting of teff and bermudagrass harvested after no poultry litter application (NL), poultry litter applied to stubble immediately after removal of the previous cutting (L0), or poultry litter applied 14 d after the previous cutting (L14). Mature, stock-type geldings ( = 5; 480 ± 52.9 kg) were used in this study arranged as a balanced incomplete block design. Horses were offered different combinations of 4 of the 6 total forages daily for 3 d in each of 3 evaluation periods that immediately followed a 10-d adaptation period. Each forage was offered at half of the total daily DMI as measured during the last 5 d of the 10-d adaptation period to encourage selection among the 4 forages. Each hay offered was randomly allocated to a corner and suspended in hay nets over muck buckets in the corners of each stall. Horses were individually housed in 3.6- by 3.6-m indoor stalls with sand bedding and access to 3.6- by 7.6-m outdoor runs. Along with hay, horses were offered oats twice daily at 0.125% of BW at each feeding. Dry matter intake was greater ( Horses spent more ( horses may prefer bermudagrass to teff and later application of poultry litter may affect voluntary intake by horses. However, all forages were mature, which may have impacted total intake and preference.

  5. Germinative potential of encrusted seed of tropical forage species

    Directory of Open Access Journals (Sweden)

    José Rafael de Souza

    Full Text Available ABSTRACT: Brazil is the largest producer, consumer and exporter of seeds of forage species, thus the adoption of new technologies for expansion and maintenance of this market is of great importance. The aim of this work was to evaluate encrustation effect on germination potential in seeds of Brachiaria sp. species. The experiment was carried out in Biofabrica laboratory from June to August 2014, in Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista-BA. The experimental design was completely randomized, in a factorial scheme 6x2, with two treatments (with and without coating and four replications. For germination quality of seeds were evaluated germination and vigor (emergence, emergence speed index, total length of seedling, shoot and root. The encrustation affected positively the germination of seeds in all species tested and encrustation did not affect the total length, shoot and root of the seedlings. Coating after chemical scarification is an alternative to improve germination of the seeds of tropical forage species.

  6. Social Learning in Bumblebees (Bombus impatiens: Worker Bumblebees Learn to Manipulate and Forage at Artificial Flowers by Observation and Communication within the Colony

    Directory of Open Access Journals (Sweden)

    Hamida B. Mirwan

    2013-01-01

    Full Text Available Social learning occurs when one individual learns from another, mainly conspecific, often by observation, imitation, or communication. Using artificial flowers, we studied social learning by allowing test bumblebees to (a see dead bumblebees arranged in foraging positions or (b watch live bumblebees actually foraging or (c communicate with nestmates within their colony without having seen foraging. Artificial flowers made from 1.5 mL microcentrifuge tubes with closed caps were inserted through the centres of blue 7 cm plastic discs as optical signals through which the bees could not forage. The reinforcer reward syrup was accessible only through holes in the sides of the tubes beneath the blue discs. Two colonies (A and B were used in tandem along with control (C and D colonies. No bee that was not exposed (i.e., from the control colonies (C and D to social learning discovered the access holes. Inside colony B, we imprisoned a group of bees that were prevented from seeing or watching. Bees that saw dead bumblebees in foraging positions, those that watched nest-mates foraging, and those that had only in-hive communication with successful foragers all foraged successfully. The means of in-hive communication are not understood and warrant intense investigation.

  7. Diffusion of novel foraging behaviour in Amazon parrots through social learning.

    Science.gov (United States)

    Morales Picard, Alejandra; Hogan, Lauren; Lambert, Megan L; Wilkinson, Anna; Seed, Amanda M; Slocombe, Katie E

    2017-03-01

    While social learning has been demonstrated in species across many taxa, the role it plays in everyday foraging decisions is not well understood. Investigating social learning during foraging could shed light on the emergence of cultural variation in different groups. We used an open diffusion experiment to examine the spread of a novel foraging technique in captive Amazon parrots. Three groups were tested using a two-action foraging box, including experimental groups exposed to demonstrators using different techniques and control birds. We also examined the influence of agonistic and pilfering behaviour on task acquisition. We found evidence of social learning: more experimental birds than control birds interacted with and opened the box. The birds were, however, no more likely to use the demonstrated technique than the non-demonstrated one, making local or stimulus enhancement the most likely mechanism. Exhibiting aggression was positively correlated with box opening, whilst receiving aggression did not reduce motivation to engage with the box, indicating that willingness to defend access to the box was important in task acquisition. Pilfering food and success in opening the box were also positively correlated; however, having food pilfered did not affect victims' motivation to interact with the box. In a group context, pilfering may promote learning of new foraging opportunities. Although previous studies have demonstrated that psittacines are capable of imitation, in this naturalistic set-up there was no evidence that parrots copied the demonstrated opening technique. Foraging behaviour in wild populations of Amazons could therefore be facilitated by low-fidelity social learning mechanisms.

  8. Influence of density-dependent competition on foraging and migratory behavior of a subtropical colonial seabird.

    Science.gov (United States)

    Lamb, Juliet S; Satgé, Yvan G; Jodice, Patrick G R

    2017-08-01

    Density-dependent competition for food resources influences both foraging ecology and reproduction in a variety of animals. The relationship between colony size, local prey depletion, and reproductive output in colonial central-place foragers has been extensively studied in seabirds; however, most studies have focused on effects of intraspecific competition during the breeding season, while little is known about whether density-dependent resource depletion influences individual migratory behavior outside the breeding season. Using breeding colony size as a surrogate for intraspecific resource competition, we tested for effects of colony size on breeding home range, nestling health, and migratory patterns of a nearshore colonial seabird, the brown pelican (Pelecanus occidentalis), originating from seven breeding colonies of varying sizes in the subtropical northern Gulf of Mexico. We found evidence for density-dependent effects on foraging behavior during the breeding season, as individual foraging areas increased linearly with the number of breeding pairs per colony. Contrary to our predictions, however, nestlings from more numerous colonies with larger foraging ranges did not experience either decreased condition or increased stress. During nonbreeding, individuals from larger colonies were more likely to migrate, and traveled longer distances, than individuals from smaller colonies, indicating that the influence of density-dependent effects on distribution persists into the nonbreeding period. We also found significant effects of individual physical condition, particularly body size, on migratory behavior, which in combination with colony size suggesting that dominant individuals remain closer to breeding sites during winter. We conclude that density-dependent competition may be an important driver of both the extent of foraging ranges and the degree of migration exhibited by brown pelicans. However, the effects of density-dependent competition on breeding

  9. Evidence for density dependence in foraging and migratory behavior of a subtropical nearshore seabird

    Science.gov (United States)

    Lamb, Juliet S.; Satgé, Yvan G.; Jodice, Patrick

    2017-01-01

    Density-dependent competition for food resources influences both foraging ecology and reproduction in a variety of animals. The relationship between colony size, local prey depletion, and reproductive output in colonial central-place foragers has been extensively studied in seabirds; however, most studies have focused on effects of intraspecific competition during the breeding season, while little is known about whether density-dependent resource depletion influences individual migratory behavior outside the breeding season. Using breeding colony size as a surrogate for intraspecific resource competition, we tested for effects of colony size on breeding home range, nestling health, and migratory patterns of a nearshore colonial seabird, the brown pelican (Pelecanus occidentalis), originating from seven breeding colonies of varying sizes in the subtropical northern Gulf of Mexico. We found evidence for density-dependent effects on foraging behavior during the breeding season, as individual foraging areas increased linearly with the number of breeding pairs per colony. Contrary to our predictions, however, nestlings from more numerous colonies with larger foraging ranges did not experience either decreased condition or increased stress. During nonbreeding, individuals from larger colonies were more likely to migrate, and traveled longer distances, than individuals from smaller colonies, indicating that the influence of density-dependent effects on distribution persists into the nonbreeding period. We also found significant effects of individual physical condition, particularly body size, on migratory behavior, which in combination with colony size suggesting that dominant individuals remain closer to breeding sites during winter. We conclude that density-dependent competition may be an important driver of both the extent of foraging ranges and the degree of migration exhibited by brown pelicans. However, the effects of density-dependent competition on breeding

  10. Congestion management using adaptive bacterial foraging algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, B.K.; Ravikumar Pandi, V. [Department of Electrical Engineering, Indian Institute of Technology, Delhi 110 016 (India)

    2009-05-15

    The economical operation of power system is associated with many sub-problems. The electric market background makes the operation of system further complicated one. The congestion management problem can be devised as the emerging problem needs to concentrate much in order to supply power to the consumers in most reliable manner. In this paper we have tried to remove the congestion in the transmission line by generation rescheduling with the cost involved in the rescheduling process should be minimized. The adaptive bacterial foraging algorithm with Nelder-Mead (ABFNM) is used in this work to optimize the congestion cost. The results are also compared with the genetic algorithm (GA), particle swarm optimization (PSO) and simple bacterial foraging (SBF) algorithms. Numerical results for the standard IEEE 30 bus system having six generating units have been presented to demonstrate the performance of the algorithm. (author)

  11. Visual perception and social foraging in birds.

    Science.gov (United States)

    Fernández-Juricic, Esteban; Erichsen, Jonathan T; Kacelnik, Alex

    2004-01-01

    Birds gather information about their environment mainly through vision by scanning their surroundings. Many prevalent models of social foraging assume that foraging and scanning are mutually exclusive. Although this assumption is valid for birds with narrow visual fields, these models have also been applied to species with wide fields. In fact, available models do not make precise predictions for birds with large visual fields, in which the head-up, head-down dichotomy is not accurate and, moreover, do not consider the effects of detection distance and limited attention. Studies of how different types of visual information are acquired as a function of body posture and of how information flows within flocks offer new insights into the costs and benefits of living in groups.

  12. Source levels of foraging humpback whale calls.

    Science.gov (United States)

    Fournet, Michelle E H; Matthews, Leanna P; Gabriele, Christine M; Mellinger, David K; Klinck, Holger

    2018-02-01

    Humpback whales produce a wide range of low- to mid-frequency vocalizations throughout their migratory range. Non-song "calls" dominate this species' vocal repertoire while on high-latitude foraging grounds. The source levels of 426 humpback whale calls in four vocal classes were estimated using a four-element planar array deployed in Glacier Bay National Park and Preserve, Southeast Alaska. There was no significant difference in source levels between humpback whale vocal classes. The mean call source level was 137 dB RMS re 1 μPa @ 1 m in the bandwidth of the call (range 113-157 dB RMS re 1 μPa @ 1 m), where bandwidth is defined as the frequency range from the lowest to the highest frequency component of the call. These values represent a robust estimate of humpback whale source levels on foraging grounds and should append earlier estimates.

  13. The impact of using alternative forages on the nutrient value within slurry and its implications for forage productivity in agricultural systems.

    Science.gov (United States)

    Crotty, Felicity V; Fychan, Rhun; Theobald, Vince J; Sanderson, Ruth; Chadwick, David R; Marley, Christina L

    2014-01-01

    Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha⁻¹) with 100 kg N ha⁻¹ inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha⁻¹ year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (Pred clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha⁻¹ yr⁻¹). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (Pforages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks.

  14. Repellent foraging scent recognition across bee families

    OpenAIRE

    Gawleta, Nadine; Zimmermann, Yvonne; Eltz, Thomas

    2005-01-01

    International audience; Honeybees and bumblebees avoid probing flowers that have been recently depleted by conspecifics, presumably repelled by odours deposited by the previous visitor (foraging scent marks). Here we show that females of the solitary wool-carder bee Anthidium manicatum (Megachilidae) discriminate against previously visited inflorescences (Stachys officinalis), and that discrimination is equally strong regardless of whether the previous visitor is conspecific or belongs to a d...

  15. Marine Forage Fishes in Puget Sound

    Science.gov (United States)

    2007-03-01

    incubation period (Penttila 2002, Rice 2006) (Figure 13). During the summer, incubation times are about two weeks, while during cold winter weather, it...Various present-day stres - sors on forage fish spawning habitats are reviewed in a fol- lowing section. With continued human population growth predicted...in microhabitats occupied by early life history stages of spawning fishes otherwise adapted to cold climates (Brennan and Culverwell 2004, Rice 2006

  16. Hybrid value foraging: How the value of targets shapes human foraging behavior.

    Science.gov (United States)

    Wolfe, Jeremy M; Cain, Matthew S; Alaoui-Soce, Abla

    2017-12-21

    In hybrid foraging, observers search visual displays for multiple instances of multiple target types. In previous hybrid foraging experiments, although there were multiple types of target, all instances of all targets had the same value. Under such conditions, behavior was well described by the marginal value theorem (MVT). Foragers left the current "patch" for the next patch when the instantaneous rate of collection dropped below their average rate of collection. An observer's specific target selections were shaped by previous target selections. Observers were biased toward picking another instance of the same target. In the present work, observers forage for instances of four target types whose value and prevalence can vary. If value is kept constant and prevalence manipulated, participants consistently show a preference for the most common targets. Patch-leaving behavior follows MVT. When value is manipulated, observers favor more valuable targets, though individual foraging strategies become more diverse, with some observers favoring the most valuable target types very strongly, sometimes moving to the next patch without collecting any of the less valuable targets.

  17. Effect of Interactions between Harvester Ants on Forager Decisions

    Science.gov (United States)

    Davidson, Jacob D.; Arauco-Aliaga, Roxana P.; Crow, Sam; Gordon, Deborah M.; Goldman, Mark S.

    2017-01-01

    Harvester ant colonies adjust their foraging activity to day-to-day changes in food availability and hour-to-hour changes in environmental conditions. This collective behavior is regulated through interactions, in the form of brief antennal contacts, between outgoing foragers and returning foragers with food. Here we consider how an ant, waiting in the entrance chamber just inside the nest entrance, uses its accumulated experience of interactions to decide whether to leave the nest to forage. Using videos of field observations, we tracked the interactions and foraging decisions of ants in the entrance chamber. Outgoing foragers tended to interact with returning foragers at higher rates than ants that returned to the deeper nest and did not forage. To provide a mechanistic framework for interpreting these results, we develop a decision model in which ants make decisions based upon a noisy accumulation of individual contacts with returning foragers. The model can reproduce core trends and realistic distributions for individual ant interaction statistics, and suggests possible mechanisms by which foraging activity may be regulated at an individual ant level. PMID:28758093

  18. Habitat-specific foraging of prothonotary warblers: Deducing habitat quality

    Science.gov (United States)

    Lyons, J.E.

    2005-01-01

    Foraging behavior often reflects food availability in predictable ways. For example, in habitats where food availability is high, predators should attack prey more often and move more slowly than in habitats where food availability is low. To assess relative food availability and habitat quality, I studied the foraging behavior of breeding Prothonotary Warblers (Protonotaria citrea) in two forest habitat types, cypress-gum swamp forest and coastal-plain levee forest. I quantified foraging behavior with focal animal sampling and continuous recording during foraging bouts. I measured two aspects of foraging behavior: 1) prey attack rate (attacks per minute), using four attack maneuvers (glean, sally, hover, strike), and 2) foraging speed (movements per minute), using three types of movement (hop, short flight [???1 m], long flight [>1 m]). Warblers attacked prey more often in cypress-gum swamp forest than in coastal-plain levee forest. Foraging speed, however, was not different between habitats. I also measured foraging effort (% time spent foraging) and relative frequency of attack maneuvers employed in each habitat; neither of these variables was influenced by forest type. I conclude that Prothonotary Warblers encounter more prey when foraging in cypress-gum swamps than in coastal-plain levee forest, and that greater food availability results in higher density and greater reproductive success for birds breeding in cypress-gum swamp.

  19. Utilisation of intensive foraging zones by female Australian fur seals.

    Directory of Open Access Journals (Sweden)

    Andrew J Hoskins

    Full Text Available Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search. For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a

  20. Individual-learning ability predicts social-foraging strategy in house sparrows.

    Science.gov (United States)

    Katsnelson, Edith; Motro, Uzi; Feldman, Marcus W; Lotem, Arnon

    2011-02-22

    Social foragers can use either a 'producer' strategy, which involves searching for food, or a 'scrounger' strategy, which involves joining others' food discoveries. While producers rely on personal information and past experience, we may ask whether the tendency to forage as a producer is related to being a better learner. To answer this question, we hand-raised house sparrow (Passer domesticus) nestlings that upon independence were given an individual-learning task that required them to associate colour signal and food presence. Following the testing phase, all fledglings were released into a shared aviary, and their social-foraging tendencies were measured. We found a significant positive correlation between individual's performance in the individual-learning task and subsequent tendency to use searching (producing) behaviour. Individual-learning score was negatively correlated with initial fear of the test apparatus and with body weight. However, the correlation between individual learning and searching remained significant after controlling for these variables. Since it was measured before the birds entered a social group, individual-learning ability could not be the outcome of being a producer. However, the two traits may be initially associated, or individual learning could facilitate producing behaviour. To our knowledge, this is the first evidence that associates individual-learning abilities with social-foraging strategies in animal groups.

  1. Boldness predicts an individual's position along an exploration-exploitation foraging trade-off.

    Science.gov (United States)

    Patrick, Samantha C; Pinaud, David; Weimerskirch, Henri

    2017-09-01

    Individuals do not have complete information about the environment and therefore they face a trade-off between gathering information (exploration) and gathering resources (exploitation). Studies have shown individual differences in components of this trade-off but how stable these strategies are in a population and the intrinsic drivers of these differences is not well understood. Top marine predators are expected to experience a particularly strong trade-off as many species have large foraging ranges and their prey often have a patchy distribution. This environment leads these species to exhibit pronounced exploration and exploitation phases but differences between individuals are poorly resolved. Personality differences are known to be important in foraging behaviour but also in the trade-off between exploration and exploitation. Here we test whether personality predicts an individual exploration-exploitation strategy using wide ranging wandering albatrosses (Diomedea exulans) as a model system. Using GPS tracking data from 276 wandering albatrosses, we extract foraging parameters indicative of exploration (searching) and exploitation (foraging) and show that foraging effort, time in patch and size of patch are strongly correlated, demonstrating these are indicative of an exploration-exploitation (EE) strategy. Furthermore, we show these are consistent within individuals and appear stable in the population, with no reproductive advantage. The searching and foraging behaviour of bolder birds placed them towards the exploration end of the trade-off, whereas shy birds showed greater exploitation. This result provides a mechanism through which individual foraging strategies may emerge. Age and sex affected components of the trade-off, but not the trade-off itself, suggesting these factors may drive behavioural compensation to maintain resource acquisition and this was supported by the evidence that there were no fitness consequence of any EE trait nor the trade

  2. Levy Foraging in a Dynamic Environment – Extending the Levy Search

    Directory of Open Access Journals (Sweden)

    Vincenzo Fioriti

    2015-07-01

    Full Text Available A common task for robots is the patrolling of an unknown area with inadequate information about target locations. Under these circumstances it has been suggested that animal foraging could provide an optimal or at least sub-optimal search methodology, namely the Levy flight search. Although still in debate, it seems that predators somehow follow this search pattern when foraging, because it avoids being trapped in a local search if the food is beyond the sensory range. A Levy flight is a particular case of the random walk. Its displacements on a 2-D surface are drawn from the Pareto-Levy probability distribution, characterized by power law tails. The Levy flight search has many applications in optical material, ladars, optics, large database search, earthquake data analysis, location of DNA sites, human mobility, stock return analysis, online auctions, astronomy, ecology and biology. Almost all studies and simulations concerning the Levy flight foraging examine static or slowly moving (with respect to the forager uniformly distributed resources. Moreover, in recent works a small swarm of underwater autonomous vehicles has been used to test the standard Levy search in the underwater environment, with good results. In this paper we extend the classical Levy foraging framework taking into consideration a moving target allocated on a 2-D surface according to a radial probability distribution and comparing its performance with the random walk search. The metric used in the numerical simulations is the detection rate. Simulations include the sensor resolution, intended as the maximum detection distance of the forager from the target. Furthermore, contrarily to the usual Levy foraging framework, we use only one target. Results show that Levy flight outperforms the random walk if the sensor detection radius is not too small or too large. We also find the Levy flight in the velocity of the center of mass model of a fish school according the Kuramoto

  3. Are seabirds foraging for unpredictable resources?

    Science.gov (United States)

    Weimerskirch, Henri

    2007-02-01

    It is generally assumed that the extreme life history traits of pelagic seabirds, such as low fecundity or slow growth of chicks, result from the difficulties obtaining energy at sea from unpredictable and patchily distributed resources. However, little information on seabird prey distribution and availability exists to sustain this widely accepted hypothesis. Using tracking studies of 68 sub-populations of flying seabirds, I examine whether it is possible to gain information on the predictability of their marine resources. Because prey are clustered from fine to large scale in nested unities, from swarms to patches and concentrations of patches, it is important to take into account spatial scale. In temperate and polar regions, at large and meso-scales, seabirds appear to have a good knowledge of the location and concentrations of patches and generally use a commuting type of trip to reach foraging zones. Predictability appears to be high at large and meso-scales, with individuals from each sub-population heading in a particular direction from the colony to reach favoured habitats of known enhanced productivity such as shelf edges, frontal zones, upwellings. Within these mesoscale features, the animals use an area-restricted search behaviour to search for patches and swarms at finer scales. Using information on foraging site fidelity of individual birds, I show that differences in predictability at coarse scales are related to the distance and time spent foraging, and in particular to the specific types of foraging habitat. Some habitats appear to be more predictable than others: birds return consistently to the same coarse-scale sectors on shelf edges, whereas predictability is low in oceanic waters, even in frontal zones. Preliminary results on tropical species suggest that the environment here is less predictable in tropic than in temperate or polar zones. This review highlights that patchiness and predictability of marine resources are complex notions

  4. Ant colony optimization algorithm for continuous domains based on position distribution model of ant colony foraging.

    Science.gov (United States)

    Liu, Liqiang; Dai, Yuntao; Gao, Jinyu

    2014-01-01

    Ant colony optimization algorithm for continuous domains is a major research direction for ant colony optimization algorithm. In this paper, we propose a distribution model of ant colony foraging, through analysis of the relationship between the position distribution and food source in the process of ant colony foraging. We design a continuous domain optimization algorithm based on the model and give the form of solution for the algorithm, the distribution model of pheromone, the update rules of ant colony position, and the processing method of constraint condition. Algorithm performance against a set of test trials was unconstrained optimization test functions and a set of optimization test functions, and test results of other algorithms are compared and analyzed to verify the correctness and effectiveness of the proposed algorithm.

  5. Foraging arena size and structural complexity affect the dynamics of food distribution in ant colonies.

    Science.gov (United States)

    Buczkowski, Grzegorz; VanWeelden, Matthew

    2010-12-01

    Food acquisition by ant colonies is a complex process that starts with acquiring food at the source (i.e., foraging) and culminates with food exchange in or around the nest (i.e., feeding). While ant foraging behavior is relatively well understood, the process of food distribution has received little attention, largely because of the lack of methodology that allows for accurate monitoring of food flow. In this study, we used the odorous house ant, Tapinoma sessile (Say) to investigate the effect of foraging arena size and structural complexity on the rate and the extent of spread of liquid carbohydrate food (sucrose solution) throughout a colony. To track the movement of food, we used protein marking and double-antibody sandwich enzyme-linked immunosorbent assay, DAS-ELISA. Variation in arena size, in conjunction with different colony sizes, allowed us to test the effect of different worker densities on food distribution. Results demonstrate that both arena size and colony size have a significant effect on the spread of the food and the number of workers receiving food decreased as arena size and colony size increased. When colony size was kept constant and arena size increased, the percentage of workers testing positive for the marker decreased, most likely because of fewer trophallactic interactions resulting from lower worker density. When arena size was kept constant and colony size increased, the percentage of workers testing positive decreased. Nonrandom (clustered) worker dispersion and a limited supply of food may have contributed to this result. Overall, results suggest that food distribution is more complete is smaller colonies regardless of the size of the foraging arena and that colony size, rather than worker density, is the primary factor affecting food distribution. The structural complexity of foraging arenas ranged from simple, two-dimensional space (empty arenas) to complex, three-dimensional space (arenas filled with mulch). The structural

  6. Information flow and organization of stingless bee foraging

    OpenAIRE

    Biesmeijer, Jacobus; Judith Slaa, E.

    2004-01-01

    International audience; Stingless bees (Hymenoptera, Apidae, Meliponini) live in populous permanent colonies and face the same problem as other foraging social insects: how to coordinate the worker's actions and respond to the spatio-temporal uncertainties of food availability in their habitat. Here we review the (social) information used by individual foragers and how organized collective foraging emerges from the individual actions. We also address intra- and interspecific competition for f...

  7. Interactions between shoal size and conformity in guppy social foraging

    OpenAIRE

    Day, R.L.; MacDonald, T; C.; Brown; Laland, K.N.; Reader, S. M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1 confirmed the prediction that in open water the first fish and focal fish of larger shoals locate food faster than in smaller shoals. However, a second experiment, in which shoals of fish were required to ...

  8. Determination of Mineral Contents of Some Legume and Cereal Forages Grown as Naturally in Pastures of Erzurum Province

    Directory of Open Access Journals (Sweden)

    Esra GÜRSOY

    2017-06-01

    Full Text Available This study was carried out to determine the mineral substances such as macro and micro minerals of legume and cereal forages grown as naturally in the pastures of Erzurum province. In present study, clover, (Medicago sativa, mountain hispanic sainfoin (Hedysarum elegans, bird vetch (Vicia cracca, hairy vetch (Vicia villosa, mountain vetch (Vicia alpestris, mountain clover (Trifolium montanum, caucasian clover (Trifolium ambiguum, the three-headed clover (Trifolium trichocephalum, tawny grass crown (Coronilla varia, the crown of the eastern horn of grass (Coronilla orientatis and yellow flowers gazelle (Lotus corniculatus from legume forages; cocksfoot (Dactylis glomerata, crested wheatgrass (Agropyron cristatum, red fescue (Festuca rubra, sheep ball (Festuca ovina, tawny bromine (Bromus variegatus, blue split (Agropyron intermedium, kelp tail grass (Phleum pratense, meadow bluegrass (Poa pratensis from cereal forages were investigated. The obtained data were subjected to an analysis of variance by using SPSS 12.0 package program. Significant differences between means were tested by using Duncan’s Multiple Range Test. Macro minerals such as Nitrogen (N, Phosphorus (P, Potassium (K, Calcium (Ca, Magnesium (Mg and Sulfur (S assigned for legume forages changed between 2.39- 3.30%, 1.16-1.28%, 0.70-2.69%, 0.56-1.61%, 0.11-0.51% and 0.16-0.27%, respectively. The amounts of micro mineral like Iron (Fe, Virgin (Cu, Zinc (Zn, Manganese (Mn and Boron (B of legume forages were determined to be 105.9-893.7 ppm, 2.22-12.36 ppm, 14.11-195 ppm, 18.18-66.58 ppm and 5.91-40.39 ppm, respectively. Instances of macro minerals of cereal forages were found for N 1.76-of 2.19%, P 1.10-1.19%, K 1.99-3.25%, Ca 0.09-1.15%, Mg 0.07-0.26% and S 0.22-0.36% in present study. Micro minerals such as Fe, Cu, Zn, Mn and B determined for cereal forages changed between 74.90-630.6 ppm, 4-9.84 ppm, 31.49-335.6 ppm, 24.63-94.51 ppm and 0.35-26.64 ppm, respectively. In conclusion

  9. Foraging optimally for home ranges

    Science.gov (United States)

    Mitchell, Michael S.; Powell, Roger A.

    2012-01-01

    Economic models predict behavior of animals based on the presumption that natural selection has shaped behaviors important to an animal's fitness to maximize benefits over costs. Economic analyses have shown that territories of animals are structured by trade-offs between benefits gained from resources and costs of defending them. Intuitively, home ranges should be similarly structured, but trade-offs are difficult to assess because there are no costs of defense, thus economic models of home-range behavior are rare. We present economic models that predict how home ranges can be efficient with respect to spatially distributed resources, discounted for travel costs, under 2 strategies of optimization, resource maximization and area minimization. We show how constraints such as competitors can influence structure of homes ranges through resource depression, ultimately structuring density of animals within a population and their distribution on a landscape. We present simulations based on these models to show how they can be generally predictive of home-range behavior and the mechanisms that structure the spatial distribution of animals. We also show how contiguous home ranges estimated statistically from location data can be misleading for animals that optimize home ranges on landscapes with patchily distributed resources. We conclude with a summary of how we applied our models to nonterritorial black bears (Ursus americanus) living in the mountains of North Carolina, where we found their home ranges were best predicted by an area-minimization strategy constrained by intraspecific competition within a social hierarchy. Economic models can provide strong inference about home-range behavior and the resources that structure home ranges by offering falsifiable, a priori hypotheses that can be tested with field observations.

  10. Review: Feeding conserved forage to horses: recent advances and recommendations.

    Science.gov (United States)

    Harris, P A; Ellis, A D; Fradinho, M J; Jansson, A; Julliand, V; Luthersson, N; Santos, A S; Vervuert, I

    2017-06-01

    The horse is a non-ruminant herbivore adapted to eating plant-fibre or forage-based diets. Some horses are stabled for most or the majority of the day with limited or no access to fresh pasture and are fed preserved forage typically as hay or haylage and sometimes silage. This raises questions with respect to the quality and suitability of these preserved forages (considering production, nutritional content, digestibility as well as hygiene) and required quantities. Especially for performance horses, forage is often replaced with energy dense feedstuffs which can result in a reduction in the proportion of the diet that is forage based. This may adversely affect the health, welfare, behaviour and even performance of the horse. In the past 20 years a large body of research work has contributed to a better and deeper understanding of equine forage needs and the physiological and behavioural consequences if these are not met. Recent nutrient requirement systems have incorporated some, but not all, of this new knowledge into their recommendations. This review paper amalgamates recommendations based on the latest understanding in forage feeding for horses, defining forage types and preservation methods, hygienic quality, feed intake behaviour, typical nutrient composition, digestion and digestibility as well as health and performance implications. Based on this, consensual applied recommendations for feeding preserved forages are provided.

  11. Habitat-specific foraging strategies in Australasian gannets

    Directory of Open Access Journals (Sweden)

    Melanie R. Wells

    2016-07-01

    Full Text Available Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26, in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

  12. Echolocation click rates and behavior of foraging Hawaiian spinner dolphins

    Science.gov (United States)

    Benoit-Bird, Kelly J.; Au, Whitlow W. L.

    2004-05-01

    Groups of spinner dolphins work together to actively aggregate small animals in the deep-scattering layer that serve as their prey. Detailed information on dolphin foraging behavior, obtained with a 200-kHz multibeam sonar (Simrad MS2000), made it possible to correlate echolocation and foraging. Fifty-six groups of spinner dolphins foraging at night within a midwater micronekton sound-scattering layer were observed with the sonar. During sonar surveys, the rates of whistles and echolocation clicks were measured using four hydrophones at 6-m depth intervals. Significant differences in click rates were found between depths and between the different stages of foraging. Groups of foraging dolphins ranged in size from 16 to 28 dolphins. Click rates were not significantly affected by the number of dolphins in a foraging group. Contrary to initial predictions, click rates were relatively low when sonar data indicated that pairs of dolphins were actively feeding. Highest echolocation rates occurred within the scattering layer, during transitions between foraging states. Whistles were only detected when dolphins were not in a foraging formation and when animals were surfacing. This suggests clicks may be used directly or indirectly to cue group movement during foraging.

  13. Social environment influences performance in a cognitive task in natural variants of the foraging gene.

    Directory of Open Access Journals (Sweden)

    Nancy R Kohn

    Full Text Available In Drosophila melanogaster, natural genetic variation in the foraging gene affects the foraging behaviour of larval and adult flies, larval reward learning, adult visual learning, and adult aversive training tasks. Sitters (for(s are more sedentary and aggregate within food patches whereas rovers (for(R have greater movement within and between food patches, suggesting that these natural variants are likely to experience different social environments. We hypothesized that social context would differentially influence rover and sitter behaviour in a cognitive task. We measured adult rover and sitter performance in a classical olfactory training test in groups and alone. All flies were reared in groups, but fly training and testing were done alone and in groups. Sitters trained and tested in a group had significantly higher learning performances compared to sitters trained and tested alone. Rovers performed similarly when trained and tested alone and in a group. In other words, rovers learning ability is independent of group training and testing. This suggests that sitters may be more sensitive to the social context than rovers. These differences in learning performance can be altered by pharmacological manipulations of PKG activity levels, the foraging (for gene's gene product. Learning and memory is also affected by the type of social interaction (being in a group of the same strain or in a group of a different strain in rovers, but not in sitters. These results suggest that for mediates social learning and memory in D. melanogaster.

  14. Social and Foraging Behavior in Northwestern Crows (Corvus caurinus): Incorporating New Analyses and Technology

    Science.gov (United States)

    Xu, Carol K.

    Both foraging and social decisions impact animals in important ways. We investigate the effects of age on foraging efficiency and sociality on Northwestern Crows (Corvus caurinus) at the beach, and use the growing field of social network analysis (SNA) to further examine social behavior in these birds. Specifically, we predict that 1) adults are more efficient foragers than juveniles, 2) juveniles interact with larger numbers of social partners than adults, 3) juveniles and adults prefer to associate with each other rather than within their own age classes, 4) crows are not associating randomly while on the beach (aka they have preferred social partners), and 5) pairs of individuals engaging in more affiliative behaviors with each other are less likely to also behave agonistically to one another, and vice versa. We also explore the uses of a remote radio detection system Encounternet by testing the validity of pilot data collected through this system against live observations conducted simultaneously. There is no effect of age on foraging efficiency; however, juveniles were found to interact with more total partners than adults, and most social associations occur between juveniles and adults. Our results also suggest crows are engaging in preferential social associations, though there is no evidence that affiliative pairs and agonistic pairs are mutually exclusive. Finally, it appears Encounternet can be useful for data collection when paired with live observations, as long as certain limitations are kept in mind. Our pilot study could be beneficial to anyone considering the use of remote detection tools in data collection on animals.

  15. Climate and foraging mode explain interspecific variation in snake metabolic rates.

    Science.gov (United States)

    Dupoué, Andréaz; Brischoux, François; Lourdais, Olivier

    2017-11-29

    The energy cost of self-maintenance is a critical facet of life-history strategies. Clarifying the determinant of interspecific variation in metabolic rate (MR) at rest is important to understand and predict ecological patterns such as species distributions or responses to climatic changes. We examined variation of MR in snakes, a group characterized by a remarkable diversity of activity rates and a wide distribution. We collated previously published MR data (n = 491 observations) measured in 90 snake species at different trial temperatures. We tested for the effects of metabolic state (standard MR (SMR) versus resting MR (RMR)), foraging mode (active versus ambush foragers) and climate (temperature and precipitation) while accounting for non-independence owing to phylogeny, body mass and thermal dependence. We found that RMR was 40% higher than SMR, and that active foragers have higher MR than species that ambush their prey. We found that MR was higher in cold environments, supporting the metabolic cold adaptation hypothesis. We also found an additive and positive effect of precipitation on MR suggesting that lower MR in arid environments may decrease dehydration and energetic costs. Altogether, our findings underline the complex influences of climate and foraging mode on MR and emphasize the relevance of these facets to understand the physiological impact of climate change. © 2017 The Author(s).

  16. Hunger effects on foraging responses to perceptual cues in immature and adult wolf spiders (Lycosidae).

    Science.gov (United States)

    Persons

    1999-01-01

    The wolf spider, Schizocosa ocreata (Hentz), varies foraging patch residence time in the presence of different sensory cues from prey, even without food rewards. This study examines the influence and interaction of hunger state, age and sex on the use of different types of sensory information to determine foraging patch sampling duration. In a series of two-chambered artificial foraging patches, I tested 26 S. ocreata once as immatures, and again as adults, under two hunger states (satiated and 7 days without food). Patches varied in the type of sensory information provided by live prey (crickets) as follows: visual cues alone; vibratory cues alone; combined visual/vibratory cues; and control (no prey). Without feeding in patches, the type of sensory stimuli available from prey strongly affected patch residence time, with spiders using primarily visual rather than vibratory cues. Hunger level as a main effect had no influence on residence time, but hunger state did mediate the importance of visual or vibratory information. Significant age- and sex-related differences in patch residence time in the presence of different sensory cues were found.These data suggest that ontogenetic and sex-specific foraging strategies are influenced by use of prefeeding perceptual cues rather than hunger state in wolf spiders. Copyright 1999 The Association for the Study of Animal Behaviour.

  17. Forage Polyphenol Oxidase and Ruminant Livestock Nutrition

    Directory of Open Access Journals (Sweden)

    Michael Richard F. Lee

    2014-12-01

    Full Text Available Polyphenol oxidase (PPO is associated with the detrimental effect of browning fruit and vegetables, however interest within PPO containing forage crops has grown since the brownng reaction was associated with reduced nitrogen (N losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage increased the quality of protein, improving N-use efficiency (NUE when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalysing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP. If the protein is an enzyme the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase un-degraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of red clover.

  18. Foraging behavior of bark-foraging birds in the Sierra Nevada

    Science.gov (United States)

    Michael L. Morrison; Kimberly A. With; Irene C. Timossi; William M. Block; Kathleen A. Milne

    1987-01-01

    Data on foraging behavior are often used for examining use of habitat and describing community structure among co-occurring species of birds using the same resource base (e.g., Johnson 1966, Eckhardt 1979, Rusterholz 1981). Differences in tree species, foliage morphology, and bark structure may influence the types of prey taken and the species of bird using the...

  19. Influence of forage source and forage inclusion level on growth performance, feeding behavior, and carcass characteristics in finishing steers.

    Science.gov (United States)

    Swanson, K C; Carlson, Z E; Ruch, M C; Gilbery, T C; Underdahl, S R; Keomanivong, F E; Bauer, M L; Islas, A

    2017-03-01

    Two experiments were conducted to determine the effects of forage source (Exp. 1) and forage inclusion level (Exp. 2) in finishing diets on growth performance and feeding behavior. In Exp. 1, sixty-four steers (394 ± 3.6 kg BW) were allotted by BW to 3 pens. Within each pen, steers were assigned randomly to 1 of 4 dietary treatments containing different forage sources: 1) alfalfa hay, 2) corn silage, 3) wheat straw, and 4) corn stover. Alfalfa hay was provided at 10% of the diet DM and the other forage sources were offered to provide the same percentage of NDF from forage. In Exp. 2, forty-four steers (451 ± 4.6 kg BW) were used in a completely randomized design and were fed dry-rolled corn-based diets containing a mixture of hay and corn silage as the forage source at 5%, 10%, 15%, or 20% forage (DM basis). Intake and feeding behavior traits were calculated from data generated by the Insentec feeding system. In Exp. 1, final BW, ADG, and G:F did not differ between treatments. Dry matter intake and feeding behavior traits responded differently depending on week (interaction ≤ 0.04) of the experiment with DMI generally greater in steers fed alfalfa or corn silage early in the experiment and time per meal generally greater and eating rate slower in steers fed diets containing wheat straw or corn stover. In Exp. 2, ADG and G:F decreased linearly ( forage inclusion. Quadratic effects ( ≤ 0.002) were observed for eating time (per visit, meal, and d) and DMI (per visit, meal, and min) with eating time greatest in the 10% forage treatment and DMI the least in the 20% forage treatment. Dry matter intake per d responded differently depending on week (interaction = 0.01) with some weeks exhibiting linear and other quadratic effects that were primarily the result of the largest decrease in DMI in the 20% forage inclusion treatment. These data indicate that growth performance was not influenced by forage source, when fed at a similar NDF inclusion level, but was

  20. Temporal effects of hunting on foraging behavior of an apex predator: Do bears forego foraging when risk is high?

    Science.gov (United States)

    Hertel, Anne G; Zedrosser, Andreas; Mysterud, Atle; Støen, Ole-Gunnar; Steyaert, Sam M J G; Swenson, Jon E

    2016-12-01

    Avoiding predators most often entails a food cost. For the Scandinavian brown bear (Ursus arctos), the hunting season coincides with the period of hyperphagia. Hunting mortality risk is not uniformly distributed throughout the day, but peaks in the early morning hours. As bears must increase mass for winter survival, they should be sensitive to temporal allocation of antipredator responses to periods of highest risk. We expected bears to reduce foraging activity at the expense of food intake in the morning hours when risk was high, but not in the afternoon, when risk was low. We used fine-scale GPS-derived activity patterns during the 2 weeks before and after the onset of the annual bear hunting season. At locations of probable foraging, we assessed abundance and sugar content, of bilberry (Vaccinium myrtillus), the most important autumn food resource for bears in this area. Bears decreased their foraging activity in the morning hours of the hunting season. Likewise, they foraged less efficiently and on poorer quality berries in the morning. Neither of our foraging measures were affected by hunting in the afternoon foraging bout, indicating that bears did not allocate antipredator behavior to times of comparably lower risk. Bears effectively responded to variation in risk on the scale of hours. This entailed a measurable foraging cost. The additive effect of reduced foraging activity, reduced forage intake, and lower quality food may result in poorer body condition upon den entry and may ultimately reduce reproductive success.

  1. Fatty acid composition of forage herb species

    DEFF Research Database (Denmark)

    Warner, D.; Jensen, Søren Krogh; Cone, J.W.

    2010-01-01

    The use of alternative forage species in grasslands for intensive livestock production is receiving renewed attention. Data on fatty acid composition of herbs are scarce, so four herbs (Plantago lanceolata, Achillea millefolium, Cichorium intybus, Pastinaca sativa) and one grass species (timothy......, Phleum pratense) were sown in a cutting trial. The chemical composition and concentration of fatty acids (FA) of individual species were determined during the growing season. Concentrations of crude protein and FA were generally higher in the herbs than in timothy. C. intybus had the highest nutritive...

  2. Forage polyphenol oxidase and ruminant livestock nutrition

    Science.gov (United States)

    Lee, Michael R. F.

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  3. Forage polyphenol oxidase and ruminant livestock nutrition.

    Science.gov (United States)

    Lee, Michael R F

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  4. [Optimized Spectral Indices Based Estimation of Forage Grass Biomass].

    Science.gov (United States)

    An, Hai-bo; Li, Fei; Zhao, Meng-li; Liu, Ya-jun

    2015-11-01

    As an important indicator of forage production, aboveground biomass will directly illustrate the growth of forage grass. Therefore, Real-time monitoring biomass of forage grass play a crucial role in performing suitable grazing and management in artificial and natural grassland. However, traditional sampling and measuring are time-consuming and labor-intensive. Recently, development of hyperspectral remote sensing provides the feasibility in timely and nondestructive deriving biomass of forage grass. In the present study, the main objectives were to explore the robustness of published and optimized spectral indices in estimating biomass of forage grass in natural and artificial pasture. The natural pasture with four grazing density (control, light grazing, moderate grazing and high grazing) was designed in desert steppe, and different forage cultivars with different N rate were conducted in artificial forage fields in Inner Mongolia. The canopy reflectance and biomass in each plot were measured during critical stages. The result showed that, due to the influence in canopy structure and biomass, the canopy reflectance have a great difference in different type of forage grass. The best performing spectral index varied in different species of forage grass with different treatments (R² = 0.00-0.69). The predictive ability of spectral indices decreased under low biomass of desert steppe, while red band based spectral indices lost sensitivity under moderate-high biomass of forage maize. When band combinations of simple ratio and normalized difference spectral indices were optimized in combined datasets of natural and artificial grassland, optimized spectral indices significant increased predictive ability and the model between biomass and optimized spectral indices had the highest R² (R² = 0.72) compared to published spectral indices. Sensitive analysis further confirmed that the optimized index had the lowest noise equivalent and were the best performing index in

  5. Ant Foraging As an Indicator of Tropical Dry Forest Restoration.

    Science.gov (United States)

    Hernández-Flores, J; Osorio-Beristain, M; Martínez-Garza, C

    2016-08-01

    Variation in foraging behavior may indicate differences in food availability and allow assessment of restoration actions. Ants are prominent bioindicators used in assessing ecological responses to disturbance. However, behavioral data have been poorly incorporated as an index. The foraging performance of red harvester ants was quantified in order to evaluate the success of a restoration ecology experiment in the tropical dry forest of Sierra de Huautla, Morelos, in central Mexico. Foraging performance by granivorous, Pogonomyrmex barbatus, ants was diminished after 6 and 8 years of cattle grazing and wood harvest were excluded as part of a restoration experiment in a highly degraded biome. Despite investing more time in foraging, ant colonies in exclusion plots showed lower foraging success and acquired less seed biomass than colonies in control plots. In line with the predictions of optimal foraging theory, in restored plots where ant foraging performance was poor, ants harvested a higher diversity of seeds. Reduced foraging success and increased harvest of non-preferred foods in exclusion plots were likely due to the growth of herbaceous vegetation, which impedes travel by foragers. Moreover, by 8 years of exclusion, 37% of nests in exclusion plots had disappeared compared to 0% of nests in control plots. Ants' foraging success and behavior were sensitive to changes in habitat quality due to the plant successional process triggered by a restoration intervention. This study spotlights on the utility of animal foraging behavior in the evaluation of habitat restoration programs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Context-dependent planktivory: interacting effects of turbidity and predation risk on adaptive foraging

    Science.gov (United States)

    Pangle, Kevin L.; Malinich, Timothy D.; Bunnell, David B.; DeVries, Dennis R.; Ludsin, Stuart A.

    2012-01-01

    By shaping species interactions, adaptive phenotypic plasticity can profoundly influence ecosystems. Predicting such outcomes has proven difficult, however, owing in part to the dependence of plasticity on the environmental context. Of particular relevance are environmental factors that affect sensory performance in organisms in ways that alter the tradeoffs associated with adaptive phenotypic responses. We explored the influence of turbidity, which simultaneously and differentially affects the sensory performance of consumers at multiple trophic levels, on the indirect effect of a top predator (piscivorous fish) on a basal prey resource (zooplankton) that is mediated through changes in the plastic foraging behavior of an intermediate consumer (zooplanktivorous fish). We first generated theoretical predictions of the adaptive foraging response of a zooplanktivore across wide gradients of turbidity and predation risk by a piscivore. Our model predicted that predation risk can change the negative relationship between intermediate consumer foraging and turbidity into a humped-shaped (unimodal) one in which foraging is low in both clear and highly turbid conditions due to foraging-related risk and visual constraints, respectively. Consequently, the positive trait-mediated indirect effect (TMIE) of the top predator on the basal resource is predicted to peak at low turbidity and decline thereafter until it reaches an asymptote of zero at intermediate turbidity levels (when foraging equals that which is predicted when the top predator is absent). We used field observations and a laboratory experiment to test our model predictions. In support, we found humped-shaped relationships between planktivory and turbidity for several zooplanktivorous fishes from diverse freshwater ecosystems with predation risk. Further, our experiment demonstrated that predation risk reduced zooplanktivory by yellow perch (Perca flavescens) at a low turbidity, but had no effect on consumption at

  7. Honeybee Foraging, Nectar Secretion, and Honey Potential of Wild Jujube Trees, Ziziphus nummularia.

    Science.gov (United States)

    Alqarni, A S

    2015-06-01

    Ziziphus trees are of economic importance due to their aggregated value (source of fruits and timber) and are the most important melliferous plants in the Arabian Peninsula. Interaction between honeybees and Ziziphus nummularia was investigated by assessing foraging, flower phenology, nectar secretion, and honey potential. It is demonstrate that both the native Apis mellifera jemenitica Ruttner and the exotic Apis mellifera carnica Pollmann foraged on Z. nummularia flowers. Bee foraging for nectar and pollen was low (2 ± 0.7 workers/200 flowers/3 min) during early morning and increased to a peak in the afternoon (100 ± 15 workers/200 flowers/3 min). Remarkable foraging activity was recorded during high temperature (35°C) and low humidity (20%) conditions. Foraging for nectar collection was more distinct than that for pollen. The flowering of Z. nummularia was gradual, and was characterized by some flowers that opened and secreted nectar early before sunrise, whereas other flowers remained opened until sunrise. The flowers lasted 2 days, with 83% of nectar secreted in the first day. The peak of nectar secretion was recorded at noon under hot and dry conditions. The lowest amount of nectar was secreted during sunrise under mild temperature (24°C) and humidity (31%) conditions. Under optimum conditions, it is assumed that the average sugar mass was 0.321 ± 0.03 mg TSS/flower, while the total sugar mass was 27.65 ± 11 g/tree. The average honey production potential of tested Z. nummularia was approximately 2.998 kg/tree and 749.475 kg/ha in the main flowering season.

  8. Ethanol concentration in food and body condition affect foraging behavior in Egyptian fruit bats ( Rousettus aegyptiacus)

    Science.gov (United States)

    Sánchez, Francisco; Korine, Carmi; Kotler, Burt P.; Pinshow, Berry

    2008-06-01

    Ethanol occurs in fleshy fruit as a result of sugar fermentation by both microorganisms and the plant itself; its concentration [EtOH] increases as fruit ripens. At low concentrations, ethanol is a nutrient, whereas at high concentrations, it is toxic. We hypothesized that the effects of ethanol on the foraging behavior of frugivorous vertebrates depend on its concentration in food and the body condition of the forager. We predicted that ethanol stimulates food consumption when its concentration is similar to that found in ripe fruit, whereas [EtOH] below or above that of ripe fruit has either no effect, or else deters foragers, respectively. Moreover, we expected that the amount of food ingested on a particular day of feeding influences the toxic effects of ethanol on a forager, and consequently shapes its feeding decisions on the following day. We therefore predicted that for a food-restricted forager, ethanol-rich food is of lower value than ethanol-free food. We used Egyptian fruit bats ( Rousettus aegyptiacus) as a model to test our hypotheses, and found that ethanol did not increase the value of food for the bats. High [EtOH] reduced the value of food for well-fed bats. However, for food-restricted bats, there was no difference between the value of ethanol-rich and ethanol-free food. Thus, microorganisms, via their production of ethanol, may affect the patterns of feeding of seed-dispersing frugivores. However, these patterns could be modified by the body condition of the animals because they might trade-off the costs of intoxication against the value of nutrients acquired.

  9. Does information sharing promote group foraging?

    Science.gov (United States)

    Sernland, Emma; Olsson, Ola; Holmgren, Noél M A

    2003-06-07

    Individuals may join groups for several reasons, one of which is the possibility of sharing information about the quality of a foraging area. Sharing information in a patch-foraging scenario gives each group member an opportunity to make a more accurate estimate of the quality of the patch. In this paper we present a mathematical model in which we study the effect of group size on patch-leaving policy and per capita intake rate. In the model, group members share information equally in a random search for food. Food is distributed in patches according to a negative binomial distribution. A prediction from our model is that, the larger the group, the earlier each group member should leave the current patch. We also find that the benefit from enhanced exchange of information does not exceed the cost of sharing food with group members. The per capita intake rate decreases as the group size increases. Therefore, animals should only form groups when other factors outweigh the costs, which is easiest to achieve when the travelling time is short.

  10. Evaluating oat cultivars for dairy forage production in the central ...

    African Journals Online (AJOL)

    The two most preferred cultivars by the farmers were Conway and Glamis. Based on DM and CP production, and farmers' choice, we conclude that Conway and Glamis stand a high chance of improving forage production in the area and other similar systems. Keywords: agronomy, Avena sativa, forage quality, livestock ...

  11. Maize and forage sorghum as silage crops under drought conditions

    African Journals Online (AJOL)

    Sorghum yielded more digestible organic matter per hectare than maize. Maize and forage sorghum silage were well preserved and stable under aerobic conditions. Keywords: digestible organic matter; drought; ensiling; forage; lichtenburg district; maize; organic matter; silage; sorghum; south africa; yield. African Journal ...

  12. Determination of forage escape protein value with in situ and ...

    African Journals Online (AJOL)

    This study was carried out to compare in situ and in vitro enzyme techniques for determining estimates of forage escape proteins. Eight forages (vetch hay, wheat silage, corn silage, wheat hay, grass hay, lentil straw, triticale hay and alfalfa hay) were used as feed materials. During 70 h, incubation with enzyme method had ...

  13. Foraging behaviour of two rodent species inhabiting a kopje (rocky ...

    African Journals Online (AJOL)

    We employed patch use theory to evaluate how several environmental factors influence the foraging behaviour of two rodent species: Grammomys dolichurus and Acomys cahirinus. Foraging efficiency was determined by measuring the remaining food in artificial food patches (giving-up densities: GUDs) from two ...

  14. Effect of Mixed Feeding of Forages and Graded Dietary Energy ...

    African Journals Online (AJOL)

    Thirty six New Zealand White X Dutch rabbits of crosses were used for the experiment to assess the effect of mixed feeding of forages and graded dietary metabolisable energy levels at 1500kcal/kg, and 2000kcal/kg and 2500kcal/kg, respectively. Forages used were Calapogonium mucunoides, Panicum maximum and ...

  15. Animal Foraging and the Evolution of Goal-Directed Cognition

    Science.gov (United States)

    Hills, Thomas T.

    2006-01-01

    Foraging-and feeding-related behaviors across eumetazoans share similar molecular mechanisms, suggesting the early evolution of an optimal foraging behavior called area-restricted search (ARS), involving mechanisms of dopamine and glutamate in the modulation of behavioral focus. Similar mechanisms in the vertebrate basal ganglia control motor…

  16. Forager abundance and dietary relationships in a Namib Desert ant ...

    African Journals Online (AJOL)

    Forager abundance and dietary relationships in a Namib Desert ant community. A.C. Marsh. Abstract. Thirteen ant species coexist on a barren gravel plain habitat in the central Namib Desert. Numerical density of foragers of all species fluctuated considerably over a 17-month period. Peaks in abundance correlated to ...

  17. Foraging behaviour and feeding ecology of the Black-cheeked ...

    African Journals Online (AJOL)

    Foraging behaviour and feeding ecology of the Black-cheeked Lovebird Agapornis nigrigenis were studied in Zambia. The birds fed on at least 39 species, and food items included seeds, leaves, flowers (especially nectar), fruit pulp, invertebrates, bark, lichen and resin. Terrestrial foraging was dominant, whereas arboreal ...

  18. Social and spatial foraging patterns of the jackass penguin ...

    African Journals Online (AJOL)

    The inshore distribution and foraging behaviour of jackass penguins Spheniscus demersus were studied between December 1982 and August 1983 in waters close to breeding islands in Saldanha Bay, South Africa. The use of a sail-boat permitted close observation of foraging penguins with minimal apparent disturbance.

  19. Boldness affects foraging decisions in barnacle geese: an experimental approach

    NARCIS (Netherlands)

    Kurvers, R.H.J.M.; Nolet, B.A.; Prins, H.H.T.; Ydenburg, R.C.; Van Oers, K.

    2012-01-01

    Individuals foraging in groups constantly need to make decisions, such as when to leave a group, when to join a group, and when to move collectively to another feeding site. In recent years, it has become evident that personality may affect these foraging decisions, but studies where individuals are

  20. State-dependent Bayesian foraging on spatially autocorrelated food distributions

    NARCIS (Netherlands)

    Van Gils, J.A.

    2010-01-01

    When prey are cryptic and are distributed in discrete clumps (patches), Bayesian foragers revise their prior expectation about a patch's prey density by using their foraging success in the patch as a source of information. Prey densities are often spatially autocorrelated, meaning that rich patches

  1. Potential for sorghum forages for dairy heifers in the midwest

    Science.gov (United States)

    Dairy heifers have lower dietary energy needs than lactating cows (63-65% TDN for 6-12 month old heifers; 58-60% TDN for >12 month old heifers), but forage-based diets containing significant amounts of corn silage often exceed the needs of pregnant heifers. Use of low-energy forages to decrease ener...

  2. The nutritive value of forage sorghum genotypes developed for the ...

    African Journals Online (AJOL)

    Jack Ouda

    for all genotypes after 24 h incubation but Lan-12 had the highest methane production after 72 h incubation. After 24 h and 72 h incubation all the genotypes produced a .... The rumen fluid used was collected from cannulated sheep kept on a maintenance diet with a 60:40 forage to concentrate composition. The forage was ...

  3. Effect of biotic and abiotic factors on composition and foraging ...

    African Journals Online (AJOL)

    Elucidating the influence of ecological factors on composition and foraging intensity of subterranean termites is critical in development of sustainable termite management strategies. Our aim was therefore to analyze the effect of selected biotic and abiotic factors on composition and foraging intensity of termites. We used ...

  4. Forage yield and quality of kenaf ( Hibiscus cannabinus L.) for ...

    African Journals Online (AJOL)

    This study was carried out to evaluate 40 kenaf accessions for forage yield and quality at Universiti Putra Malaysia in 2009. Forage yield and quality traits were measured at the initial flowering stage. The kenaf accessions showed highly significant variation for most of trait studied. Plant dry matter yield ranged from 5286 kg ...

  5. Energetic costs of foraging in breeding Cape gannets Morus capensis

    NARCIS (Netherlands)

    Mullers, Ralf H.E.; Navarro, René A.; Daan, Serge; Tinbergen, Joost M.; Meijer, Harro A.J.

    2009-01-01

    Seabirds fly considerable distances during the breeding season in search for food for themselves and their young. Variation in the distance from the breeding colony to the offshore food resources is expected to impact the energy spent on foraging trips. In 2005-06 and 2006-07 we studied foraging

  6. Proximate and Anti-Nutritional Constituents of Forage Legumes at ...

    African Journals Online (AJOL)

    Five non-conventional forage legumes used as alternative plant protein sources in livestock nutrition in Nigeria were assayed for proximate and anti-nutritional compositions. The forages, Cajanus cajan, Vigna radiata, Mucuna ghana, Mucuna conchinchinensis and Mucuna rajada were harvested at emergence, 4 and 8 ...

  7. Forage Potential of Photoperiod-Sensitive millet ( Pennisetum ...

    African Journals Online (AJOL)

    In Nigeria, millet, an important cereal of the dry tropics, could be grown for forage in the low land forest zone where it is not normally cultivated and where the rainy season lasts eight or more months. To determine its potential as an annual forage, 'Maiwa', which is a short-day photoperiod-sensitive millet (Pennisetum ...

  8. Female mice respond differently to costly foraging versus food restriction

    NARCIS (Netherlands)

    Schubert, Kristin A.; Vaanholt, Lobke M.; Stavasius, Fanny; Demas, Gregory E.; Daan, Serge; Visser, G. Henk

    2008-01-01

    Experimental manipulation of foraging costs per food reward can be used to study the plasticity of physiological systems involved in energy metabolism. This approach is useful for understanding adaptations to natural variation in food availability. Earlier studies have shown that animals foraging on

  9. Foraging of a coastal seabird: flight patterns and movements of ...

    African Journals Online (AJOL)

    Cape gannets Morus capensis are predatory seabirds in the coastal waters of southern Africa where they feed on commercially important fish species. Using a combination of intensive monitoring at nest sites, tracking of radio-tagged birds and diet sampling, we determined the foraging ranges and foraging areas used by ...

  10. Forest disturbance type differentially affects seasonal moose forage

    Science.gov (United States)

    R.A. Lautenschlager; Hewlette S. Crawford; Martin R. Stokes; Timothy L. Stone

    1997-01-01

    We examined the effects of forest disturbance on forage availability, moose (Alces alces) seasonal forage selection, and predicted in vivo digestibility in eastern Maine. Wet-mass estimates and dry-mass conversions of species consumed by 3 tamed moose were made throughout the year (late winter, early spring, late spring, summer, fall, early winter)...

  11. Auto-Clustering using Particle Swarm Optimization and Bacterial Foraging

    DEFF Research Database (Denmark)

    Rutkowski Olesen, Jakob; Cordero, Jorge; Zeng, Yifeng

    2009-01-01

    This paper presents a hybrid approach for clustering based on particle swarm optimization (PSO) and bacteria foraging algorithms (BFA). The new method AutoCPB (Auto-Clustering based on particle bacterial foraging) makes use of autonomous agents whose primary objective is to cluster chunks of data...

  12. Variability in foraging behaviour and prey of the Common Fiscal ...

    African Journals Online (AJOL)

    Foraging success also increased from summer to winter in all except the Harrismith subpopulation, and was dependant upon the size of prey attacked. ... Even if shrikes seek to maximise encounters with larger (higher energy) items, the low capture rates and short duration of foraging attempts when taking smaller items ...

  13. Effects of high selenium forages on reproduction in sheep

    Science.gov (United States)

    High Se-containing forages grow on seleniferous soils in many parts of world and can cause acute or chronic selenosis in livestock. Anecdotal reports of decreased reproductive rates in livestock grazing seleniferous forages have been reported and it has been speculated that reproductive failure is o...

  14. Forager abundance and dietary relationships Namib Desert ant ...

    African Journals Online (AJOL)

    Thirteen ant species coexist on a barren gravel plain habitat in the central Namib Desert. Numerical density of foragers of all species fluctuated considerably over a 17-month period. Peaks in abundance correlated to rainfall events and hence primary production pulses. The majority of foragers were noctumal in summer and ...

  15. Honeybee forage, bee visitation counts and the properties of honey ...

    African Journals Online (AJOL)

    The aim of the survey was to document honeybee forage plants and asses honeybee visitation counts on different forage plants and properties of honey from selected agro-ecological zones of Uganda. In order to achieve the objectives of the study, a survey of the apiaries and beekeepers was done by selecting fifteen bee ...

  16. Refinement for a model describing forage production, animal ...

    African Journals Online (AJOL)

    An existing model describing the influence of Acacia karoo density on forage production, animal production and profitablility is reviewed and amended to introduce recent research results. The refined model predicts that maximum forage production can be attained at 1 220 tree equivalents (TE) per ha, maximum livemass ...

  17. A Comparison of Foraging Site Characteristics of Two African ...

    African Journals Online (AJOL)

    A Comparison of Foraging Site Characteristics of Two African Resident Insectivorous Birds in a Burned Habitat. ... Data on food availability and vegetation structures were obtained by quadrate sampling while foraging spots were determined from four stratified transects each surveyed four times during the study.

  18. Editorial Greater international exposure for African range and forage ...

    African Journals Online (AJOL)

    Password, Remember me, or Register. DOWNLOAD FULL TEXT Open Access DOWNLOAD FULL TEXT Subscription or Fee Access. Editorial Greater international exposure for African range and forage science. Susi Vetter. Abstract. Click on the link to view the editorial. African Journal of Range & Forage Science 2009, ...

  19. Potential nutritive value of some forage species used as ruminants ...

    African Journals Online (AJOL)

    A study was conducted to determine rumen degradability (in sacco) of dry matter and in vitro gas production of the most important forage species grown in Iran, to compare forage species according to calculated degradation and in vitro gas production parameters, and to establish prediction equations for relative feed value ...

  20. Multiobjective fuzzy dominance based bacterial foraging algorithm to solve economic emission dispatch problem

    Energy Technology Data Exchange (ETDEWEB)

    Panigrahi, B.K.; Ravikumar Pandi, V. [Department of Electrical Engineering, IIT, Hauz Khas, New Delhi 110016 (India); Das, Sanjoy [Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506 (United States); Das, Swagatam [Department of electronics and Telecomm. Engineering, Jadavpur University, Kolkata (India)

    2010-12-15

    This paper proposes the bacterial foraging meta-heuristic algorithm for multiobjective optimization. In this multiobjective bacterial foraging optimization technique, the most recent bacterial locations are obtained by chemotaxis process. Next, Fuzzy dominance based sorting procedure is used here to select the Pareto optimal front (POF). To test the suitability of our proposed algorithm we have considered a highly constrained optimization problem namely economic/emission dispatch. Now-a-days environmental concern that arises due to the operation of fossil fuel fired electric generators and global warming, transforms the classical economic load dispatch problem into multiobjective environmental/economic dispatch (EED) problem. In the proposed work, we have considered the standard IEEE 30-bus six-generator test system and the results obtained by proposed algorithm are compared with the other recently reported results. Simulation results demonstrate that the proposed algorithm is a capable candidate in solving the multiobjective economic emission load dispatch problem. (author)

  1. FORAGE AND GRAIN YIELD PERFORMANCES OF SOYBEAN LINES

    Directory of Open Access Journals (Sweden)

    Ugur BILGILI

    2006-05-01

    Full Text Available Field experiments were conducted to evaluate the yield and yield components of twelve soybean genotypes as a forage and a grain crop in Marmara Region of Turkey in 2003-2004 growing seasons. Forage and dry matter yield and yield components at one vegetative stage (V5 and two reproductive stages (R2, and R4 and seed yield was determined in all soybean genotypes. The experiments showed that the harvest stages had signifi cant effects on forage and dry matter yield, and R4 reproductive stage had the highest forage and dry matter yield. Dry matter partitioning of soybean plant parts was greatly affected by harvest stages, while the genotypes had little effect on dry matter partitioning of soybean plant parts. There were statistically signifi cant differences between soybean genotypes in seed yield, but the differences were small. The correlations between forage and dry matter yield and seed yield were not statistically signifi cant.

  2. Mapping of wood stork foraging habitat with satellite data

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, J.R.; Coulter, M.; Mackey, H.E. Jr.; Hodgson, M.E.

    1985-01-01

    Potential foraging sites for an endangered species, the wood stork, were identified using Landsat thematic mapper data for a section of north central Georgia and the Savannah River floodplain swamp in South Carolina. This was accomplished using innovative clustering techniques applied to known wood stork foraging sites around the Birdsville Colony in Georgia. The signatures for known sites were then geographically extended to a 1520-square-kilometer region surrounding the Birdsville Colony. Thematic maps were produced and foraging area acreages computed providing a regional assessment of existing and potential wood stork foraging sites. Approximately 1744 hectarea of potential shallow water and macrophyte foraging habitat were identified in the area surroundings the Birdsville Colony. 14 refs., 3 figs.

  3. Field energetics and foraging mode of Kalahari lacertid lizards

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, K.A.; Huey, R.B.; Bennett, A.F.

    1984-04-01

    The authors examined the energetic costs associated with foraging mode in the widely foraging lizard Eremias lugubris (mean mass 3.83 g) and the sit-and-wait lizard Eremias lineoocellata (3.27 g). These lizards are broadly sympatric in the Kalahari desert. The widely foraging species had significantly higher field metabolic rates (800 vs. 544 J/d, as measured with doubly labeled water), feeding rates (metabolizable energy of 1165 vs. 739 J/d), production rates (365 vs. 195 J/d) and water influx rates (0.285 vs. 0.156 mL/d). Measurements were made before the reproductive season began; there were no significant differences in these measures between sexes within either species. Resting metabolic rates (measured as O/sub 2/ consumed) were similar at 37/sup 0/C (0.240 vs. 0.252 mL g/sup -1/ H/sup -1/) and 26/sup 0/ (0.094 vs. 0.103 mL g/sup -1/ h/sup -1/), the field active and nocturnal burrow temperatures respectively, of both species. Field metabolic rates, on a 24-h basis, were 3.1 x resting in E. lugubris and 2.2 x resting in E. lineoocellata. Energy expenditures during the activity period were 12.0 x resting in the wide forager and 2.8 x resting in the sit-and-wait predator. Foraging efficiency (metabolizable energy gained while foraging/total energy spent while foraging) was higher in the wide forager (2.0 than in the sit-and-wait predator. The wide forager grew nearly twice as fast as did the sit-and-wait predator during this study. On an annual basis, variation in food availability or differences in predation rate may alter the relative fitness of these foraging modes.

  4. Is Bumblebee Foraging Efficiency Mediated by Morphological Correspondence to Flowers?

    Directory of Open Access Journals (Sweden)

    Ikumi Dohzono

    2011-01-01

    Full Text Available Preference for certain types of flowers in bee species may be an adaptation for efficient foraging, and they often prefer flowers whose shape fits their mouthparts. However, it is unclear whether such flowers are truly beneficial for them. We address this issue by experimentally measuring foraging efficiency of bumblebees, the volume of sucrose solution consumed over handling time (μL/second, using long-tongued Bombus diversus Smith and short-tongued B. honshuensis Tkalcu that visit Clematis stans Siebold et Zuccarini. The corolla tube length of C. stans decreases during a flowering period, and male flowers are longer than female flowers. Long- and short-tongued bumblebees frequently visited longer and shorter flowers, respectively. Based on these preferences, we hypothesized that bumblebee foraging efficiency is higher when visiting flowers that show a good morphological fit between the proboscis and the corolla tube. Foraging efficiency of bumblebees was estimated using flowers for which nectar quality and quantity were controlled, in an experimental enclosure. We show that 1 the foraging efficiency of B. diversus was enhanced when visiting younger, longer flowers, and that 2 the foraging efficiency of B. honshuensis was higher when visiting shorter female flowers. This suggests that morphological correspondence between insects and flowers is important for insect foraging efficiency. However, in contradiction to our prediction, 3 short-tongued bumblebees B. honshuensis sucked nectar more efficiently when visiting younger, longer flowers, and 4 there was no significant difference in the foraging efficiency of B. diversus between flower sexes. These results suggest that morphological fit between the proboscis and the corolla tube is not a sole determinant of foraging efficiency. Bumblebees may adjust their sucking behavior in response to available rewards, and competition over rewards between bumblebee species might change visitation patterns

  5. Testing forage legume technologies with smallholder dairy farmers ...

    African Journals Online (AJOL)

    Mo

    breeds as potentially viable enterprise to improve household income and nutrition. The realization of ... under “real-life” agro-ecological and management conditions; farmers' capacity and expertise for conducting collaborative research is built up and ..... want to risk their land being sold for defaulting. Mureithi and Thorpe.

  6. Breeding limits foraging time : Evidence of interrupted foraging response from body mass variation in a tropical environment

    NARCIS (Netherlands)

    Nwaogu, Chima J.; Dietz, Maurine W.; Tieleman, B. Irene; Cresswell, Will

    Birds should store body reserves if starvation risk is anticipated; this is known as an ‘interrupted foraging response’. If foraging remains unrestricted, however, body mass should remain low to limit the predation risk that gaining and carrying body reserves entails. In temperate environments mass

  7. Arithmetic-Like Reasoning in Wild Vervet Monkeys: A Demonstration of Cost-Benefit Calculation in Foraging

    Directory of Open Access Journals (Sweden)

    Sayaka Tsutsumi

    2011-01-01

    Full Text Available Arithmetic-like reasoning has been demonstrated in various animals in captive and seminatural environments, but it is unclear whether such competence is practiced in the wild. Using a hypothetical foraging paradigm, we demonstrate that wild vervet monkeys spontaneously adjust their “foraging behavior” deploying arithmetic-like reasoning. Presented with arithmetic-like problems in artificially controlled feeding conditions, all the monkeys tested attempted to retrieve “artificial prey” according to the quantity of the remainder when the task involved one subtraction only (i.e., “2−1”, while one monkey out of four did so when it was sequentially subtracted twice (i.e., “2−1−1”. This monkey also adjusted his “foraging behavior” according to the quantity of the reminder for a task requiring stepwise mental manipulation (i.e., “(2−1−1”, though the results became less evident. This suggests that vervet monkeys are capable of spontaneously deploying mental manipulations of numerosity for cost-benefit calculation of foraging but that the extent of such capacity varies among individuals. Different foraging strategies might be deployed according to different levels of mental manipulation capacity in each individual in a given population. In addition to providing empirical data, the current study provides an easily adaptable field technique that would allow comparison across taxa and habitat using a uniform method.

  8. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density.

    Science.gov (United States)

    Hazen, Elliott Lee; Friedlaender, Ari Seth; Goldbogen, Jeremy Arthur

    2015-10-01

    Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency.

  9. The influence of chemoreception on the foraging behaviour of two species of sandpiper, calidris alba and calidris alpina

    Science.gov (United States)

    Van Heezik, Y. M.; Gerritsen, A. F. C.; Swennen, C.

    This study is concerned with the ability of two wader species, the sanderling, Calidris alba and the dunlin, C. alpina to determine the presence of prey in a sediment by using their sense of taste, and whether they use this information while foraging for prey hidden in the sediment. Preference tests were designed in which the birds were presented with a choice of 2 jars filled with sand from 3 possible combination pairs: (1) "food" and "no taste", (2) "food" and "taste", and (3) "taste" and "no taste". Preferences were measured as the relative amount of time spent foraging in each jar of each pair. Significantly more time was spent on "taste" than on "no taste" for the "taste" and "no taste" combination. More time was spent on "taste" than on "no taste" when each was paired with "food" for 3 out of 4 situations. Foraging technique on "taste" was observed to be more purposeful and methodical than on "no taste". Both species are shown to be able to use taste while foraging to determine whether prey is present, and can modify their foraging behaviour by persisting in a spot that gives no information on the presence of prey other than taste, and by using a different, more determined searching technique.

  10. Efficiency in pollen foraging by honey bees: Time, motion and pollen depletion on flowers of Sisyrinchium palmifolium Linnaeus (Asparagales: Iridaceae

    Directory of Open Access Journals (Sweden)

    Breno M. Freitas

    2013-10-01

    Full Text Available Honey bees depend on flower resources (nectar and pollen to supply individual and colony needs. Although behavioural studies already assessed optimum foraging patterns of bumblebees, honey bees foraging behavioural patterns have been poorly assessed. We used Sysirinchium palmifolium L. (Iridaceae, a low-growing, abundant and anthophilous grassland flower to test the hypotheses that Apis mellifera workers would i spend more time, ii visit a greater number of flowers, and iii travel greater distances within patches of S. palmifolium which were newly opened or not been visited by other pollinators when compared to foraging on patches that were available to pollinators during its whole blooming period (only one day. In two different sunny days, we measured bee activities in an area opened for visitation during the whole anthesis (OP plot treatment and another opened for visitation only half of anthesis (CL plot treatment. We observed bees spending more time, visiting more flowers and travelling more in S. palmifolium CL treatment than the OP plot treatment. Previous studies already showed bees alter their foraging behaviour in the lack of resources. Honey bees are able to remember the period of the day when resources are usually the higher, they probably detect the most promising period to gather resources on S. palmifolium flowers. Since A. mellifera is a pollinator with a wide-distribution and is considered an important cause of changes on native pollinator communities, we support additional studies evaluating its foraging behaviours to better understand how it explores flower resources.

  11. Contrasting Patterns of Gene Flow for Amazonian Snakes That Actively Forage and Those That Wait in Ambush.

    Science.gov (United States)

    de Fraga, Rafael; Lima, Albertina P; Magnusson, William E; Ferrão, Miquéias; Stow, Adam J

    2017-07-01

    Knowledge of genetic structure, geographic distance and environmental heterogeneity can be used to identify environmental features and natural history traits that influence dispersal and gene flow. Foraging mode is a trait that might predict dispersal capacity in snakes, because actively foragers typically have greater movement rates than ambush predators. Here, we test the hypothesis that 2 actively foraging snakes have higher levels of gene flow than 2 ambush predators. We evaluated these 4 co-distributed species of snakes in the Brazilian Amazon. Snakes were sampled along an 880 km transect from the central to the southwest of the Amazon basin, which covered a mosaic of vegetation types and seasonal differences in climate. We analyzed thousands of single nucleotide polymorphisms to compare patterns of neutral gene flow based on isolation by geographic distance (IBD) and environmental resistance (IBR). We show that IBD and IBR were only evident in ambush predators, implying lower levels of dispersal than the active foragers. Therefore, gene flow was high enough in the active foragers analyzed here to prevent any build-up of spatial genotypic structure with respect to geographic distance and environmental heterogeneity. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Effects of sainfoin (Onobrychis viciifolia) extract and monomers of condensed tannins on the association of abomasal nematode larvae with fundic explants.

    Science.gov (United States)

    Brunet, S; Jackson, F; Hoste, H

    2008-06-01

    Tannin-rich forages offer an alternative to anthelmintic chemicals to control gastrointestinal nematodes. However, the mode of action of such bioactive plants still needs to be assessed. Previous studies have shown that extracts of tannin-rich plants interfere with the first phase of host invasion, i.e., the exsheathment of infective larvae (L3s). In the current study, we examined the hypothesis that exposure to tannins could also affect the second phase of larval establishment, i.e., the tissue association/penetration of the exsheathed L3s into the digestive mucosae. An in vitro direct challenge technique using fundic explants was applied in this study. The main parasite model was Haemonchus contortus. The objectives were to verify: (i) whether a modification of the association/penetration of L3s with the mucosae occurred after contact with sainfoin extract; (ii) whether this is a dose-dependent phenomenon; (iii) whether tannins were responsible for these effects; (iv) whether these effects were dependent on the parasite species; and (v) how the biochemical structure of tannins might influence these effects. Following 3h contact with sainfoin extract at 1,200 microg/ml, the penetration of exsheathed L3s of H. contortus and Teladorsagia circumcincta into fundic explants was significantly reduced. Moreover, a dose-response relationship was found for H. contortus. For both nematodes, the changes were totally alleviated after addition of polyvinyl polypyrrolidone, an inhibitor of tannins, to the sainfoin extract, suggesting that tannins play a major role in the observed effects. Comparison of results obtained with different monomers of condensed tannins confirms a relationship between structure and activity, the prodelphinidin monomers and galloyl-derivatives being more effective than the procyanidin monomers. Combined with the delay or the inhibition of larval exsheathment previously shown, these effects could explain how tanniniferous plants reduce the establishment

  13. Long bone cross-sectional geometric properties of Later Stone Age foragers and herder�foragers

    Directory of Open Access Journals (Sweden)

    Michelle E. Cameron

    2014-09-01

    Full Text Available Diaphyseal cross-sectional geometry can be used to infer activity patterns in archaeological populations. We examined the cross-sectional geometric (CSG properties of adult Later Stone Age (LSA herder-forager long bones from the inland lower Orange River Valley of South Africa (n=5 m, 13 f. We then compared their CSG properties to LSA forager adults from the coastal fynbos (n=23 m, 14 f and forest (n=17 m, 19 f regions, building on a previous report (Stock and Pfeiffer, 2004. The periosteal mould method was used to quantify total subperiosteal area, torsional strength, bilateral asymmetry and diaphyseal circularity (Imax/Imin at the mid-distal (35% location of upper arms (humeri and the mid-shaft (50% location of upper legs (femora. Maximum humerus and femur lengths were similar among the three samples, suggesting that adult stature was similar in all three regions. When compared to the previous study, CSG property values obtained using the periosteal mould method correlated well, and there were no significant differences between data collected using the different methods. No statistically significant differences were found among the humerus or femur CSG properties from the different regions. This finding suggests that all individuals undertook similar volitional habitual activities in regard to their upper limbs, and also had similar degrees of terrestrial mobility. These results indicate relative behavioural homogeneity among LSA foragers and herder foragers from South Africa. The small degree of regional variation apparent among the three samples may reflect local ecology and the subsistence demands affecting populations in these different regions.

  14. Is visual search really like foraging?

    Science.gov (United States)

    Gilchrist, I D; North, A; Hood, B

    2001-01-01

    The visual-search paradigm provides a controlled and easy to implement experimental situation in which to study the search process. However, little work has been carried out in humans to investigate the extent to which traditional visual-search tasks are similar to more general search or foraging. Here we report results from a task in which search involves walking around a room and leaning down to inspect individual locations. Consistent with more traditional search tasks, search time increases linearly with display size, and the target-present to target-absent search slope is 1:2. However, although rechecking of locations did occur, compared to more traditional search it was relatively rare, suggesting an increased role for memory.

  15. Pandora neoaphidis transmission and aphid foraging behaviour.

    Science.gov (United States)

    Baverstock, J; Alderson, P G; Pell, J K

    2005-09-01

    Pandora neoaphidis is an aphid-specific entomopathogen that produces infective conidia. As aphid movement increases, so does the likelihood of contact with conidia. Volatile distress signals released in response to aphid infestation as an indirect defence against herbivory may affect aphid foraging and, therefore, the fungus-aphid interaction. In this study, two different methods were used to investigate the effect of plant volatiles and P. neoaphidis-sporulating cadavers on (1) the colonisation of Vicia faba plants by Acyrthosiphon pisum and (2) P. neoaphidis transmission. This study indicates that A. pisum does not avoid bean plants containing P. neoaphidis and that transmission of conidia occurs during plant colonisation and, to a lesser extent, during in situ feeding. Although significantly more aphids were recovered from damaged plants compared to undamaged plants, the likelihood of infection was not affected by previous infestation by aphids.

  16. Foraging Cognition: Reviving the Ecological Intelligence Hypothesis.

    Science.gov (United States)

    Rosati, Alexandra G

    2017-09-01

    What are the origins of intelligent behavior? The demands associated with living in complex social groups have been the favored explanation for the evolution of primate cognition in general and human cognition in particular. However, recent comparative research indicates that ecological variation can also shape cognitive abilities. I synthesize the emerging evidence that 'foraging cognition' - skills used to exploit food resources, including spatial memory, decision-making, and inhibitory control - varies adaptively across primates. These findings provide a new framework for the evolution of human cognition, given our species' dependence on costly, high-value food resources. Understanding the origins of the human mind will require an integrative theory accounting for how humans are unique in both our sociality and our ecology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Information Foraging in E-Voting

    DEFF Research Database (Denmark)

    Vatrapu, Ravi; Robertson, Scott

    2009-01-01

    with others. Interaction analysis of the case study data consisted of applying Information Foraging Theory to understand participant specific behaviors in searching and browsing. Case study results show skewed time allocation to activities, a tradeoff between enrichment vs. exploitation of search results......In this paper, we present a case study of human-information interaction in the online realm of politics. The case study consists of a participant observed while searching and browsing the internet for campaign information in a mock-voting situation while taking notes that were to be shared......, and issues with lack of scent, low value perception, and value depletion of information. Potential implications for voter-centered design of evoting portals are discussed and future work is outlined....

  18. Utilization of male sterility in forage crops

    Energy Technology Data Exchange (ETDEWEB)

    Suginobu, Ken-ichi (National Grassland Research Inst., Nishinasuno, Tochigi (Japan))

    1982-03-01

    The genetic nature of male sterility in forage crops was reviewed. Many workers have suggested that hybrids in forage crops are quite promising. First, the selection of the most desirable parental genotype from a large original population is improtant in heterosis breeding programs. After the more promising inbreds or clones have been selected on the basis of good general combining ability, it is necessary to identify the particular single, three-way or double cross that will produce the highest yields. A high seed yield potential is also important in a new variety so that the seeds can be sold at lower prices than other varieties. A tentative scheme for hybrid seed production by using inbred lines of male sterile or normal parents is proposed. At a breeding station, the seeds for male sterile F/sub 1/(AB), maintainer S/sub 1/(C-S/sub 1/) and either maintainer or restorer S/sub 1/s(D-S/sub 1/, E-S/sub 1/) are produced from the parental clones. At a seed increase agency, the seeds for male sterile F/sub 1/(ABC) and either maintainer or restorer S/sub 2/(D-S/sub 2/) are produced. In the case that D-S/sub 2/ seed production is difficult, maintainer or restorer F/sub 1/(DE) should be produced from D-S/sub 1/ x E-S/sub 1/. These seeds are used for commercial seed production. Seeds of hybrid F/sub 1/(ABCD) or hybrid F/sub 1/(ABCDE) are for practical use.

  19. Stature in Holocene foragers of North India.

    Science.gov (United States)

    Lukacs, John R; Pal, J N; Nelson, Greg C

    2014-03-01

    The Ganga Plain of North India provides an archaeological and skeletal record of semi-nomadic Holocene foragers in association with an aceramic Mesolithic culture. Prior estimates of stature for Mesolithic Lake Cultures (MLC) used inappropriate equations from an American White reference group and need revision. Attention is given to intralimb body proportions and geo-climatic provenance of MLC series in considering the most suitable reference population. Regression equations from ancient Egyptians are used in reconstructing stature for MLC skeletal series from Damdama (DDM), Mahadaha (MDH), and Sarai Nahar Rai (SNR). Mean stature is estimated at between 174 (MDH) and 178 cm (DDM and SNR) for males, and between 163 cm (MDH) and 179 cm (SNR) for females. Stature estimates based on ancient Egyptian equations are significantly shorter (from 3.5 to 7.1 cm shorter in males; from 3.2 to 7.5 cm shorter in females) than estimates using the American White reference group. Revised stature estimates from tibia length and from femur + tibia more accurately estimate MLC stature for two reasons: a) these elements are highly correlated with stature and have lower standard estimates of error, and b) uncertainty regarding methods of measuring tibia length is avoided. When compared with Holocene samples of native Americans and Mesolithic Europeans, MLC series from North India are tall. This aspect of their biological variation confirms earlier assessments and results from the synergistic influence of balanced nutrition from broad-spectrum foraging, body-proportions adapted to a seasonally hot and arid climate, and the functional demands of a mobile, semi-nomadic life-style. Copyright © 2013 Wiley Periodicals, Inc.

  20. Experimental manipulation of predation risk and food quality: effect on grazing behaviour in a central-place foraging herbivore

    NARCIS (Netherlands)

    Bakker, E.S.; Reiffers, R.C.; Olff, H.; Gleichman, J.M.

    2005-01-01

    Abstract The relative importance of predation risk and food quality on spatial grazing pressure and activity patterns was tested in a central-place foraging herbivore: the European rabbit. Rabbits grazed less with increasing distance from their burrows into adjacent grassland, thereby creating a

  1. Experimental manipulation of predation risk and food quality : effect on grazing behaviour in a central-place foraging herbivore

    NARCIS (Netherlands)

    Bakker, ES; Reiffers, RC; Olff, H; Gleichman, JM; Brandl, Roland

    2005-01-01

    The relative importance of predation risk and food quality on spatial grazing pressure and activity patterns was tested in a central-place foraging herbivore: the European rabbit. Rabbits grazed less with increasing distance from their burrows into adjacent grassland, thereby creating a gradient of

  2. Effects of Saccharomyces cerevisiae fermentation product on in vitro fermentation and microbial communities of low-quality forages and mixed diets.

    Science.gov (United States)

    Mao, Hui-ling; Mao, Hua-long; Wang, J K; Liu, J X; Yoon, I

    2013-07-01

    Two experiments were conducted to investigate the effects of a Saccharomyces cerevisiae fermentation product (XP, Diamond V, Cedar Rapids, IA) on in vitro ruminal fermentation of single forage and mixed diets. In Exp. 1, an in vitro test was used to determine the effects of various concentrations (0, 1, 2, and 3 g/L) of XP on ruminal fermentation of the major forage sources of China (rice straw, RS; corn stover, CS; corn silage without grain, CSNG; and corn silage with grain, CSG). Total VFA reached a peak at 1 g/L XP for RS, CSNG, and CSG and increased linearly (P forages except CSNG. The population of Ruminococcus flavefaciens increased (P forages and mixed diets by stimulating the number of fiber-digesting rumen microbes, especially fungi populations.

  3. Production and transcriptional regulation of proanthocyanidin biosynthesis in forage legumes.

    Science.gov (United States)

    Zhou, Meiliang; Wei, Li; Sun, Zhanmin; Gao, Lihua; Meng, Yu; Tang, Yixiong; Wu, Yanmin

    2015-05-01

    Proanthocyanidins (PA), also known as condensed tannins, contribute to important forage legumes traits including disease resistance and forage quality. PA in forage plants has both positive and negative effects on feed digestibility and animal performance. The analytical methods and their applicability in measuring the contents of PA in forage plants are essential to studies on their nutritional effects. In spite of important breakthroughs in our understanding of the PA biosynthesis, important questions still remain to be answered such as the PA polymerization and transport. Recent advances in the understanding of transcription factor-mediated gene regulation mechanisms in anthocyanin and PA biosynthetic pathway in model plants suggest new approaches for the metabolic engineering of PA in forage plants. The present review will attempt to present the state-of-the-art of research in these areas and provide an update on the production and metabolic engineering of PA in forage plants. We hope that this will contribute to a better understanding of the ways in which PA production to manipulate the content of PA for beneficial effects in forage plants.

  4. Personality, Foraging and Fitness Consequences in a Long Lived Seabird

    Science.gov (United States)

    Patrick, Samantha C.; Weimerskirch, Henri

    2014-01-01

    While personality differences in animals are defined as consistent behavioural variation between individuals, the widely studied field of foraging specialisation in marine vertebrates has rarely been addressed within this framework. However there is much overlap between the two fields, both aiming to measure the causes and consequences of consistent individual behaviour. Here for the first time we use both a classic measure of personality, the response to a novel object, and an estimate of foraging strategy, derived from GPS data, to examine individual personality differences in black browed albatross and their consequences for fitness. First, we examine the repeatability of personality scores and link these to variation in foraging habitat. Bolder individuals forage nearer the colony, in shallower regions, whereas shyer birds travel further from the colony, and fed in deeper oceanic waters. Interestingly, neither personality score predicted a bird’s overlap with fisheries. Second, we show that both personality scores are correlated with fitness consequences, dependent on sex and year quality. Our data suggest that shyer males and bolder females have higher fitness, but the strength of this relationship depends on year quality. Females who forage further from the colony have higher breeding success in poor quality years, whereas males foraging close to the colony always have higher fitness. Together these results highlight the potential importance of personality variation in seabirds and that the fitness consequences of boldness and foraging strategy may be highly sex dependent. PMID:24504180

  5. Personality, foraging and fitness consequences in a long lived seabird.

    Science.gov (United States)

    Patrick, Samantha C; Weimerskirch, Henri

    2014-01-01

    While personality differences in animals are defined as consistent behavioural variation between individuals, the widely studied field of foraging specialisation in marine vertebrates has rarely been addressed within this framework. However there is much overlap between the two fields, both aiming to measure the causes and consequences of consistent individual behaviour. Here for the first time we use both a classic measure of personality, the response to a novel object, and an estimate of foraging strategy, derived from GPS data, to examine individual personality differences in black browed albatross and their consequences for fitness. First, we examine the repeatability of personality scores and link these to variation in foraging habitat. Bolder individuals forage nearer the colony, in shallower regions, whereas shyer birds travel further from the colony, and fed in deeper oceanic waters. Interestingly, neither personality score predicted a bird's overlap with fisheries. Second, we show that both personality scores are correlated with fitness consequences, dependent on sex and year quality. Our data suggest that shyer males and bolder females have higher fitness, but the strength of this relationship depends on year quality. Females who forage further from the colony have higher breeding success in poor quality years, whereas males foraging close to the colony always have higher fitness. Together these results highlight the potential importance of personality variation in seabirds and that the fitness consequences of boldness and foraging strategy may be highly sex dependent.

  6. Foraging niche segregation in Malaysian babblers (Family: Timaliidae).

    Science.gov (United States)

    Mansor, Mohammad Saiful; Ramli, Rosli

    2017-01-01

    Tropical rainforests are considered as hotspots for bird diversity, yet little is known about the system that upholds the coexistence of species. Differences in body size that are associated with foraging strategies and spatial distribution are believed to promote the coexistence of closely related species by reducing competition. However, the fact that many babbler species do not differ significantly in their morphology has challenged this view. We studied the foraging ecology of nine sympatric babbler species (i.e., Pellorneum capistratum, P. bicolor, P. malaccense, Malacopteron cinereum, M. magnum, Stachyris nigriceps, S. nigricollis, S. maculata, and Cyanoderma erythropterum) in the Krau Wildlife Reserve in Peninsular Malaysia. We investigated; i) how these babblers forage in the wild and use vegetation to obtain food, and ii) how these trophically similar species differ in spatial distribution and foraging tactics. Results indicated that most babblers foraged predominantly on aerial leaf litter and used gleaning manoeuvre in intermediate-density foliage but exhibited wide ranges of vertical strata usage, thus reducing interspecific competition. The principal component analysis indicated that two components, i.e., foraging height and substrate are important as mechanisms to allow the coexistence of sympatric babblers. The present findings revealed that these bird species have unique foraging niches that are distinct from each other, and this may apply to other insectivorous birds inhabiting tropical forests. This suggests that niche separation does occur among coexisting birds, thus following Gause' law of competitive exclusion, which states two species occupying the same niche will not stably coexist.

  7. Forage fish, their fisheries, and their predators: who drives whom?

    DEFF Research Database (Denmark)

    Engelhard, Georg H.; Peck, Myron A.; Rindorf, Anna

    2014-01-01

    The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries ...... with forage fish for zooplankton resources. In complex systems, changes in the impact of fisheries on forage fish may have potentially complex (and perhaps unanticipated) consequences on other commercially and/or ecologically important species...... exist, as in the North Sea. Sandeel appears to be the most important prey forage fish. Seabirds are most dependent on forage fish, due to specialized diet and distributional constraints (breeding colonies). Other than fisheries, key predators of forage fish are a few piscivorous fish species including......The North Sea has a diverse forage fish assemblage, including herring, targeted for human consumption; sandeel, sprat, and Norway pout, exploited by industrial fisheries; and some sardine and anchovy, supporting small-scale fisheries. All show large abundance fluctuations, impacting on fisheries...

  8. Functional visual sensitivity to ultraviolet wavelengths in the Pileated Woodpecker (Dryocopus pileatus), and its influence on foraging substrate selection

    Science.gov (United States)

    O'Daniels, Sean T.; Kesler, Dylan C.; Mihail, Jeanne D.; Webb, Elisabeth B.; Werner, Scott J.

    2017-01-01

    Most diurnal birds are presumed visually sensitive to near ultraviolet (UV) wavelengths, however, controlled behavioral studies investigating UV sensitivity remain few. Although woodpeckers are important as primary cavity excavators and nuisance animals, published work on their visual systems is limited. We developed a novel foraging-based behavioral assay designed to test UV sensitivity in the Pileated Woodpecker (Dryocopus pileatus). We acclimated 21 wild-caught woodpeckers to foraging for frozen mealworms within 1.2 m sections of peeled cedar (Thuja spp.) poles. We then tested the functional significance of UV cues by placing frozen mealworms behind UV-reflective covers, UV-absorptive covers, or decayed red pine substrates within the same 1.2 m poles in independent experiments. Behavioral responses were greater toward both UV-reflective and UV-absorptive substrates in three experiments. Study subjects therefore reliably differentiated and attended to two distinct UV conditions of a foraging substrate. Cue-naïve subjects showed a preference for UV-absorptive substrates, suggesting that woodpeckers may be pre-disposed to foraging from such substrates. Behavioral responses were greater toward decayed pine substrates (UV-reflective) than sound pine substrates suggesting that decayed pine can be a useful foraging cue. The finding that cue-naïve subjects selected UV-absorbing foraging substrates has implications for ecological interactions of woodpeckers with fungi. Woodpeckers transport fungal spores, and communication methods analogous to those of plant-pollinator mutualisms (i.e. UV-absorbing patterns) may have evolved to support woodpecker-fungus mutualisms.

  9. Departure time influences foraging associations in little penguins.

    Science.gov (United States)

    Sutton, Grace J; Hoskins, Andrew J; Berlincourt, Maud; Arnould, John P Y

    2017-01-01

    Recent studies have documented that little penguins (Eudyptula minor) associate at sea, displaying synchronised diving behaviour throughout a foraging trip. However, previous observations were limited to a single foraging trip where only a small number of individuals were simultaneously tracked. Consequently, it is not known whether coordinated behaviour is consistent over time, or what factors influence it. In the present study, breeding adults were concurrently instrumented with GPS and dive behaviour data loggers for at least 2 consecutive foraging trips during guard and post-guard stage at two breeding colonies (London Bridge and Gabo Island, south-eastern Australia) of contrasting population size (approximately 100 and 30,000-40,000, respectively). At both colonies, individuals were sampled in areas of comparable nesting density and spatial area. At London Bridge, where individuals use a short (23 m) common pathway from their nests to the shoreline, > 90% (n = 42) of birds displayed foraging associations and 53-60% (n = 20) maintained temporally consistent associations with the same conspecifics. Neither intrinsic (sex, size or body condition) nor extrinsic (nest proximity) factors were found to influence foraging associations. However, individuals that departed from the colony at a similar time were more likely to associate during a foraging trip. At Gabo Island, where individuals use a longer (116 m) pathway with numerous tributaries to reach the shoreline, few individuals (< 31%; n = 13) from neighbouring nests associated at sea and only 1% (n = 1) maintained associations over subsequent trips. However, data from animal-borne video cameras indicated individuals at this colony displayed foraging associations of similar group size to those at London Bridge. This study reveals that group foraging behaviour occurs at multiple colonies and the pathways these individuals traverse with conspecifics may facilitate opportunistic group formation and resulting in

  10. Individual foraging strategies reveal niche overlap between endangered galapagos pinnipeds.

    Directory of Open Access Journals (Sweden)

    Stella Villegas-Amtmann

    Full Text Available Most competition studies between species are conducted from a population-level approach. Few studies have examined inter-specific competition in conjunction with intra-specific competition, with an individual-based approach. To our knowledge, none has been conducted on marine top predators. Sympatric Galapagos fur seals (Arctocephalus galapagoensis and sea lions (Zalophus wollebaeki share similar geographic habitats and potentially compete. We studied their foraging niche overlap at Cabo Douglas, Fernandina Island from simultaneously collected dive and movement data to examine spatial and temporal inter- and intra-specific competition. Sea lions exhibited 3 foraging strategies (shallow, intermediate and deep indicating intra-specific competition. Fur seals exhibited one foraging strategy, diving predominantly at night, between 0-80 m depth and mostly at 19-22 h. Most sea lion dives also occurred at night (63%, between 0-40 m, within fur seals' diving depth range. 34% of sea lions night dives occurred at 19-22 h, when fur seals dived the most, but most of them occurred at dawn and dusk, when fur seals exhibited the least amount of dives. Fur seals and sea lions foraging behavior overlapped at 19 and 21 h between 0-30 m depths. Sea lions from the deep diving strategy exhibited the greatest foraging overlap with fur seals, in time (19 h, depth during overlapping time (21-24 m, and foraging range (37.7%. Fur seals foraging range was larger. Cabo Douglas northwest coastal area, region of highest diving density, is a foraging "hot spot" for both species. Fur seals and sea lions foraging niche overlap occurred, but segregation also occurred; fur seals primarily dived at night, while sea lions exhibited night and day diving. Both species exploited depths and areas exclusive to their species. Niche breadth generally increases with environmental uncertainty and decreased productivity. Potential competition between these species could be greater during

  11. In vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg population.

    Science.gov (United States)

    Foster, Joyce G; Cassida, Kimberly A; Turner, Kenneth E

    2011-08-25

    The anthelmintic activity of chicory (Cichorium intybus L.) herbage has been attributed to sesquiterpene lactones. Chicory leaves contain significant amounts of lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), but the proportions of these three sesquiterpene lactones vary among forage chicory cultivars. To determine whether the individual compounds differ in anthelmintic activity, we prepared sesquiterpene lactone-enriched extracts from leaves of two forage chicory cultivars, 'Grasslands Puna' (Puna) and 'Forage Feast', and tested their effects on the hatching of a predominantly Haemonchus contortus egg population. The dominant constituents in the Puna and Forage Feast extracts were DOL and LAC, respectively; LPIC concentrations in the two extracts were similar. Extracts from both cultivars inhibited egg hatching at all concentrations tested (Psesquiterpene lactone concentrations increased from 0 to 6.7 mg/ml. Treatment with higher concentrations resulted in a sharp decline in egg hatchability. Concentrations of sesquiterpene lactones required for 50% lethality were determined by probit dose-effect analysis to be 2.6 mg/ml (95% confidence interval: 2.4-2.8 mg/ml) for the Puna extract and 6.4 mg/ml (95% confidence interval: 5.9-7.2mg/ml) for the Forage Feast extract (Psesquiterpene lactones in chicory leaf extracts suggest that Puna may be a better cultivar than Forage Feast for use in bioactive pastures for gastrointestinal parasite control in small ruminants. Published by Elsevier B.V.

  12. Colour learning when foraging for nectar and pollen: bees learn two colours at once.

    Science.gov (United States)

    Muth, Felicity; Papaj, Daniel R; Leonard, Anne S

    2015-09-01

    Bees are model organisms for the study of learning and memory, yet nearly all such research to date has used a single reward, nectar. Many bees collect both nectar (carbohydrates) and pollen (protein) on a single foraging bout, sometimes from different plant species. We tested whether individual bumblebees could learn colour associations with nectar and pollen rewards simultaneously in a foraging scenario where one floral type offered only nectar and the other only pollen. We found that bees readily learned multiple reward-colour associations, and when presented with novel floral targets generalized to colours similar to those trained for each reward type. These results expand the ecological significance of work on bee learning and raise new questions regarding the cognitive ecology of pollination. © 2015 The Author(s).

  13. Wolf, Canis lupus, visits to white-tailed deer, Odocoileus virginianus, summer ranges: Optimal foraging?

    Science.gov (United States)

    Demma, D.J.; Mech, L.D.

    2009-01-01

    We tested whether Wolf (Canis lupus) visits to individual female White-tailed Deer (Odocoileus virginianus) summer ranges during 2003 and 2004 in northeastern Minnesota were in accord with optimal-foraging theory. Using GPS collars with 10- to 30-minute location attempts on four Wolves and five female deer, plus eleven VHF-collared female deer in the Wolves' territory, provided new insights into the frequency of Wolf visits to summer ranges of female deer. Wolves made a mean 0.055 visits/day to summer ranges of deer three years and older, significantly more than their 0.032 mean visits/day to ranges of two-year-old deer, which generally produce fewer fawns, and most Wolf visits to ranges of older deer were much longer than those to ranges of younger deer. Because fawns comprise the major part of the Wolf's summer diet, this Wolf behavior accords with optimal-foraging theory.

  14. Application of genomics to forage crop breeding for quality traits

    DEFF Research Database (Denmark)

    Lübberstedt, Thomas

    2007-01-01

    Forage quality depends on the digestibility of fodder, and can be directly measured by the intake and metabolic conversion in animal trials. However, animal trials are time-consuming, laborious, and thus expensive. It is not possible to study thousands of plant genotypes, as required in breeding...... in model species and major forage crops such as ryegrass and alfalfa. Key genes involved in developmental and biochemical pathways affecting forage quality such as cell-wall, lignin, fructan, and tannin biosynthesis have been isolated and characterized. For some of these genes, allelic variation has been...

  15. Mineral composition of legumes forages cultivated under different levels of shade

    Directory of Open Access Journals (Sweden)

    João Carlos de Carvalho Almeida

    2015-02-01

    Full Text Available The objective of this study was to evaluate the composition of calcium, phosphorus and potassium, and the leaf: stem ratio of four tropical forage legumes: Calopogonium mucunoides (calopo, Pueraria phaseoloides (puero, Macrotyloma axillare (archer and Neonotonia wightii (perennial soybean, under different levels of artificial shade (0, 30, 50 and 70% in the summer and autumn seasons of 2006 and 2007, respectively. The experimental design was a randomized complete block in factorial 4x4 design with four replications. Was used SNK test at 5% probability to evaluate the effect of the legume species and regression analysis to test the effect of the level of shading. There was a trend of increase in the concentration of 3 independent minerals examined the season. In contrast, there was a reduction in the leaf: stem ratio and a slight increase in specific leaf area archer, perennial soybean and puero (R2 ? 40%, which suggests small effect of shading on the morphology of leaves of 3 forage legumes, which in turn have little effect concentrating minerals, besides these finding is confirmed the annual calopo behavior, which prevents their use as legume forage for the autumn season.

  16. Variable ingestion rate and its role in optimal foraging behavior of marine deposit feeders

    Energy Technology Data Exchange (ETDEWEB)

    Taghon, G.L.; Jumars, P.A.

    1984-04-01

    Tests of optimal foraging theory have focused generally on food item selection by mobile, high-trophic-level predators. Deposit-feeding invertebrates are aquatic organisms with limited mobility and hence limited ability to forage actively for food-rich patches. In addition, there is little evidence for a major role of behaviorally mediated food item choice in these animals, and growing evidence of mechanical limitations in food particle choice. Given such limited food-selection ability, varying ingestion rate in response to changes in food value is likely to be an important animal response affecting feeding energetics. A previously developed optimal foraging model predicted that ingestion rate and food value should covary positively in order to maximize net time rate of energy gain. To test this general prediction, the authors fed three species of deposit-feeding polychaetes artifical sediments which varied only in protein content (food value); other physical and chemical properties which might affect ingestion rate were kept constant. In support of the model, ingestion rates increased as protein levels increased.

  17. Optimal foraging by deposit-feeding invertebrates: roles of particle size and organic coating

    Energy Technology Data Exchange (ETDEWEB)

    Taghon, G.L.

    1982-01-01

    Feeding experiments were conducted on marine, deposit-feeding benthic invertebrates to test the predictions of an optimal foraging model. Food item selection based on sediment particle size and presence or absence of an organic coating on particles was investigated. Animals displaying a wide range of feeding mechanisms were studied in particle size-selection experiments using artificial sediment of closely controlled size composition. While these trends of selection of smaller particles and protein-coated particles follow qualitatively the predictions of the optimal foraging model, the animals did not ingest exclusively the preferred particle types. Mechanics of particle handling rather than behavioral responses to particle characteristics appear to offer the better explanation for the observed selection patterns. In particular, the results support strongly the recently proposed role of mucous adhesion in particle selection by deposit feeders. These and other results from studies of deposit feeders suggest that factors in addition to food item selection must be considered when testing the assumptions and predictions of optimal foraging theory.

  18. Grasping complex matter : large herbivore foraging in patches of heterogeneous resources

    NARCIS (Netherlands)

    Drescher, M.F.

    2003-01-01

    Key words: herbivory; functional response; grazing; food intake; food quality; selectivity; cattle; savanna The functional response, defined as the relationship of forage intake with forage availability, is the principal link between a forager and a forage resource, and as such connects the trophic

  19. Hydrocarbons emitted by waggle-dancing honey bees increase forager recruitment by stimulating dancing.

    Science.gov (United States)

    Gilley, David C

    2014-01-01

    Hydrocarbons emitted by waggle-dancing honey bees are known to reactivate experienced foragers to visit known food sources. This study investigates whether these hydrocarbons also increase waggle-dance recruitment by observing recruitment and dancing behavior when the dance compounds are introduced into the hive. If the hydrocarbons emitted by waggle-dancing bees affect the recruitment of foragers to a food source, then the number of recruits arriving at a food source should be greater after introduction of dance compounds versus a pure-solvent control. This prediction was supported by the results of experiments in which recruits were captured at a feeder following introduction of dance-compounds into a hive. This study also tested two nonexclusive behavioral mechanism(s) by which the compounds might stimulate recruitment; 1) increased recruitment could occur by means of increasing the recruitment effectiveness of each dance and/or 2) increased recruitment could occur by increasing the intensity of waggle-dancing. These hypotheses were tested by examining video records of the dancing and recruitment behavior of individually marked bees following dance-compound introduction. Comparisons of numbers of dance followers and numbers of recruits per dance and waggle run showed no significant differences between dance-compound and solvent-control introduction, thus providing no support for the first hypothesis. Comparison of the number of waggle-dance bouts and the number of waggle runs revealed significantly more dancing during morning dance-compound introduction than morning solvent-control introduction, supporting the second hypothesis. These results suggest that the waggle-dance hydrocarbons play an important role in honey bee foraging recruitment by stimulating foragers to perform waggle dances following periods of inactivity.

  20. Hydrocarbons emitted by waggle-dancing honey bees increase forager recruitment by stimulating dancing.

    Directory of Open Access Journals (Sweden)

    David C Gilley

    Full Text Available Hydrocarbons emitted by waggle-dancing honey bees are known to reactivate experienced foragers to visit known food sources. This study investigates whether these hydrocarbons also increase waggle-dance recruitment by observing recruitment and dancing behavior when the dance compounds are introduced into the hive. If the hydrocarbons emitted by waggle-dancing bees affect the recruitment of foragers to a food source, then the number of recruits arriving at a food source should be greater after introduction of dance compounds versus a pure-solvent control. This prediction was supported by the results of experiments in which recruits were captured at a feeder following introduction of dance-compounds into a hive. This study also tested two nonexclusive behavioral mechanism(s by which the compounds might stimulate recruitment; 1 increased recruitment could occur by means of increasing the recruitment effectiveness of each dance and/or 2 increased recruitment could occur by increasing the intensity of waggle-dancing. These hypotheses were tested by examining video records of the dancing and recruitment behavior of individually marked bees following dance-compound introduction. Comparisons of numbers of dance followers and numbers of recruits per dance and waggle run showed no significant differences between dance-compound and solvent-control introduction, thus providing no support for the first hypothesis. Comparison of the number of waggle-dance bouts and the number of waggle runs revealed significantly more dancing during morning dance-compound introduction than morning solvent-control introduction, supporting the second hypothesis. These results suggest that the waggle-dance hydrocarbons play an important role in honey bee foraging recruitment by stimulating foragers to perform waggle dances following periods of inactivity.

  1. Shoaling generates social learning of foraging information in guppies

    Science.gov (United States)

    Laland; Williams

    1997-06-01

    Two experimental studies are reported which investigate the social learning of foraging information in guppies, Poecilia reticulataIn both cases, untrained adult female guppies swam with trained conspecifics to feed, and in the process learned a route to a food source. In experiment 1, subjects were given 5 days experience swimming with demonstrator fish trained to take one of two equivalent routes to food. When tested alone, subjects preferentially used the route of their demonstrators. Experiment 2 investigated whether this social learning could mediate the stable transmission of route preferences among small populations of fish. This experiment used a transmission chain design, in which fish in small founder populations were trained to take one of the two routes, with founder members gradually replaced by untrained conspecifics. Three days after all founder members had been removed, populations of untrained fish still maintained strong preferences for the routes of their founders. The results suggest that the tendency to shoal may facilitate a simple form of guided social learning, which allows guppies to learn about their local environments. They also imply that selectively neutral behavioural alternatives may be maintained as traditions in aggregated animal populations by very simple social mechanisms. The transmission chain method may be particularly useful for studying social species, such as the guppy, that do not respond well to isolation testing.

  2. Ecological implications of reduced forage quality on growth and survival of sympatric geese.

    Science.gov (United States)

    Richman, Samantha E; Leafloor, James O; Karasov, William H; McWilliams, Scott R

    2015-01-01

    Allometric constraints associated with digesting leaves require relatively small avian herbivores to consume high-quality forage. How such constraints are overcome during ontogeny when energy and nutrient requirements are relatively high has not been adequately explored. We compared growth trajectories of Canada and lesser snow goose goslings raised on grass-based diets that differed in protein (10%, 14% or 18%) and fibre (30% or 45%) with those of free-living goslings on Akimiski Island, Canada. This common-garden experiment allowed us to test the hypotheses that (i) smaller-bodied geese are more negatively affected by reduced forage quality than larger-bodied geese, and (ii) goslings from subarctic brood-rearing areas have a limited capacity to slow growth in response to reduced forage quality. Canada goose goslings fed low-protein (10%) diets were on average 44% lighter in body mass, had slower growth rates and were delayed >20 days in reaching 90% of asymptotic size compared with Canada goose goslings fed 18% protein. In contrast, snow goose goslings were unable to survive on the low-protein diets, and those fed high- or medium-protein diets grew at a similar rate and achieved similar asymptotic size. Canada and snow goose goslings fed low-protein diets had reduced growth rates of the tarsus and delayed emergence of the 9th primary. Free-ranging Canada goslings on Akimiski Island were similar in mass and structural size to captive-reared goslings fed low-protein diets. In contrast, snow goslings were similar in mass and structural size to the captive-reared goslings fed the high- and medium-protein diets. This suggests that degraded habitats with mostly low-protein forage may be able to support Canada goslings better than snow goslings which require higher-quality forage to survive. Size-related differences in gosling growth and survival in response to diminished diet quality may influence population size when available food reaches a lower threshold in

  3. Further experimental analysis of the social learning and transmission of foraging information amongst Norway rats.

    Science.gov (United States)

    Laland, K N; Plotkin, H C

    1992-01-01

    Adult male Norway rats were tested to see if their foraging efficiency could be improved by social learning and to investigate whether foraging information could be socially transmitted along a chain of animals. In Experiment 1, 'observers' were placed in one of four conditions, distinguished by the nature of their experience during an observation phase, in which they either observed: (1) a trained conspecific unearthing buried carrot; (2) a trained conspecific digging; (3) carrot pieces only; or (4) an empty enclosure (the control group). When tested 24 h later it was found that subjects in group 1 alone exhibited a significantly elevated foraging ability relative to the control group, being more active, and unearthing more carrot pieces in total. The results show that perception of a trained demonstrator conspecific successfully foraging for food is necessary for social learning of foraging information to occur, probably by a local enhancement mechanism. In Experiment 2, chains of transmission were established by allowing each observer to act 24 h later as the demonstrator for the next observer. In one of two transmission groups subjects were given an extra period of individual foraging experience in the test enclosure, with no demonstrator present. Enhanced levels of foraging efficiency were maintained across eight transmission episodes for both transmission groups relative to a no-transmission control. Subjects in the group with the additional experience unearthed significantly more buried food than subjects in the other transmission group. The experiments extend our standard transmission group was upheld. The superior performance of demonstrators in this group, as reflected in their higher level of carrot digging, suggests that the extra period of experience did indeed enhance their ability to act as effective demonstrators. The elevated performance of subjects in this group is attributed to a combination of social and individual learning. This finding

  4. Nutrient value of spray field forages fed to pigs and the use of feed enzymes to enhance nutrient digestibility.

    Science.gov (United States)

    Passos, A A; Andrade, C; Phillips, C E; Coffey, M T; Kim, S W

    2015-04-01

    This study determined the DE, ME, apparent total tract digestibility (ATTD) of N, and N retention of spray field forages (Bermuda grass, forage sorghum, and sweet sorghum) fed to pigs and the effects of the supplemental feed enzymes on energy and N utilization. A basal diet was formulated with 96% corn and 4% amino acids, minerals, and vitamins. Test diets contained 85% basal diet + 15% Bermuda grass, forage sorghum, or sweet sorghum. Allzyme SSF (Alltech, Nicholasville, KY) was used as a feed enzyme, which was composed of cellulase, glucanase, xylanase, phytase, and protease. The basal diet and test diets were evaluated by using 4 sets of 2 × 2 Latin square designs consisting of 2 pigs and 2 periods with a total of 32 barrows (38.7 ± 7.9 kg). Each period (10-d adjustment and 4-d collection) had 2 Latin squares. The 2 treatments were levels of enzyme supplementation (0 or 200 mg/kg). Pigs received experimental diets twice daily (0700 and 1700 h) at a fixed amount based on BW of pigs (0.09 × BW0.75 kg). On d 10, chromic oxide (0.5%) was added to the diets at 1700 h as an external marker. Fecal and urine samples were collected during 4 consecutive days. The basal diet contained 3,850 kcal DE/kg, 3,769 kcal ME/kg, 86.06% ATTD of N, and 71.10% N retention and was not affected by enzyme supplementation. Bermuda grass contained 893 kcal DE/kg, 845 kcal ME/kg, -16.50% ATTD of N, and -37.49% N retention and tended to be improved by enzyme supplementation to 1,211 kcal DE/kg (P = 0.098), 1,185 kcal ME/kg (P = 0.081), and -10.54% N retention (P = 0.076). The ATTD of N of Bermuda grass increased (P forage sorghum contained 1,520 kcal DE/kg, 1,511 kcal ME/kg, -0.72% ATTD of N, and -16.99% N retention. The sweet sorghum contained 1,086 kcal DE/kg, 1,061 kcal ME/kg, -75.47% ATTD of N, and -49.22% N retention. Enzyme supplementation did not improve energy digestibility of forage sorghum and sweet sorghum. Nitrogen in these forages was poorly utilized. In conclusion, spray

  5. Alfalfa (Medicago Sativa L As A Promising Forage In Indonesia

    Directory of Open Access Journals (Sweden)

    Sajimin

    2011-06-01

    Full Text Available Alfalfa (Medicago sativa L or Lucerne is a perennial herbaceous legume with superior forage quality. It is the most important forage crop in the world and it was the first domesticated forage crop. Alfalfa is able to fix nitrogen from the air through a symbiotic relationship with Rhizobium bacteria with N production 7.85 – 10.37 g/m2. Its rooting system can reach 4.5 m that allows it to escape drought. Forage production can reach 15.48 tons of dry matter per ha/year and containing 18.0 – 29.1 % crude protein. Plants can live 3 to 12 years depending on climatic conditions and crop varieties. However, alfalfa is not a tropical plant, thus it has not been widely cultivated in Indonesia. The problem of alfalfa cultivation are high pest attacks and competition with weeds. Therefore, alfalfa cultivation requires attention and good management to obtain optimum yield.

  6. Variation in relative palatability of different forages fed to rabbits ...

    African Journals Online (AJOL)

    P < 0.01) in relative palatability index (RPI) were detected among the diferent forages offered. Based on their RPI rabbits preferred in descending order of magnitude Centrosema pubescens, Calopogonium mucunoides and Elaeis guineensi ...

  7. Traffic noise reduces foraging efficiency in wild owls

    Science.gov (United States)

    Senzaki, Masayuki; Yamaura, Yuichi; Francis, Clinton D.; Nakamura, Futoshi

    2016-08-01

    Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls’ ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls’ ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise.

  8. Chaos–order transition in foraging behavior of ants

    National Research Council Canada - National Science Library

    Lixiang Li; Haipeng Peng; Jürgen Kurths; Yixian Yang; Hans Joachim Schellnhuber

    2014-01-01

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques...

  9. Foraging behaviour and population status of the white-breasted ...

    African Journals Online (AJOL)

    Foraging behaviour and population status of the white-breasted cormorant ( Phalacrocorax lucidus ) ... Ethiopian Journal of Biological Sciences ... Data were collected from January–December 2014 to include dry and wet seasons mainly based ...

  10. Epigenetic mechanisms modulate differences in Drosophila foraging behavior.

    Science.gov (United States)

    Anreiter, Ina; Kramer, Jamie M; Sokolowski, Marla B

    2017-11-21

    Little is known about how genetic variation and epigenetic marks interact to shape differences in behavior. The foraging (for) gene regulates behavioral differences between the rover and sitter Drosophila melanogaster strains, but the molecular mechanisms through which it does so have remained elusive. We show that the epigenetic regulator G9a interacts with for to regulate strain-specific adult foraging behavior through allele-specific histone methylation of a for promoter (pr4). Rovers have higher pr4 H3K9me dimethylation, lower pr4 RNA expression, and higher foraging scores than sitters. The rover-sitter differences disappear in the presence of G9a null mutant alleles, showing that G9a is necessary for these differences. Furthermore, rover foraging scores can be phenocopied by transgenically reducing pr4 expression in sitters. This compelling evidence shows that genetic variation can interact with an epigenetic modifier to produce differences in gene expression, establishing a behavioral polymorphism in Drosophila.

  11. Multipurpose uses of forage species, estimation of availability and ...

    African Journals Online (AJOL)

    Multipurpose uses of forage species, estimation of availability and distribution of grass species, and effect of location on the crude fibre and ash contents of common browse species in Nsukka, Nigeria.

  12. Jellyfish, Forage Fish, and the World's Major Fisheries

    National Research Council Canada - National Science Library

    Kelly L. Robinson; James J. Ruzicka; Mary Beth Decker; Richard D. Brodeur; Frank J. Hernandez; Javier Quiñones; E. Marcelo Acha; Shin-ichi Uye; Hermes Mianzan; William M. Graham

    2014-01-01

    ... fishes, seabirds, and marine mammals. Because the plankton production that drives forage fish also drives jellyfish production, these taxa often overlap in space, time, and diet in coastal ecosystem...

  13. Dimorphic foraging behaviors and the evolution of hominid hunting.

    Science.gov (United States)

    Fessler, Daniel M T

    2002-01-01

    In contemporary foraging societies men typically hunt more than women. This observation has played an important role in many reconstructions of hominid evolution. The gender difference in human hunting, likely a product of both ecological and cultural factors, is mirrored by a similar sex difference among nonhuman primates. Existing explanations of such primate behavioral dimorphism are augmented by the recognition of an additional factor that may contribute to differences between males and females in the value of meat. Episodic female immunosuppression is a normal part of reproduction. Because meat is a source of pathogens, females can be expected to exhibit less constant attraction to meat. Sexual dimorphism in the attraction to meat may then contribute to dimorphic foraging specializations, a divergence that is likely augmented by the differential value of insectivory across the sexes. With the rise of cultural transmission of foraging knowledge, dimorphic foraging behaviors would have been reinforced, creating a more comprehensive gender-based division of labor.

  14. Production and partial characterization of pectinases from forage ...

    African Journals Online (AJOL)

    PG), pectin lyase (PL) and pectinesterase (PE) produced by Aspergillus niger URM4645 was studied in solid-state fermentation (SSF) using forage palm as the substrate. The effect of variable substrate amount, inoculum concentration and ...

  15. Evaluation of nutritional value some forage species available in Iran ...

    African Journals Online (AJOL)

    Novin

    2012-07-17

    Jul 17, 2012 ... potential supplements for ruminants in Iran, and it seems that RFV index of six forage .... The metabolizable energy (ME), and organic matter digestibility ..... metabolism, nutritional strategies, the cellulolytic fermentation and.

  16. Moving Evidence into Practice: Cost Analysis and Assessment of Macaques’ Sustained Behavioral Engagement with Videogames and Foraging Devices

    Science.gov (United States)

    Bennett, Allyson J.; Perkins, Chaney M.; Tenpas, Parker D.; Reinebach, Alma L.; Pierre, Peter J.

    2017-01-01

    Environmental enrichment plans for captive nonhuman primates often include provision of foraging devices. The rationale for using foraging devices is to promote species-typical activity patterns that encourage physical engagement and provide multi-sensory stimulation. However, these devices have been shown to be ineffective at sustaining manipulation over long periods of time, and often produce minimal cognitive engagement. Here we use an evidence-based approach to directly compare the amount of object-directed behavior with a foraging device and a computer-based videogame system. We recorded 11adult male rhesus monkeys’ interactions with a foraging device and two tasks within a joystick videogame cognitive test battery. Both techniques successfully produced high levels of engagement during the initial 20-min of observation. After 1-hr the monkeys manipulated the foraging device significantly less than the joystick, F(2,10)= 43.93, p videogame play for the majority of a 5-hr period, provided that they received a 94mg chow pellet upon successful completion of trials. Using a model approach we developed previously as a basis for standardized cost:benefit analysis to inform facility decisions, we calculated the comprehensive cost of incorporating a videogame system as an enrichment strategy. The videogame system has a higher initial cost compared to widely-used foraging devices however, the ongoing labor and supply costs are relatively low. Our findings add to two decades of empirical studies by a number of laboratories that have demonstrated the successful use of videogame-based systems to promote sustained non-social cognitive engagement for macaques. The broader significance of the work lies in the application of a systematic approach to compare and contrast enrichment strategies and encourage evidence-based decision making when choosing an enrichment strategy in a manner that promotes meaningful cognitive enrichment to the animals. PMID:27404766

  17. Moving evidence into practice: cost analysis and assessment of macaques' sustained behavioral engagement with videogames and foraging devices.

    Science.gov (United States)

    Bennett, Allyson J; Perkins, Chaney M; Tenpas, Parker D; Reinebach, Alma L; Pierre, Peter J

    2016-12-01

    Environmental enrichment plans for captive nonhuman primates often include provision of foraging devices. The rationale for using foraging devices is to promote species-typical activity patterns that encourage physical engagement and provide multi-sensory stimulation. However, these devices have been shown to be ineffective at sustaining manipulation over long periods of time, and often produce minimal cognitive engagement. Here we use an evidence-based approach to directly compare the amount of object-directed behavior with a foraging device and a computer-based videogame system. We recorded 11 adult male rhesus monkeys' interactions with a foraging device and two tasks within a joystick videogame cognitive test battery. Both techniques successfully produced high levels of engagement during the initial 20 min of observation. After 1 hr the monkeys manipulated the foraging device significantly less than the joystick, F(2,10) = 43.93, P videogame play for the majority of a 5 hr period, provided that they received a 94 mg chow pellet upon successful completion of trials. Using a model approach, we developed previously as a basis for standardized cost:benefit analysis to inform facility decisions, we calculated the comprehensive cost of incorporating a videogame system as an enrichment strategy. The videogame system has a higher initial cost compared to widely-used foraging devices, however, the ongoing labor and supply costs are relatively low. Our findings add to two decades of empirical studies by a number of laboratories that have demonstrated the successful use of videogame-based systems to promote sustained non-social cognitive engagement for macaques. The broader significance of the work lies in the application of a systematic approach to compare and contrast enrichment strategies and encourage evidence-based decision making when choosing an enrichment strategy in a manner that promotes meaningful cognitive enrichment to the animals. © 2016 Wiley

  18. Climate-driven Sympatry does not Lead to Foraging Competition Between Adélie and Gentoo Penguins

    Science.gov (United States)

    Cimino, M. A.; Moline, M. A.; Fraser, W.; Patterson-Fraser, D.; Oliver, M. J.

    2016-02-01

    Climate-driven sympatry may lead to competition for food resources between species, population shifts and changes in ecosystem structure. Rapid warming in the West Antarctic Peninsula (WAP) is coincident with increasing gentoo penguin and decreasing Adélie penguin populations, suggesting that competition for food may exacerbate the Adélie penguin decline. At Palmer Station, we tested for foraging competition between these species by comparing their prey, Antarctic krill, distributions and penguin foraging behaviors on fine scales. To study these predator-prey dynamics, we simultaneously deployed penguin satellite transmitters, and a REMUS autonomous underwater vehicle that acoustically detected krill aggregations and measured physical and biological properties of the water column. We detected krill aggregations within the horizontal and vertical foraging ranges of Adélie and gentoo penguin. In the upper 100 m of the water column, the distribution of krill aggregations were mainly associated with CHL and light, suggesting that krill selected for habitats that balance the need to consume food and avoid predation. Adélie and gentoo penguins mainly had spatially segregated foraging areas but in areas of overlap, gentoo penguins switched foraging behavior by foraging at deeper depths, a strategy which limits competition with Adélie penguins. This suggests that climate-driven sympatry does not necessarily result in competitive exclusion. Contrary to a recent theory, which suggests that increased competition for krill is the major driver of Adélie penguin population declines, we suggest that declines in Adélie penguins along the WAP are more likely due to direct and indirect climate impacts on their life histories.

  19. Foraging responses of black-legged kittiwakes to prolonged food-shortages around colonies on the Bering Sea shelf.

    Science.gov (United States)

    Paredes, Rosana; Orben, Rachael A; Suryan, Robert M; Irons, David B; Roby, Daniel D; Harding, Ann M A; Young, Rebecca C; Benoit-Bird, Kelly; Ladd, Carol; Renner, Heather; Heppell, Scott; Phillips, Richard A; Kitaysky, Alexander

    2014-01-01

    We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla) have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008-2010) at two sites in the Pribilof Islands, where the population has either declined (St. Paul) or remained stable (St. George). Foraging conditions were assessed from changes in (1) bird diets, (2) the biomass and distribution of juvenile pollock (Theragra chalcogramma) in 2008 and 2009, and (3) eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability). In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids). Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress.

  20. Foraging responses of black-legged kittiwakes to prolonged food-shortages around colonies on the Bering Sea shelf.

    Directory of Open Access Journals (Sweden)

    Rosana Paredes

    Full Text Available We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008-2010 at two sites in the Pribilof Islands, where the population has either declined (St. Paul or remained stable (St. George. Foraging conditions were assessed from changes in (1 bird diets, (2 the biomass and distribution of juvenile pollock (Theragra chalcogramma in 2008 and 2009, and (3 eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability. In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids. Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress.

  1. Grasping complex matter : large herbivore foraging in patches of heterogeneous resources

    OpenAIRE

    Drescher, M.F.

    2003-01-01

    Key words: herbivory; functional response; grazing; food intake; food quality; selectivity; cattle; savanna The functional response, defined as the relationship of forage intake with forage availability, is the principal link between a forager and a forage resource, and as such connects the trophic levels of consumers and producers. This thesis deals with the effects of forage resource structure on the shape of the functional response curve. Special attention was paid to the effects of the pr...

  2. Foraging strategy switch of a top marine predator according to seasonal resource differences

    OpenAIRE

    O'Toole, Malcolm D.; Lea, Mary-Anne; Guinet, Christophe; Schick, Robert; Hindell, Mark A

    2015-01-01

    The spatio-temporal variability in marine resources influences the foraging behavior and success of top marine predators. However, little is known about the links between these animals and ocean productivity, specifically, how plankton density influences their foraging behavior. Southern elephant seals (Mirounga leonina) have two annual at-sea foraging trips: a 2 month post-breeding foraging trip (Nov–Jan) that coincides with elevated summer productivity; and an 8 month post-molting foraging ...

  3. Forage based animal production systems and sustainability, an invited keynote

    Directory of Open Access Journals (Sweden)

    Abdul Shakoor Chaudhry

    2008-07-01

    Full Text Available Forages are essential for the successful operation of animal production systems. This is more relevant to ruminants which are heavily dependant upon forages for their health and production in a cost-effective and sustainable manner. While forages are an economical source of nutrients for animal production, they also help conserve the soil integrity, water supply and air quality. Although the role of these forages for animal production could vary depending upon the regional preferences for the animal and forage species, climate and resources, their importance in the success of ruminant production is acknowledged. However with the increasing global human population and urbanisation, the sustainability of forage based animal production systems is sometimes questioned due to the interrelationship between animal production and the environment. It is therefore vital to examine the suitability of these systems for their place in the future to supply quality food which is safe for human consumption and available at a competitive price to the growing human population. Grassland and forage crops are recognised for their contribution to the environment, recreation and efficiency of meat and milk production,. To maintain sustainability, it is crucial that such farming systems remain profitable and environmentally friendly while producing nutritious foods of high economical value. Thus, it is pertinent to improve the nutritive value of grasses and other forage plants in order to enhance animal production to obtain quality food. It is also vital to develop new forages which are efficiently utilised and wasted less by involving efficient animals. A combination of forage legumes, fresh or conserved grasses, crop residues and other feeds could help develop an animal production system which is economically efficient, beneficial and viable. Also, it is crucial to use efficient animals, improved forage conservation methods, better manure handling, and minimum

  4. Oxidative phenols in forage crops containing polyphenol oxidase enzymes.

    Science.gov (United States)

    Parveen, Ifat; Threadgill, Michael D; Moorby, Jon M; Winters, Ana

    2010-02-10

    Polyphenol oxidases (PPOs) are copper-containing enzymes that catalyze oxidation of endogenous monophenols to ortho-dihydroxyaryl compounds and of ortho-dihydroxyaryl compounds to ortho-quinones. Subsequent nucleophilic addition reactions of phenols, amino acids, and proteins with the electrophilic ortho-quinones form brown-, black-, or red-colored secondary products associated with the undesired discolouration of fruit and vegetables. Several important forage plants also exhibit significant PPO activity, and a link with improved efficiency of ruminant production has been established. In ruminant animals, extensive degradation of forage proteins, following consumption, can result in high rates of excretion of nitrogen, which contributes to point-source and diffuse pollution. Reaction of quinones with forage proteins leads to the formation of protein-phenol complexes that are resistant to proteolytic activity during ensilage and during rumen fermentation. Thus, PPO in red clover (Trifolium pratense) has been shown to improve protein utilization by ruminants. While PPO activity has been demonstrated in a number of forage crops, little work has been carried out to identify substrates of PPO, knowledge of which would be beneficial for characterizing this trait in these forages. In general, a wide range of 1,2-dihydroxyarenes can serve as PPO substrates because these are readily oxidized because of the ortho positioning of the hydroxy groups. Naturally occurring phenols isolated from forage crops with PPO activity are reviewed. A large number of phenols, which may be directly or indirectly oxidized as a consequence of PPO activity, have been identified in several forage grass, legume, cereal, and brassica species; these include hydroxybenzoic acids, hydroxycinnamates, and flavonoids. In conclusion, a number of compounds are known or postulated to enable PPO activity in important PPO-expressing forage crops. Targeting the matching of these compounds with PPO activity

  5. Intercropping of Cereals and Legumes for Forage Production

    OpenAIRE

    Hamdollah ESKANDARI; Ghanbari, Ahmad; Abdollah JAVANMARD

    2009-01-01

    Cereals are high important in feeding ruminant animals for their high dry matter production and low cost. However, cereals forage is poor in protein content which shows their low quality and nutritive value. Regarding to high feed costs of protein supplementations, legumes can be used in livestock nutrition for their high protein content and, thus, providing cost saving. Since legumes have low dry matter yield, acceptable forage yield and quality can obtained from intercropping of cereals and...

  6. Visualising and animating visual information foraging in context

    OpenAIRE

    Chen, C.; Cribbin, T

    2001-01-01

    Optimal information foraging provides a potentially useful framework for modelling, analysing, and interpreting search strategies of users through a spatial-semantic interface. Improving the understanding of behavioural patterns of users in such environments has implications for the design and refinement of a range of user interfaces. In this article, we outline the role of optimal information foraging in the study of visual information retrieval and how one may use visualisation and animatio...

  7. Chaos–order transition in foraging behavior of ants

    OpenAIRE

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-01-01

    We have studied the foraging behavior of group animals that live in fixed colonies (especially ants) as an important problem in ecology. Building on former findings on deterministic chaotic activities of single ants, we uncovered that the transition from chaotic to periodic regimes results from an optimization scheme of the self-organization of such an animal colony. We found that an effective foraging of ants mainly depends on their nest as well as their physical abilities and knowledge due ...

  8. Foraging in honeybees--when does it pay to dance?

    OpenAIRE

    Madeleine Beekman,; Jie Bin Lew

    2008-01-01

    Honeybees are unique in that they are the only social insects that are known to recruit nest mates using the waggle dance. This waggle dance is used by successful foragers to convey information about both the direction and distance to food sources. Nest mates can use this spatial information, increasing their chances of locating the food source. But how effective is the bees' dance communication? Previous work has shown that dancing does not benefit a honeybee colony under all foraging condit...

  9. Information flow principles for plasticity in foraging robot swarms

    OpenAIRE

    Pitonakova, Lenka; Crowder, Richard; Bullock, Seth

    2016-01-01

    An important characteristic of a robot swarm that must operate in the real world is the ability to cope with changeable environments by exhibiting behavioural plasticity at the collective level. For example, a swarm of foraging robots should be able to repeatedly reorganise in order to exploit resource deposits that appear intermittently in different locations throughout their environment. In this paper, we report on simulation experiments with homogeneous foraging robot teams and show that a...

  10. The use of edge habitats by commuting and foraging bats

    OpenAIRE

    Verboom, B.

    1998-01-01

    Travelling routes and foraging areas of many bat species are mainly along edge habitats, such as treelines, hedgerows, forest edges, and canal banks. This thesis deals with the effects of density, configuration, and structural features of edge habitats on the occurrence of bats. Four hypothetical functions of edge habitats for bats were studied: foraging areas, shelter from wind, shelter from avian predators, and acoustical landmarks.

    Both wind and food abundance we...

  11. Yield responses of forage sorghums to salinity and irrigation frequency

    African Journals Online (AJOL)

    The irrigation frequency was found to affect growth and yield of the forage sorghums. When irrigation was delayed in leaf water potential of -1.0 to -2.0 MPa, the yield and yield components were found to decrease. The maximum dry forage yields were 45.1, 38.9 and 38.5 g plant-1 for frequent, intermediate and infrequent ...

  12. Foraging parameters influencing the detection and interpretation of area-restricted search behaviour in marine predators: a case study with the masked booby.

    Directory of Open Access Journals (Sweden)

    Julia Sommerfeld

    Full Text Available Identification of Area-restricted search (ARS behaviour is used to better understand foraging movements and strategies of marine predators. Track-based descriptive analyses are commonly used to detect ARS behaviour, but they may be biased by factors such as foraging trip duration or non-foraging behaviours (i.e. resting on the water. Using first-passage time analysis we tested if (I daylight resting at the sea surface positions falsely increase the detection of ARS behaviour and (II short foraging trips are less likely to include ARS behaviour in Masked Boobies Sula dactylatra. We further analysed whether ARS behaviour may be used as a proxy to identify important feeding areas. Depth-acceleration and GPS-loggers were simultaneously deployed on chick-rearing adults to obtain (1 location data every 4 minutes and (2 detailed foraging activity such as diving rates, time spent sitting on the water surface and in flight. In 82% of 50 foraging trips, birds adopted ARS behaviour. In 19.3% of 57 detected ARS zones, birds spent more than 70% of total ARS duration resting on the water, suggesting that these ARS zones were falsely detected. Based on generalized linear mixed models, the probability of detecting false ARS zones was 80%. False ARS zones mostly occurred during short trips in close proximity to the colony, with low or no diving activity. This demonstrates the need to account for resting on the water surface positions in marine animals when determining ARS behaviour based on foraging locations. Dive rates were positively correlated with trip duration and the probability of ARS behaviour increased with increasing number of dives, suggesting that the adoption of ARS behaviour in Masked Boobies is linked to enhanced foraging activity. We conclude that ARS behaviour may be used as a proxy to identify important feeding areas in this species.

  13. Exploring the thrifty genotype's food-shortage assumptions: a cross-cultural comparison of ethnographic accounts of food security among foraging and agricultural societies.

    Science.gov (United States)

    Benyshek, Daniel C; Watson, James T

    2006-09-01

    The "thrifty genotype hypothesis" has become firmly entrenched as one of the orienting concepts in biomedical anthropology, since first being proposed by Neel (1962 Am. J. Hum. Genet. 14:353-362) over 40 years ago. Its influence on inquiries into the evolutionary origins of diabetes, lactose tolerance, and other metabolic disorders can hardly be underestimated, as evidenced by its continued citation in many top scientific and medical journals. However, its fundamental assumption, that foragers are more likely to experience regular and severe food shortages than sedentary agriculturalists, remains largely untested. The present report tests this assumption by making a cross-cultural statistical comparison of the quantity of available food and the frequency and extent of food shortages among 94 foraging and agricultural societies as reported in the ethnographic record. Our results indicate that there is no statistical difference (P food, or the frequency or extent of food shortages in these reports between preindustrial foragers, recent foragers, and agriculturalists. The findings presented here add to a growing literature that calls into question assumptions about forager food insecurity and nutritional status in general, and ultimately, the very foundation of the thrifty genotype hypothesis: the presumed food shortages that selected for a "thrifty" metabolism in past foraging populations. 2006 Wiley-Liss, Inc.

  14. Large pollen loads of a South African asclepiad do not interfere with the foraging behaviour or efficiency of pollinating honey bees

    Science.gov (United States)

    Coombs, G.; Dold, A. P.; Brassine, E. I.; Peter, C. I.

    2012-07-01

    The pollen of asclepiads (Asclepiadoideae, Apocynaceae) and most orchids (Orchidaceae) are packaged as large aggregations known as pollinaria that are removed as entire units by pollinators. In some instances, individual pollinators may accumulate large loads of these pollinaria. We found that the primary pollinator of Cynanchum ellipticum (Apocynaceae—Asclepiadoideae), the honey bee Apis mellifera, accumulate very large agglomerations of pollinaria on their mouthparts when foraging on this species. We tested whether large pollinarium loads negatively affected the foraging behaviour and foraging efficiency of honey bees by slowing foraging speeds or causing honey bees to visit fewer flowers, and found no evidence to suggest that large pollinarium loads altered foraging behaviour. C. ellipticum displayed consistently high levels of pollination success and pollen transfer efficiency (PTE). This may be a consequence of efficiently loading large numbers of pollinaria onto pollinators even when primary points of attachment on pollinators are already occupied and doing so in a manner that does not impact the foraging behaviour of pollinating insects.

  15. Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

    Science.gov (United States)

    Hloucalová, Pavlína; Skládanka, Jiří; Horký, Pavel; Klejdus, Bořivoj; Pelikán, Jan; Knotová, Daniela

    2016-01-01

    Simple Summary Phytoestrogens comprise a group of substances negatively influencing the development and function of animal reproductive organs. Their appearance in forage crops can reduce feeding values, cause dietary disorders, and lead to animal health damage. This study evaluated the occurrence of individual phytoestrogens in various species of annual and perennial legumes and their levels in dry forage. It appeared that feeding large amounts of red clover presents a potential risk, but red clover can be replaced with the annual Persian clover, in which markedly lower phytoestrogen levels were detected. Abstract The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety “Amos”), alfalfa (variety “Holyně”), and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography–mass spectrometry (LC-MS). Higher levels (p forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest. PMID:27429009

  16. Nutritional Characteristics of Forage Grown in South of Benin

    Directory of Open Access Journals (Sweden)

    Nadia Musco

    2016-01-01

    Full Text Available In order to provide recommendations on the most useful forage species to smallholder farmers, eleven grass and eleven legume forages grown in Abomey-Calavi in Republic of Benin were investigated for nutritive value (i.e. chemical composition and energy content and fermentation characteristics (i.e. gas and volatile fatty acid production, organic matter degradability. The in vitro gas production technique was used, incubating the forages for 120 h under anaerobic condition with buffalo rumen fluid. Compared to legume, tropical grass forages showed lower energy (8.07 vs 10.57 MJ/kg dry matter [DM] and crude protein level (16.10% vs 19.91% DM and higher cell wall content (neutral detergent fiber: 63.8% vs 40.45% DM, respectively. In grass forages, the chemical composition showed a quite high crude protein content; the in vitro degradability was slightly lower than the range of tropical pasture. The woody legumes were richer in protein and energy and lower in structural carbohydrates than herbaceous plants, however, their in vitro results are influenced by the presence of complex compounds (i.e. tannins. Significant correlations were found between chemical composition and in vitro fermentation characteristics. The in vitro gas production method appears to be a suitable technique for the evaluation of the nutritive value of forages in developing countries.

  17. Forage maize nutritional quality according to organic and inorganic fertilization

    Directory of Open Access Journals (Sweden)

    Alejandro Moreno-Reséndez

    2017-01-01

    Full Text Available The research was conducted on a commercial land plot from the ejido Granada, municipality of M atamoros, Coahuila, situated inside the Comarca Lagunera, from April to August 2015, in order to establish the effect of two fertilization sources – organic and inorganic, upon the nutritional quality of forage maize during the spring - summer cycle with a r andomized block experimental design. T 1 = Acadian soil +Acadian foliage (marine algae extracts and T 2 = Regional control, with 16 replications. The evaluated variables were the nutritional quality of forage maize and the milk production (L•t - 1 dry matter an d L•ha - 1 . Due to the effect of the evaluated treatments, statistical differences were registered, both for, nutritional values of forage maize, such as: neutral and acid detergent fiber, non - fiber carbohydrates, total digestible nutrients, total net energ y for lactation and for milk production, in favor of organic fertilization. Therefore, it can be concluded that fertilizers of marine origin applied to forage maize increased both nutritional quality of forage maize and milk yield per ton of dry matter and per hectare of this forage.

  18. Chaos-order transition in foraging behavior of ants.

    Science.gov (United States)

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-06-10

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants' physical abilities, and ants' knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal.

  19. Chaos–order transition in foraging behavior of ants

    Science.gov (United States)

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-01-01

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants’ physical abilities, and ants’ knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal. PMID:24912159

  20. Patch shape, connectivity, and foraging by oldfield mice (Peromyscus polionotus).

    Energy Technology Data Exchange (ETDEWEB)

    Orrock, John, L.; Danielson, Brent J

    2005-06-01

    We examined how corridors and patch shape affect foraging by the oldfield mouse (Peromyscus polionotus) by deploying foraging trays and live traps in experimental landscapes with 3 different patch types: patches connected with a corridor, unconnected patches with projecting corridorlike portions (winged patches), and unconnected rectangular patches. Corridors did not lead to different levels of activity of P. polionotus among the 3 patch types. Rather, corridors influenced activity by changing patch shape: foraging in seed trays and total number of captures of P. polionotus tended to be greater at the patch center than at the patch edge, but only in connected and winged patches where corridors or wings increased the amount of patch edge relative to the amount of core habitat in the patch. P. polionotus avoided open microhabitats near the patch edge in winged and connected patches, but not open microhabitats near the patch interior, suggesting that predation risk caused shifts in foraging near edges in connected and winged patches. Foraging in corridors and wings was generally low, suggesting that both are high-risk habitats where predation risk is not ameliorated by proximity to vegetative cover. By changing patch shape, corridors caused changes in within-patch activity of P. polionotus, changing foraging patterns and potentially altering the dynamics of P. polionotus and the seeds they consume.

  1. Information Foraging in Nuclear Power Plant Control Rooms

    Energy Technology Data Exchange (ETDEWEB)

    R.L. Boring

    2011-09-01

    nformation foraging theory articulates the role of the human as an 'informavore' that seeks information and follows optimal foraging strategies (i.e., the 'information scent') to find meaningful information. This paper briefly reviews the findings from information foraging theory outside the nuclear domain and then discusses the types of information foraging strategies operators employ for normal and off-normal operations in the control room. For example, operators may employ a predatory 'wolf' strategy of hunting for information in the face of a plant upset. However, during routine operations, the operators may employ a trapping 'spider' strategy of waiting for relevant indicators to appear. This delineation corresponds to information pull and push strategies, respectively. No studies have been conducted to determine explicitly the characteristics of a control room interface that is optimized for both push and pull information foraging strategies, nor has there been empirical work to validate operator performance when transitioning between push and pull strategies. This paper explores examples of control room operators as wolves vs. spiders and con- cludes by proposing a set of research questions to investigate information foraging in control room settings.

  2. Evidence for ship noise impacts on humpback whale foraging behaviour.

    Science.gov (United States)

    Blair, Hannah B; Merchant, Nathan D; Friedlaender, Ari S; Wiley, David N; Parks, Susan E

    2016-08-01

    Noise from shipping activity in North Atlantic coastal waters has been steadily increasing and is an area of growing conservation concern, as it has the potential to disrupt the behaviour of marine organisms. This study examines the impacts of ship noise on bottom foraging humpback whales (Megaptera novaeangliae) in the western North Atlantic. Data were collected from 10 foraging whales using non-invasive archival tags that simultaneously recorded underwater movements and the acoustic environment at the whale. Using mixed models, we assess the effects of ship noise on seven parameters of their feeding behaviours. Independent variables included the presence or absence of ship noise and the received level of ship noise at the whale. We found significant effects on foraging, including slower descent rates and fewer side-roll feeding events per dive with increasing ship noise. During 5 of 18 ship passages, dives without side-rolls were observed. These findings indicate that humpback whales on Stellwagen Bank, an area with chronically elevated levels of shipping traffic, significantly change foraging activity when exposed to high levels of ship noise. This measureable reduction in within-dive foraging effort of individual whales could potentially lead to population-level impacts of shipping noise on baleen whale foraging success. © 2016 The Author(s).

  3. Applicability to foraging simulation of a reinforcement schedule controlling the response energy of pigeons.

    Science.gov (United States)

    Kono, Masanori

    2013-12-01

    In optimal foraging theory (OFT), energy expenditure is an important variable for predicting foraging behavior. However, early studies, including operant simulations of foraging, did not measure energy expenditure. In the present study, an adjusting energy (AE) schedule was developed to control energy expenditure. Interresponse energy (IRE), a measure of the energy expenditure during a response, was calculated by dividing the square of the elapsed time between two consecutive responses by the square of the straight-line distance between the locations of the same two responses. An adjusting procedure was employed to estimate the indifference point between the requirements of the AE schedule and a fixed ratio (FR) schedule, which has been used in many operant simulations. In the adjusting procedure, pigeons adjusted the requirement of the AE schedule to that of the FR schedule. The results showed a systematic relationship between the requirements of the AE and FR schedules. Moreover, the total IRE per reinforcement systematically increased with the AE requirement. Thus, the present study demonstrates the utility of the AE schedule as a procedure for testing the validity of OFT.

  4. Evaluation of germoplasm of Paspalum genus with potential for foraging production

    Directory of Open Access Journals (Sweden)

    Marina Gabriela Berchiol da Silva

    2012-12-01

    Full Text Available This study was carried out in Fazenda Canchim in São Carlos-SP, physical base of Southeast – Embrapa Cattle, aiming to select, based on the agronomic characteristics of productivity of dry matter and quality of the forage, the accesses of suitable gender Paspalum for possessing potentiality of use as foraging plants. Were evaluated for 3 years, with 22 forage grasses, being 19 of Paspalum and three more of control species: Brachiaria decumbens, Andropogon gayanus cv. Baetí and Panicum maximum cv. Tanzania, submitted to two intensification levels: high (fertilizer after each cut and supplemental irrigation and low (only fertilizer of annual replacement without irrigation. The experimental design was a randomized complete block with two replications assigned to a split-plot arrangement. Means were compared using the Scott-Knott test. The studied variables were: dry matter production, in vitro dry matter digestibility and crude protein content. The results indicate that the accesses responded to the intensification level minimizing the negative effect of the seasonal production. Based on the studied variables, the selected accesses were: BRA-011401 (Paspalum glaucescens; BRA-011681 (P. atratum; BRA009661 (P. atratum and BRA-019186 (P. regnellii.

  5. Intraindividual Behavioral Variability Predicts Foraging Outcome in a Beach-dwelling Jumping Spider.

    Science.gov (United States)

    Lichtenstein, James L L; Chism, Gregory T; Kamath, Ambika; Pruitt, Jonathan N

    2017-12-22

    Animal personality, defined as consistent differences between individuals in behavior, has been the subject of hundreds if not thousands of papers. However, little work explores the fitness consequences of variation in behavior within individuals, or intraindividual variability (IIV). We probe the effects of behavioral IIV on predator-prey interaction outcomes in beach-dwelling jumping spiders (Terralonus californicus). Prior studies have found that spiders with higher body condition (body mass relative to size) behave more variably. Thus, we hypothesized that jumping spider activity level IIV would relate positively to foraging performance. To address this, we tested for associations between activity IIV, average activity level, and two measures of foraging success in laboratory mesocosms: change in spider mass and the number of prey killed. Activity IIV positively correlated with the mass that spiders gained from prey, but not with the number of prey killed. This suggests that spiders with high IIV consumed a greater proportion of their prey or used less energy. Interestingly, average activity level (personality) predicted neither metric of foraging success, indicating that behavioral IIV can predict metrics of success that personality does not. Therefore, our findings suggest that IIV should be considered alongside personality in studies of predator-prey interactions.

  6. Effect of soil type and forage crops on manganese content in roughage

    Directory of Open Access Journals (Sweden)

    Jakšić Snežana

    2017-01-01

    Full Text Available The aim of this study was to examine the effects of soil type and forage crops on the content of manganese (Mn in roughages, and forage quality regarding Mn content. The trial was carried out on chernozem and humogley under alfalfa and red clover. Samples for determination of Mn content in plant and total Mn content in soil were digested using the apparatus Milestone Ethos 1 and for Mn determination on ICP-OES Vista Pro-Axial Varian. Average total Mn content in soil of the tested sites was 473.1 mg/kg. Total Mn content in chernozem was higher than in humogley. Average Mn content in forage crops was 28.7 mg/kg. Dry matter Mn content was lower in crops grown on humogley. Mn content was significantly higher in red clover. Significant positive correlation was found between total Mn content in soil and Mn content in crops. Mn concentration in crops was below critical and toxic value.

  7. An Adaptive Bacterial Foraging Optimization Algorithm with Lifecycle and Social Learning

    Directory of Open Access Journals (Sweden)

    Xiaohui Yan

    2012-01-01

    Full Text Available Bacterial Foraging Algorithm (BFO is a recently proposed swarm intelligence algorithm inspired by the foraging and chemotactic phenomenon of bacteria. However, its optimization ability is not so good compared with other classic algorithms as it has several shortages. This paper presents an improved BFO Algorithm. In the new algorithm, a lifecycle model of bacteria is founded. The bacteria could split, die, or migrate dynamically in the foraging processes, and population size varies as the algorithm runs. Social learning is also introduced so that the bacteria will tumble towards better directions in the chemotactic steps. Besides, adaptive step lengths are employed in chemotaxis. The new algorithm is named BFOLS and it is tested on a set of benchmark functions with dimensions of 2 and 20. Canonical BFO, PSO, and GA algorithms are employed for comparison. Experiment results and statistic analysis show that the BFOLS algorithm offers significant improvements than original BFO algorithm. Particulary with dimension of 20, it has the best performance among the four algorithms.

  8. Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence.

    Science.gov (United States)

    Crall, J D; Chang, J J; Oppenheimer, R L; Combes, S A

    2017-02-06

    Natural environments are characterized by variable wind that can pose significant challenges for flying animals and robots. However, our understanding of the flow conditions that animals experience outdoors and how these impact flight performance remains limited. Here, we combine laboratory and field experiments to characterize wind conditions encountered by foraging bumblebees in outdoor environments and test the effects of these conditions on flight. We used radio-frequency tags to track foraging activity of uniquely identified bumblebee (Bombus impatiens) workers, while simultaneously recording local wind flows. Despite being subjected to a wide range of speeds and turbulence intensities, we find that bees do not avoid foraging in windy conditions. We then examined the impacts of turbulence on bumblebee flight in a wind tunnel. Rolling instabilities increased in turbulence, but only at higher wind speeds. Bees displayed higher mean wingbeat frequency and stroke amplitude in these conditions, as well as increased asymmetry in stroke amplitude-suggesting that bees employ an array of active responses to enable flight in turbulence, which may increase the energetic cost of flight. Our results provide the first direct evidence that moderate, environmentally relevant turbulence affects insect flight performance, and suggest that flying insects use diverse mechanisms to cope with these instabilities.

  9. To forage, mate, or thermoregulate: Influence of resource manipulation on male rattlesnake behavior.

    Science.gov (United States)

    Tetzlaff, Sasha J; Carter, Evin T; DeGregorio, Brett A; Ravesi, Michael J; Kingsbury, Bruce A

    2017-08-01

    Male animals should preferentially allocate their time to performing activities that promote enhancing reproductive opportunity, but the need to acquire resources for growth and survival may compete with those behaviors in the short term. Thus, behaviors which require differing movement patterns such as ambushing prey and actively searching for mates can be mutually exclusive. Consequently, males that succeed at foraging could invest greater time and energy into mate searching. We radio-tracked sixteen male massasauga rattlesnakes (Sistrurus catenatus) and supplemented the diets of half the snakes with mice across an active season. We tested the predictions that reduced foraging needs would allow fed snakes to move (i.e., mate search) more, but that they would consequently be stationary to thermoregulate less, than unfed controls. Contrary to our first prediction, we found no evidence that fed snakes altered their mate searching behavior compared to controls. However, we found controls maintained higher body temperatures than fed snakes during the breeding season, perhaps because fed snakes spent less time in exposed ambush sites. Fed snakes had higher body condition scores than controls when the breeding season ended. Our results suggest the potential costs incurred by devoting time to stationary foraging may be outweighed by the drive to increase mating opportunities. Such instances may be especially valuable for massasaugas and other temperate reptiles that can remain inactive for upwards of half their lives or longer in some cases, and for female rattlesnakes that generally exhibit biennial or more protracted reproductive cycles.

  10. Foraging proficiency during the nonbreeding season of a specialized forager: are juvenile American Oystercatchers "bumble-beaks" compared to adults?

    Science.gov (United States)

    Hand, Christine E.; Sanders, Felicia J.; Jodice, Patrick G.R.

    2010-01-01

    In many species, immature individuals are less proficient at foraging than are adults, and this difference may be especially critical during winter when survival can be at its minimum. We investigated the foraging proficiency of adult and immature American Oystercatchers (Haematopus palliatus) during the nonbreeding season. Oystercatchers forage on prey that must be handled with specialized skills, so age-related differences in foraging behavior may be expected. We found that adults spent more time searching than did immatures, a trend toward immatures taking longer to handle prey than did adults, and immatures more often handling prey unsuccessfully than did adults. Feeding rates and diet composition did not differ by age class. We posit that the immature birds traded off longer handling times with shorter searching times and that ultimately the abundant prey in the region may contribute to the ability of immature birds to feed at rates similar to those of adults.

  11. Tandem carrying, a new foraging strategy in ants: description, function, and adaptive significance relative to other described foraging strategies

    Science.gov (United States)

    Guénard, Benoit; Silverman, Jules

    2011-08-01

    An important aspect of social insect biology lies in the expression of collective foraging strategies developed to exploit food. In ants, four main types of foraging strategies are typically recognized based on the intensity of recruitment and the importance of chemical communication. Here, we describe a new type of foraging strategy, "tandem carrying", which is also one of the most simple recruitment strategies, observed in the Ponerinae species Pachycondyla chinensis. Within this strategy, workers are directly carried individually and then released on the food resource by a successful scout. We demonstrate that this recruitment is context dependent and based on the type of food discovered and can be quickly adjusted as food quality changes. We did not detect trail marking by tandem-carrying workers. We conclude by discussing the importance of tandem carrying in an evolutionary context relative to other modes of recruitment in foraging and nest emigration.

  12. Test

    DEFF Research Database (Denmark)

    Bendixen, Carsten

    2014-01-01

    Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers.......Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers....

  13. Impact of Ground-Applied Termiticides on the Above-Ground Foraging Behavior of the Formosan Subterranean Termite

    Directory of Open Access Journals (Sweden)

    Gregg Henderson

    2016-08-01

    Full Text Available We conducted a laboratory study to determine the impact of ground-applied termiticides on the above-ground foraging behavior of Coptotermes formosanus. Two concentrations (1 and 10 ppm each of three termiticides, viz. fipronil, imidacloprid and chlorantraniliprole, were tested. After one month post-treatment (fipronil 10 ppm was run for 12 days only and all other treatments were run for one month, fipronil had the lowest percentage of survival (3%–4% at both concentrations. Termite survival ranged from 31% to 40% in the case of imidacloprid treatments and 10 ppm chlorantraniliprole. However, 1 ppm chlorantraniliprole did not cause significant mortality compared to the controls. Foraging on the bottom substrate was evident in all replicates for all chemicals initially. However, a portion of the foraging population avoided the ground treatment toxicants after several days of bottom foraging. Only the slower-acting non-repellents created this repellent barrier, causing avoidance behavior that was most likely due to dead termites and fungus buildup on the treated bottom substrate. Fipronil appeared more toxic and faster acting at the concentrations tested, thus limiting this repellent effect. Suggestions by the pest control industry in Louisiana that some non-repellents can create a repellent barrier stranding live termites above ground are supported by this laboratory study.

  14. Nectar yeasts in the tall Larkspur Delphinium barbeyi (Ranunculaceae and effects on components of pollinator foraging behavior.

    Directory of Open Access Journals (Sweden)

    Robert N Schaeffer

    Full Text Available Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54-77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness.

  15. Alternative foraging strategies enable a mountain ungulate to persist after migration loss

    Science.gov (United States)

    Courtemanch, Alyson B.; Kauffman, Matthew J.; Kilpatrick, Steve; Dewey, Sarah R.

    2017-01-01

    The persistence of many migratory ungulate populations worldwide is threatened due to anthropogenic impacts to seasonal ranges and migration routes. While many studies have linked migratory ungulate declines to migration disruption or loss, very few have explored the underlying factors that determine whether a population perishes or persists. In some cases, populations undergo severe declines and extirpation after migration loss; however, others appear able to persist as residents. We predict that to persist, populations must replace the traditional benefits of migration by altering the foraging strategies they employ as residents within one seasonal range. We propose the alternative foraging strategies (AFS) hypothesis as a framework for identifying various behavioral strategies that populations may use to cope with migration loss. We tested the hypothesis using the formerly migratory Teton bighorn sheep population in northwest Wyoming, which ceased migrating over 60 yr ago, but has persisted as a resident population. We used global positioning system data to evaluate winter and summer habitat selection and seasonal elevational movements for 28 adult female bighorn sheep (Ovis canadensis) from 2008 to 2010. Resource selection functions revealed that bighorn sheep employ winter foraging strategies to survive as residents by seeking out rugged, high-elevation, windswept ridgelines. Seasonal movement analyses indicated that bighorn sheep undergo a newly documented “abbreviated migration” strategy that is closely synchronized with vegetation green-up patterns within their one range. Bighorn sheep descend 500 m in elevation and travel up to 10 km in spring, gaining access to newly emergent forage approximately 30 d before it appears on their high-elevation winter and summer ranges. Our findings indicate that the Teton bighorn sheep population has persisted due to its habitat selection, AFS, and unique movement patterns, which allow migration loss to be mediated

  16. Effect of Gynosaponin on Rumen Methanogenesis under Different Forage-Concentrate Ratios

    Directory of Open Access Journals (Sweden)

    Bakhetgul Manatbay

    2014-08-01

    Full Text Available The study aimed to investigate the effects of gynosaponin on in vitro methanogenesis under different forage-concentrate ratios (F:C ratios. Experiment was conducted with two kinds of F:C ratios (F:C = 7:3 and F:C = 3:7 and gynosaponin addition (0 mg and 16 mg in a 2×2 double factorial design. In the presence of gynosaponin, methane production and acetate concentration were significantly decreased, whereas concentration of propionate tended to be increased resulting in a significant reduction (p<0.05 of acetate:propionate ratio (A:P ratio, in high-forage substrate. Gynosaponin treatment increased (p<0.05 the butyrate concentration in both F:C ratios. Denaturing gradient gel electrophoresis (DGGE analysis showed there was no apparent shift in the composition of total bacteria, protozoa and methanogens after treated by gynosaponin under both F:C ratios. The real-time polymerase chain reaction (PCR analysis indicated that variable F:C ratios significantly affected the abundances of Fibrobacter succinogenes, Rumninococcus flavefaciens, total fungi and counts of protozoa (p<0.05, but did not affect the mcrA gene copies of methanogens and abundance of total bacteria. Counts of protozoa and abundance of F.succinogenes were decreased significantly (p<0.05, whereas mcrA gene copies of methanogens were decreased slightly (p<0.10 in high-forage substrate after treated by gynosaponin. However, gynosaponin treatment under high-concentrate level did not affect the methanogenesis, fermentation characteristics and tested microbes. Accordingly, overall results suggested that gynosaponin supplementation reduced the in vitro methanogenesis and improved rumen fermentation under high-forage condition by changing the abundances of related rumen microbes.

  17. Effect of an invasive plant and moonlight on rodent foraging behavior in a coastal dune ecosystem.

    Science.gov (United States)

    Johnson, Matthew D; De León, Yesenia L

    2015-01-01

    Understanding how invasive plants may alter predator avoidance behaviors is important for granivorous rodents because their foraging can trigger ripple effects in trophic webs. Previous research has shown that European beach grass Ammophila arenaria, an invasive species in coastal California, affects the predation of other seeds by the rodents Microtus californicus, Peromyscus maniculatus, and Reithrodontomys megalotis. This may be due to lower perceived predation risk by rodents foraging in close proximity to the cover provided by Ammophila, but this mechanism has not yet been tested. We examined the perceived predation risk of rodents by measuring the 'giving up density' of food left behind in experimental patches of food in areas with and without abundant cover from Ammophila and under varying amount of moonlight. We found strong evidence that giving up density was lower in the thick uniform vegetation on Ammophila-dominated habitat than it was in the more sparsely and diversely vegetated restored habitat. There was also evidence that moonlight affected giving up density and that it mediated the effects of habitat, although with our design we were unable to distinguish the effects of lunar illumination and moon phase. Our findings illustrate that foraging rodents, well known to be risk-averse during moonlit nights, are also affected by the presence of an invasive plant. This result has implications for granivory and perhaps plant demography in invaded and restored coastal habitats. Future research in this system should work to unravel the complex trophic links formed by a non-native invasive plant (i.e., Ammophila) providing cover favored by native rodents, which likely forage on and potentially limit the recruitment of native and non-native plants, some of which have ecosystem consequences of their own.

  18. Effect of an invasive plant and moonlight on rodent foraging behavior in a coastal dune ecosystem.

    Directory of Open Access Journals (Sweden)

    Matthew D Johnson

    Full Text Available Understanding how invasive plants may alter predator avoidance behaviors is important for granivorous rodents because their foraging can trigger ripple effects in trophic webs. Previous research has shown that European beach grass Ammophila arenaria, an invasive species in coastal California, affects the predation of other seeds by the rodents Microtus californicus, Peromyscus maniculatus, and Reithrodontomys megalotis. This may be due to lower perceived predation risk by rodents foraging in close proximity to the cover provided by Ammophila, but this mechanism has not yet been tested. We examined the perceived predation risk of rodents by measuring the 'giving up density' of food left behind in experimental patches of food in areas with and without abundant cover from Ammophila and under varying amount of moonlight. We found strong evidence that giving up density was lower in the thick uniform vegetation on Ammophila-dominated habitat than it was in the more sparsely and diversely vegetated restored habitat. There was also evidence that moonlight affected giving up density and that it mediated the effects of habitat, although with our design we were unable to distinguish the effects of lunar illumination and moon phase. Our findings illustrate that foraging rodents, well known to be risk-averse during moonlit nights, are also affected by the presence of an invasive plant. This result has implications for granivory and perhaps plant demography in invaded and restored coastal habitats. Future research in this system should work to unravel the complex trophic links formed by a non-native invasive plant (i.e., Ammophila providing cover favored by native rodents, which likely forage on and potentially limit the recruitment of native and non-native plants, some of which have ecosystem consequences of their own.

  19. The role of root architecture in foraging behavior of entomopathogenic nematodes.

    Science.gov (United States)

    Demarta, Lanila; Hibbard, Bruce E; Bohn, Martin O; Hiltpold, Ivan

    2014-10-01

    As obligate parasites, entomopathogenic nematodes (EPN) rely on insect hosts to complete their development. In insect pest management, EPN infectiousness has varied a lot. A better understanding of their host-finding behavior in the rhizosphere is therefore crucial to enhance EPN potential in biological control. As previously demonstrated, roots can be used as a pathway to insect hosts by EPN, but this interaction and its impact on EPN foraging remain poorly documented. Three artificial model-roots with different degrees of complexity and connectivity were designed to investigate the impact of root architecture on foraging behavior of the EPN Heterorhabditis megidis. Insect baits were placed at the bottom of each model-root that was subsequently buried in moist sand. After injection of the EPN, the number of EPN-infected baits as well as the number of mature nematodes inside each individual carcass was recorded. The influence of insect-induced root volatiles was also evaluated by spiking the baits with a synthetic version of a natural insect-induced root cue. The ecological relevance of the results was tested in soil with two maize genotypes each exhibiting broadly different root architectures. H. megidi performed better in presence of model-roots. Foraging performances of H. megidis declined with the increasing model-root complexity. Adding the synthetic root volatile dramatically changed this pattern and favored the EPN on the most complex model-roots. H. megidis also moved in the vicinity of maize roots to find the insect baits in soil, and natural root architecture also tended to shape H. megidis foraging behavior. This study adds to the scarce body of literature characterizing physical and chemical interactions between EPN and roots. The present data illustrate that root architecture not only modifies plant quality but also shapes upper trophic levels' ecology. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Capuchin monkeys (Cebus nigritus) use spatial and visual information during within-patch foraging.

    Science.gov (United States)

    Gomes, Daniela Fichtner; Bicca-Marques, Júlio César

    2012-01-01

    Foraging in large-scale (navigation between patches), small-scale (choice of within-patch feeding sites), and micro-scale (close inspection of food items) space presents variable cognitive challenges. The reliability and usefulness of spatial memory and perceptual cues during food search in a forest environment vary among these spatial scales. This research applied an experimental field design to test the ability of a free-ranging group composed of eight black-horned capuchin monkeys, Cebus nigritus, inhabiting a forest fragment in Porto Alegre, State of Rio Grande do Sul, Brazil, to use food-associated spatial, visual, olfactory, and quantitative (amount of food) cues during small-scale foraging decisions. The experimental design involved the establishment of a feeding station composed of eight feeding platforms distributed in a circular arrangement. A series of six experiments, each lasting 20 days, was conducted from March to August 2005. Two feeding platforms in each experimental session contained a food reward (real banana), whereas the remaining six platforms contained either a sham banana or an inaccessible real banana. Data on capuchin monkey foraging behavior at the feeding stations were collected by the "all occurrences" sampling method. The performance of the capuchins in the experiments was analyzed based on the first two platforms inspected in each session. The study group inspected feeding platforms in 571 occasions during 113 sessions. Capuchins used visual cues and spatial information (and adopted a win-return strategy) for finding the platforms baited with real bananas and showed weak evidence of the integration of spatial and quantitative cues, but failed to show evidence of using olfactory cues. In addition, individual differences in social rank and foraging behavior affected opportunities for learning and the performance in the cognitive tasks. © 2011 Wiley-Liss, Inc.

  1. Arctic warming: nonlinear impacts of sea-ice and glacier melt on seabird foraging.

    Science.gov (United States)

    Grémillet, David; Fort, Jérôme; Amélineau, Françoise; Zakharova, Elena; Le Bot, Tangi; Sala, Enric; Gavrilo, Maria

    2015-03-01

    Arctic climate change has profound impacts on the cryosphere, notably via shrinking sea-ice cover and retreating glaciers, and it is essential to evaluate and forecast the ecological consequences of such changes. We studied zooplankton-feeding little auks (Alle alle), a key sentinel species of the Arctic, at their northernmost breeding site in Franz-Josef Land (80°N), Russian Arctic. We tested the hypothesis that little auks still benefit from pristine arctic environmental conditions in this remote area. To this end, we analysed remote sensing data on sea-ice and coastal glacier dynamics collected in our study area across 1979-2013. Further, we recorded little auk foraging behaviour using miniature electronic tags attached to the birds in the summer of 2013, and compared it with similar data collected at three localities across the Atlantic Arctic. We also compared current and historical data on Franz-Josef Land little auk diet, morphometrics and chick growth curves. Our analyses reveal that summer sea-ice retreated markedly during the last decade, leaving the Franz-Josef Land archipelago virtually sea-ice free each summer since 2005. This had a profound impact on little auk foraging, which lost their sea-ice-associated prey. Concomitantly, large coastal glaciers retreated rapidly, releasing large volumes of melt water. Zooplankton is stunned by cold and osmotic shock at the boundary between glacier melt and coastal waters, creating new foraging hotspots for little auks. Birds therefore switched from foraging at distant ice-edge localities, to highly profitable feeding at glacier melt-water fronts within <5 km of their breeding site. Through this behavioural plasticity, little auks maintained their chick growth rates, but showed a 4% decrease in adult body mass. Our study demonstrates that arctic cryosphere changes may have antagonistic ecological consequences on coastal trophic flow. Such nonlinear responses complicate modelling exercises of current and future

  2. Evidence of hypoxic foraging forays by yellow perch (Perca flavescens) and potential consequences for prey consumption

    Science.gov (United States)

    Roberts, James J.; Grecay, Paul A.; Ludsin, Stuart A.; Pothoven, Steve A.; Vanderploeg, Henry A.; Höök, Tomas O.

    2012-01-01

    Previous studies in a variety of ecosystems have shown that ecologically and economically important benthic and bentho-pelagic fishes avoid hypoxic (−1) habitats by moving vertically or horizontally to more oxygenated areas. While avoidance of hypoxic conditions generally leads to a complete shift away from preferred benthic prey, some individual fish continue to consume benthic prey items in spite of bottom hypoxia, suggesting complex habitat utilisation and foraging patterns. For example, Lake Erie yellow perch (Perca flavescens) continue to consume benthic prey, despite being displaced vertically and horizontally by hypolimnetic hypoxia. We hypothesised that hypolimnetic hypoxia can negatively affect yellow perch by altering their distribution and inducing energetically expensive foraging behaviour. To test this hypothesis, we used drifting hydroacoustics and trawl sampling to quantify water column distribution, sub-daily vertical movement and foraging behaviour of yellow perch within hypoxic and normoxic habitats of Lake Erie’s central basin during August-September 2007. We also investigated the effects of rapid changes in ambient oxygen conditions on yellow perch consumption potential by exposing yellow perch to various static and fluctuating oxygen conditions in a controlled laboratory experiment. Our results indicate that, while yellow perch in general avoid hypoxic conditions, some individuals undertake foraging forays into hypoxic habitats where they experience greater fluctuations in abiotic conditions (pressure, temperature and oxygen concentration) than at normoxic sites. However, laboratory results suggest short-term exposure to low oxygen conditions did not negatively impact consumption potential of yellow perch. Detailed understanding of sub-daily individual behaviours may be crucial for determining interactive individual- and ecosystem-level effects of stressors such as hypoxia.

  3. Seed softening patterns of forage legumes in a temperate/subtropical environment in Uruguay

    Directory of Open Access Journals (Sweden)

    Javier Do Canto

    2013-03-01

    Full Text Available Few studies have been conducted in annual and perennial forage legumes to investigate the development of hardseededness and the subsequent pattern of seed softening in temperate and subtropical regions of South America. Experiments were conducted during 2007 and 2008 in central Uruguay to follow the pattern of seed softening in 35 annual and perennial forage legumes, including three native species of Uruguay and five commercial cultivars. Newly ripened seeds of each plant material were placed in mesh packets on the soil surface in mid-summer. Samples were recovered monthly for germination tests and the proportion of residual hard seeds determined. The native species Adesmia bicolor (Poir. DC., Adesmia securigerifolia Herter, and Ornithopus micranthus (Benth. Arechav., together with Ornithopus pinnatus (Mill. Druce cv. INIA Molles behaved similarly. They showed high levels of initial hard seed from 78% in A. bicolor to 99% in A. securigerifolia and O. pinnatus cv. INIA Molles in 2007; displayed pulses of seed softening, particularly in autumn, and retained moderate levels of residual hard seed for the development of a soil seed bank ranging from 15% in A. bicolor to 49% in O. micranthus. These appear to be desirable characteristics for persistence of forage legumes in subtropical grasslands, both for annual and perennial species. Trifolium repens L. and Lotus corniculatus L. produced few hard seeds, only 2% and 13% respectively were hard after 1-mo in the field and were completely soft by July placing extra reliance on their vegetative propagation for persistence. Materials of L. arenarius Brot. showed pronounced late autumn softening, while materials of L. ornithopodioides L. showed extremely high levels of hardseededness (between 96% and 100% and no softening during the evaluation period, apart from two materials that were completely soft seeded. Mediterranean forage legumes should be properly evaluated in temperate and subtropical regions as

  4. Digesting or swimming? Integration of the postprandial metabolism, behavior and locomotion in a frequently foraging fish.

    Science.gov (United States)

    Nie, Li-Juan; Cao, Zhen-Dong; Fu, Shi-Jian

    2017-02-01

    Fish that are active foragers usually perform routine activities while digesting their food; thus, their postprandial swimming capacity and related behavior adjustments might be ecologically important. To test whether digestion affect swimming performance and the relationships of digestion with metabolism and behavior in an active forager, we investigated the postprandial metabolic response, spontaneous swimming activities, critical swimming speed (Ucrit), and fast-start escape performance of both fasted and digesting (3h after feeding to satiation) juvenile rose bitterling (Rhodeus ocellatus). Feeding to satiation elicited a 50% increase in the oxygen consumption rate, which peaked at 3h after feeding and returned to the prefeeding state after another 3h. However, approximately 50% and 90% of individuals resumed feeding behavior at 2 and 3h postfeeding, respectively, although the meal size varied substantially. Digestion showed no effect on either steady swimming performance as suggested by the Ucrit or unsteady swimming performance indicated by the maximum linear velocity in fast-start escape movement. However, digesting fish showed more spontaneous activity as indicated by the longer total distance traveled, mainly through an increased percentage of time spent moving (PTM). A further analysis found that fasting individuals with high swimming speed were more inclined to increase their PTM during digestive processes. The present study suggests that as an active forager With a small meal size and hence limited postprandial physiological and morphological changes, the swimming performance of rose bitterling is maintained during digestion, which might be crucial for its active foraging mode and anti-predation strategy. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Ant Foraging Behavior for Job Shop Problem

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    Mahad Diyana Abdul

    2016-01-01

    Full Text Available Ant Colony Optimization (ACO is a new algorithm approach, inspired by the foraging behavior of real ants. It has frequently been applied to many optimization problems and one such problem is in solving the job shop problem (JSP. The JSP is a finite set of jobs processed on a finite set of machine where once a job initiates processing on a given machine, it must complete processing and uninterrupted. In solving the Job Shop Scheduling problem, the process is measure by the amount of time required in completing a job known as a makespan and minimizing the makespan is the main objective of this study. In this paper, we developed an ACO algorithm to minimize the makespan. A real set of problems from a metal company in Johor bahru, producing 20 parts with jobs involving the process of clinching, tapping and power press respectively. The result from this study shows that the proposed ACO heuristics managed to produce a god result in a short time.

  6. Foraging strategy switching in an antlion larva.

    Science.gov (United States)

    Tsao, Yu-Jen; Okuyama, Toshinori

    2012-09-01

    Antlion larvae are typically considered as trap-building predators, but some species of antlions always forage without using pits or only sometimes use pits to capture prey; they can ambush prey without pits. This study examined a species that switches its strategy between pit-trapping and ambushing and asked the mechanism behind the switching behaviour. A dynamic optimization model incorporating tradeoffs between the two strategies was built. The tradeoffs were prey capture success and predation risk (both are higher when pit-trapping). The model predicted that antlions should use the trap-building strategy when their energy status is low and should use the ambush strategy when their energy status is high. These predictions as well as an assumption (i.e., predation risk associated with pit-trapping is higher than that associated with ambushing) of the model were empirically confirmed. The results suggest that antlions flexibly switch between pit-trapping and ambushing to maximize their fitness by balancing the costs and benefits of the two strategies. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Ocean acidification impairs crab foraging behaviour.

    Science.gov (United States)

    Dodd, Luke F; Grabowski, Jonathan H; Piehler, Michael F; Westfield, Isaac; Ries, Justin B

    2015-07-07

    Anthropogenic elevation of atmospheric CO2 is driving global-scale ocean acidification, which consequently influences calcification rates of many marine invertebrates and potentially alters their susceptibility to predation. Ocean acidification may also impair an organism's ability to process environmental and biological cues. These counteracting impacts make it challenging to predict how acidification will alter species interactions and community structure. To examine effects of acidification on consumptive and behavioural interactions between mud crabs (Panopeus herbstii) and oysters (Crassostrea virginica), oysters were reared with and without caged crabs for 71 days at three pCO2 levels. During subsequent predation trials, acidification reduced prey consumption, handling time and duration of unsuccessful predation attempt. These negative effects of ocean acidification on crab foraging behaviour more than offset any benefit to crabs resulting from a reduction in the net rate of oyster calcification. These findings reveal that efforts to evaluate how acidification will alter marine food webs should include quantifying impacts on both calcification rates and animal behaviour. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Foraging strategy of vermivorous conid gastropods. [Conus sp

    Energy Technology Data Exchange (ETDEWEB)

    Leviten, P.J.

    1976-01-01

    A heuristic model, developed from simple assumptions, generates testable hypotheses that predict the foraging patterns of predators which invest a significantly greater amount of energy in search for, as compared to pursuit and handling of, prey. Given: (1) the environmental distribution of potential food size, (2) the environmental distribution of potential food diversity within food size, and (3) the manner in which the limits of consumable food size vary with predator size; food and microhabitat niche breadths as a function of predator size can be predicted. The assumptions and derived hypotheses of the model are tested with data from vermivorous prosobranch gastropods of the genus Conus, ubiquitous associates of tropical Pacific Ocean and Indian Ocean coral reefs. Predictions are: (1) small Conus (less than 10 mm shell length) are trophic specialists; (2) medium-sized Conus (10 to 25 mm shell length), trophic generalists; and (3) large Conus (greater than 25 mm shell length), trophic specialists. This pattern is supported by both within- and between-species comparisons of Conus populations of different mean sizes. Relationships of food niche breadth with predator size are interpreted in light of the marked behavioral and morphological stereotypy of Conus, probably evolved in response to evolutionary and proximate predictability of available prey.

  9. Predator foraging altitudes reveal the structure of aerial insect communities.

    Science.gov (United States)

    Helms, Jackson A; Godfrey, Aaron P; Ames, Tayna; Bridge, Eli S

    2016-06-29

    The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins flew up to 1,889 meters above ground, and nestling provisioning trips ranged up to 922 meters. Insect communities were structured by body size such that species of all sizes flew near the ground but only light insects flew to the highest altitudes. Ant maximum flight altitudes decreased by 60% from the lightest to the heaviest species. Winged sexuals of social insects (ants, honey bees, and termites) dominated the Purple Martin diet, making up 88% of prey individuals and 45% of prey biomass. By transferring energy from terrestrial to aerial food webs, mating swarms of social insects play a substantial role in aerial ecosystems. Although we focus on Purple Martins and ants, our combined logger and diet method could be applied to a range of aerial organisms.

  10. Conservation tillage reduces PM10 emissions in dairy forage rotations

    Science.gov (United States)

    Madden, N. M.; Southard, R. J.; Mitchell, J. P.

    2008-05-01

    The San Joaquin Valley (SJV) is a United States Environmental Protection Agency (USEPA) serious non-attainment area for PM10, particulate matter with an aerodynamic diameter dairy forage production to determine if, and to what extent, CT can reduce agricultural PM10. Vertical profiling methods were used to calculate PM10 emission factors for both systems at two farm locations. Test results showed CT reduced PM10 emissions by about 85% on both farms in spring 2004 and by 52% on one farm to 93% on another farm in spring 2005. PM10 reductions were mainly due to the fewer number of tillage operations in CT systems (zero or one operation compared to three to six in ST) and the higher soil water contents at which CT operations can be performed. Aside from soil moisture, degree of soil pulverization, characterized in the second year of this study by weighted mean ped diameter (WMPD) also proved to be an important determinant of PM10 emissions. The ST second disking always had a higher PM10 emission factor than the first disking despite any change in soil water content. The WMPD decreased 39% between the two diskings. Large discrepancies between PM10 emission factors measured in this study and those used for regulatory purposes in California emphasize the continued need to refine monitoring strategies under varying field conditions to improve accuracy of emission factors and to understand how soil and cropping management affect dust production.

  11. Repellence and attraction of Apis mellifera foragers by nectar alkaloids

    Directory of Open Access Journals (Sweden)

    Hroncová Z.

    2016-03-01

    Full Text Available Plant secondary metabolites present naturally in nectar, such as alkaloids, may change the behavioural responses of floral visitors and affect pollination. Some studies have shown that nectar containing low concentrations of these secondary metabolites is preferred by honey bee foragers over pure nectar. However, it remains unclear whether this is caused by dependence or addictive behaviour, a simple taste preference, or by other conditions such as self-medication. In our choice experiment, free-flying bees were presented with artificial flowers holding 20% sucrose containing 0.5−50 μg ml−1 of one of the naturally occurring nectar alkaloids - caffeine, nicotine, senecionine, and gelsemine. Nectar uptake was determined by weighing each flower and comparing the weight to that of the control flower. Our experimental design minimized memorizing and marking; despite this, caffeine was significantly preferred at concentrations 0.5−2 μg ml−1 over control nectar; this preference was not observed for other alkaloids. All of the compounds tested were repellent at concentrations above 5 μg ml−1. We confirmed previous reports that bees exhibit a preference for caffeine, and hypothesize that this is not due only to addictive behaviour but is at least partially mediated by taste preference. We observed no significant preference for nicotine or any other alkaloid.

  12. Sublethal imidacloprid effects on honey bee flower choices when foraging.

    Science.gov (United States)

    Karahan, Ahmed; Çakmak, Ibrahim; Hranitz, John M; Karaca, Ismail; Wells, Harrington

    2015-11-01

    Neonicotinoids, systemic neuro-active pesticides similar to nicotine, are widely used in agriculture and are being investigated for a role in honey bee colony losses. We examined one neonicotinoid pesticide, imidacloprid, for its effects on the foraging behavior of free-flying honey bees (Apis mellifera anatoliaca) visiting artificial blue and white flowers. Imidacloprid doses, ranging from 1/5 to 1/50 of the reported LD50, were fed to bees orally. The study consisted of three experimental parts performed sequentially without interruption. In Part 1, both flower colors contained a 4 μL 1 M sucrose solution reward. Part 2 offered bees 4 μL of 1.5 M sucrose solution in blue flowers and a 4 μL 0.5 M sucrose solution reward in white flowers. In Part 3 we reversed the sugar solution rewards, while keeping the flower color consistent. Each experiment began 30 min after administration of the pesticide. We recorded the percentage of experimental bees that returned to forage after treatment. We also recorded the visitation rate, number of flowers visited, and floral reward choices of the bees that foraged after treatment. The forager return rate declined linearly with increasing imidacloprid dose. The number of foraging trips by returning bees was also affected adversely. However, flower fidelity was not affected by imidacloprid dose. Foragers visited both blue and white flowers extensively in Part 1, and showed greater fidelity for the flower color offering the higher sugar solution reward in Parts 2 and 3. Although larger samples sizes are needed, our study suggests that imidacloprid may not affect the ability to select the higher nectar reward when rewards were reversed. We observed acute, mild effects on foraging by honey bees, so mild that storage of imidacloprid tainted-honey is very plausible and likely to be found in honey bee colonies.

  13. Modelling foraging movements of diving predators: a theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency.

    Science.gov (United States)

    Chimienti, Marianna; Bartoń, Kamil A; Scott, Beth E; Travis, Justin M J

    2014-01-01

    Foraging in the marine environment presents particular challenges for air-breathing predators. Information about prey capture rates, the strategies that diving predators use to maximise prey encounter rates and foraging success are still largely unknown and difficult to observe. As well, with the growing awareness of potential climate change impacts and the increasing interest in the development of renewable sources it is unknown how the foraging activity of diving predators such as seabirds will respond to both the presence of underwater structures and the potential corresponding changes in prey distributions. Motivated by this issue we developed a theoretical model to gain general understanding of how the foraging efficiency of diving predators may vary according to landscape structure and foraging strategy. Our theoretical model highlights that animal movements, intervals between prey capture and foraging efficiency are likely to critically depend on the distribution of the prey resource and the size and distribution of introduced underwater structures. For multiple prey loaders, changes in prey distribution affected the searching time necessary to catch a set amount of prey which in turn affected the foraging efficiency. The spatial aggregation of prey around small devices (∼ 9 × 9 m) created a valuable habitat for a successful foraging activity resulting in shorter intervals between prey captures and higher foraging efficiency. The presence of large devices (∼ 24 × 24 m) however represented an obstacle for predator movement, thus increasing the intervals between prey captures. In contrast, for single prey loaders the introduction of spatial aggregation of the resources did not represent an advantage suggesting that their foraging efficiency is more strongly affected by other factors such as the timing to find the first prey item which was found to occur faster in the presence of large devices. The development of this theoretical model represents a useful

  14. Modelling foraging movements of diving predators: a theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency

    Directory of Open Access Journals (Sweden)

    Marianna Chimienti

    2014-09-01

    Full Text Available Foraging in the marine environment presents particular challenges for air-breathing predators. Information about prey capture rates, the strategies that diving predators use to maximise prey encounter rates and foraging success are still largely unknown and difficult to observe. As well, with the growing awareness of potential climate change impacts and the increasing interest in the development of renewable sources it is unknown how the foraging activity of diving predators such as seabirds will respond to both the presence of underwater structures and the potential corresponding changes in prey distributions. Motivated by this issue we developed a theoretical model to gain general understanding of how the foraging efficiency of diving predators may vary according to landscape structure and foraging strategy. Our theoretical model highlights that animal movements, intervals between prey capture and foraging efficiency are likely to critically depend on the distribution of the prey resource and the size and distribution of introduced underwater structures. For multiple prey loaders, changes in prey distribution affected the searching time necessary to catch a set amount of prey which in turn affected the foraging efficiency. The spatial aggregation of prey around small devices (∼ 9 × 9 m created a valuable habitat for a successful foraging activity resulting in shorter intervals between prey captures and higher foraging efficiency. The presence of large devices (∼ 24 × 24 m however represented an obstacle for predator movement, thus increasing the intervals between prey captures. In contrast, for single prey loaders the introduction of spatial aggregation of the resources did not represent an advantage suggesting that their foraging efficiency is more strongly affected by other factors such as the timing to find the first prey item which was found to occur faster in the presence of large devices. The development of this theoretical model

  15. Performance and economic analyses of year-round forage systems for forage-fed beef production in the Gulf Coast.

    Science.gov (United States)

    Scaglia, G; Rodriguez, J; Gillespie, J; Bhandari, B; Wang, J J; McMillin, K W

    2014-12-01

    On a global scale, most beef is produced from grazing pastures or rangelands. Certain limitations exist, however, such as not having adequate animal rates of gain for marbling and availability of adequate forage nutritional value and quantity for constant animal weight gains. In the last 20 yr, there has been an increased interest in forage-fed beef for multiple reasons (health related, environmental concerns, and welfare issues). Starting on June 5, 13, 14, and 8 in 4 consecutive yr, 54 steers (initial BW=259±5.6 kg; average of 9 mo of age) were randomly allotted to 3 yr-round forage systems. Each system occupied 6 ha/replicate and had the same stocking rate. System 1 had annual ryegrass (Lolium multiflorum) for winter grazing and bermudagrass (Cynodon dactylon) for summer grazing; while Systems 2 and 3 added rye and a clover mix to the ryegrass and diversified the use of pastures in the fall (dallisgrass [Paspalum dilatatum] and clovers [Trifolium spp.]). System 3 added the use of annual summer forages. During their respective growing season for each forage or forage mix, mass and height did not limit animal performance; however, there was a sampling date effect (Psystems (P=0.78) during summer was lower than expected and might have been limited by the observed temperature as well as forage nutritive value. Systems 1 and 2 had more grazing days (P=0.03) during summer (155 and 146 d, respectively) compared to System 3 (132 d) due to the greater pasture area of bermudagrass in those systems. Steers in System 3 were fed more hay for a longer period of time (Psystems. System 1 and 2 produced more hay per hectare than System 3 (P0.05) were detected between systems in ADG year round, during the winter season, or carcass characteristics. Return over total direct costs and total specified expenses were greater for Systems 1 and 2, while System 3 was the lowest. Hay making and bale sales played a major role in explaining the economic results of this study. Where possible

  16. roduction and nutritional value of fertirrigates forages

    Directory of Open Access Journals (Sweden)

    Ariadna Mendes da Abadia

    2011-02-01

    Full Text Available The objective was to determine the production and chemical composition of three cultures (millet, corn and sorghum on two substrates (fine sawdust and chopped dried grass by the technique of fertirrigated forage production at Federal University of Goias, Campus Jatai, in a randomized block design, 3 x 2 factorial arrangement with four replications represented by blocks distributed seedling to the location of the beds. Seeds were pre-germinated in water and all the management was carried out using corn production recommendations. Samples were collected 17 days after planting to calculated and analyzed the contents and productivity (GMP, dry matter (DM and DMP, mineral matter (MM and MMP, crude protein (CP and CPP, neutral detergent fiber (NDF and NDFP and acid detergent fiber (ADF and ADFP. Data were subjected to analysis of variance by SAS version 9.0 at 5% significance, data considered for comparison and contrast of statistical analysis, the split plot effect of blocks, the effect of culture in the plot and the substrate in subplot. There was no interaction (P>0.05 between factors (substrates and cultures when they were evaluated for chemical composition and production and regardless of culture, the sawdust substrate had higher levels of (P <0.05 dry matter (DM, neutral detergent fiber (NDF and acid detergent fiber (ADF levels and production, but not greater nutritional value. There was significant effect (P <0.05 of culture for the DM, CP, NDF and ADF allowing to affirm that corn culture responded more appropriately when grown on chopped dry grass.

  17. The aversive effect of electromagnetic radiation on foraging bats: a possible means of discouraging bats from approaching wind turbines.

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    Barry Nicholls

    Full Text Available Large numbers of bats are killed by collisions with wind turbines and there is at present no accepted method of reducing or preventing this mortality. Following our demonstration that bat activity is reduced in the vicinity of large air traffic control and weather radars, we tested the hypothesis that an electromagnetic signal from a small portable radar can act as a deterrent to foraging bats. From June to September 2007 bat activity was compared at 20 foraging sites in northeast Scotland during experimental trials (radar switched on and control trials (no radar signal. Starting 45 minutes after sunset, bat activity was recorded for a period of 30 minutes during each trial and the order of trials were alternated between nights. From July to September 2008 aerial insects at 16 of these sites were sampled using two miniature light-suction traps. At each site one of the traps was exposed to a radar signal and the other functioned as a control. Bat activity and foraging effort per unit time were significantly reduced during experimental trials when the radar antenna was fixed to produce a unidirectional signal therefore maximising exposure of foraging bats to the radar beam. However, although bat activity was significantly reduced during such trials, the radar had no significant effect on the abundance of insects captured by the traps.

  18. WATER DEFICIT EFFECT ON YIELD AND FORAGE QUALITY OF MEDICAGO SATIVA POPULATIONS UNDER FIELD CONDITIONS IN MARRAKESH AREA (MOROCCO

    Directory of Open Access Journals (Sweden)

    Mohamed FARISSI

    2014-06-01

    Full Text Available The present study focused the effect of water deficit on agronomic potential and some traits related to forage quality in plants of Moroccan Alfalfa (Medicago sativa L. populations (Taf 1, Taf 2, Dem and Tata originated from Oasis and High Atlas of Morocco and an introduced variety from Australia (Siriver. The experiment was conducted under field conditions in experimental station of INRA-Marrakech and under two irrigation treatments. The first treatment was normal irrigation, providing an amount of water corresponding to the potential evapo-transpiration of the crop, and the second treatment was water deficit stress (one irrigation per cut. For each treatment, the experiment was conducted as a split plot based on a randomized complete block design with four replications. The plants were measured and analyzed over three cuts. Some agronomic traits as, plant height, fresh and dry forage yields were measured. The forage quality was evaluated by leaf:stem ratio and the contents of plants in proteins and nitrogen. The results indicated that the water deficit has negatively affected the plant height and forage yield. The decrease in leaf:stem ratio was observed under water deficit conditions. However, the proteins and nitrogen contents were unaffected. The behavior of tested alfalfa genotypes was significantly different. The Moroccan alfalfa populations were more adapted to water deficit conditions comparatively to Siriver variety and the Tata population was the most adapted one.

  19. A molecular phylogeny of Dorylus army ants provides evidence for multiple evolutionary transitions in foraging niche

    DEFF Research Database (Denmark)

    Kronauer, Daniel J C; Schöning, Caspar; Vilhelmsen, Lars

    2007-01-01

    in the leaf-litter and some as conspicuous swarm raiders on the forest floor and in the lower vegetation (the infamous driver ants). Here we use a combination of nuclear and mitochondrial DNA sequences to reconstruct the phylogeny of the Dorylus s.l. army ants and to infer the evolutionary transitions...... in foraging niche and associated morphological adaptations. RESULTS: Underground foraging is basal and gave rise to leaf-litter foraging. Leaf-litter foraging in turn gave rise to two derived conditions: true surface foraging (the driver ants) and a reversal to subterranean foraging (a clade with most...

  20. Foraging Behavior and Energetics of Albatrosses in Contrasting Breeding Environments

    Directory of Open Access Journals (Sweden)

    Michelle Antolos

    2017-12-01

    Full Text Available Animals can maximize fitness by optimizing energy acquisition through the selection of favorable foraging habitats, but trade-offs exist between time spent in preferred feeding habitats, energetic costs of travel, and reproductive constraints. For pelagic seabirds, geographic distribution of suitable breeding islands can restrict access to marine prey resources and influence foraging strategies. Laysan (Phoebastria immutabilis and black-footed albatrosses (P. nigripes breeding in the Northwest Hawaiian Islands, and Indian yellow-nosed albatrosses (Thalassarche carteri breeding in the Southern Indian Ocean, utilize productive subtropical-subpolar transition zones during their breeding and non-breeding periods, but this marine feature is at a comparatively greater distance for Hawaiian albatrosses during the breeding period due to location of nesting islands. We investigated the foraging behavior and energetics of these three species to evaluate how proximity to preferred marine habitats has influenced their overall foraging strategies. During incubation, all three species traveled to subtropical-subpolar transition zones, however, Hawaiian albatrosses ranged farther to reach this habitat. All species reduced time at sea during brooding, and Hawaiian albatrosses reduced their foraging ranges to distances similar to yellow-nosed albatrosses. As a consequence, Hawaiian albatrosses foraged in the warm, oligotrophic environment of the subtropical gyre during brooding while yellow-nosed albatrosses continued to forage in a subtropical-subpolar transition zone. Landing rates, an indicator of foraging effort, did not differ between reproductive stages and were highly variable within and among species. Hawaiian albatrosses generally spent more time in flight compared to yellow-nosed albatrosses, a strategy that may relate to searching for dispersed and unpredictable prey. Mean absolute field-metabolic rate (FMR was greatest for black-footed albatrosses

  1. Evidence for foraging -site fidelity and individual foraging behavior of pelagic cormorants rearing chicks in the gulf of Alaska

    Science.gov (United States)

    Kotzerka, J.; Hatch, Shyla A.; Garthe, S.

    2011-01-01

    The Pelagic Cormorant (Phalacrocorax pelagicus) is the most widespread cormorant in the North Pacific, but little is known about its foraging and diving behavior. However, knowledge of seabirds' foraging behavior is important to understanding their function in the marine environment. In 2006, using GPS dataloggers, we studied the foraging behavior of 14 male Pelagic Cormorants rearing chicks on Middleton Island, Alaska. For foraging, the birds had high fidelity to a small area 8 km north of the colony. Within that area, the cormorants' diving activity was of two distinct kinds-near-surface dives (1-6 m) and benthic dives (28-33 m). Individuals were consistent in the depths of their dives, either mostly shallow or mostly deep. Few showed no depth preference. Dive duration, time at maximum depth, and pauses at the water surface between consecutive dives were shorter for shallow dives than for deep dives. The cormorants made dives of both types throughout the day, but the frequency of deep dives increased toward evening. Maximum foraging range was 9 km; maximum total distance traveled per trip was 43.4 km. Trip durations ranged from 0.3 to 7.7 hr. Maximum depth of a dive was 42.2 m, and duration of dives ranged from 4 to 120 sec. We found that Pelagic Cormorants at Middleton Island were faithful to one particular foraging area and individuals dived in distinct patterns. Distinct, specialized foraging behavior may be advantageous in reducing intra- and interspecific competition but may also render the species vulnerable to changing environmental conditions. Copyright ?? The Cooper Ornithological Society 2011.

  2. Foraging motivation favors the occurrence of Lévy walks.

    Science.gov (United States)

    Anselme, Patrick; Otto, Tobias; Güntürkün, Onur

    2018-02-01

    Lévy walks are a property of random movements often observed among foraging animals (and humans), and they might confer some advantages for survival in an unpredictable environment, in comparison with Brownian walks. In animals with a nervous system, specific neurotransmitters associated with some psychological states could play a crucial role in controlling the occurrence of Lévy walks. We argue that incentive motivation, a dopamine-dependent process that in vertebrates makes rewards and their predictive conditioned stimuli attractive, has behavioral effects that may favor their occurrence: incentive motivation is higher when food is unpredictable and it strongly underpins foraging activity. An individual-based computer model is used to determine whether changes in incentive motivation can influence the probability that Lévy walks occur among foraging agents. Our results suggest that they are produced more often under an unpredictable than a predictable food access, and more often in strongly rather than weakly motivated foragers exposed to an unpredictable food access. Also, our motivational framework indicates that the occurrence of Lévy walks are correlated with, but not causally linked to, the number of food items consumed and the ability to store fat reserves. We conclude that Lévy walks can confer some advantages for survival in an unpredictable environment, provided that they appear in foragers with a high motivation to seek food. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Potency Of Clitoria Ternatea As Forage For Livestock

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    Endang Sutedi

    2013-06-01

    Full Text Available Availability of forage is one of the factors determining the success of ruminant livestock production, especially during drought that resulting in poor livestock condition. Forage legume is an important group of forage plants, containing high nutritive value. One of the legume plants which potential as ruminant feed is Clitoria ternatea. This plant can grow well in all types of soil and dry conditions, also produces seed continously. The production of forage was 25-29 ton DM/ha with seed production was 2.2 ton DM/ha per harvest (42 day cutting interval. The crude protein and crude fiber contents of C. ternatea leaf were 21.5 and 29%, respectively. Meanwhile, the crude protein, crude fat and sugar contents of C. ternatea seed were 25-38,10 and 5%, respectively. This plant can be fed to ruminant as fresh forage or hay with no negative effect on growth performance of animal. The average daily gain of cattle grazing on mixture of Brachiaria mutica grass and C. ternatea was 680 g/day. The value of DM and OM digestibilities of C. ternatea in cattle were 50.15 and 53.47%, respectively. Feeding C. ternatea to dairy cow impoved the content of fat and total solid of milk, meanwhile feeding it to male sheep improved quality of semen.

  4. Bats Can Use Magnetic Compass in Foraging Behavior

    Science.gov (United States)

    Tian, L.; Zhang, B.; Pan, Y.; Zhu, R.

    2016-12-01

    Foraging plays an important role in an animal's ability to survive and reproduce. It is widely recognized that many animals and microorganisms can use geomagnetic compass in migration or homing orientation. Among them, bats, the only flying mammals, can use the magnetic compass in migrating orientations. For instance, we found the migratory microbat, Nyctalus plancyi, could use the magnetic polarity compass in roosting orientation under the strength range at least from a much weaker magnetic field than the present-day geomagnetic field (as low as 10 μT) to up to stronger magnetic field (100 μT). This high sensitivity to magnetic fields intensity may explain how magnetic orientation could have long-term evolved in bats even as the Earth's magnetic field strength varied as the polarity reversed many times in the past. Recently, we carried out foraging behavioral experiments on N. plancyi under various magnetic field conditions. Interestingly, it has shown that, although the auditory including echolocation, or olfactory sense may be the primary methods for seeking food under totally dark circumstance, the bats showed preferred foraging orientations at the magnetic north-south directions when any other sensory cues are insufficient for location of the food. It confirmed that bats could optimally use multiple directional cues including the geomagnetic field in their foraging in field. When bats foraging, they would navigate along the magnetic field direction if there were no direct sensory cues. As it gets close, the direct cues from food would guide them to the food.

  5. Fragmentation of nest and foraging habitat affects time budgets of solitary bees, their fitness and pollination services, depending on traits: Results from an individual-based model.

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    Everaars, Jeroen; Settele, Josef; Dormann, Carsten F

    2018-01-01

    Solitary bees are important but declining wild pollinators. During daily foraging in agricultural landscapes, they encounter a mosaic of patches with nest and foraging habitat and unsuitable matrix. It is insufficiently clear how spatial allocation of nesting and foraging resources and foraging traits of bees affect their daily foraging performance. We investigated potential brood cell construction (as proxy of fitness), number of visited flowers, foraging habitat visitation and foraging distance (pollination proxies) with the model SOLBEE (simulating pollen transport by solitary bees, tested and validated in an earlier study), for landscapes varying in landscape fragmentation and spatial allocation of nesting and foraging resources. Simulated bees varied in body size and nesting preference. We aimed to understand effects of landscape fragmentation and bee traits on bee fitness and the pollination services bees provide, as well as interactions between them, and the general consequences it has to our understanding of the system. This broad scope gives multiple key results. 1) Body size determines fitness more than landscape fragmentation, with large bees building fewer brood cells. High pollen requirements for large bees and the related high time budgets for visiting many flowers may not compensate for faster flight speeds and short handling times on flowers, giving them overall a disadvantage compared to small bees. 2) Nest preference does affect distribution of bees over the landscape, with cavity-nesting bees being restricted to nesting along field edges, which inevitably leads to performance reductions. Fragmentation mitigates this for cavity-nesting bees through increased edge habitat. 3) Landscape fragmentation alone had a relatively small effect on all responses. Instead, the local ratio of nest to foraging habitat affected bee fitness positively through reduced local competition. The spatial coverage of pollination increases steeply in response to this ratio

  6. Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico.

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    Shaver, Donna J; Hart, Kristen M; Fujisaki, Ikuko; Rubio, Cynthia; Sartain, Autumn R; Peña, Jaime; Burchfield, Patrick M; Gamez, Daniel Gomez; Ortiz, Jaime

    2013-07-01

    For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998-2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their "final" foraging sites. We identified new foraging "hotspots" where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13-year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at-sea foraging habitats for this imperiled species.

  7. Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico

    Science.gov (United States)

    Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Rubio, Cynthia; Sartain-Iverson, Autumn R.; Peña, Jaime; Burchfield, Patrick M.; Gamez, Daniel Gomez; Ortiz, Jaime

    2013-01-01

    For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998–2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their "final" foraging sites. We identified new foraging "hotspots" where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13-year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at-sea foraging habitats for this imperiled species.

  8. Biosynthesis and regulation of cyanogenic glycoside production in forage plants.

    Science.gov (United States)

    Sun, Zhanmin; Zhang, Kaixuan; Chen, Cheng; Wu, Yanmin; Tang, Yixiong; Georgiev, Milen I; Zhang, Xinquan; Lin, Min; Zhou, Meiliang

    2017-10-12

    The natural products cyanogenic glycosides (CNglcs) are present in various forage plant species including Sorghum spp., Trifolium spp., and Lotus spp. The release of toxic hydrogen cyanide (HCN) from endogenous CNglcs, which is known as cyanogenesis, leads to a serious problem for animal consumption while as defensive secondary metabolites, CNglcs play multiple roles in plant development and responses to adverse environment. Therefore, it is highly important to fully uncover the molecular mechanisms of CNglc biosynthesis and regulation to manipulate the contents of CNglcs in forage plants for fine-tuning the balance between defensive responses and food safety. This review summarizes recent studies on the production, function, polymorphism, and regulation of CNglcs in forage plants, aiming to provide updated knowledge on the ways to manipulate CNglcs for further beneficial economic effects.

  9. Evaluation some Forage Legumes in Limited Irrigation Condition

    Directory of Open Access Journals (Sweden)

    Hassan Moniri Far

    2015-11-01

    Full Text Available Forage legumes respond differently to limited irrigation regimes. Their evaluation may, thus, help to select drought tolerant types for limited irrigation conditions. In this study four type of forage legume were studied for two years in Tikma-Dash Research Station of East Azarbaijan Agricultural and Natural Research Center, Tabriz, Iran, in a randomized complete block design using split-plot experiment in 2011-2013 years. Irrigation regimes (without irrigation, one irrigation and two irrigations were assigned to main plots and four forage types (hairy vetch, grass pea, Pannonica sativa and lathyrus were assigned to subplots. The results of analysis of variance showed that the effect of irrigation on plant height, number of shoots, leaf area and plant fresh and dry weights were not significant. Howere, legume types affected these traits significantly (P≤0.01. The effect of irrigation levels and legume types on protein content of hay were significant (P

  10. Trait-mediated trophic interactions: is foraging theory keeping up?

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    Railsback, Steven F; Harvey, Bret C

    2013-02-01

    Many ecologists believe that there is a lack of foraging theory that works in community contexts, for populations of unique individuals each making trade-offs between food and risk that are subject to feedbacks from behavior of others. Such theory is necessary to reproduce the trait-mediated trophic interactions now recognized as widespread and strong. Game theory can address feedbacks but does not provide foraging theory for unique individuals in variable environments. 'State- and prediction-based theory' (SPT) is a new approach that combines existing trade-off methods with routine updating: individuals regularly predict future food availability and risk from current conditions to optimize a fitness measure. SPT can reproduce a variety of realistic foraging behaviors and trait-mediated trophic interactions with feedbacks, even when the environment is unpredictable. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Children's Play and Culture Learning in an Egalitarian Foraging Society.

    Science.gov (United States)

    Boyette, Adam H

    2016-05-01

    Few systematic studies of play in foragers exist despite their significance for understanding the breadth of contexts for human development and the ontogeny of cultural learning. Forager societies lack complex social hierarchies, avenues for prestige or wealth accumulation, and formal educational institutions, and thereby represent a contrast to the contexts of most play research. Analysis of systematic observations of children's play among Aka forest foragers (n = 50, ages 4-16, M = 9.5) and Ngandu subsistence farmers (n = 48, ages 4-16, M = 9.1) collected in 2010 illustrates that while play and work trade off during development in both groups, and consistent patterns in sex-role development are evident, Aka children engage in significantly less rough-and-tumble play and competitive games than children among their socially stratified farming neighbors. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

  12. The role of disease in bee foraging ecology.

    Science.gov (United States)

    Koch, Hauke; Brown, Mark Jf; Stevenson, Philip C

    2017-06-01

    Diseases have important but understudied effects on bee foraging ecology. Bees transmit and contract diseases on flowers, but floral traits including plant volatiles and inflorescence architecture may affect transmission. Diseases spill over from managed or invasive pollinators to native wild bee species, and impacts of emerging diseases are of particular concern, threatening pollinator populations and pollination services. Here we review how parasites can alter the foraging behaviour of bees by changing floral preferences and impairing foraging efficiency. We also consider how changes to pollinator behaviours alter or reduce pollination services. The availability of diverse floral resources can, however, ameliorate bee diseases and their impacts through better nutrition and antimicrobial effects of plant compounds in pollen and nectar. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Location and foraging as basis for classification of biotic interactions.

    Science.gov (United States)

    Khabibullin, Viner F

    2016-06-01

    Ecologists face an overwhelming diversity of ecological relationships in natural communities. In this paper, I propose to differentiate various types of the interspecific relations on the basis of two factors: relative localization and foraging activity of interacting partners. I advocate recognition of four types of environments: internal, surface, proximate external and distant external. Then I distinguish four types of synoikia-one partner lives in different degree of proximity to another; and four types of synmensalism: one partner forages in different degree of proximity to another. Intersection of localization-based (four subtypes of synoikia) and foraging-based (four subtypes of synmensalism) rows results in 16 types of interactions. This scheme can serve as a framework that manages diverse biotic interactions in a standardized way. I have made the first step to set up nomenclature standards for terms describing interspecific interactions and hope that this will facilitate research and communication.

  14. Optimal foraging for specific nutrients in predatory beetles

    Science.gov (United States)

    Jensen, Kim; Mayntz, David; Toft, Søren; Clissold, Fiona J.; Hunt, John; Raubenheimer, David; Simpson, Stephen J.

    2012-01-01

    Evolutionary theory predicts that animals should forage to maximize their fitness, which in predators is traditionally assumed equivalent to maximizing energy intake rather than balancing the intake of specific nutrients. We restricted female predatory ground beetles (Anchomenus dorsalis) to one of a range of diets varying in lipid and protein content, and showed that total egg production peaked at a target intake of both nutrients. Other beetles given a choice to feed from two diets differing only in protein and lipid composition selectively ingested nutrient combinations at this target intake. When restricted to nutritionally imbalanced diets, beetles balanced the over- and under-ingestion of lipid and protein around a nutrient composition that maximized egg production under those constrained circumstances. Selective foraging for specific nutrients in this predator thus maximizes its reproductive performance. Our findings have implications for predator foraging behaviour and in the structuring of ecological communities. PMID:22237910

  15. The Müller-Lyer illusion in ant foraging.

    Directory of Open Access Journals (Sweden)

    Tomoko Sakiyama

    Full Text Available The Müller-Lyer illusion is a classical geometric illusion in which the apparent (perceived length of a line depends on whether the line terminates in an arrow tail or arrowhead. This effect may be caused by economic compensation for the gap between the physical stimulus and visual fields. Here, we show that the Müller-Lyer illusion can also be produced by the foraging patterns of garden ants (Lasius niger and that the pattern obtained can be explained by a simple, asynchronously updated foraging ant model. Our results suggest that the geometric illusion may be a byproduct of the foraging process, in which local interactions underlying efficient exploitation can also give rise to global exploration, and that visual information processing in human could implement similar modulation between local efficient processing and widespread computation.

  16. Contrafreeloading in grizzly bears: implications for captive foraging enrichment.

    Science.gov (United States)

    McGowan, Ragen T S; Robbins, Charles T; Alldredge, J Richard; Newberry, Ruth C

    2010-01-01

    Although traditional feeding regimens for captive animals were focused on meeting physiological needs to assure good health, more recently emphasis has also been placed on non-nutritive aspects of feeding. The provision of foraging materials to diversify feeding behavior is a common practice in zoos but selective consumption of foraging enrichment items over more balanced "chow" diets could lead to nutrient imbalance. One alternative is to provide balanced diets in a contrafreeloading paradigm. Contrafreeloading occurs when animals choose resources that require effort to exploit when identical resources are freely available. To investigate contrafreeloading and its potential as a theoretical foundation for foraging enrichment, we conducted two experiments with captive grizzly bears (Ursus arctos horribilis). In Experiment 1, bears were presented with five foraging choices simultaneously: apples, apples in ice, salmon, salmon in ice, and plain ice under two levels of food restriction. Two measures of contrafreeloading were considered: weight of earned food consumed and time spent working for earned food. More free than earned food was eaten, with only two bears consuming food extracted from ice, but all bears spent more time manipulating ice containing salmon or apples than plain ice regardless of level of food restriction. In Experiment 2, food-restricted bears were presented with three foraging choices simultaneously: apples, apples inside a box, and an empty box. Although they ate more free than earned food, five bears consumed food from boxes and all spent more time manipulating boxes containing apples than empty boxes. Our findings support the provision of contrafreeloading opportunities as a foraging enrichment strategy for captive wildlife. (c) 2009 Wiley-Liss, Inc.

  17. Physiological effects of increased foraging effort in a small passerine.

    Science.gov (United States)

    Yap, Kang Nian; Kim, Oh Run; Harris, Karilyn C; Williams, Tony D

    2017-11-15

    Foraging to obtain food, either for self-maintenance or at presumably elevated rates to provide for offspring, is thought to be an energetically demanding activity but one that is essential for fitness (higher reproductive success and survival). Nevertheless, the physiological mechanisms that allow some individuals to support higher foraging performance, and the mechanisms underlying costs of high workload, remain poorly understood. We experimentally manipulated foraging behaviour in zebra finches (Taeniopygia guttata) using the technique described by Koetsier and Verhulst (2011) Birds in the 'high foraging effort' (HF) group had to obtain food either while flying/hovering or by making repeated hops or jumps from the ground up to the feeder, behaviour typical of the extremely energetically expensive foraging mode observed in many free-living small passerines. HF birds made significantly more trips to the feeder per 10 min, whereas control birds spent more time (perched) at the feeder. Despite this marked change in foraging behaviour, we documented few short- or long-term effects of 'training' (3 days and 90 days of 'training', respectively) and some of these effects were sex specific. There were no effects of treatment on basal metabolic rate, haematocrit, haemoglobin or plasma glycerol, triglyceride and glucose levels, and masses of kidney, crop, large intestine, small intestine, gizzard and liver. HF females had higher masses of flight muscle, leg muscle, heart and lung compared with controls. In contrast, HF males had lower heart mass than controls and there were no differences for other organs. When both sexes were pooled, there were no effects of treatment on body composition. Finally, birds in the HF treatment group had higher levels of reactive oxygen metabolites (dROMs) and, consequently, although treatment did not affect total anti-oxidant capacity, birds in the HF treatment group had higher oxidative stress. © 2017. Published by The Company of

  18. Monitoring Forage Production of California Rangeland Using Remote Sensing Observations

    Science.gov (United States)

    Liu, H.; Jin, Y.; Dahlgren, R. A.; O'Geen, A. T.; Roche, L. M.; Smith, A. M.; Flavell, D.

    2016-12-01

    Pastures and rangeland cover more than 10 million hectares in California's coastal and inland foothill regions, providing feeds to livestock and important ecosystem services. Forage production in California has a large year-to-year variation due to large inter-annual and seasonal variabilities in precipitation and temperature. It also varies spatially due to the variability in climate and soils. Our goal is to develop a robust and cost-effective tool to map the near-real-time and historical forage productivity in California using remote sensing observations from Landsat and MODIS satellites. We used a Monteith's eco-physiological plant growth theory: the aboveground net primary production (ANPP) is determined by (i) the absorbed photosynthetically active radiation (APAR) and the (ii) light use efficiency (LUE): ANPP = APAR * LUEmax * f(T) * f(SM), where LUEmax is the maximum LUE, and f(T) and f(SM) are the temperature and soil moisture constrains on LUE. APAR was estimated with Landsat and MODIS vegetation index (VI), and LUE was calibrated with a statewide point dataset of peak forage production measurements at 75 annual rangeland sites. A non-linear optimization was performed to derive maximum LUE and the parameters for temperature and soil moisture regulation on LUE by minimizing the differences between the estimated and measured ANPP. Our results showed the satellite-derived annual forage production estimates correlated well withcontemporaneous in-situ forage measurements and captured both the spatial and temporal productivity patterns of forage productivity well. This remote sensing algorithm can be further improved as new field measurements become available. This tool will have a great importance in maintaining a sustainable range industry by providing key knowledge for ranchers and the stakeholders to make managerial decisions.

  19. Ecology and caudal skeletal morphology in birds: the convergent evolution of pygostyle shape in underwater foraging taxa.

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    Ryan N Felice

    Full Text Available Birds exhibit a specialized tail that serves as an integral part of the flight apparatus, supplementing the role of the wings in facilitating high performance aerial locomotion. The evolution of this function for the tail contributed to the diversification of birds by allowing them to utilize a wider range of flight behaviors and thus exploit a greater range of ecological niches. The shape of the wings and the tail feathers influence the aerodynamic properties of a bird. Accordingly, taxa that habitually utilize different flight behaviors are characterized by different flight apparatus morphologies. This study explores whether differences in flight behavior are also associated with variation in caudal vertebra and pygostyle morphology. Details of the tail skeleton were characterized in 51 Aequornithes and Charadriiformes species. Free caudal vertebral morphology was measured using linear metrics. Variation in pygostyle morphology was characterized using Elliptical Fourier Analysis, a geometric morphometric method for the analysis of outline shapes. Each taxon was categorized based on flight style (flap, flap-glide, dynamic soar, etc. and foraging style (aerial, terrestrial, plunge dive, etc.. Phylogenetic MANOVAs and Flexible Discriminant Analyses were used to test whether caudal skeletal morphology can be used to predict flight behavior. Foraging style groups differ significantly in pygostyle shape, and pygostyle shape predicts foraging style with less than 4% misclassification error. Four distinct lineages of underwater foraging birds exhibit an elongate, straight pygostyle, whereas aerial and terrestrial birds are characterized by a short, dorsally deflected pygostyle. Convergent evolution of a common pygostyle phenotype in diving birds suggests that this morphology is related to the mechanical demands of using the tail as a rudder during underwater foraging. Thus, distinct locomotor behaviors influence not only feather attributes but also

  20. Where to Forage in the Absence of Sea Ice? Bathymetry As a Key Factor for an Arctic Seabird.

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    Françoise Amélineau

    Full Text Available The earth is warming at an alarming rate, especially in the Arctic, where a marked decline in sea ice cover may have far-ranging consequences for endemic species. Little auks, endemic Arctic seabirds, are key bioindicators as they forage in the marginal ice zone and feed preferentially on lipid-rich Arctic copepods and ice-associated amphipods sensitive to the consequences of global warming. We tested how little auks cope with an ice-free foraging environment during the breeding season. To this end, we took advantage of natural variation in sea ice concentration along the east coast of Greenland. We compared foraging and diving behaviour, chick diet and growth and adult body condition between two years, in the presence versus nearby absence of sea ice in the vicinity of their breeding site. Moreover, we sampled zooplankton at sea when sea ice was absent to evaluate prey location and little auk dietary preferences. Little auks foraged in the same areas both years, irrespective of sea ice presence/concentration, and targeted the shelf break and the continental shelf. We confirmed that breeding little auks showed a clear preference for larger copepod species to feed their chick, but caught smaller copepods and nearly no ice-associated amphipod when sea ice was absent. Nevertheless, these dietary changes had no impact on chick growth and adult body condition. Our findings demonstrate the importance of bathymetry for profitable little auk foraging, whatever the sea-ice conditions. Our investigations, along with recent studies, also confirm more flexibility than previously predicted for this key species in a warming Arctic.