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Sample records for parabiotic ants highly

  1. Tropical parabiotic ants: Highly unusual cuticular substances and low interspecific discrimination

    Directory of Open Access Journals (Sweden)

    Schmitt Thomas

    2008-10-01

    Full Text Available Abstract Background Associations between animal species require that at least one of the species recognizes its partner. Parabioses are associations of two ant species which co-inhabit the same nest. Ants usually possess an elaborate nestmate recognition system, which is based on cuticular hydrocarbons and allows them to distinguish nestmates from non-nestmates through quantitative or qualitative differences in the hydrocarbon composition. Hence, living in a parabiotic association probably necessitates changes of the nestmate recognition system in both species, since heterospecific ants have to be accepted as nestmates. Results In the present study we report highly unusual cuticular profiles in the parabiotic species Crematogaster modiglianii and Camponotus rufifemur from the tropical rainforest of Borneo. The cuticle of both species is covered by a set of steroids, which are highly unusual surface compounds. They also occur in the Dufour gland of Crematogaster modiglianii in high quantities. The composition of these steroids differed between colonies but was highly similar among the two species of a parabiotic nest. In contrast, hydrocarbon composition of Cr. modiglianii and Ca. rufifemur differed strongly and only overlapped in three regularly occurring and three trace compounds. The hydrocarbon profile of Camponotus rufifemur consisted almost exclusively of methyl-branched alkenes of unusually high chain lengths (up to C49. This species occurred in two sympatric, chemically distinct varieties with almost no hydrocarbons in common. Cr. modiglianii discriminated between these two varieties. It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others. However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety. Conclusion We conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur

  2. ANT

    DEFF Research Database (Denmark)

    van der Duim, René; Ren, Carina Bregnholm; Jóhannesson, Gunnar Thór

    2017-01-01

    Ten years ago actor-network theory (ANT) entered this journal. To illustrate how the relational ontology and sensibilities of ANT lend themselves to particular kinds of research, we first interrogate the main controversies as a way to open up and discuss the main premises of ANT. These debates...... concern the status and agency of objects and non-humans, ANT’s denial of the explanatory power of social structures, and the political implications of ANT. Second we present ANT’s relevance for tourism studies and discuss what ANT ‘does’ in practice. After summarizing a decade of relations between ANT...... and tourism, we conclude by tracing three future trajectories of how we have ‘moved away with’ ANT into new areas of discovery....

  3. Standardization of an isolated pig heart preparation with parabiotic circulation: methodological considerations

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    Petrucci Júnior O.

    2003-01-01

    Full Text Available In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max, first derivative of minimum pressure (dP/dt min, systolic stress of the left ventricle (sigmas, and maximum elastance of the left ventricle. Isolated hearts subjected to regional and global ischemia presented significant worsening of all measured parameters. Less discriminative parameters were dP/dt max and dP/dt min. Elastance was the most sensitive parameter during the reperfusion period, demonstrating an early loss of ventricular function during reperfusion. The model proved to be stable and reproducible and permitted the study of several variables in the isolated heart, such as ischemia and reperfusion phenomena, the effects of different drugs, surgical interventions, etc. The model introduces an advantage over the classical models which use crystalloid solutions as perfusate, because parabiotic circulation mimics heart surgery with extracorporeal circulation.

  4. Urban physiology: city ants possess high heat tolerance.

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    Michael J Angilletta

    Full Text Available Urbanization has caused regional increases in temperature that exceed those measured on a global scale, leading to urban heat islands as much as 12 degrees C hotter than their surroundings. Optimality models predict ectotherms in urban areas should tolerate heat better and cold worse than ectotherms in rural areas. We tested these predications by measuring heat and cold tolerances of leaf-cutter ants from South America's largest city (São Paulo, Brazil. Specifically, we compared thermal tolerances of ants from inside and outside of the city. Knock-down resistance and chill-coma recovery were used as indicators of heat and cold tolerances, respectively. Ants from within the city took 20% longer to lose mobility at 42 degrees C than ants from outside the city. Interestingly, greater heat tolerance came at no obvious expense of cold tolerance; hence, our observations only partially support current theory. Our results indicate that thermal tolerances of some organisms can respond to rapid changes in climate. Predictive models should account for acclimatory and evolutionary responses during climate change.

  5. ACTIVITY OF LEAF-CUTTING ANT Atta sexdens piriventris SUBMITED TO HIGH DILUTION HOMEOPATHIC PREPARATIONS

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    Alexandre Giesel

    2013-02-01

    Full Text Available The effect of high dilution preparations on the movement and foraging activities of Atta sexdens piriventris was evaluated. Five colonies of ants were located on each of the five experimental areas using a randomized complete block design. Three main forage trails from each colony were selected from where evaluations were made. Ten mL of high dilution preparation of Atta sexdens piriventris nosodes and Belladonna homeopathy solution were sprayed over 0.5 m of each selected trail, 1.0 m far from the nest. The controls were pure water and non treated trails. Applications were made daily during 10 days. The total number of ants moving on each trail one meter away from the nest, carrying or not plant fragments, were assessed before the daily application. Dilution preparations at 30CH (thirtieth centesimal Hahnemannian dilution of A. sexdens piriventris nosodes and Belladonna reduced the activities of ants from the fifth day after the first application. The treatment effect lasted more than 20 days after the last application. The use of preparation at 30CH dilution order to reduce the foraging activity of leaf-cutting ants is a potential non residual method to manage leaf-cutting ants.

  6. Ground-dwelling ant fauna of sites with high levels of copper.

    Science.gov (United States)

    Diehl, E; Sanhudo, C E; Diehl-Fleig, Ed

    2004-02-01

    Richness and diversity of ant species are related to environmental factors such as vegetation, soil, presence of heavy metals, and insecticides, which allow the use of the assemblage members as terrestrial indicators of environmental conservation status. This study presents the results of ground ants surveyed in Minas do Camaquã in the municipality of Cacapava do Sul (Camaquã Basin), State of Rio Grande do Sul. Collections were performed in four sites, which high levels of copper in the soil, three of which--a mine, a liquid reject, and a solid reject-, had sparse or no plant cover, and one site where Pinus has been used for rehabilitation. Parque das Guaritas was the control site, since it presented normal levels of copper and a dense savanna cover. For each site, three transect lines extending 100 m were draw, and at each 10 m sardine baits were distributed; after two hours the ants present were collected. Hand collections in all five sites were performed during one hour (capture effort). A total of 51 species belonging to 17 genera were collected. The control site was the richest in ant species (r = 45). Sites with high level of copper and poor plant cover presented the lowest richness: mine (r = 14), solid reject (r = 15), and liquid reject (r = 16). In contrast, the site planted with Pinus presented an increment in richness (r = 24) of ground-dwelling ants, suggesting a reahabilitation process.

  7. Ground-dwelling ant fauna of sites with high levels of copper

    Directory of Open Access Journals (Sweden)

    E. Diehl

    Full Text Available Richness and diversity of ant species are related to environmental factors such as vegetation, soil, presence of heavy metals, and insecticides, which allow the use of the assemblage members as terrestrial indicators of environmental conservation status. This study presents the results of ground ants surveyed in Minas do Camaquã in the municipality of Caçapava do Sul (Camaquã Basin, State of Rio Grande do Sul. Collections were performed in four sites, with high levels of copper in the soil, three of which - a mine, a liquid reject, and a solid reject -, had sparse or no plant cover, and one site where Pinus has been used for rehabilitation. Parque das Guaritas was the control site, since it presented normal levels of copper and a dense savanna cover. For each site, three transect lines extending 100 m were draw, and at each 10 m sardine baits were distributed; after two hours the ants present were collected. Hand collections in all five sites were performed during one hour (capture effort. A total of 51 species belonging to 17 genera were collected. The control site was the richest in ant species (r = 45. Sites with high level of copper and poor plant cover presented the lowest richness: mine (r = 14, solid reject (r = 15, and liquid reject (r = 16. In contrast, the site planted with Pinus presented an increment in richness (r = 24 of ground-dwelling ants, suggesting a reahabilitation process.

  8. Scalable Clustering of High-Dimensional Data Technique Using SPCM with Ant Colony Optimization Intelligence

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    Thenmozhi Srinivasan

    2015-01-01

    Full Text Available Clusters of high-dimensional data techniques are emerging, according to data noisy and poor quality challenges. This paper has been developed to cluster data using high-dimensional similarity based PCM (SPCM, with ant colony optimization intelligence which is effective in clustering nonspatial data without getting knowledge about cluster number from the user. The PCM becomes similarity based by using mountain method with it. Though this is efficient clustering, it is checked for optimization using ant colony algorithm with swarm intelligence. Thus the scalable clustering technique is obtained and the evaluation results are checked with synthetic datasets.

  9. Biomimetic Ant-Nest Electrode Structures for High Sulfur Ratio Lithium-Sulfur Batteries.

    Science.gov (United States)

    Ai, Guo; Dai, Yiling; Mao, Wenfeng; Zhao, Hui; Fu, Yanbao; Song, Xiangyun; En, Yunfei; Battaglia, Vincent S; Srinivasan, Venkat; Liu, Gao

    2016-09-14

    The lithium-sulfur (Li-S) rechargeable battery has the benefit of high gravimetric energy density and low cost. Significant research currently focuses on increasing the sulfur loading and sulfur/inactive-materials ratio, to improve life and capacity. Inspired by nature's ant-nest structure, this research results in a novel Li-S electrode that is designed to meet both goals. With only three simple manufacturing-friendly steps, which include slurry ball-milling, doctor-blade-based laminate casting, and the use of the sacrificial method with water to dissolve away table salt, the ant-nest design has been successfully recreated in an Li-S electrode. The efficient capabilities of the ant-nest structure are adopted to facilitate fast ion transportation, sustain polysulfide dissolution, and assist efficient precipitation. High cycling stability in the Li-S batteries, for practical applications, has been achieved with up to 3 mg·cm(-2) sulfur loading. Li-S electrodes with up to a 85% sulfur ratio have also been achieved for the efficient design of this novel ant-nest structure.

  10. Ghrelin in small intestine, its contribution to regulation of food intake and body weight in cross-intestinal parabiotic rats.

    Science.gov (United States)

    Noguchi, Hitoshi; Masaki, Takayuki; Kakuma, Tetsuya; Nakazato, Masamitsu; Yoshimatsu, Hironobu

    2011-01-01

    Ghrelin has been shown to be associated with feeding behavior in humans and rodents. It has been suggested that ghrelin may play a role behind the effect of bariatric surgery. Inbred rats were made into parabiotic pairs so that they shared a single abdominal cavity. A further operation is performed later in which the small intestines are transected and re-connected so that one rat continually lost nutrition to its partner. Changes in food intake and body weight were recorded. Seven weeks later, content of ghrelin in the plasma, stomach and upper intestines were measured in the paired rats. Rats which lost nutrients to its counterpart (Loss rats) ingested significantly more food than sham control rats (pgained nutrient (Gain rats) ingested less than controls (pweight, blood glucose, insulin, free fatty acids and triglycerides between the paired rats. There was significantly higher levels of ghrelin in the plasma (pGain rats, which ate less than controls. Because no remarkable changes in the ghrelin content were observed in the stomach, difference in the quality of the chime may affect the local synthesis and release of ghrelin.

  11. Breeding system and reproductive skew in a highly polygynous ant population

    DEFF Research Database (Denmark)

    Haag-Liautard, C.; Pedersen, Jes Søe; Ovaskainen, O.

    2008-01-01

    of mature queens by mark-release-recapture in 29 nests and dissected a sub-sample of queens to assess their reproductive status. We also used microsatellites to estimate relatedness within and between all classes of nestmates (queens, their mates, worker brood, queen brood and male brood). Queen number...... Factors affecting relatedness among nest members in ant colonies with high queen number are still poorly understood. In order to identify the major determinants of nest kin structure, we conducted a detailed analysis of the breeding system of the ant Formica exsecta. We estimated the number...... was very high, with an arithmetic mean of 253 per nest. Most queens (90%) were reproductively active, consistent with the genetic analyses revealing that there was only a minimal reproductive skew among nestmate queens. Despite the high queen number and low reproductive skew, almost all classes...

  12. Ant mosaics in Bornean primary rain forest high canopy depend on spatial scale, time of day, and sampling method

    Directory of Open Access Journals (Sweden)

    Kalsum M. Yusah

    2018-01-01

    Full Text Available Background Competitive interactions in biological communities can be thought of as giving rise to “assembly rules” that dictate the species that are able to co-exist. Ant communities in tropical canopies often display a particular pattern, an “ant mosaic”, in which competition between dominant ant species results in a patchwork of mutually exclusive territories. Although ant mosaics have been well-documented in plantation landscapes, their presence in pristine tropical forests remained contentious until recently. Here we assess presence of ant mosaics in a hitherto under-investigated forest stratum, the emergent trees of the high canopy in primary tropical rain forest, and explore how the strength of any ant mosaics is affected by spatial scale, time of day, and sampling method. Methods To test whether these factors might impact the detection of ant mosaics in pristine habitats, we sampled ant communities from emergent trees, which rise above the highest canopy layers in lowland dipterocarp rain forests in North Borneo (38.8–60.2 m, using both baiting and insecticide fogging. Critically, we restricted sampling to only the canopy of each focal tree. For baiting, we carried out sampling during both the day and the night. We used null models of species co-occurrence to assess patterns of segregation at within-tree and between-tree scales. Results The numerically dominant ant species on the emergent trees sampled formed a diverse community, with differences in the identity of dominant species between times of day and sampling methods. Between trees, we found patterns of ant species segregation consistent with the existence of ant mosaics using both methods. Within trees, fogged ants were segregated, while baited ants were segregated only at night. Discussion We conclude that ant mosaics are present within the emergent trees of the high canopy of tropical rain forest in Malaysian Borneo, and that sampling technique, spatial scale, and time

  13. Low levels of nestmate discrimination despite high genetic differentiation in the invasive pharaoh ant

    DEFF Research Database (Denmark)

    Schmidt, Anna M; d'Ettorre, Patrizia; Pedersen, Jes Søe

    2010-01-01

    Background Ants typically distinguish nestmates from non-nestmates based on the perception of colony-specific chemicals, particularly cuticular hydrocarbons present on the surface of the ants' exoskeleton. These recognition cues are believed to play an important role in the formation of vast so...

  14. Yersinia pestis strains of ancient phylogenetic branch 0.ANT are widely spread in the high-mountain plague foci of Kyrgyzstan.

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    Eroshenko, Galina A; Nosov, Nikita Yu; Krasnov, Yaroslav M; Oglodin, Yevgeny G; Kukleva, Lyubov M; Guseva, Natalia P; Kuznetsov, Alexander A; Abdikarimov, Sabyrzhan T; Dzhaparova, Aigul K; Kutyrev, Vladimir V

    2017-01-01

    Fifty six Yersinia pestis strains, isolated over the period of more than 50 years in three high-mountain foci of Kyrgyzstan (Tien Shan, Alai, and Talas), have been characterized by means of PCR and single nucleotide polymorphism (SNP) typing methods. Seven of these strains were also characterized by means of whole genome sequencing and genome-wide SNP phylogenetic analysis. It was found that forty two strains belong to 0.ANT2, 0.ANT3 and 0.ANT5 phylogenetic branches. From these, strains of 0.ANT2 and 0.ANT3 branches were earlier detected in China only, whereas 0.ANT5 phylogenetic branch was identified for Y. pestis phylogeny for the first time. According to the results of genome-wide SNP analysis, 0.ANT5 strains are ones of the most closely related to Y. pestis strain responsible for the Justinianic Plague. We have also found out that four of the studied strains belong to the phylogenetic branch 2.MED1, and ten strains from Talas high-mountain focus belong to the phylogenetic branch 0.PE4 (sub-branch 0.PE4t). Established diversity of Y. pestis strains and extensive dissemination of the strains pertaining to the 0.ANT branch confirm the antiquity of the mentioned above plague foci and suggest that strains of the 0.ANT branch, which serve as precursors for all highly virulent Y. pestis strains, had their origin in the Tien Shan mountains.

  15. Sampling high-altitude and stratified mating flights of red imported fire ant.

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    Fritz, Gary N; Fritz, Ann H; Vander Meer, Robert K

    2011-05-01

    With the exception of an airplane equipped with nets, no method has been developed that successfully samples red imported fire ant, Solenopsis invicta Buren, sexuals in mating/dispersal flights throughout their potential altitudinal trajectories. We developed and tested a method for sampling queens and males during mating flights at altitudinal intervals reaching as high as "140 m. Our trapping system uses an electric winch and a 1.2-m spindle bolted to a swiveling platform. The winch dispenses up to 183 m of Kevlar-core, nylon rope and the spindle stores 10 panels (0.9 by 4.6 m each) of nylon tulle impregnated with Tangle-Trap. The panels can be attached to the rope at various intervals and hoisted into the air by using a 3-m-diameter, helium-filled balloon. Raising or lowering all 10 panels takes approximately 15-20 min. This trap also should be useful for altitudinal sampling of other insects of medical importance.

  16. Sick ants become unsociable

    DEFF Research Database (Denmark)

    Bos, Nicky Peter Maria; Lefevre, T.; Jensen, A.B.

    2012-01-01

    Parasites represent a severe threat to social insects, which form high-density colonies of related individuals, and selection should favour host traits that reduce infection risk. Here, using a carpenter ant (Camponotus aethiops) and a generalist insect pathogenic fungus (Metarhizium brunneum), we...... show that infected ants radically change their behaviour over time to reduce the risk of colony infection. Infected individuals (i) performed less social interactions than their uninfected counterparts, (ii) did not interact with brood anymore and (iii) spent most of their time outside the nest from...... day 3 post-infection until death. Furthermore, infected ants displayed an increased aggressiveness towards non-nestmates. Finally, infected ants did not alter their cuticular chemical profile, suggesting that infected individuals do not signal their physiological status to nestmates. Our results...

  17. Isolation of xanthyletin, an inhibitor of ants' symbiotic fungus, by high-speed counter-current chromatography.

    Science.gov (United States)

    Cazal, Cristiane de Melo; Domingues, Vanessa de Cássia; Batalhão, Jaqueline Raquel; Bueno, Odair Corrêa; Filho, Edson Rodrigues; da Silva, Maria Fátima G Fernandes; Vieira, Paulo Cezar; Fernandes, João Batista

    2009-05-08

    Xanthyletin, an inhibitor of symbiotic fungus (Leucoagaricus gongylophorus) of leaf-cutting ant (Atta sexdens rubropilosa), as well as suberosin, seselin and xanthoxyletin were isolated from Citrus sinensis grafted on Citrus limonia. A two-phase solvent system composed of hexane/ethanol/acetonitrile/water (10:8:1:1, v/v) was used for the high-speed counter-current chromatographic isolation of xanthyletin with high yield and over 99% purity as determined by liquid and gas chromatography with mass spectrometry detection. Identifications were performed by UV spectra, IR spectra, (1)H NMR and (13)C NMR.

  18. Beyond ANT

    DEFF Research Database (Denmark)

    Jansen, Till

    2017-01-01

    Actor-Network-Theory (ANT) offers an ‘infra-language’ of the social that allows one to trace social relations very dynamically, while at the same time dissolving human agency, thus providing a flat and de-centred way into sociology. However, ANT struggles with its theoretical design that may lead...... us to reduce agency to causation and to conceptualize actor-networks as homogeneous ontologies of force. This article proposes to regard ANT’s inability to conceptualize reflexivity and the interrelatedness of different ontologies as the fundamental problem of the theory. Drawing on Günther......, it offers an ‘infra-language’ of reflexive relations while maintaining ANT’s de-centred approach. This would enable us to conceptualize actor-networks as non-homogeneous, dynamic and connecting different societal rationales while maintaining the main strengths of ANT....

  19. The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants

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    Woodcock, Paul; Edwards, David P.; Fayle, Tom M.; Newton, Rob J.; Khen, Chey Vun; Bottrell, Simon H.; Hamer, Keith C.

    2011-01-01

    South East Asia is widely regarded as a centre of threatened biodiversity owing to extensive logging and forest conversion to agriculture. In particular, forests degraded by repeated rounds of intensive logging are viewed as having little conservation value and are afforded meagre protection from conversion to oil palm. Here, we determine the biological value of such heavily degraded forests by comparing leaf-litter ant communities in unlogged (natural) and twice-logged forests in Sabah, Borneo. We accounted for impacts of logging on habitat heterogeneity by comparing species richness and composition at four nested spatial scales, and examining how species richness was partitioned across the landscape in each habitat. We found that twice-logged forest had fewer species occurrences, lower species richness at small spatial scales and altered species composition compared with natural forests. However, over 80 per cent of species found in unlogged forest were detected within twice-logged forest. Moreover, greater species turnover among sites in twice-logged forest resulted in identical species richness between habitats at the largest spatial scale. While two intensive logging cycles have negative impacts on ant communities, these degraded forests clearly provide important habitat for numerous species and preventing their conversion to oil palm and other crops should be a conservation priority. PMID:22006966

  20. Fire Ant Bites

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    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  1. What do myrmecophagous geckos eat when ants are not available ...

    African Journals Online (AJOL)

    Like other Pristurus species, P. samhaensis on Samha and P. sokotranus on Socotra were highly myrmecophagous (76.7% and 38.6% ants, respectively). However, ants were absent from the diet of P. samhaensis on Darsa. In contrast to the rich native ant fauna of the other islands, only one ant species was reported for ...

  2. High recombination frequency creates genotypic diversity in colonies of the leaf-cutting ant Acromyrmex echinatior

    DEFF Research Database (Denmark)

    Sirviö, A.; Gadau, J.; Rueppell, O.

    2006-01-01

    Honeybees are known to have genetically diverse colonies because queens mate with many males and the recombination rate is extremely high. Genetic diversity among social insect workers has been hypothesized to improve general performance of large and complex colonies, but this idea has not been t...

  3. Microorganisms transported by ants induce changes in floral nectar composition of an ant-pollinated plant.

    Science.gov (United States)

    de Vega, Clara; Herrera, Carlos M

    2013-04-01

    Interactions between plants and ants abound in nature and have significant consequences for ecosystem functioning. Recently, it has been suggested that nectar-foraging ants transport microorganisms to flowers; more specifically, they transport yeasts, which can potentially consume sugars and alter nectar composition. Therefore, ants could indirectly change nectar sugar profile, an important floral feature involved in the plant-pollinator mutualism. But this novel role for ants has never been tested. We here investigate the effects of nectarivorous ants and their associated yeasts on the floral nectar sugar composition of an ant-pollinated plant. Differences in the nectar sugar composition of ant-excluded and ant-visited flowers were examined in 278 samples by using high-performance liquid-chromatography. The importance of the genetic identity and density of ant-transported basidiomycetous and ascomycetous yeasts on the variation of nectar traits was also evaluated. Ant visitation had significant effects on nectar sugar composition. The nectar of ant-visited flowers contained significantly more fructose, more glucose, and less sucrose than the nectar of ant-excluded flowers, but these effects were context dependent. Nectar changes were correlated with the density of yeast cells in nectar. The magnitude of the effects of ant-transported ascomycetes was much higher than that of basiodiomycetes. Ants and their associated yeasts induce changes in nectar sugar traits, reducing the chemical control of the plant over this important floral trait. The potential relevance of this new role for ants as indirect nectar modifiers is a rich topic for future research into the ecology of ant-flower interactions.

  4. The external costs of low probability-high consequence events: Ex ante damages and lay risks

    International Nuclear Information System (INIS)

    Krupnick, A.J.; Markandya, A.; Nickell, E.

    1994-01-01

    This paper provides an analytical basis for characterizing key differences between two perspectives on how to estimate the expected damages of low probability - high consequence events. One perspective is the conventional method used in the U.S.-EC fuel cycle reports [e.g., ORNL/RFF (1994a,b]. This paper articulates another perspective, using economic theory. The paper makes a strong case for considering this, approach as an alternative, or at least as a complement, to the conventional approach. This alternative approach is an important area for future research. I Interest has been growing worldwide in embedding the external costs of productive activities, particularly the fuel cycles resulting in electricity generation, into prices. In any attempt to internalize these costs, one must take into account explicitly the remote but real possibilities of accidents and the wide gap between lay perceptions and expert assessments of such risks. In our fuel cycle analyses, we estimate damages and benefits' by simply monetizing expected consequences, based on pollution dispersion models, exposure-response functions, and valuation functions. For accidents, such as mining and transportation accidents, natural gas pipeline accidents, and oil barge accidents, we use historical data to estimate the rates of these accidents. For extremely severe accidents--such as severe nuclear reactor accidents and catastrophic oil tanker spills--events are extremely rare and they do not offer a sufficient sample size to estimate their probabilities based on past occurrences. In those cases the conventional approach is to rely on expert judgments about both the probability of the consequences and their magnitude. As an example of standard practice, which we term here an expert expected damage (EED) approach to estimating damages, consider how evacuation costs are estimated in the nuclear fuel cycle report

  5. The external costs of low probability-high consequence events: Ex ante damages and lay risks

    Energy Technology Data Exchange (ETDEWEB)

    Krupnick, A J; Markandya, A; Nickell, E

    1994-07-01

    This paper provides an analytical basis for characterizing key differences between two perspectives on how to estimate the expected damages of low probability - high consequence events. One perspective is the conventional method used in the U.S.-EC fuel cycle reports [e.g., ORNL/RFF (1994a,b]. This paper articulates another perspective, using economic theory. The paper makes a strong case for considering this, approach as an alternative, or at least as a complement, to the conventional approach. This alternative approach is an important area for future research. I Interest has been growing worldwide in embedding the external costs of productive activities, particularly the fuel cycles resulting in electricity generation, into prices. In any attempt to internalize these costs, one must take into account explicitly the remote but real possibilities of accidents and the wide gap between lay perceptions and expert assessments of such risks. In our fuel cycle analyses, we estimate damages and benefits' by simply monetizing expected consequences, based on pollution dispersion models, exposure-response functions, and valuation functions. For accidents, such as mining and transportation accidents, natural gas pipeline accidents, and oil barge accidents, we use historical data to estimate the rates of these accidents. For extremely severe accidents--such as severe nuclear reactor accidents and catastrophic oil tanker spills--events are extremely rare and they do not offer a sufficient sample size to estimate their probabilities based on past occurrences. In those cases the conventional approach is to rely on expert judgments about both the probability of the consequences and their magnitude. As an example of standard practice, which we term here an expert expected damage (EED) approach to estimating damages, consider how evacuation costs are estimated in the nuclear fuel cycle report.

  6. Ecosystem services delivered by weaver ants

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    Weaver ants (Oecopgylla spp.) are increasingly being utilized as efficient biocontrol agents in a number of tropical tree crops, as they prey on pest insects and increase yields. However, recent studies and a review of the literature reveal that a number of other services may derive from the pres......Weaver ants (Oecopgylla spp.) are increasingly being utilized as efficient biocontrol agents in a number of tropical tree crops, as they prey on pest insects and increase yields. However, recent studies and a review of the literature reveal that a number of other services may derive from...... the presence of these ants. First of all, the chemical footprint left by the high density of ants in managed host trees may results in additional benefits. (i) Ant deposits may lead to improved fruit quality, e.g. increased sugar content, (ii) ant deposits may deter important pests (chemical deterrence) from...... crops, and lastly, (iii) ant waste products deposited ias anal spots contain urea that may be taken up by plant leaves and in this way fertilize ant-plants. On top of chemical services, weaver ants have been shown to reduce plant disease incidence via competitive exclusion of other ant species because...

  7. Ant-cave structured MnCO3/Mn3O4 microcubes by biopolymer-assisted facile synthesis for high-performance pseudocapacitors

    Science.gov (United States)

    Chandra Sekhar, S.; Nagaraju, Goli; Yu, Jae Su

    2018-03-01

    Porous and ant-cave structured MnCO3/Mn3O4 microcubes (MCs) were facilely synthesized via a biopolymer-assisted hydrothermal approach. Herein, chitosan was used as a natural biopolymer, which greatly controls the surface morphology and size of the prepared composite. The amino and hydroxyl group-functionalized chitosan engraves the outer surface of MCs during the hydrothermal process, which designs the interesting morphology of nanopath ways on the surface of MCs. When used as an electrode material for pseudocapacitors, the ant-cave structured MnCO3/Mn3O4 MCs showed superior energy storage values compared to the material prepared without chitosan in aqueous electrolyte solution. Precisely, the prepared ant-cave structured MnCO3/Mn3O4 MCs exhibited a maximum specific capacitance of 116.2 F/g at a current density of 0.7 A/g with an excellent cycling stability of 73.86% after 2000 cycles. Such facile and low-cost synthesis of pseudocapacitive materials with porous nanopaths is favorable for the fabrication of high-performance energy storage devices.

  8. How ants drop out: ant abundance on tropical mountains.

    Science.gov (United States)

    Longino, John T; Branstetter, Michael G; Colwell, Robert K

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

  9. How ants drop out: ant abundance on tropical mountains.

    Directory of Open Access Journals (Sweden)

    John T Longino

    Full Text Available In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica and examined the impact of elevation (as a proxy for temperature and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

  10. The distribution of weaver ant pheromones on host trees

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2007-01-01

    The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested for ...... to leaves. Also there was a positive correlation between spot density and the likelihood of being detected by ants. Anal spots may thus function as reliable cues to interacting species and be an important factor in shaping the community around Oecophylla colonies.......The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested...... for correlations between spot density, ant activity and the likelihood of being detected by an ant. Spots were only found on trees with ants. On ant-trees, spots were distributed throughout the trees but with higher densities in areas with high ant activity and pheromone densities were higher on twigs compared...

  11. Oecophylla smaragdina food conversion efficiency: prospects for ant farming

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim

    2011-01-01

    can be combined with the use of the ants in biological control programmes in tropical plantations where pest insects are converted into ant biomass. To assess the cost-benefits of ant farming based on artificial feeding, food consumption and food conversion efficiency (ECI) of Oecophylla smaragdina......Oecophylla ants are sold at high prices on several commercial markets as a human delicacy, as pet food or as traditional medicine. Currently markets are supplied by ants collected from the wild; however, an increasing interest in ant farming exists as all harvest is easily sold and as ant farming...... selling prices these efficiencies led to rates of return from 1.52 to 4.56, respectively, if: (i) protein is supplied from commercial products; or (ii) alternatively supplied from free sources such as insects and kitchen waste. These results suggest that Oecophylla ant farming may become highly profitable...

  12. Ant- and Ant-Colony-Inspired ALife Visual Art.

    Science.gov (United States)

    Greenfield, Gary; Machado, Penousal

    2015-01-01

    Ant- and ant-colony-inspired ALife art is characterized by the artistic exploration of the emerging collective behavior of computational agents, developed using ants as a metaphor. We present a chronology that documents the emergence and history of such visual art, contextualize ant- and ant-colony-inspired art within generative art practices, and consider how it relates to other ALife art. We survey many of the algorithms that artists have used in this genre, address some of their aims, and explore the relationships between ant- and ant-colony-inspired art and research on ant and ant colony behavior.

  13. The use of weaver ants (Oecophylla spp.) in tropical agriculture

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim

    2011-01-01

    by the consumed pest insects, can be harvested and utilised for nutrition as they are tasty and high in proteins, vitamins and minerals. Thus, plantations may function as ant farms and in addition to plant production also hosts the production of edible animal protein. In this setup harmful pest insects are turned...... farming as a way forward to solve an increasing future demand for protein. Weaver ant farming may build on natural food collected by the ants or alternatively be boosted by feeding the ant colonies actively with protein and sugar. In both cases, when ant biocontrol is combined with ant farming......, the environmental cost of protein production may fall even lower than for other insects as the ants feed on pests that would otherwise reduce the plant yield and since the farming area is simultaneously in use for plant production. In this presentation I provide data showing (i) how the harvest of ants can...

  14. Are ant feces nutrients for plants? A metabolomics approach to elucidate the nutritional effects on plants hosting weaver ants

    DEFF Research Database (Denmark)

    Vidkjær, Nanna Hjort; Wollenweber, Bernd; Gislum, René

    2015-01-01

    Weaver ants (genus Oecophylla) are tropical carnivorous ant species living in high numbers in the canopies of trees. The ants excrete copious amounts of fecal matter on leaf surfaces, and these feces may provide nutrients to host trees. This hypothesis is supported by studies of ant......-plant interactions involving other ant species that have demonstrated the transfer of nutrients from ants to plants. In this 7-months study, a GC–MS-based metabolomics approach along with an analysis of total nitrogen and carbon levels was used to study metabolic changes in ant-hosting Coffea arabica plants compared...... with control plants. The results showed elevated levels of total nitrogen, amino acids, fatty acids, caffeine, and secondary metabolites of the phenylpropanoid pathway in leaves from ant-hosting plants. Minor effects were observed for sugars, whereas little or no effect was observed for organic acids, despite...

  15. Riding with the ants

    NARCIS (Netherlands)

    Duarte, A. P. M.; Attili-Angelis, D.; Baron, N. C.; Groenewald, Johannes Z.; Crous, Pedro W.; Pagnocca, F. C.

    Isolates of Teratosphaeriaceae have frequently been found in the integument of attine ants, proving to be common and diverse in this microenvironment. The LSU phylogeny of the ant-isolated strains studied revealed that they cluster in two main lineages. The first was associated with the genus

  16. Padronização de modelo de coração isolado "working heart" com circulação parabiótica Development of isolated swine "working heart model" with parabiotic circulation

    Directory of Open Access Journals (Sweden)

    Lindemberg da Mota Silveira Filho

    2008-03-01

    Full Text Available OBJETIVO: Desenvolver modelo de coração isolado de suíno "working heart" sob suporte por circulação parabiótica e verificar se o mesmo é estável e se possibilitou de forma efetiva a mensuração dos dados propostos. MÉTODOS: O modelo foi padronizado durante preparação para estudo de associação de agente à solução cardioplégica. Foram realizados 18 experimentos com um animal suporte e um animal doador em cada. O coração do animal doador foi perfundido como coração isolado pelo animal suporte em modo de execução de trabalho ("coração ejetante". O coração isolado foi submetido à isquemia regional por pinçamento da artéria interventricular anterior seguido de isquemia global. Durante reperfusão, com o coração ejetante (em modo "working heart", aos 30, 60 e 90 minutos foram medidos parâmetros hemodinâmicos de contratilidade e metabólicos, obtendo-se assim a elastância máxima (Emáx, o trabalho sistólico pré-recrutável (PRSW, rigidez do ventrículo (EDPRV, fluxo coronariano, consumo de oxigênio e dosagens de lactato e glicose. RESULTADOS: Os animais suporte ficaram estáveis durante todo o experimento. O pH, a pressão parcial de oxigênio e o hematócrito foram mantidos estáveis e dentro da faixa fisiológica. O coração isolado foi perfundido de forma adequada durante todo o experimento. Os dados hemodinâmicos e metabólicos propostos puderam ser mensurados adequadamente e sempre com o coração ejetante, em modo de execução de trabalho ("working heart". CONCLUSÃO: O modelo de coração isolado desenvolvido tipo "working heart" se manteve estável durante todo o experimento, sem a administração de drogas cardiotônicas e possibilitou a mensuração de todos os dados propostos de forma efetiva com o coração executando trabalho.OBJECTIVE: To develop an isolated working heart model with parabiotic circulaton in swines and verify its stability and possibility to allow effective measurements of

  17. Pheromone disruption of Argentine ant trail integrity

    Science.gov (United States)

    Suckling, D.M.; Peck, R.W.; Manning, L.M.; Stringer, L.D.; Cappadonna, J.; El-Sayed, A. M.

    2008-01-01

    Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation, with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m2) to 1- and 4-m2 plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level impacts can be expected. ?? 2008 Springer Science+Business Media, LLC.

  18. CO2 efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand

    OpenAIRE

    Hasin, Sasitorn; Ohashi, Mizue; Yamada, Akinori; Hashimoto, Yoshiaki; Tasen, Wattanachai; Kume, Tomonori; Yamane, Seiki

    2014-01-01

    Many ant species construct subterranean nests. The presence of their nests may explain soil respiration “hot spots”, an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO2 efflux among ant species. We determi...

  19. Revolutionizing Remote Exploration with ANTS

    Science.gov (United States)

    Clark, P. E.; Rilee, M. L.; Curtis, S.; Truszkowski, W.

    2002-05-01

    We are developing the Autonomous Nano-Technology Swarm (ANTS) architecture based on an insect colony analogue for the cost-effective, efficient, systematic survey of remote or inaccessible areas with multiple object targets, including planetary surface, marine, airborne, and space environments. The mission context is the exploration in the 2020s of the most compelling remaining targets in the solar system: main belt asteroids. Main belt asteroids harbor important clues to Solar System origins and evolution which are central to NASA's goals in Space Science. Asteroids are smaller than planets, but their number is far greater, and their combined surface area likely dwarfs the Earth's. An asteroid survey will dramatically increase our understanding of the local resources available for the Human Exploration and Development of Space. During the mission composition, shape, gravity, and orbit parameters could be returned to Earth for perhaps several thousand asteroids. A survey of this area will rival the great explorations that encircled this globe, opened up the New World, and laid the groundwork for the progress and challenges of the last centuries. The ANTS architecture for a main belt survey consists of a swarm of as many as a thousand or more highly specialized pico-spacecraft that form teams to survey as many as one hundred asteroids a month. Multi-level autonomy is critical for ANTS and the objective of the proposed study is to work through the implications and constraints this entails. ANTS couples biologically inspired autonomic control for basic functions to higher level artificial intelligence that together enable individual spacecraft to operate as specialized, cooperative, social agents. This revolutionary approach postulates highly advanced, but familiar, components integrated and operated in a way that uniquely transcends any evolutionary extrapolation of existing trends and enables thousand-spacecraft missions.

  20. Fire ants perpetually rebuild sinking towers

    Science.gov (United States)

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Hu, David L.; Tovey, Craig

    2017-07-01

    In the aftermath of a flood, fire ants, Solenopsis invicta, cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

  1. Ansiedad ante los exámenes en alumnos de Educación Secundaria Obligatoria || Anxiety in students from junior high-school

    Directory of Open Access Journals (Sweden)

    Alba Rodríguez

    2014-12-01

    Full Text Available El presente trabajo tiene como objetivo identificar el grado de ansiedad ante los exámenes. Para llevar a cabo el estudio se ha utilizado el Cuestionario de Evaluación de Ansiedad ante los Exámenes (CAEX administrado a 325 estudiantes de ESO. Los resultados pusieron de manifiesto que el perfil de estudiante que posee mayores niveles de ansiedad ante los exámenes es una mujer de 12 años, que estudia 1º ESO en un colegio privado-concertado y aprueba todas las asignaturas. Se puede concluir en primer lugar que la ansiedad ante los exámenes afecta significativamente a los estudiantes de la muestra, y en segundo lugar, se han encontrado diferencias estadísticamente significativas en las variables edad, sexo, tipo de centro, curso y rendimiento académico.

  2. Toxic industrial deposit remediation by ant activity

    Science.gov (United States)

    Jilkova, Veronika; Frouz, Jan

    2016-04-01

    Toxic industrial deposits are often contaminated by heavy metals and the substrates have low pH values. In such systems, soil development is thus slowed down by high toxicity and acidic conditions which are unfavourable to soil fauna. Ants (Hymenoptera, Formicidae) are considered tolerant to heavy metal pollution and are known to increase organic matter content and microbial activity in their nests. Here, we focused on soil remediation caused by three ant species (Formica sanguinea, Lasius niger, and Tetramorium sp.) in an ore-washery sedimentation basin near Chvaletice (Czech Republic). Soil samples were taken from the centre of ant nests and from the nest surroundings (>3 m from nests). Samples were then analyzed for microbial activity and biomass and contents of organic matter and nutrients. As a result, ant species that most influenced soil properties was F. sanguinea as there were higher microbial activity and total nitrogen and ammonia contents in ant nests than in the surrounding soil. We expected such a result because F. sanguinea builds conspicuous large nests and is a carnivorous species that brings substantial amounts of nitrogen in insect prey to their nests. Effects of the other two ant species might be lower because of smaller nests and different feeding habits as they rely mainly on honeydew from aphids or on plant seeds that do not contain much nutrients.

  3. Food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions in an arid environment

    Science.gov (United States)

    Flores-Flores, Rocío Vianey; Aguirre, Armando; Anjos, Diego V.; Neves, Frederico S.; Campos, Ricardo I.; Dáttilo, Wesley

    2018-02-01

    In this study, we conducted a series of experiments in a population of Vachellia constricta (Fabaceae) in the arid Tehuacan-Cuicatláan valley, Mexico, in order to evaluate if the food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions. Using an experiment with artificial nectaries, we observed that ants foraging on food sources with higher concentration of sugar are quicker in finding and attacking potential herbivorous insects. More specifically, we found that the same ant species may increase their defence effectiveness according to the quality of food available. These findings indicate that ant effectiveness in plant protection is context-dependent and may vary according to specific individual characteristics of plants. In addition, we showed that competitively superior ant species tend to dominate plants in periods with high nectar activity, emphasizing the role of the dominance hierarchy structuring ant-plant interactions. However, when high sugar food sources were experimentally available ad libitum, the nocturnal and competitively superior ant species, Camponotus atriceps, did not dominate the artificial nectaries during the day possibly due to limitation of its thermal tolerance. Therefore, temporal niche partitioning may be allowing the coexistence of two dominant ant species (Camponotus rubritorax during the day and C. atriceps at night) on V. constricta. Our findings indicate that the quality of the food source, and temporal shifts in ant dominance are key factors which structure the biotic plant defences in an arid environment.

  4. The Grasshopper and the Ant: Motivational Responses of Low-Achieving Students to High-Stakes Testing.

    Science.gov (United States)

    Roderick, Melissa; Engel, Mimi

    2001-01-01

    Examined the responses of 102 low achieving sixth and eighth graders to Chicago's highly publicized efforts to end social promotion. Students generally described increased work efforts, and students with high levels of work effort generally had greater than average learning gains and positive outcomes in terms of promotion. About one-third of…

  5. Commentary: Warring ants

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 27; Issue 2. Commentary: Warring ants: Lessons from Lanchester's laws of combat? Renee M Borges. Volume 27 Issue 2 March 2002 pp 75-78. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/jbsc/027/02/0075-0078 ...

  6. Antílope

    Directory of Open Access Journals (Sweden)

    Pedro Anderson Martinho Moçambique

    2015-10-01

    Full Text Available Essa espécie de antílope só é encontrada em território angolano, sendo assim um símbolo nacional. Segundo a mitologia africana é símbolo de vivacidade, velocidade e beleza - Angola.

  7. Antílope

    Directory of Open Access Journals (Sweden)

    Pedro Anderson Martinho Moçambique

    2011-04-01

    Full Text Available Essa espécie de antílope só é encontrada em território angolano, sendo assim um símbolo nacional. Segundo a mitologia africana é símbolo de vivacidade, velocidade e beleza - Angola.

  8. Fire Ant Allergy

    Science.gov (United States)

    ... venom in a fire ant sting will kill bacteria and some of your skin cells. This results in the formation of a blister that fills with a cloudy white material in about 24 hours. While this looks like a pus-filled lesion that should be drained, ...

  9. "Ant-egg" cataract revisited

    DEFF Research Database (Denmark)

    Clemmensen, Kåre; Enghild, Jan J; Ivarsen, Anders

    2017-01-01

    -ray scans and electron microscopy. The purpose of this study was to further characterize "ant-egg" cataract using modern technology and display the history of the "ant-eggs" after cataract extraction. METHODS: "Ant-eggs" were examined using Heidelberg SPECTRALIS Optical Coherence Tomography (OCT...

  10. Ant Colony Optimization for Control

    NARCIS (Netherlands)

    Van Ast, J.M.

    2010-01-01

    The very basis of this thesis is the collective behavior of ants in colonies. Ants are an excellent example of how rather simple behavior on a local level can lead to complex behavior on a global level that is beneficial for the individuals. The key in the self-organization of ants is communication

  11. Hybrid Optimization of Object-Based Classification in High-Resolution Images Using Continous ANT Colony Algorithm with Emphasis on Building Detection

    Science.gov (United States)

    Tamimi, E.; Ebadi, H.; Kiani, A.

    2017-09-01

    Automatic building detection from High Spatial Resolution (HSR) images is one of the most important issues in Remote Sensing (RS). Due to the limited number of spectral bands in HSR images, using other features will lead to improve accuracy. By adding these features, the presence probability of dependent features will be increased, which leads to accuracy reduction. In addition, some parameters should be determined in Support Vector Machine (SVM) classification. Therefore, it is necessary to simultaneously determine classification parameters and select independent features according to image type. Optimization algorithm is an efficient method to solve this problem. On the other hand, pixel-based classification faces several challenges such as producing salt-paper results and high computational time in high dimensional data. Hence, in this paper, a novel method is proposed to optimize object-based SVM classification by applying continuous Ant Colony Optimization (ACO) algorithm. The advantages of the proposed method are relatively high automation level, independency of image scene and type, post processing reduction for building edge reconstruction and accuracy improvement. The proposed method was evaluated by pixel-based SVM and Random Forest (RF) classification in terms of accuracy. In comparison with optimized pixel-based SVM classification, the results showed that the proposed method improved quality factor and overall accuracy by 17% and 10%, respectively. Also, in the proposed method, Kappa coefficient was improved by 6% rather than RF classification. Time processing of the proposed method was relatively low because of unit of image analysis (image object). These showed the superiority of the proposed method in terms of time and accuracy.

  12. HYBRID OPTIMIZATION OF OBJECT-BASED CLASSIFICATION IN HIGH-RESOLUTION IMAGES USING CONTINOUS ANT COLONY ALGORITHM WITH EMPHASIS ON BUILDING DETECTION

    Directory of Open Access Journals (Sweden)

    E. Tamimi

    2017-09-01

    Full Text Available Automatic building detection from High Spatial Resolution (HSR images is one of the most important issues in Remote Sensing (RS. Due to the limited number of spectral bands in HSR images, using other features will lead to improve accuracy. By adding these features, the presence probability of dependent features will be increased, which leads to accuracy reduction. In addition, some parameters should be determined in Support Vector Machine (SVM classification. Therefore, it is necessary to simultaneously determine classification parameters and select independent features according to image type. Optimization algorithm is an efficient method to solve this problem. On the other hand, pixel-based classification faces several challenges such as producing salt-paper results and high computational time in high dimensional data. Hence, in this paper, a novel method is proposed to optimize object-based SVM classification by applying continuous Ant Colony Optimization (ACO algorithm. The advantages of the proposed method are relatively high automation level, independency of image scene and type, post processing reduction for building edge reconstruction and accuracy improvement. The proposed method was evaluated by pixel-based SVM and Random Forest (RF classification in terms of accuracy. In comparison with optimized pixel-based SVM classification, the results showed that the proposed method improved quality factor and overall accuracy by 17% and 10%, respectively. Also, in the proposed method, Kappa coefficient was improved by 6% rather than RF classification. Time processing of the proposed method was relatively low because of unit of image analysis (image object. These showed the superiority of the proposed method in terms of time and accuracy.

  13. Graveyards on the Move: The Spatio-Temporal Distribution of Dead Ophiocordyceps-Infected Ants

    DEFF Research Database (Denmark)

    Pontoppidan, Maj-Britt; Himaman, Winanda; Hywel-Jones, Nigel L.

    2009-01-01

    rainforest. We established that high density aggregations exist (up to 26 dead ants/m2), which we coined graveyards. We further established that graveyards are patchily distributed in a landscape with no or very few O. unilateralis-killed ants. At some, but not all, spatial scales of analysis the density...... unilateralis, which is pan-tropical in distribution, causes infected worker ants to leave their nest and die under leaves in the understory of tropical rainforests. Working in a forest dynamic plot in Southern Thailand we mapped the occurrence of these dead ants by examining every leaf in 1,360 m2 of primary...... of dead ants correlated with temperature, humidity and vegetation cover. Remarkably, having found 2243 dead ants inside graveyards we only found 2 live ants of the principal host, ant Camponotus leonardi, suggesting that foraging host ants actively avoid graveyards. We discovered that the principal host...

  14. Signals can trump rewards in attracting seed-dispersing ants.

    Directory of Open Access Journals (Sweden)

    Kyle M Turner

    Full Text Available Both rewards and signals are important in mutualisms. In myrmecochory, or seed dispersal by ants, the benefits to plants are relatively well studied, but less is known about why ants pick up and move seeds. We examined seed dispersal by the ant Aphaenogaster rudis of four co-occurring species of plants, and tested whether morphology, chemical signaling, or the nutritional quality of fatty seed appendages called elaiosomes influenced dispersal rates. In removal trials, ants quickly collected diaspores (seeds plus elaiosomes of Asarum canadense, Trillium grandiflorum, and Sanguinaria canadensis, but largely neglected those of T. erectum. This discrepancy was not explained by differences in the bulk cost-benefit ratio, as assessed by the ratio of seed to elaiosome mass. We also provisioned colonies with diaspores from one of these four plant species or no diaspores as a control. Colonies performed best when fed S. canadensis diaspores, worst when fed T. grandiflorum, and intermediately when fed A. canadense, T. erectum, or no diaspores. Thus, the nutritional rewards in elaiosomes affected colony performance, but did not completely predict seed removal. Instead, high levels of oleic acid in T. grandiflorum elaiosomes may explain why ants disperse these diaspores even though they reduce ant colony performance. We show for the first time that different elaiosome-bearing plants provide rewards of different quality to ant colonies, but also that ants appear unable to accurately assess reward quality when encountering seeds. Instead, we suggest that signals can trump rewards as attractants of ants to seeds.

  15. Standardization of an experimental model of parabiotic isolated heart in rabbits Padronização de modelo experimental de coração isolado parabiótico em coelhos

    Directory of Open Access Journals (Sweden)

    Antônio Sérgio Martins

    2000-09-01

    Full Text Available The objective was to standardize an experimental model of parabiotic isolated heart in rabbits, testing their stability and durability for use in cardiovascular research. Sixty-six Norfolk-2000 rabbits were used and divided in 2 groups: donors of the isolated heart and support animals, in a total of 33 preparations. Circulatory support for the isolated heart was established with the aid of peristaltic pumps and the flow was kept constant (16ml/min.. An intraventricular balloon was inserted in the left ventriculum, and was adjusted to produce diastolic pressure of ± 10mmHg. Heart rate was established at 120 beats per minute with the use of a pacemaker. Hemodynamic, laboratory and histopathological parameters were evaluated. Of the 33 preparations, 13 were excluded according to preestablished criteria. Of the 20 remaining preparations, 10 completed the maximum protocol time (180 minutes. There was progressive hemodynamic deterioration with decrease of mean blood pressure (89.30±6.09mmHg->47.50±6.35mmHg in the support animal. There was hemodynamic stability of the isolated heart for the 10 preparations that completed the 180 minutes of the protocol. Laboratory parameters showed progressive decrease of sodium, potassium and hemoglobin, which is compatible with hemodilution. Histopathology showed greater distance among the fibers, compatible with edema. The present model showed 100% stability and activity of the preparations within 60 minutes, and 50% of the active preparations were progressively lost within 180 minutes. The present model is viable for cardiovascular research.O objetivo foi a padronização de modelo experimental de coração isolado parabiótico em coelhos, testando sua estabilidade e durabilidade, para fins de pesquisa cardiovascular. Foram utilizados 66 coelhos raça Norfolk-2000 divididos em grupo doador do coração isolado e animais suporte, totalizando 33 preparações. Mediante auxilio de bombas peristálticas estabeleceu

  16. Endophytic fungi reduce leaf-cutting ant damage to seedlings

    Science.gov (United States)

    Bittleston, L. S.; Brockmann, F.; Wcislo, W.; Van Bael, S. A.

    2011-01-01

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (Ehigh) or low (Elow) densities of endophytes. The Ehigh seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the Elow treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from Elow relative to Ehigh seedlings and had a tendency to recruit more ants to Elow plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities. PMID:20610420

  17. Kin-informative recognition cues in ants

    DEFF Research Database (Denmark)

    Nehring, Volker; Evison, Sophie E F; Santorelli, Lorenzo A

    2011-01-01

    behaviour is thought to be rare in one of the classic examples of cooperation--social insect colonies--because the colony-level costs of individual selfishness select against cues that would allow workers to recognize their closest relatives. In accord with this, previous studies of wasps and ants have...... found little or no kin information in recognition cues. Here, we test the hypothesis that social insects do not have kin-informative recognition cues by investigating the recognition cues and relatedness of workers from four colonies of the ant Acromyrmex octospinosus. Contrary to the theoretical...... prediction, we show that the cuticular hydrocarbons of ant workers in all four colonies are informative enough to allow full-sisters to be distinguished from half-sisters with a high accuracy. These results contradict the hypothesis of non-heritable recognition cues and suggest that there is more potential...

  18. Runtime analysis of the 1-ANT ant colony optimizer

    DEFF Research Database (Denmark)

    Doerr, Benjamin; Neumann, Frank; Sudholt, Dirk

    2011-01-01

    The runtime analysis of randomized search heuristics is a growing field where, in the last two decades, many rigorous results have been obtained. First runtime analyses of ant colony optimization (ACO) have been conducted only recently. In these studies simple ACO algorithms such as the 1-ANT...... that give us a more detailed impression of the 1-ANT’s performance. Furthermore, the experiments also deal with the question whether using many ant solutions in one iteration can decrease the total runtime....

  19. The metapleural gland of ants

    DEFF Research Database (Denmark)

    Yek, Sze Huei; Mueller, Ulrich G

    2011-01-01

    The metapleural gland (MG) is a complex glandular structure unique to ants, suggesting a critical role in their origin and ecological success. We synthesize the current understanding of the adaptive function, morphology, evolutionary history, and chemical properties of the MG. Two functions......-compressible invagination of the integument and the secretion is thought to ooze out passively through the non-closable opening of the MG or is groomed off by the legs and applied to target surfaces. MG loss has occurred repeatedly among the ants, particularly in the subfamilies Formicinae and Myrmicinae, and the MG...... is more commonly absent in males than in workers. MG chemistry has been characterized mostly in derived ant lineages with unique biologies (e.g. leafcutter ants, fire ants), currently precluding any inferences about MG chemistry at the origin of the ants. A synthetic approach integrating functional...

  20. Current and potential ant impacts in the Pacific region

    Science.gov (United States)

    Loope, Lloyd L.; Krushelnycky, Paul D.

    2007-01-01

    . They generally have multiple queens per colony, are unicolonial (lacking internest aggression), quickly recruit to food items, thrive in a variety of habitats including disturbed areas, and can be highly aggressive to other ant species (McGlynn 1999). Hawaii’s arthropod fauna evolved in the absence of ants and has been observed by many biologists to be highly vulnerable to displacement by non-native ants. Pacific island biotas have also very likely suffered greatly from displacement by ants. However, in contrast to Hawaii, virtually nothing has been published on effects of non-native ants on native arthropod fauna elsewhere on Pacific islands, with the exception of the Galapagos archipelago, which may have at least four species of endemic ants (Lubin 1984, Nishida and Evenhuis 2000) and New Caledonia (Jourdan et al. 2001, Le Breton et al. 2005). In addition, many ant species in the Pacific have long been a nuisance for humans, and significant agricultural impacts have occurred from ants tending hemipteran insects of crop plants.

  1. Egg-laying butterflies distinguish predaceous ants by sight.

    Science.gov (United States)

    Sendoya, Sebastián F; Freitas, André V L; Oliveira, Paulo S

    2009-07-01

    Information about predation risks is critical for herbivorous insects, and natural selection favors their ability to detect predators before oviposition and to select enemy-free foliage when offspring mortality risk is high. Food plants are selected by ovipositing butterflies, and offspring survival frequently varies among plants because of variation in the presence of predators. Eunica bechina butterflies oviposit on Caryocar brasiliense, an ant-defended plant. Experiments with dried Camponotus and Cephalotes ants pinned to leaves revealed that butterflies use ant size and form as visual cues to avoid ovipositing on plant parts occupied by ants more likely to kill larval offspring. Presence of sap-sucking bugs did not affect butterfly oviposition. This is the first demonstration that visual recognition of predators can mediate egg-laying decisions by an insect herbivore and that an insect will discriminate among different species of potential predators. This unusual behavioral capability permits specialization on a risky, ant-defended food plant.

  2. Hospitales seguros ante desastres

    OpenAIRE

    Celso Vladimir Bambaren Alatrista; María Del Socorro Alatrista Gutierrez

    2007-01-01

    Entre 1982 a 2005 se registraron daños en 1 143 establecimientos de salud en el Perú, generalmente debido a sismos, lluvias e inundaciones. Los daños en los servicios de salud producen la interrupción de la atención de la población y de los programas de salud, así como generan un gran gasto para la rehabilitación y reconstrucción. Por ello, se requiere proteger a los establecimientos de salud y desarrollar una política de hospitales seguros ante desastres que incluya medidas para prevenir o r...

  3. La vivienda ante emergencias

    Directory of Open Access Journals (Sweden)

    Arq. María Eugenia Gonzàlez Chipont

    2014-12-01

    Full Text Available Este trabajo propone analizar la evolución de la vivienda como respuesta ante emergencias desde principios del siglo XX hasta nuestros días. La secuencia de casos a analizar no sigue una cronología estricta sino que se organiza en función de un creciente grado de complejidad. Comienza con los aportes fundamentales de la vivienda mínima del movimiento moderno, con un fuerte acento en lo tecnológico, para ir profundizando, mientras avanzamos en el siglo, en los aspectos sociales de la arquitectura. Sin intentar oponer lo tecnológico y lo social, la estructura propuesta expresa un enriquecimiento de la cuestión técnica conforme se van ampliando sus objetivos sociales. Mientras los requerimientos tecnológicos como la inmediatez y la masividad de la respuesta, permanecen a lo largo del tiempo, la vivienda ante emergencias puede plantearse objetivos sociales cada vez más profundos. Los casos fueron elegidos a partir de autores renombrados de la Historia de la Arquitectura partiendo de ejemplos cercanos a la génesis del movimiento moderno para acercarnos cada vez más hacia el contexto actual de Latinoamérica. Se logra así un barrido geográfco pero principalmente cultural: desde las fuentes de la modernidad, bajo el paradigma sólido de la industrialización, hasta la inestabilidad de la ciudad posindustrial latinoamericana

  4. Pest repellent properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2012-01-01

    of ant pheromones may be sufficient to repel pest insects from ant territories. The study of ant semiochemicals is in its infancy, yet, evidence for their potential use in pest management is starting to build up. Pheromones from four of five tested ant species have been shown to deter herbivorous insect...... prey and competing ant species are also deterred by ant deposits, whereas ant symbionts may be attracted to them. Based on these promising initial findings, it seems advisable to further elucidate the signaling properties of ant pheromones and to test and develop their use in future pest management....

  5. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L; Doug Martin, D; Michael Paller, M; Eric Nelson, E

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here. This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.

  6. Hospitales seguros ante desastres

    Directory of Open Access Journals (Sweden)

    Celso Vladimir Bambaren Alatrista

    2007-07-01

    Full Text Available Entre 1982 a 2005 se registraron daños en 1 143 establecimientos de salud en el Perú, generalmente debido a sismos, lluvias e inundaciones. Los daños en los servicios de salud producen la interrupción de la atención de la población y de los programas de salud, así como generan un gran gasto para la rehabilitación y reconstrucción. Por ello, se requiere proteger a los establecimientos de salud y desarrollar una política de hospitales seguros ante desastres que incluya medidas para prevenir o reducción de la vulnerabilidad estructural, no estructural y funcional en los nuevos establecimientos y en los existentes.(Rev Med Hered 2007;18:149-154.

  7. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Directory of Open Access Journals (Sweden)

    Alessandro Ossola

    2015-10-01

    Full Text Available Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i ant abundance and species richness would be higher in high-complexity urban habitats, (ii ant assemblages would differ between low- and high-complexity habitats and (iii ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.

  8. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    Science.gov (United States)

    Nash, Michael A.; Christie, Fiona J.; Hahs, Amy K.; Livesley, Stephen J.

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size. PMID:26528416

  9. The diversity of microorganisms associated with Acromyrmex leafcutter ants

    Directory of Open Access Journals (Sweden)

    Boomsma Jacobus J

    2002-05-01

    Full Text Available Abstract Background Molecular biological techniques are dramatically changing our view of microbial diversity in almost any environment that has so far been investigated. This study presents a systematic survey of the microbial diversity associated with a population of Acromyrmex leafcutter ants. In contrast to previous studies on social insects, which targeted specific groups of symbionts occurring in the gut (termites, Tetraponera ants or in specialised cells (Camponotus ants the objective of our present study was to do a total screening of all possible micro-organisms that can be found inside the bodies of these leafcutter ants. Results We amplified, cloned and sequenced SSU rRNA encoding gene fragments from 9 microbial groups known to have insect-associated representatives, and show that: (1 representatives of 5 out of 9 tested groups are present, (2 mostly several strains per group are present, adding up to a total of 33 different taxa. We present the microbial taxa associated with Acromymex ants in a phylogenetic context (using sequences from GenBank to assess and illustrate to which known microorganisms they are closely related. The observed microbial diversity is discussed in the light of present knowledge on the evolutionary history of Acromyrmex leafcutter ants and their known mutualistic and parasitic symbionts. Conclusions The major merits of the screening approach documented here is its high sensitivity and specificity, which allowed us to identify several microorganisms that are promising candidates for further study of their interactions with Acromyrmex leafcutter ants or their gardens.

  10. Heat-induced symmetry breaking in ant (Hymenoptera: Formicidae escape behavior.

    Directory of Open Access Journals (Sweden)

    Yuan-Kai Chung

    Full Text Available The collective egress of social insects is important in dangerous situations such as natural disasters or enemy attacks. Some studies have described the phenomenon of symmetry breaking in ants, with two exits induced by a repellent. However, whether symmetry breaking occurs under high temperature conditions, which are a common abiotic stress, remains unknown. In our study, we deposited a group of Polyrhachis dives ants on a heated platform and counted the number of escaping ants with two identical exits. We discovered that ants asymmetrically escaped through two exits when the temperature of the heated platform was >32.75°C. The degree of asymmetry increased linearly with the temperature of the platform. Furthermore, the higher the temperature of heated platform was, the more ants escaped from the heated platform. However, the number of escaping ants decreased for 3 min when the temperature was higher than the critical thermal limit (39.46°C, which is the threshold for ants to endure high temperature without a loss of performance. Moreover, the ants tended to form small groups to escape from the thermal stress. A preparatory formation of ant grouping was observed before they reached the exit, indicating that the ants actively clustered rather than accidentally gathered at the exits to escape. We suggest that a combination of individual and grouping ants may help to optimize the likelihood of survival during evacuation.

  11. Disease dynamics in a specialized parasite of ant societies.

    Directory of Open Access Journals (Sweden)

    Sandra B Andersen

    Full Text Available Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests and that hyperparasites often castrate Ophiocordyceps. However, once fruiting bodies become sexually mature they appear robust. Such parasite life-history traits are consistent with iteroparity--a reproductive strategy rarely considered in fungi. We discuss how tropical habitats with high biodiversity of hyperparasites and high spore mortality has likely been crucial for the evolution and maintenance of iteroparity in parasites with low dispersal potential.

  12. Heavy metal pollution disturbs immune response in wild ant populations

    International Nuclear Information System (INIS)

    Sorvari, Jouni; Rantala, Liisa M.; Rantala, Markus J.; Hakkarainen, Harri; Eeva, Tapio

    2007-01-01

    Concern about the effects of environmental contaminants on immune function in both humans and wildlife is growing and practically nothing is known about this impact on terrestrial invertebrates, even though they are known to easily accumulate pollutants. We studied the effect of industrial heavy metal contamination on immune defense of a free-living wood ant (Formica aquilonia). To find out whether ants show an adapted immune function in a polluted environment, we compared encapsulation responses between local and translocated colonies. Local colonies showed higher heavy metal levels than the translocated ones but the encapsulation response was similar between the two groups, indicating that the immune system of local ants has not adapted to high contamination level. The encapsulation response was elevated in moderate whereas suppressed in high heavy metal levels suggesting higher risk for infections in heavily polluted areas. - Heavy metal pollution affects immune function in ants

  13. Competitive assembly of South Pacific invasive ant communities

    Directory of Open Access Journals (Sweden)

    Sarty Megan

    2009-01-01

    Full Text Available Abstract Background The relative importance of chance and determinism in structuring ecological communities has been debated for nearly a century. Evidence for determinism or assembly rules is often evaluated with null models that randomize the occurrence of species in particular locales. However, analyses of the presence or absence of species ignores the potential influence of species abundances, which have long been considered of major importance on community structure. Here, we test for community assembly rules in ant communities on small islands of the Tokelau archipelago using both presence-absence and abundance data. We conducted three sets of analyses on two spatial scales using three years of sampling data from 39 plots on 11 islands. Results First, traditional null model tests showed support for negative species co-occurrence patterns among plots within islands, but not among islands. A plausible explanation for this result is that analyses at larger spatial scales merge heterogeneous habitats that have considerable effects on species occurrences. Second, analyses of ant abundances showed that samples with high ant abundances had fewer species than expected by chance, both within and among islands. One ant species, the invasive yellow crazy ant Anoplolepis gracilipes, appeared to have a particularly strong effect on community structure correlated with its abundance. Third, abundances of most ant species were inversely correlated with the abundances of all other ants at both spatial scales. This result is consistent with competition theory, which predicts species distributions are affected by diffuse competition with suites of co-occurring species. Conclusion Our results support a pluralistic explanation for ant species abundances and assembly. Both stochastic and deterministic processes interact to determine ant community assembly, though abundance patterns clearly drive the deterministic patterns in this community. These deterministic

  14. Absence of jamming in ant trails: feedback control of self-propulsion and noise.

    Science.gov (United States)

    Chaudhuri, Debasish; Nagar, Apoorva

    2015-01-01

    We present a model of ant traffic considering individual ants as self-propelled particles undergoing single-file motion on a one-dimensional trail. Recent experiments on unidirectional ant traffic in well-formed natural trails showed that the collective velocity of ants remains approximately unchanged, leading to the absence of jamming even at very high densities [John et al., Phys. Rev. Lett. 102, 108001 (2009)]. Assuming a feedback control mechanism of self-propulsion force generated by each ant using information about the distance from the ant in front, our model captures all the main features observed in the experiment. The distance headway distribution shows a maximum corresponding to separations within clusters. The position of this maximum remains independent of average number density. We find a non-equilibrium first-order transition, with the formation of an infinite cluster at a threshold density where all the ants in the system suddenly become part of a single cluster.

  15. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  16. A cellular automata model for ant trails

    Indian Academy of Sciences (India)

    In this study, the unidirectional ant traffic flow with U-turn in an ant trail was inves- tigated using ... the literature, it was considered in the model that (i) ant colony consists of two kinds of ants, good- ... ponents without a central controller [8].

  17. ANT, tourism and situated globality

    DEFF Research Database (Denmark)

    Jóhannesson, Gunnar Thór; Ren, Carina Bregnholm; van der Duim, René

    2015-01-01

    viable descriptions of the collective condition of humans and more-than-humans in the Anthropocene. Also and moving past a merely descriptive approach, it discusses it as a useful tool to engage with the situated globalities which come into being through the socio-spatial coupling of tourism......In recent years Actor-network theory (ANT) has increasingly been felt in the field of tourism studies (Van der Duim, Ren, & Jóhannesson, 2012). An important implication of the meeting between ANT and tourism studies is the notion of tourism being described as a heterogeneous assemblage of what we...... are used to define as the separate spheres of nature and culture. This paper explores and relates the central tenets of ANT in tourism with regard to the concept of the Anthropocene. It presents the ANT approach as a flat and object-oriented ontology and methodology and explores its potentials to carve out...

  18. A phylogenetic perspective on the association between ants (Hymenoptera: Formicidae) and black yeasts (Ascomycota: Chaetothyriales).

    Science.gov (United States)

    Vasse, Marie; Voglmayr, Hermann; Mayer, Veronika; Gueidan, Cécile; Nepel, Maximilian; Moreno, Leandro; de Hoog, Sybren; Selosse, Marc-André; McKey, Doyle; Blatrix, Rumsaïs

    2017-03-15

    The frequency and the geographical extent of symbiotic associations between ants and fungi of the order Chaetothyriales have been highlighted only recently. Using a phylogenetic approach based on seven molecular markers, we showed that ant-associated Chaetothyriales are scattered through the phylogeny of this order. There was no clustering according to geographical origin or to the taxonomy of the ant host. However, strains tended to be clustered according to the type of association with ants: strains from ant-made carton and strains from plant cavities occupied by ants ('domatia') rarely clustered together. Defining molecular operational taxonomic units (MOTUs) with an internal transcribed spacer sequence similarity cut-off of 99% revealed that a single MOTU could be composed of strains collected from various ant species and from several continents. Some ant-associated MOTUs also contained strains isolated from habitats other than ant-associated structures. Altogether, our results suggest that the degree of specialization of the interactions between ants and their fungal partners is highly variable. A better knowledge of the ecology of these interactions and a more comprehensive sampling of the fungal order are needed to elucidate the evolutionary history of mutualistic symbioses between ants and Chaetothyriales. © 2017 The Author(s).

  19. Ants Orase kultuurisõnum

    Index Scriptorium Estoniae

    2007-01-01

    26. jaanuaril toimub Tallinna Ülikooli Akadeemilises Raamatukogus seminar silmapaistvast Eesti teadlasest ja tõlkijast Ants Orasest. Esinevad kirjandusteadlased Tallinna Ülikoolist, Tartu Ülikoolist ja Eesti Kirjandusmuuseumist. Avaettekandeks on sõna Oklahoma Ülikooli professoril Vincent B. Leitchil, kes oli Ants Orase viimaseks juhendatavaks doktorandiks. Seminari korraldavad Tallinna Ülikool ja Eesti Kirjandusmuuseum. Vt ka Postimees, 26, jaan., lk. 18

  20. Sperm length evolution in the fungus-growing ants

    DEFF Research Database (Denmark)

    Baer, B.; Dijkstra, M. B.; Mueller, U. G.

    2009-01-01

    -growing ants, representing 9 of the 12 recognized genera, and mapped these onto the ant phylogeny. We show that average sperm length across species is highly variable and decreases with mature colony size in basal genera with singly mated queens, suggesting that sperm production or storage constraints affect...... the evolution of sperm length. Sperm length does not decrease further in multiply mating leaf-cutting ants, despite substantial further increases in colony size. In a combined analysis, sexual dimorphism explained 63.1% of the variance in sperm length between species. As colony size was not a significant...... predictor in this analysis, we conclude that sperm production trade-offs in males have been the major selective force affecting sperm length across the fungus-growing ants, rather than storage constraints in females. The relationship between sperm length and sexual dimorphism remained robust...

  1. Novel fungal disease in complex leaf-cutting ant societies

    DEFF Research Database (Denmark)

    Hughes, David Peter; Evans, Harry C.; Hywel-Jones, Nigel

    2009-01-01

    1. The leaf-cutting ants practise an advanced system of mycophagy where they grow a fungus as a food source. As a consequence of parasite threats to their crops, they have evolved a system of morphological, behavioural, and chemical defences, particularly against fungal pathogens (mycopathogens). 2....... Specific fungal diseases of the leaf-cutting ants themselves have not been described, possibly because broad spectrum anti-fungal defences against mycopathogens have reduced their susceptibility to entomopathogens. 3. Using morphological and molecular tools, the present study documents three rare infection...... events of Acromyrmex and Atta leaf-cutting ants by Ophiocordyceps fungi, agenus of entomopathogens that is normally highly specific in its host choice. 4. As leaf-cutting ants have been intensively studied, the absence of prior records of Ophiocordyceps suggests that these infections may be a novel event...

  2. Ant-caterpillar antagonism at the community level: interhabitat variation of tritrophic interactions in a neotropical savanna.

    Science.gov (United States)

    Sendoya, Sebastián F; Oliveira, Paulo S

    2015-03-01

    Ant foraging on foliage can substantially affect how phytophagous insects use host plants and represents a high predation risk for caterpillars, which are important folivores. Ant-plant-herbivore interactions are especially pervasive in cerrado savanna due to continuous ant visitation to liquid food sources on foliage (extrafloral nectaries, insect honeydew). While searching for liquid rewards on plants, aggressive ants frequently attack or kill insect herbivores, decreasing their numbers. Because ants vary in diet and aggressiveness, their effect on herbivores also varies. Additionally, the differential occurrence of ant attractants (plant and insect exudates) on foliage produces variable levels of ant foraging within local floras and among localities. Here, we investigate how variation of ant communities and of traits among host plant species (presence or absence of ant attractants) can change the effect of carnivores (predatory ants) on herbivore communities (caterpillars) in a cerrado savanna landscape. We sampled caterpillars and foliage-foraging ants in four cerrado localities (70-460 km apart). We found that: (i) caterpillar infestation was negatively related with ant visitation to plants; (ii) this relationship depended on local ant abundance and species composition, and on local preference by ants for plants with liquid attractants; (iii) this was not related to local plant richness or plant size; (iv) the relationship between the presence of ant attractants and caterpillar abundance varied among sites from negative to neutral; and (v) caterpillars feeding on plants with ant attractants are more resistant to ant predation than those feeding on plants lacking attractants. Liquid food on foliage mediates host plant quality for lepidopterans by promoting generalized ant-caterpillar antagonism. Our study in cerrado shows that the negative effects of generalist predatory ants on herbivores are detectable at a community level, affecting patterns of abundance and

  3. Species diversity and distribution patterns of the ants of Amazonian Ecuador.

    Directory of Open Access Journals (Sweden)

    Kari T Ryder Wilkie

    2010-10-01

    Full Text Available Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647-736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this

  4. Using Ants as bioindicators: Multiscale Issues in Ant Community Ecology

    Directory of Open Access Journals (Sweden)

    Alan Andersen

    1997-06-01

    Full Text Available Ecological patterns and processes are characteristically scale dependent, and research findings often cannot be translated easily from one scale to another. Conservation biology is challenged by a lack of congruence between the spatial scales of ecological research (typically involving small plots and land management (typically involving whole landscapes. Here, I discuss spatial scaling issues as they relate to an understanding of ant communities and, consequently, their use as bioindicators in land management. Our perceptions of fundamental patterns and processes in ant communities depend on scale: taxa that are behaviorally dominant at one scale are not necessarily so at others, functional groups recognized at one scale are often inappropriate for others, and the role of competition in community structure depends on the scale of analysis. Patterns of species richness and composition, and the ability of total richness to be estimated by surrogates, are all also scale dependent. Ant community ecology has a tradition of detailed studies in small plots, but the use of ants as bioindicators requires a predictive understanding of community structure and dynamics at a range of spatial scales. Such an appreciation of ant communities and their most effective use as bioindicators is best served by studies integrating results from plot-scale research with the broad-scale paradigms of biogeography, systematics, and evolutionary biology.

  5. Monoculture of leafcutter ant gardens.

    Directory of Open Access Journals (Sweden)

    Ulrich G Mueller

    2010-09-01

    Full Text Available Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens.Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens and extended lifespans (10-20 years. In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells, and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys.Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants, an analog of artificial selection.

  6. Pest repelling properties of ant pheromones

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2014-01-01

    Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini-review sh......-review shows that four out of five tested ant species deposit pheromones that repel herbivorous prey from their host plants.......Ants control pests via predation and physical deterrence; however, ant communication is based on chemical cues which may serve as warning signals to potential prey and other intruders. The presence of ant pheromones may, thus, be sufficient to repel pests from ant territories. This mini...

  7. Arboreal ant colonies as 'hot-points' of cryptic diversity for myrmecophiles: the weaver ant Camponotus sp. aff. textor and its interaction network with its associates.

    Directory of Open Access Journals (Sweden)

    Gabriela Pérez-Lachaud

    Full Text Available INTRODUCTION: Systematic surveys of macrofaunal diversity within ant colonies are lacking, particularly for ants nesting in microhabitats that are difficult to sample. Species associated with ants are generally small and rarely collected organisms, which makes them more likely to be unnoticed. We assumed that this tendency is greater for arthropod communities in microhabitats with low accessibility, such as those found in the nests of arboreal ants that may constitute a source of cryptic biodiversity. MATERIALS AND METHODS: We investigated the invertebrate diversity associated with an undescribed, but already threatened, Neotropical Camponotus weaver ant. As most of the common sampling methods used in studies of ant diversity are not suited for evaluating myrmecophile diversity within ant nests, we evaluated the macrofauna within ant nests through exhaustive colony sampling of three nests and examination of more than 80,000 individuals. RESULTS: We identified invertebrates from three classes belonging to 18 taxa, some of which were new to science, and recorded the first instance of the co-occurrence of two brood parasitoid wasp families attacking the same ant host colony. This diversity of ant associates corresponded to a highly complex interaction network. Agonistic interactions prevailed, but the prevalence of myrmecophiles was remarkably low. CONCLUSIONS: Our data support the hypothesis of the evolution of low virulence in a variety of symbionts associated with large insect societies. Because most myrmecophiles found in this work are rare, strictly specific, and exhibit highly specialized biology, the risk of extinction for these hitherto unknown invertebrates and their natural enemies is high. The cryptic, far unappreciated diversity within arboreal ant nests in areas at high risk of habitat loss qualifies these nests as 'hot-points' of biodiversity that urgently require special attention as a component of conservation and management

  8. Arboreal ant colonies as 'hot-points' of cryptic diversity for myrmecophiles: the weaver ant Camponotus sp. aff. textor and its interaction network with its associates.

    Science.gov (United States)

    Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul

    2014-01-01

    Systematic surveys of macrofaunal diversity within ant colonies are lacking, particularly for ants nesting in microhabitats that are difficult to sample. Species associated with ants are generally small and rarely collected organisms, which makes them more likely to be unnoticed. We assumed that this tendency is greater for arthropod communities in microhabitats with low accessibility, such as those found in the nests of arboreal ants that may constitute a source of cryptic biodiversity. We investigated the invertebrate diversity associated with an undescribed, but already threatened, Neotropical Camponotus weaver ant. As most of the common sampling methods used in studies of ant diversity are not suited for evaluating myrmecophile diversity within ant nests, we evaluated the macrofauna within ant nests through exhaustive colony sampling of three nests and examination of more than 80,000 individuals. We identified invertebrates from three classes belonging to 18 taxa, some of which were new to science, and recorded the first instance of the co-occurrence of two brood parasitoid wasp families attacking the same ant host colony. This diversity of ant associates corresponded to a highly complex interaction network. Agonistic interactions prevailed, but the prevalence of myrmecophiles was remarkably low. Our data support the hypothesis of the evolution of low virulence in a variety of symbionts associated with large insect societies. Because most myrmecophiles found in this work are rare, strictly specific, and exhibit highly specialized biology, the risk of extinction for these hitherto unknown invertebrates and their natural enemies is high. The cryptic, far unappreciated diversity within arboreal ant nests in areas at high risk of habitat loss qualifies these nests as 'hot-points' of biodiversity that urgently require special attention as a component of conservation and management programs.

  9. Arboreal Ant Colonies as ‘Hot-Points’ of Cryptic Diversity for Myrmecophiles: The Weaver Ant Camponotus sp. aff. textor and Its Interaction Network with Its Associates

    Science.gov (United States)

    Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul

    2014-01-01

    Introduction Systematic surveys of macrofaunal diversity within ant colonies are lacking, particularly for ants nesting in microhabitats that are difficult to sample. Species associated with ants are generally small and rarely collected organisms, which makes them more likely to be unnoticed. We assumed that this tendency is greater for arthropod communities in microhabitats with low accessibility, such as those found in the nests of arboreal ants that may constitute a source of cryptic biodiversity. Materials and Methods We investigated the invertebrate diversity associated with an undescribed, but already threatened, Neotropical Camponotus weaver ant. As most of the common sampling methods used in studies of ant diversity are not suited for evaluating myrmecophile diversity within ant nests, we evaluated the macrofauna within ant nests through exhaustive colony sampling of three nests and examination of more than 80,000 individuals. Results We identified invertebrates from three classes belonging to 18 taxa, some of which were new to science, and recorded the first instance of the co-occurrence of two brood parasitoid wasp families attacking the same ant host colony. This diversity of ant associates corresponded to a highly complex interaction network. Agonistic interactions prevailed, but the prevalence of myrmecophiles was remarkably low. Conclusions Our data support the hypothesis of the evolution of low virulence in a variety of symbionts associated with large insect societies. Because most myrmecophiles found in this work are rare, strictly specific, and exhibit highly specialized biology, the risk of extinction for these hitherto unknown invertebrates and their natural enemies is high. The cryptic, far unappreciated diversity within arboreal ant nests in areas at high risk of habitat loss qualifies these nests as ‘hot-points’ of biodiversity that urgently require special attention as a component of conservation and management programs. PMID:24941047

  10. [Ants as carriers of microorganisms in hospital environments].

    Science.gov (United States)

    Pereira, Rogério Dos Santos; Ueno, Mariko

    2008-01-01

    Concern exists regarding the real possibility of public health threats caused by pathogenic agents that are carried by urban ants. The present study had the objective of isolating and identifying the microorganisms that are associated with ants in hospital environments. One hundred and twenty-five ants of the same species were collected from different units of a university hospital. Each ant was collected using a swab soaked with physiological solution and was transferred to a tube containing brain heart infusion broth and incubated at 35 degrees C for 24 hours. From each tube, with growth, inoculations were made into specific culturing media, to isolate any microorganisms. The ants presented a high capacity for carrying microorganism groups: spore-producing Gram-positive bacilli 63.5%, Gram-negative bacilli 6.3%, Gram-positive cocci 23.1%, filamentous fungi 6.7% and yeast 0.5%. Thus, it can be inferred that ants may be one of the agents responsible for disseminating microorganisms in hospital environments.

  11. Aversive learning of odor-heat associations in ants.

    Science.gov (United States)

    Desmedt, Lucie; Baracchi, David; Devaud, Jean-Marc; Giurfa, Martin; d'Ettorre, Patrizia

    2017-12-15

    Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general. © 2017. Published by The Company of Biologists Ltd.

  12. Individual-based ant-plant networks: diurnal-nocturnal structure and species-area relationship.

    Directory of Open Access Journals (Sweden)

    Wesley Dáttilo

    Full Text Available Despite the importance and increasing knowledge of ecological networks, sampling effort and intrapopulation variation has been widely overlooked. Using continuous daily sampling of ants visiting three plant species in the Brazilian Neotropical savanna, we evaluated for the first time the topological structure over 24 h and species-area relationships (based on the number of extrafloral nectaries available in individual-based ant-plant networks. We observed that diurnal and nocturnal ant-plant networks exhibited the same pattern of interactions: a nested and non-modular pattern and an average level of network specialization. Despite the high similarity in the ants' composition between the two collection periods, ant species found in the central core of highly interacting species totally changed between diurnal and nocturnal sampling for all plant species. In other words, this "night-turnover" suggests that the ecological dynamics of these ant-plant interactions can be temporally partitioned (day and night at a small spatial scale. Thus, it is possible that in some cases processes shaping mutualistic networks formed by protective ants and plants may be underestimated by diurnal sampling alone. Moreover, we did not observe any effect of the number of extrafloral nectaries on ant richness and their foraging on such plants in any of the studied ant-plant networks. We hypothesize that competitively superior ants could monopolize individual plants and allow the coexistence of only a few other ant species, however, other alternative hypotheses are also discussed. Thus, sampling period and species-area relationship produces basic information that increases our confidence in how individual-based ant-plant networks are structured, and the need to consider nocturnal records in ant-plant network sampling design so as to decrease inappropriate inferences.

  13. Application of an Image Tracking Algorithm in Fire Ant Motion Experiment

    Directory of Open Access Journals (Sweden)

    Lichuan Gui

    2009-04-01

    Full Text Available An image tracking algorithm, which was originally used with the particle image velocimetry (PIV to determine velocities of buoyant solid particles in water, is modified and applied in the presented work to detect motion of fire ant on a planar surface. A group of fire ant workers are put to the bottom of a tub and excited with vibration of selected frequency and intensity. The moving fire ants are captured with an image system that successively acquires image frames of high digital resolution. The background noise in the imaging recordings is extracted by averaging hundreds of frames and removed from each frame. The individual fire ant images are identified with a recursive digital filter, and then they are tracked between frames according to the size, brightness, shape, and orientation angle of the ant image. The speed of an individual ant is determined with the displacement of its images and the time interval between frames. The trail of the individual fire ant is determined with the image tracking results, and a statistical analysis is conducted for all the fire ants in the group. The purpose of the experiment is to investigate the response of fire ants to the substrate vibration. Test results indicate that the fire ants move faster after being excited, but the number of active ones are not increased even after a strong excitation.

  14. Diapriinae Wasps (Hymenoptera: Diaprioidea: Diapriidae Associated with Ants (Hymenoptera: Formicidae in Argentina

    Directory of Open Access Journals (Sweden)

    Marta S. Loiácono

    2013-01-01

    Full Text Available We provide an overview of diapriid wasps associated with ants in Argentina and the diversity of interactions they have developed with their hosts. As a result, we report 16 species of nine genera of Diapriinae, two new geographic distributions, three new association records, illustrations, and photographs. We highlight myrmecophile symphylic species, with a high degree of integration with the host ants, adaptation being morphological and behavioral. A table with diapriid species and ant hosts is given.

  15. Tree-Dwelling Ants: Contrasting Two Brazilian Cerrado Plant Species without Extrafloral Nectaries

    Directory of Open Access Journals (Sweden)

    Jonas Maravalhas

    2012-01-01

    Full Text Available Ants dominate vegetation stratum, exploiting resources like extrafloral nectaries (EFNs and insect honeydew. These interactions are frequent in Brazilian cerrado and are well known, but few studies compare ant fauna and explored resources between plant species. We surveyed two cerrado plants without EFNs, Roupala montana (found on preserved environments of our study area and Solanum lycocarpum (disturbed ones. Ants were collected and identified, and resources on each plant noted. Ant frequency and richness were higher on R. montana (67%; 35 spp than S. lycocarpum (52%; 26, the occurrence of the common ant species varied between them, and similarity was low. Resources were explored mainly by Camponotus crassus and consisted of scale insects, aphids, and floral nectaries on R. montana and two treehopper species on S. lycocarpum. Ants have a high diversity on cerrado plants, exploring liquid and prey-based resources that vary in time and space and affect their presence on plants.

  16. Comparing different methods to assess weaver ant abundance in plantation trees

    DEFF Research Database (Denmark)

    Wargui, Rosine; Offenberg, Joachim; Sinzogan, Antonio

    2015-01-01

    Weaver ants (Oecophylla spp.) are widely used as effective biological control agents. In order to optimize their use, ant abundance needs to be tracked. As several methods have been used to estimate ant abundance on plantation trees, abundances are not comparable between studies and no guideline...... is available on which method to apply in a particular study. This study compared four existing methods: three methods based on the number of ant trails on the main branches of a tree (called the Peng 1, Peng 2 and Offenberg index) and one method based on the number of ant nests per tree. Branch indices did...... not produce equal scores and cannot be compared directly. The Peng 1 index was the fastest to assess, but showed only limited seasonal fluctuations when ant abundance was high, because it approached its upper limit. The Peng 2 and Offenberg indices were lower and not close to the upper limit and therefore...

  17. Male parentage in army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel J C; Schöning, Caspar; Boomsma, Jacobus J

    2006-01-01

    of active research in insect sociobiology. Here we present microsatellite data for 176 males from eight colonies of the African army ant Dorylus (Anomma) molestus. Comparison with worker genotypes and inferred queen genotypes from the same colonies show that workers do not or at best very rarely reproduce...

  18. ANT tuner retrofit for LEB cavity

    International Nuclear Information System (INIS)

    Walling, L.; Goren, Y.; Kwiatkowski, S.

    1994-03-01

    This report describes a ferrite tuner design for the LEB cavity that utilizes techniques for bonding ferrite to metallic cooling plates that is utilized in the high-power rf and microwave industry. A test tuner was designed to fit into the existing LEB-built magnet and onto the Grimm LEB Cavity. It will require a new vacuum window in order to attain maximal tuning range and high voltage capability and a new center conductor of longer length and a different vacuum window connection than the Grimm center conductor. However, the new center conductor will be essentially identical to the Grimm center conductor in its basic construction and in the way it connects to the stand for support. The tuner is mechanically very similar to high-power stacked circulators built by ANT of Germany and was designed according to ANT's established engineering and design criteria and SSC LEB tuning and power requirements. The tuner design incorporates thin tiles of ferrite glued using a high-radiation-resistance epoxy to copper-plated stainless steel cooling plates of thickness 6.5 mm with water cooling channels inside the plates. The cooling plates constitute 16 pie-shaped segments arranged in a disk. They are electrically isolated from each other to suppress eddy currents. Five of these disks are arranged in parallel with high-pressure rf contacts between the plates at the outer radius. The end walls are slotted copper-plated stainless steel of thickness 3 mm

  19. Coevolved crypts and exocrine glands support mutualistic bacteria in fungus-growing ants

    DEFF Research Database (Denmark)

    Currie, Cameron R; Poulsen, Michael; Mendenhall, John

    2006-01-01

    Attine ants engage in a quadripartite symbiosis with fungi they cultivate for food, specialized garden parasites, and parasite-inhibiting bacteria. Molecular phylogenetic evidence supports an ancient host-pathogen association between the ant-cultivar mutualism and the garden parasite. Here we show...... that ants rear the antibiotic-producing bacteria in elaborate cuticular crypts, supported by unique exocrine glands, and that these structures have been highly modified across the ants' evolutionary history. This specialized structural evolution, together with the absence of these bacteria and modifications...

  20. A cellular automata model for ant trails

    Indian Academy of Sciences (India)

    In this study, the unidirectional ant traffic flow with U-turn in an ant trail was investigated using one-dimensional cellular automata model. It is known that ants communicate with each other by dropping a chemical, called pheromone, on the substrate. Apart from the studies in the literature, it was considered in the model that ...

  1. Fungal Adaptations to Mutualistic Life with Ants

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus

    Fungus-growing ants (Attini) feed off a fungus they cultivate in a mutualistic symbiosis in underground chambers by providing it substrate they collect outside the colony. The tribe of Attine ants ranges from small colonies of the paleo- and basal Attine species with a few hundred workers that fo...... that the fungus evolved some incredible adaptations to a mutualistic life with the ants....

  2. Effects of invasive European fire ants (Myrmica rubra on herring gull (Larus argentatus reproduction.

    Directory of Open Access Journals (Sweden)

    Luke E DeFisher

    Full Text Available Various invasive ant species have negatively affected reproductive success in birds by disrupting nest site selection, incubation patterns, food supply, and by direct predation on nestlings. Impacts can be particularly severe when non-native ants colonize seabird nesting islands where thousands of birds may nest in high densities on the ground or in burrows or crevices. Here we report on the first documented effects of Myrmica rubra, the European fire ant, on the reproduction of birds in its non-native range. We documented herring gulls (Larus argentatus on Appledore Island, Maine, engaging in more erratic incubation behaviors at nests infested by the ants. Newly-hatched chicks in some nests were swarmed by ants, leading to rapid chick death. Due to high overall rates of chick mortality, survival probabilities did not vary between nests with and without ant activity, however chick growth rates were slower at nests with ants than at ant-free nests. Ant infestation likely leads to longer-term fitness consequences because slower growth rates early in life may ultimately lead to lower post-fledging survival probabilities.

  3. Impact of African weaver ant nests [Oecophylla longinoda Latreille (Hymenoptera: Formicidae)] on Mango [Mangifera indica L. (Sapindales: Anacardiaceae)] leaves

    DEFF Research Database (Denmark)

    Anato, Florence; Sinzogan, Antonio; Adandonon, Appolinaire

    2015-01-01

    Oecophylla ants are appreciated for their control of pests in plantation crops. However, the ants´ nest building may have negative impacts on trees. In this study we tested the effect of ant densities and nest building on the leaf performance of mango trees. Trees were divided into three groups......: trees without ants, trees with low and trees with high ant densities. Subsequently, the total number of leaves, the proportion of leaves used for nest construction, and tree growth was compared between these groups. The percentage of leaves used for nests was between 0.42-1.2 % (mean = 0...

  4. Application of ant colony optimization in NPP classification fault location

    International Nuclear Information System (INIS)

    Xie Chunli; Liu Yongkuo; Xia Hong

    2009-01-01

    Nuclear Power Plant is a highly complex structural system with high safety requirements. Fault location appears to be particularly important to enhance its safety. Ant Colony Optimization is a new type of optimization algorithm, which is used in the fault location and classification of nuclear power plants in this paper. Taking the main coolant system of the first loop as the study object, using VB6.0 programming technology, the NPP fault location system is designed, and is tested against the related data in the literature. Test results show that the ant colony optimization can be used in the accurate classification fault location in the nuclear power plants. (authors)

  5. Ant colonies prefer infected over uninfected nest sites

    DEFF Research Database (Denmark)

    Pontieri, Luigi; Vojvodic, Svjetlana; Graham, Riley

    2014-01-01

    with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice...... the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites...... and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown...

  6. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  7. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  8. The evolution of invasiveness in garden ants.

    Directory of Open Access Journals (Sweden)

    Sylvia Cremer

    Full Text Available It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects.

  9. The Evolution of Invasiveness in Garden Ants

    Science.gov (United States)

    Cremer, Sylvia; Ugelvig, Line V.; Drijfhout, Falko P.; Schlick-Steiner, Birgit C.; Steiner, Florian M.; Seifert, Bernhard; Hughes, David P.; Schulz, Andreas; Petersen, Klaus S.; Konrad, Heino; Stauffer, Christian; Kiran, Kadri; Espadaler, Xavier; d'Ettorre, Patrizia; Aktaç, Nihat; Eilenberg, Jørgen; Jones, Graeme R.; Nash, David R.; Pedersen, Jes S.; Boomsma, Jacobus J.

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects. PMID:19050762

  10. Ants avoid superinfections by performing risk-adjusted sanitary care.

    Science.gov (United States)

    Konrad, Matthias; Pull, Christopher D; Metzler, Sina; Seif, Katharina; Naderlinger, Elisabeth; Grasse, Anna V; Cremer, Sylvia

    2018-03-13

    Being cared for when sick is a benefit of sociality that can reduce disease and improve survival of group members. However, individuals providing care risk contracting infectious diseases themselves. If they contract a low pathogen dose, they may develop low-level infections that do not cause disease but still affect host immunity by either decreasing or increasing the host's vulnerability to subsequent infections. Caring for contagious individuals can thus significantly alter the future disease susceptibility of caregivers. Using ants and their fungal pathogens as a model system, we tested if the altered disease susceptibility of experienced caregivers, in turn, affects their expression of sanitary care behavior. We found that low-level infections contracted during sanitary care had protective or neutral effects on secondary exposure to the same (homologous) pathogen but consistently caused high mortality on superinfection with a different (heterologous) pathogen. In response to this risk, the ants selectively adjusted the expression of their sanitary care. Specifically, the ants performed less grooming and more antimicrobial disinfection when caring for nestmates contaminated with heterologous pathogens compared with homologous ones. By modulating the components of sanitary care in this way the ants acquired less infectious particles of the heterologous pathogens, resulting in reduced superinfection. The performance of risk-adjusted sanitary care reveals the remarkable capacity of ants to react to changes in their disease susceptibility, according to their own infection history and to flexibly adjust collective care to individual risk.

  11. New fossil ants in French Cretaceous amber (Hymenoptera: Formicidae)

    Science.gov (United States)

    Perrichot, Vincent; Nel, André; Néraudeau, Didier; Lacau, Sébastien; Guyot, Thierry

    2008-02-01

    Recent studies on the ant phylogeny are mainly based on the molecular analyses of extant subfamilies and do not include the extinct, only Cretaceous subfamily Sphecomyrminae. However, the latter is of major importance for ant relationships, as it is considered the most basal subfamily. Therefore, each new discovery of a Mesozoic ant is of high interest for improving our understanding of their early history and basal relationships. In this paper, a new sphecomyrmine ant, allied to the Burmese amber genus Haidomyrmex, is described from mid-Cretaceous amber of France as Haidomyrmodes mammuthus gen. and sp. n. The diagnosis of the tribe Haidomyrmecini is emended based on the new type material, which includes a gyne (alate female) and two incomplete workers. The genus Sphecomyrmodes, hitherto known by a single species from Burmese amber, is also reported and a new species described as S. occidentalis sp. n. after two workers remarkably preserved in a single piece of Early Cenomanian French amber. The new fossils provide additional information on early ant diversity and relationships and demonstrate that the monophyly of the Sphecomyrminae, as currently defined, is still weakly supported.

  12. Stigmergic construction and topochemical information shape ant nest architecture.

    Science.gov (United States)

    Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

    2016-02-02

    The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

  13. The AINTEGUMENTA genes, MdANT1 and MdANT2, are associated with the regulation of cell production during fruit growth in apple (Malus × domestica Borkh.).

    Science.gov (United States)

    Dash, Madhumita; Malladi, Anish

    2012-06-25

    Fruit growth in apple (Malus × domestica Borkh.) is mediated by cell production and expansion. Genes involved in regulating these processes and thereby fruit growth, are not well characterized. We hypothesized that the apple homolog(s) of AINTEGUMENTA (ANT), an APETALA2-repeat containing transcription factor, regulates cell production during fruit growth in apple. Two ANT genes, MdANT1 and MdANT2, were isolated from apple and their expression was studied during multiple stages of fruit development. MdANT1 and MdANT2 expression was high during early fruit growth coincident with the period of cell production, rapidly declined during exit from cell production, and remained low during the rest of fruit development. The effects of increase in carbohydrate availability during fruit growth were characterized. Increase in carbohydrate availability enhanced fruit growth largely through an increase in cell production. Expression of MdANT1 and MdANT2 increased sharply by up to around 5-fold in response to an increase in carbohydrate availability. Expression of the ANT genes was compared across two apple genotypes, 'Gala' and 'Golden Delicious Smoothee' (GS), which differ in the extent of fruit growth, largely due to differences in cell production. In comparison to 'Gala', the larger fruit-size genotype, GS, displayed higher levels and a longer duration of MdANT1 and MdANT2 expression. Expression of the ANTs and cell cycle genes in the fruit core and cortex tissues isolated using laser capture microdissection was studied. During early fruit growth, expression of the MdANTs was higher within the cortex, the tissue that constitutes the majority of the fruit. Additionally, MdANT1 and MdANT2 expression was positively correlated with that of A- and B-type CYCLINS, B-type CYCLIN-DEPENDENT-KINASES (CDKBs) and MdDEL1. Multiple lines of evidence from this study suggest that MdANT1 and MdANT2 regulate cell production during fruit growth in apple. ANTs may coordinate the expression of

  14. Ant-plant mutualism: a dietary by-product of a tropical ant's macronutrient requirements.

    Science.gov (United States)

    Arcila Hernández, Lina M; Sanders, Jon G; Miller, Gabriel A; Ravenscraft, Alison; Frederickson, Megan E

    2017-12-01

    Many arboreal ants depend on myrmecophytic plants for both food and shelter; in return, these ants defend their host plants against herbivores, which are often insects. Ant-plant and other mutualisms do not necessarily involve the exchange of costly rewards or services; they may instead result from by-product benefits, or positive outcomes that do not entail a cost for one or both partners. Here, we examined whether the plant-ant Allomerus octoarticulatus pays a short-term cost to defend their host plants against herbivores, or whether plant defense is a by-product benefit of ant foraging for insect prey. Because the food offered by ant-plants is usually nitrogen-poor, arboreal ants may balance their diets by consuming insect prey or associating with microbial symbionts to acquire nitrogen, potentially shifting the costs and benefits of plant defense for the ant partner. To determine the effect of ant diet on an ant-plant mutualism, we compared the behavior, morphology, fitness, stable isotope signatures, and gaster microbiomes of A. octoarticulatus ants nesting in Cordia nodosa trees maintained for nearly a year with or without insect herbivores. At the end of the experiment, ants from herbivore exclosures preferred protein-rich baits more than ants in the control (i.e., herbivores present) treatment. Furthermore, workers in the control treatment were heavier than in the herbivore-exclusion treatment, and worker mass predicted reproductive output, suggesting that foraging for insect prey directly increased ant colony fitness. The gaster microbiome of ants was not significantly affected by the herbivore exclusion treatment. We conclude that the defensive behavior of some phytoecious ants is a by-product of their need for external protein sources; thus, the consumption of insect herbivores by ants benefits both the ant colony and the host plant. © 2017 by the Ecological Society of America.

  15. ANT Advanced Neural Tool

    Energy Technology Data Exchange (ETDEWEB)

    Labrador, I.; Carrasco, R.; Martinez, L.

    1996-07-01

    This paper describes a practical introduction to the use of Artificial Neural Networks. Artificial Neural Nets are often used as an alternative to the traditional symbolic manipulation and first order logic used in Artificial Intelligence, due the high degree of difficulty to solve problems that can not be handled by programmers using algorithmic strategies. As a particular case of Neural Net a Multilayer Perception developed by programming in C language on OS9 real time operating system is presented. A detailed description about the program structure and practical use are included. Finally, several application examples that have been treated with the tool are presented, and some suggestions about hardware implementations. (Author) 15 refs.

  16. ANT Advanced Neural Tool

    International Nuclear Information System (INIS)

    Labrador, I.; Carrasco, R.; Martinez, L.

    1996-01-01

    This paper describes a practical introduction to the use of Artificial Neural Networks. Artificial Neural Nets are often used as an alternative to the traditional symbolic manipulation and first order logic used in Artificial Intelligence, due the high degree of difficulty to solve problems that can not be handled by programmers using algorithmic strategies. As a particular case of Neural Net a Multilayer Perception developed by programming in C language on OS9 real time operating system is presented. A detailed description about the program structure and practical use are included. Finally, several application examples that have been treated with the tool are presented, and some suggestions about hardware implementations. (Author) 15 refs

  17. Roadside Survey of Ants on Oahu, Hawaii

    Science.gov (United States)

    Tong, Reina L.; Grace, J. Kenneth; Krushelnycky, Paul D.

    2018-01-01

    Hawaii is home to over 60 ant species, including five of the six most damaging invasive ants. Although there have been many surveys of ants in Hawaii, the last island-wide hand-collection survey of ants on Oahu was conducted in 1988–1994. In 2012, a timed hand-collection of ants was made at 44 sites in a systematic, roadside survey throughout Oahu. Ants were identified and species distribution in relation to elevation, precipitation and soil type was analyzed. To assess possible convenience sampling bias, 15 additional sites were sampled further from roads to compare with the samples near roads. Twenty-four species of ants were found and mapped; Pheidole megacephala (F.), Ochetellus glaber (Mayr), and Technomyrmex difficilis Forel were the most frequently encountered ants. For six ant species, a logistic regression was performed with elevation, average annual precipitation, and soil order as explanatory variables. O. glaber was found in areas with lower precipitation around Oahu. Paratrechina longicornis (Latrielle) and Tetramorium simillimum (Smith, F.) were found more often in lower elevations and in areas with the Mollisol soil order. Elevation, precipitation, and soil type were not significant sources of variation for P. megacephala, Plagiolepis alluaudi Emery, and T. difficilis. P. megacephala was associated with fewer mean numbers of ants where it occurred. Ant assemblages near and far from roads did not significantly differ. Many species of ants remain established on Oahu, and recent invaders are spreading throughout the island. Mapping ant distributions contributes to continued documentation and understanding of these pests. PMID:29439503

  18. Canopy cover negatively affects arboreal ant species richness in a tropical open habitat

    Directory of Open Access Journals (Sweden)

    A. C. M. Queiroz

    Full Text Available Abstract We tested the hypothesis of a negative relationship between vegetation characteristics and ant species richness in a Brazilian open vegetation habitat, called candeial. We set up arboreal pitfalls to sample arboreal ants and measured the following environmental variables, which were used as surrogate of environmental heterogeneity: tree richness, tree density, tree height, circumference at the base of the plants, and canopy cover. Only canopy cover had a negative effect on the arboreal ant species richness. Vegetation characteristics and plant species composition are probably homogeneous in candeial, which explains the lack of relationship between other environmental variables and ant richness. Open vegetation habitats harbor a large number of opportunistic and generalist species, besides specialist ants from habitats with high temperatures. An increase in canopy cover decreases sunlight incidence and may cause local microclimatic differences, which negatively affect the species richness of specialist ants from open areas. Canopy cover regulates the richness of arboreal ants in open areas, since only few ant species are able to colonize sites with dense vegetation; most species are present in sites with high temperature and luminosity. Within open vegetation habitats the relationship between vegetation characteristics and species richness seems to be the opposite from closed vegetation areas, like forests.

  19. Salticid predation as one potential driving force of ant mimicry in jumping spiders

    Science.gov (United States)

    Huang, Jin-Nan; Cheng, Ren-Chung; Li, Daiqin; Tso, I-Min

    2011-01-01

    Many spiders possess myrmecomorphy, and species of the jumping spider genus Myrmarachne exhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods. PMID:20961898

  20. Ant Larval Demand Reduces Aphid Colony Growth Rates in an Ant-Aphid Interaction

    Directory of Open Access Journals (Sweden)

    James M. Cook

    2012-02-01

    Full Text Available Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial experiment, we tested whether the presence of larvae in Lasius niger ant colonies affected the growth rate of Aphis fabae colonies. Other explanatory variables tested were the origin of ant colonies (two separate colonies were used and previous diet (sugar only or sugar and protein. We found that the presence of larvae in the ant colony significantly reduced the growth rate of aphid colonies. Previous diet and colony origin did not affect aphid colony growth rates. Our results suggest that ant colonies balance the flow of two separate resources from aphid colonies- renewable sugars or a protein-rich meal, depending on demand from ant larvae within the nest. Aphid payoffs from the ant-aphid interaction may change on a seasonal basis, as the demand from larvae within the ant colony waxes and wanes.

  1. The distribution and diversity of insular ants

    DEFF Research Database (Denmark)

    Roura-Pascual, Núria; Sanders, Nate; Hui, Cang

    2016-01-01

    Aim: To examine the relationship between island characteristics (area, distance to the nearest continent, climate and human population size) and ant species richness, as well as the factors underlying global geographical clustering of native and exotic ant composition on islands. Location: One...... hundred and two islands from 20 island groups around the world. Methods: We used spatial linear models that consider the spatial structure of islands to examine patterns of ant species richness. We also performed modularity analyses to identify clusters of islands hosting a similar suite of species...... and constructed conditional inference trees to assess the characteristics of islands that explain the formation of these island-ant groups. Results: Island area was the best predictor of ant species richness. However, distance to the nearest continent was an important predictor of native ant species richness...

  2. Temperature limits trail following behaviour through pheromone decay in ants

    Science.gov (United States)

    van Oudenhove, Louise; Billoir, Elise; Boulay, Raphaël; Bernstein, Carlos; Cerdá, Xim

    2011-12-01

    In Mediterranean habitats, temperature affects both ant foraging behaviour and community structure. Many studies have shown that dominant species often forage at lower temperature than subordinates. Yet, the factors that constrain dominant species foraging activity in hot environments are still elusive. We used the dominant ant Tapinoma nigerrimum as a model species to test the hypothesis that high temperatures hinder trail following behaviour by accelerating pheromone degradation. First, field observations showed that high temperatures (> 30°C) reduce the foraging activity of T. nigerrimum independently of the daily and seasonal rhythms of this species. Second, we isolated the effect of high temperatures on pheromone trail efficacy from its effect on worker physiology. A marked substrate was heated during 10 min (five temperature treatments from 25°C to 60°C), cooled down to 25°C, and offered in a test choice to workers. At hot temperature treatments (>40°C), workers did not discriminate the previously marked substrate. High temperatures appeared therefore to accelerate pheromone degradation. Third, we assessed the pheromone decay dynamics by a mechanistic model fitted with Bayesian inference. The model predicted ant choice through the evolution of pheromone concentration on trails as a function of both temperature and time since pheromone deposition. Overall, our results highlighted that the effect of high temperatures on recruitment intensity was partly due to pheromone evaporation. In the Mediterranean ant communities, this might affect dominant species relying on chemical recruitment, more than subordinate ant species, less dependent on chemical communication and less sensitive to high temperatures.

  3. Antígona y la muerte

    OpenAIRE

    Pérez Alcolea, Simona Micaela

    2012-01-01

    La ponencia analiza la muerte de Antígona en la obra de Sófocles. Se propone que su suicidio es un acto consciente de voluntad preanunciado a lo largo de toda la obra y no una medida desesperada. Con ese fin se exploran las posibles motivaciones de Antígona para poner fin a su vida. En el análisis se proponen tres respuestas (no necesariamente excluyentes): -Antígona responde a la ética homérica. Está en lucha con Creón, y su suicidio es su golpe de gracia al poder del rey. -Antígona...

  4. Ant-plant symbioses: Stalking the chuyachaqui.

    Science.gov (United States)

    Davidson, D W; McKey, D

    1993-09-01

    According to Quechua-speaking peoples, orchard-like stands ('Supay Chacras') of two Amazonian ant-plant species are cultivated by the devil, or 'Chuyachaqui'. These "devil gardens" offer extreme examples of specializations that have evolved repeatedly in ant-plant associations. Numerous investigations are beginning to disclose the identity of the Chuyachaqui - the forces behind evolutionary specialization in ant-plant symbioses. These developments have important implications for our understanding of modes of coevolution in symbiotic mutualism, remarkable convergent similarities in the form of ant-plant symbioses on different continents, and pronounced intercontinental differences in the diversity and taxonomic composition of associates. Copyright © 1993. Published by Elsevier Ltd.

  5. From Ant Trails to Pedestrian Dynamics

    Directory of Open Access Journals (Sweden)

    Andreas Schadschneider

    2003-01-01

    Full Text Available This paper presents a model for the simulation of pedestrian dynamics inspired by the behaviour of ants in ant trails. Ants communicate by producing a pheromone that can be smelled by other ants. In this model, pedestrians produce a virtual pheromone that influences the motion of others. In this way all interactions are strictly local, and so even large crowds can be simulated very efficiently. Nevertheless, the model is able to reproduce the collective effects observed empirically, eg the formation of lanes in counterflow. As an application, we reproduce a surprising result found in experiments of evacuation from an aircraft.

  6. Pollination and facultative ant-association in the African leopard ...

    African Journals Online (AJOL)

    The role of extra-floral nectar appears to be recruitment of foraging ants to tend the flowers resulting in a facultative ant-association between the orchid and gregarious ants. Four different ant species were found to forage on A. africana's inflorescences. Ant-tended inflorescences suffered significantly less damage by insects.

  7. Foraging of Psilocybe basidiocarps by the leaf-cutting ant Acromyrmex lobicornis in Santa Fé, Argentina.

    Science.gov (United States)

    Masiulionis, Virginia E; Weber, Roland Ws; Pagnocca, Fernando C

    2013-12-01

    It is generally accepted that material collected by leaf-cutting ants of the genus Acromyrmex consists solely of plant matter, which is used in the nest as substrate for a symbiotic fungus providing nutrition to the ants. There is only one previous report of any leaf-cutting ant foraging directly on fungal basidiocarps. Basidiocarps of Psilocybe coprophila growing on cow dung were actively collected by workers of Acromyrmex lobicornis in Santa Fé province, Argentina. During this behaviour the ants displayed typical signals of recognition and continuously recruited other foragers to the task. Basidiocarps of different stages of maturity were being transported into the nest by particular groups of workers, while other workers collected plant material. The collection of mature basidiocarps with viable spores by leaf-cutting ants in nature adds substance to theories relating to the origin of fungiculture in these highly specialized social insects.

  8. Improved phylogenetic analyses corroborate a plausible position of Martialis heureka in the ant tree of life.

    Directory of Open Access Journals (Sweden)

    Patrick Kück

    Full Text Available Martialinae are pale, eyeless and probably hypogaeic predatory ants. Morphological character sets suggest a close relationship to the ant subfamily Leptanillinae. Recent analyses based on molecular sequence data suggest that Martialinae are the sister group to all extant ants. However, by comparing molecular studies and different reconstruction methods, the position of Martialinae remains ambiguous. While this sister group relationship was well supported by Bayesian partitioned analyses, Maximum Likelihood approaches could not unequivocally resolve the position of Martialinae. By re-analysing a previous published molecular data set, we show that the Maximum Likelihood approach is highly appropriate to resolve deep ant relationships, especially between Leptanillinae, Martialinae and the remaining ant subfamilies. Based on improved alignments, alignment masking, and tree reconstructions with a sufficient number of bootstrap replicates, our results strongly reject a placement of Martialinae at the first split within the ant tree of life. Instead, we suggest that Leptanillinae are a sister group to all other extant ant subfamilies, whereas Martialinae branch off as a second lineage. This assumption is backed by approximately unbiased (AU tests, additional Bayesian analyses and split networks. Our results demonstrate clear effects of improved alignment approaches, alignment masking and data partitioning. We hope that our study illustrates the importance of thorough, comprehensible phylogenetic analyses using the example of ant relationships.

  9. The demographic consequences of mutualism: ants increase host-plant fruit production but not population growth.

    Science.gov (United States)

    Ford, Kevin R; Ness, Joshua H; Bronstein, Judith L; Morris, William F

    2015-10-01

    The impact of mutualists on a partner's demography depends on how they affect the partner's multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and simulations of long-term population dynamics to quantify the demographic impact of a guild of ant species on the plant Ferocactus wislizeni. The ants feed at the plant's extrafloral nectaries and attack herbivores attempting to consume reproductive organs. Ant-guarded plants produced significantly more fruit, but ants had no significant effect on individual growth or survival. After integrating ant effects across these vital rates, we found that projected population growth was not significantly different between unguarded and ant-guarded plants because population growth was only weakly influenced by differences in fruit production (though strongly influenced by differences in individual growth and survival). However, simulations showed that ants could positively affect long-term plant population dynamics through services provided during rare but important events (herbivore outbreaks that reduce survival or years of high seedling recruitment associated with abundant precipitation). Thus, in this seemingly clear example of mutualism, the interaction may actually yield no clear benefit to plant population growth, or if it does, may only do so through the actions of the ants during rare events. These insights demonstrate the value of taking a demographic approach to studying the consequences of mutualism.

  10. CO2 efflux from subterranean nests of ant communities in a seasonal tropical forest, Thailand.

    Science.gov (United States)

    Hasin, Sasitorn; Ohashi, Mizue; Yamada, Akinori; Hashimoto, Yoshiaki; Tasen, Wattanachai; Kume, Tomonori; Yamane, Seiki

    2014-10-01

    Many ant species construct subterranean nests. The presence of their nests may explain soil respiration "hot spots", an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical seasonal forest, Thailand. We examined differences in nest CO2 efflux among ant species. We determined the effects of environmental factors on nest CO2 efflux and calculated an index of nest structure. The mean CO2 efflux from nests was significantly higher than those from the surrounding soil in the wet and dry seasons. The CO2 efflux was species-specific, showing significant differences among the 13 ant species. The soil moisture content significantly affected nest CO2 efflux, but there was no clear relationship between nest CO2 efflux and nest soil temperature. The diameter of the nest entrance hole affected CO2 efflux. However, there was no significant difference in CO2 efflux rates between single-hole and multiple-hole nests. Our results suggest that in a tropical forest ecosystem the increase in CO2 efflux from subterranean ant nests is caused by species-specific activity of ants, the nest soil environment, and nest structure.

  11. A mutualism without honeydew: what benefits for Melissotarsus emeryi ants and armored scale insects (Diaspididae?

    Directory of Open Access Journals (Sweden)

    Christian Peeters

    2017-07-01

    Full Text Available Mutualisms between ants and sap-sucking insects generally involve clear benefits for both partners: the ants provide protection in exchange for honeydew. However, a single ant genus associates with armoured scale insects (Diaspididae that do not excrete honeydew. We studied three colonies of Melissotarsus emeryi ants from two localities in Mozambique. Vast numbers of the diaspidid Morganella conspicua occupied galleries dug by the ants under the bark of living trees. Unlike free-living M. conspicua and other diaspidids, M. conspicua living with ants are known to lack shields, likely because they gain protection against enemies and desiccation. Nevertheless, we documented the occurrence of rare individuals with shields inside ant galleries, indicating that their glands continue to secrete wax and proteins as building material. This is likely to constitute a significant portion of the ants’ diet, in addition to diaspidid exuviae and excretions from the Malpighian tubules. Indeed, Melissotarsus workers cannot walk outside the galleries due to modified middle legs, forcing them to obtain all nourishment within the tree. Melissotarsus founding queens, however, must locate a suitable host tree while flying, and acquire diaspidid crawlers. This mutualism involves ants that are highly specialised to chew through living wood, and diaspidids that can also live freely outside the bark. It is extremely widespread in Africa and Madagascar, recorded from 20 tree families, and harmful effects on plant hosts require rapid study.

  12. The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens.

    Directory of Open Access Journals (Sweden)

    Isabel E Moller

    Full Text Available The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants.

  13. Michael Jackson antes del caos

    OpenAIRE

    Juan Luciano Nieves

    2015-01-01

    Michael Jackson es un buen ejemplo de cómo utilizar las relaciones públicas para realizar o manipular la imagen de un producto a través de los medios de comunicación. Este ensayo pretende analizar los eventos que tuvieron lugar antes de que el cantante fuera acusado de abuso sexual contra un menor. Dichos eventos formaron parte de un plan muy bien delineado para disminuir los efectos de la inminente crisis que se acercaba. Este trabajo combina la crítica retórica de temas de fantasía con teor...

  14. Viaje Antártico

    OpenAIRE

    Lasa, Gorka

    2017-01-01

    Ah, qué grandiosa sensación esta de poder caminar por los eternos hielos y dejar que mi vista se pierda en el horizonte crepuscular de esta desolada región! Aquellas solitarias islas, lamentos blancos en la distancia, aquellos azules glaciares llorando su neblina de frío y siglos. Al llamado lejano, mi alma se ve arrastrada por los vientos australes. Mítico ensueño que genera en mi imaginación el gran continente antártico. Belleza misteriosa e intimidante de la vastedad casi mágica que envuel...

  15. Benefits conferred by "timid" ants: active anti-herbivore protection of the rainforest tree Leonardoxa africana by the minute ant Petalomyrmex phylax.

    Science.gov (United States)

    Gaume, Laurence; McKey, Doyle; Anstett, Marie-Charlotte

    1997-10-01

    In this study, we demonstrate that an important benefit provided by the small host-specific ant Petalomyrmex phylax to its host plant Leonardoxa africana is efficient protection against herbivores. We estimate that in the absence of ants, insect herbivory would reduce the leaf area by about one-third. This contributes considerably to the fitness of the plant. Our estimates take into account not only direct damage, such as removal of leaf surface by chewing insects, but also the effects of sucking insects on leaf growth and expansion. Sucking insects are numerically predominant in this system, and the hitherto cryptic effects of ant protection against the growth-reducing effects of sucking insects accounted for half of the total estimated benefit of ant protection. We propose that the small size of workers confers a distinct advantage in this system. Assuming that resource limitation implies a trade off between size and number of ants, and given the small size of phytophagous insects that attack Leonardoxa, we conclude that fine-grained patrolling by a large number of small workers maximises protection of young leaves of this plant. Since herbivores are small and must complete their development on the young leaves of Leonardoxa, and since a high patrolling density is required for a fine-grained search for these enemies, numerous small ants should provide the most effective protection of young leaves of Leonardoxa. We also discuss other factors that may have influenced worker size in this ant.

  16. Foliar uptake of nitrogen from ant fecal droplets: an overlooked service to ant plants

    DEFF Research Database (Denmark)

    Pinkalski, Christian Alexander Stidsen; Jensen, Karl-Martin Vagn; Damgaard, Christian Frølund

    2018-01-01

    and subsequently deposited fecal droplets on the seedlings, coffee leaves showed increased levels of 15N and total N compared to control plants without ants. This was evident for both exposed leaves and leaves covered in plastic bags (i.e. not directly exposed to ants). Thus, N from ant excretions was absorbed...

  17. Biodiversity on Broadway--enigmatic diversity of the societies of ants (Formicidae on the streets of New York City.

    Directory of Open Access Journals (Sweden)

    Marko Pećarević

    2010-10-01

    Full Text Available Each year, a larger proportion of the Earth's surface is urbanized, and a larger proportion of the people on Earth lives in those urban areas. The everyday nature, however, that humans encounter in cities remains poorly understood. Here, we consider perhaps the most urban green habitat, street medians. We sampled ants from forty-four medians along three boulevards in New York City and examined how median properties affect the abundance and species richness of native and introduced ants found on them. Ant species richness varied among streets and increased with area but was independent of the other median attributes measured. Ant assemblages were highly nested, with three numerically dominant species present at all medians and additional species present at a subset of medians. The most common ant species were the introduced Pavement ant (Tetramorium caespitum and the native Thief ant (Solenopsis molesta and Cornfield ant (Lasius neoniger. The common introduced species on the medians responded differently to natural and disturbed elements of medians. Tetramorium caespitum was most abundant in small medians, with the greatest edge/area ratio, particularly if those medians had few trees, whereas Nylanderia flavipes was most abundant in the largest medians, particularly if they had more trees. Many of the species encountered in Manhattan were similar to those found in other large North American cities, such that a relatively small subset of ant species probably represent most of the encounters humans have with ants in North America.

  18. Variation in the effectiveness of biotic defence: the case of an opportunistic ant-plant protection mutualism.

    Science.gov (United States)

    Giusto, Bruno; Anstett, Marie-Charlotte; Dounias, Edmond; McKey, Doyle B

    2001-11-01

    Benefits to plants in facultative ant protection mutualisms are highly variable. This allows examination of the sources of this variation and the mechanisms by which ants protect plants. We studied opportunistic interactions between ants and an extrafloral nectary-bearing vine, Dioscorea praehensilis, during 3 different years. Variation in plant protection among years was striking. Several factors affected the effectiveness of the biotic defence. Stems recently emerged from the underground tuber were self-supporting, contacting no other plants and encountering few foraging ants. Stems then became lianescent, and contact with supporting plants greatly increased ant recruitment. Both species and number of ant workers influenced the effect of ants on the major herbivore, the chrysomelid beetle Lilioceris latipennis. Protective actions included limitation of oviposition (reduction in the number of eggs laid on the plant) and predation, leading to increased larval mortality. The probability of successful predation was strongly dependent on larval size. If temporarily low ant-patrolling activity allows larvae to grow beyond a critical size, their mechanical (thick integument) or chemical (plant-derived compounds in a fecal shield) defences become more effective against ants. Secondary metabolites derived from the host plant thus appear to be important for the anti-predator mechanisms of this beetle, being necessary for its survival and reproduction on a host plant that actively recruits ants as a biotic defence against herbivores.

  19. The evolution of genome size in ants

    Directory of Open Access Journals (Sweden)

    Spagna Joseph C

    2008-02-01

    Full Text Available Abstract Background Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta, and the two published estimates for this species differ by 146.7 Mb (0.15 pg. Results Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile, Neotropical army ants (genera Eciton and Labidus, trapjaw ants (Odontomachus, fungus-growing ants (Apterostigma, Atta and Sericomyrmex, harvester ants (Messor, Pheidole and Pogonomyrmex, carpenter ants (Camponotus, a fire ant (Solenopsis, and a bulldog ant (Myrmecia. Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship. Conclusion This is the first analysis of genome size in ants (Formicidae and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may

  20. Hybrid chaotic ant swarm optimization

    International Nuclear Information System (INIS)

    Li Yuying; Wen Qiaoyan; Li Lixiang; Peng Haipeng

    2009-01-01

    Chaotic ant swarm optimization (CASO) is a powerful chaos search algorithm that is used to find the global optimum solution in search space. However, the CASO algorithm has some disadvantages, such as lower solution precision and longer computational time, when solving complex optimization problems. To resolve these problems, an improved CASO, called hybrid chaotic swarm optimization (HCASO), is proposed in this paper. The new algorithm introduces preselection operator and discrete recombination operator into the CASO; meanwhile it replaces the best position found by own and its neighbors' ants with the best position found by preselection operator and discrete recombination operator in evolution equation. Through testing five benchmark functions with large dimensionality, the experimental results show the new method enhances the solution accuracy and stability greatly, as well as reduces the computational time and computer memory significantly when compared to the CASO. In addition, we observe the results can become better with swarm size increasing from the sensitivity study to swarm size. And we gain some relations between problem dimensions and swam size according to scalability study.

  1. Discovery of the Dinoponera lucida male (Hymenoptera, Formicidae), a threatened giant ant from the Atlantic rain forest.

    Science.gov (United States)

    Escárraga, Mayron E; Lattke, John E; Azevedo, Celso O

    2017-11-10

    The male of the endangered ant Dinoponera lucida Emery is described, providing morphometric measurements, high-resolution images, and a distribution map of the species. This ant inhabits the Brazilian Atlantic forest, an ecosystem strongly impacted by fragmentation. The males show clear morphological differences from the known males of other species of Dinoponera. We briefly discuss the relevance of the male description for the conservation strategies of this ant.

  2. Ant-egg cataract. A study of a family with dominantly inherited congenital (ant-egg) cataract, including a histological examination of the formed elements

    DEFF Research Database (Denmark)

    Nissen, Steffen; Schrøder, H D

    1979-01-01

    A family with "ant-egg" cataract in three generations is described. The cataract is congenital, probably of autosomal dominant inheritance. Light microscopy of the ant-eggs showed that they are made up of a peripheral zone of lens material and a large almost homogenous centre. Element analysis by......-ray spectrophotometry showed a high content of calcium and phosphorus in the centre. The cataract has been easy to operate on and the postoperative visual results have been good....

  3. The Biochemical Toxin Arsenal from Ant Venoms

    Directory of Open Access Journals (Sweden)

    Axel Touchard

    2016-01-01

    Full Text Available Ants (Formicidae represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents.

  4. Hey! A Fire Ant Stung Me!

    Science.gov (United States)

    ... Videos for Educators Search English Español Hey! A Fire Ant Stung Me! KidsHealth / For Kids / Hey! A ... Me picó una roja o colorada! What's a Fire Ant? There are many different types of fire ...

  5. The Biochemical Toxin Arsenal from Ant Venoms

    Science.gov (United States)

    Touchard, Axel; Aili, Samira R.; Fox, Eduardo Gonçalves Paterson; Escoubas, Pierre; Orivel, Jérôme; Nicholson, Graham M.; Dejean, Alain

    2016-01-01

    Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:26805882

  6. Effects of dam-induced landscape fragmentation on amazonian ant-plant mutualistic networks.

    Science.gov (United States)

    Emer, Carine; Venticinque, Eduardo Martins; Fonseca, Carlos Roberto

    2013-08-01

    Mutualistic networks are critical to biological diversity maintenance; however, their structures and functionality may be threatened by a swiftly changing world. In the Amazon, the increasing number of dams poses a large threat to biological diversity because they greatly alter and fragment the surrounding landscape. Tight coevolutionary interactions typical of tropical forests, such as the ant-myrmecophyte mutualism, where the myrmecophyte plants provide domatia nesting space to their symbiotic ants, may be jeopardized by the landscape changes caused by dams. We analyzed 31 ant-myrmecophyte mutualistic networks in undisturbed and disturbed sites surrounding Balbina, the largest Central Amazonian dam. We tested how ant-myrmecophyte networks differ among dam-induced islands, lake edges, and undisturbed forests in terms of species richness, composition, structure, and robustness (number of species remaining in the network after partner extinctions). We also tested how landscape configuration in terms of area, isolation, shape, and neighborhood alters the structure of the ant-myrmecophyte networks on islands. Ant-myrmecophytic networks were highly compartmentalized in undisturbed forests, and the compartments had few strongly connected mutualistic partners. In contrast, networks at lake edges and on islands were not compartmentalized and were negatively affected by island area and isolation in terms of species richness, density, and composition. Habitat loss and fragmentation led to coextinction cascades that contributed to the elimination of entire ant-plant compartments. Furthermore, many myrmecophytic plants in disturbed sites lost their mutualistic ant partners or were colonized by opportunistic, nonspecialized ants. Robustness of ant-myrmecophyte networks on islands was lower than robustness near lake edges and in undisturbed forest and was particularly susceptible to the extinction of plants. Beyond the immediate habitat loss caused by the building of large dams

  7. Behavioral mechanisms and morphological symptoms of zombie ants dying from fungal infection

    Directory of Open Access Journals (Sweden)

    Himaman Winanda

    2011-05-01

    Full Text Available Abstract Background Parasites that manipulate host behavior can provide prominent examples of extended phenotypes: parasite genomes controlling host behavior. Here we focus on one of the most dramatic examples of behavioral manipulation, the death grip of ants infected by Ophiocordyceps fungi. We studied the interaction between O. unilateralis s.l. and its host ant Camponotus leonardi in a Thai rainforest, where infected ants descend from their canopy nests down to understory vegetation to bite into abaxial leaf veins before dying. Host mortality is concentrated in patches (graveyards where ants die on sapling leaves ca. 25 cm above the soil surface where conditions for parasite development are optimal. Here we address whether the sequence of ant behaviors leading to the final death grip can also be interpreted as parasite adaptations and describe some of the morphological changes inside the heads of infected workers that mediate the expression of the death grip phenotype. Results We found that infected ants behave as zombies and display predictable stereotypical behaviors of random rather than directional walking, and of repeated convulsions that make them fall down and thus precludes returning to the canopy. Transitions from erratic wandering to death grips on a leaf vein were abrupt and synchronized around solar noon. We show that the mandibles of ants penetrate deeply into vein tissue and that this is accompanied by extensive atrophy of the mandibular muscles. This lock-jaw means the ant will remain attached to the leaf after death. We further present histological data to show that a high density of single celled stages of the parasite within the head capsule of dying ants are likely to be responsible for this muscular atrophy. Conclusions Extended phenotypes in ants induced by fungal infections are a complex example of behavioral manipulation requiring coordinated changes of host behavior and morphology. Future work should address the

  8. Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions.

    Science.gov (United States)

    Oña, L; Lachmann, M

    2011-03-01

    Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  9. Compass cues used by a nocturnal bull ant, Myrmecia midas.

    Science.gov (United States)

    Freas, Cody A; Narendra, Ajay; Cheng, Ken

    2017-05-01

    Ants use both terrestrial landmarks and celestial cues to navigate to and from their nest location. These cues persist even as light levels drop during the twilight/night. Here, we determined the compass cues used by a nocturnal bull ant, Myrmecia midas , in which the majority of individuals begin foraging during the evening twilight period. Myrmecia midas foragers with vectors of ≤5   m when displaced to unfamiliar locations did not follow the home vector, but instead showed random heading directions. Foragers with larger home vectors (≥10   m) oriented towards the fictive nest, indicating a possible increase in cue strength with vector length. When the ants were displaced locally to create a conflict between the home direction indicated by the path integrator and terrestrial landmarks, foragers oriented using landmark information exclusively and ignored any accumulated home vector regardless of vector length. When the visual landmarks at the local displacement site were blocked, foragers were unable to orient to the nest direction and their heading directions were randomly distributed. Myrmecia midas ants typically nest at the base of the tree and some individuals forage on the same tree. Foragers collected on the nest tree during evening twilight were unable to orient towards the nest after small lateral displacements away from the nest. This suggests the possibility of high tree fidelity and an inability to extrapolate landmark compass cues from information collected on the tree and at the nest site to close displacement sites. © 2017. Published by The Company of Biologists Ltd.

  10. AntStar: Enhancing Optimization Problems by Integrating an Ant System and A⁎ Algorithm

    Directory of Open Access Journals (Sweden)

    Mohammed Faisal

    2016-01-01

    Full Text Available Recently, nature-inspired techniques have become valuable to many intelligent systems in different fields of technology and science. Among these techniques, Ant Systems (AS have become a valuable technique for intelligent systems in different fields. AS is a computational system inspired by the foraging behavior of ants and intended to solve practical optimization problems. In this paper, we introduce the AntStar algorithm, which is swarm intelligence based. AntStar enhances the optimization and performance of an AS by integrating the AS and A⁎ algorithm. Applying the AntStar algorithm to the single-source shortest-path problem has been done to ensure the efficiency of the proposed AntStar algorithm. The experimental result of the proposed algorithm illustrated the robustness and accuracy of the AntStar algorithm.

  11. Cryptococcus neoformans carried by Odontomachus bauri ants

    Directory of Open Access Journals (Sweden)

    Mariana Santos de Jesus

    2012-06-01

    Full Text Available Cryptococcus neoformans is the most common causative agent of cryptococcosis worldwide. Although this fungus has been isolated from a variety of organic substrates, several studies suggest that hollow trees constitute an important natural niche for C. neoformans. A previously surveyed hollow of a living pink shower tree (Cassia grandis positive for C. neoformans in the city of Rio de Janeiro, Brazil, was chosen for further investigation. Odontomachus bauri ants (trap-jaw ants found inside the hollow were collected for evaluation as possible carriers of Cryptococcus spp. Two out of 10 ants were found to carry phenoloxidase-positive colonies identified as C. neoformans molecular types VNI and VNII. The ants may have acted as a mechanical vector of C. neoformans and possibly contributed to the dispersal of the fungi from one substrate to another. To the best of our knowledge, this is the first report on the association of C. neoformans with ants of the genus Odontomachus.

  12. Recurrence analysis of ant activity patterns.

    Directory of Open Access Journals (Sweden)

    Felipe Marcel Neves

    Full Text Available In this study, we used recurrence quantification analysis (RQA and recurrence plots (RPs to compare the movement activity of individual workers of three ant species, as well as a gregarious beetle species. RQA and RPs quantify the number and duration of recurrences of a dynamical system, including a detailed quantification of signals that could be stochastic, deterministic, or both. First, we found substantial differences between the activity dynamics of beetles and ants, with the results suggesting that the beetles have quasi-periodic dynamics and the ants do not. Second, workers from different ant species varied with respect to their dynamics, presenting degrees of predictability as well as stochastic signals. Finally, differences were found among minor and major caste of the same (dimorphic ant species. Our results underscore the potential of RQA and RPs in the analysis of complex behavioral patterns, as well as in general inferences on animal behavior and other biological phenomena.

  13. Ants defend aphids against lethal disease

    Science.gov (United States)

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  14. Persistence of pollination mutualisms in the presence of ants.

    Science.gov (United States)

    Wang, Yuanshi; Wang, Shikun

    2015-01-01

    This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.

  15. Density-dependent effects of ants on selection for bumble bee pollination in Polemonium viscosum.

    Science.gov (United States)

    Galen, Candace; Geib, Jennifer C

    2007-05-01

    Mutualisms are commonly exploited by cheater species that usurp rewards without providing reciprocal benefits. Yet most studies of selection between mutualist partners ignore interactions with third species and consequently overlook the impact of cheaters on evolution in the mutualism. Here, we explicitly investigate how the abundance of nectar-thieving ants (cheaters) influences selection in a pollination mutualism between bumble bees and the alpine skypilot, Polemonium viscosum. As suggested in past work with this species, bumble bees accounted for most of the seed production (78% +/- 6% [mean +/- SE]) in our high tundra study population and, in the absence of ants, exerted strong selection for large flowers. We tested for indirect effects of ant abundance on seed set through bumble bee pollination services (pollen delivery and pollen export) and a direct effect through flower damage. Ants reduced seed set per flower by 20% via flower damage. As ant density increased within experimental patches, the rate of flower damage rose, but pollen delivery and export did not vary significantly, showing that indirect effects of increased cheater abundance on pollinator service are negligible in this system. To address how ants affect selection for plant participation in the pollination mutualism we tested the impact of ant abundance on selection for bumble bee-mediated pollination. Results show that the impact of ants on fitness (seed set) accruing under bumble bee pollination is density dependent in P. viscosum. Selection for bumble bee pollination declined with increasing ant abundance in experimental patches, as predicted if cheaters constrain fitness returns of mutualist partner services. We also examined how ant abundance influences selection on flower size, a key component of plant investment in bumble bee pollination. We predicted that direct effects of ants would constrain bumble bee selection for large flowers. However, selection on flower size was significantly

  16. Michael Jackson antes del caos

    Directory of Open Access Journals (Sweden)

    Juan Luciano Nieves

    2015-01-01

    Full Text Available Michael Jackson es un buen ejemplo de cómo utilizar las relaciones públicas para realizar o manipular la imagen de un producto a través de los medios de comunicación. Este ensayo pretende analizar los eventos que tuvieron lugar antes de que el cantante fuera acusado de abuso sexual contra un menor. Dichos eventos formaron parte de un plan muy bien delineado para disminuir los efectos de la inminente crisis que se acercaba. Este trabajo combina la crítica retórica de temas de fantasía con teoría de comunicación.

  17. Individual Recognition in Ant Queens

    DEFF Research Database (Denmark)

    D'Ettorre, Patrizia; Heinze, Jürgen

    2005-01-01

    Personal relationships are the cornerstone of vertebrate societies, but insect societies are either too large for individual recognition, or their members were assumed to lack the necessary cognitive abilities 1 and 2 . This paradigm has been challenged by the recent discovery that paper wasps...... recognize each other's unique facial color patterns [3] . Individual recognition is advantageous when dominance hierarchies control the partitioning of work and reproduction 2 and 4 . Here, we show that unrelated founding queens of the ant Pachycondyla villosa use chemical cues to recognize each other...... individually. Aggression was significantly lower in pairs of queens that had previously interacted than in pairs with similar social history but no experience with one another. Moreover, subordinates discriminated familiar and unfamiliar dominants in choice experiments in which physical contact, but not odor...

  18. FDTD-ANT User Manual

    Science.gov (United States)

    Zimmerman, Martin L.

    1995-01-01

    This manual explains the theory and operation of the finite-difference time domain code FDTD-ANT developed by Analex Corporation at the NASA Lewis Research Center in Cleveland, Ohio. This code can be used for solving electromagnetic problems that are electrically small or medium (on the order of 1 to 50 cubic wavelengths). Calculated parameters include transmission line impedance, relative effective permittivity, antenna input impedance, and far-field patterns in both the time and frequency domains. The maximum problem size may be adjusted according to the computer used. This code has been run on the DEC VAX and 486 PC's and on workstations such as the Sun Sparc and the IBM RS/6000.

  19. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant-plant mutualism.

    Science.gov (United States)

    Pringle, Elizabeth G

    2014-06-22

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant-plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.

  20. Collective search by ants in microgravity

    Directory of Open Access Journals (Sweden)

    Stefanie M. Countryman

    2015-03-01

    Full Text Available The problem of collective search is a tradeoff between searching thoroughly and covering as much area as possible. This tradeoff depends on the density of searchers. Solutions to the problem of collective search are currently of much interest in robotics and in the study of distributed algorithms, for example to design ways that without central control robots can use local information to perform search and rescue operations. Ant colonies operate without central control. Because they can perceive only local, mostly chemical and tactile cues, they must search collectively to find resources and to monitor the colony's environment. Examining how ants in diverse environments solve the problem of collective search can elucidate how evolution has led to diverse forms of collective behavior. An experiment on the International Space Station in January 2014 examined how ants (Tetramorium caespitum perform collective search in microgravity. In the ISS experiment, the ants explored a small arena in which a barrier was lowered to increase the area and thus lower ant density. In microgravity, relative to ground controls, ants explored the area less thoroughly and took more convoluted paths. It appears that the difficulty of holding on to the surface interfered with the ants’ ability to search collectively. Ants frequently lost contact with the surface, but showed a remarkable ability to regain contact with the surface.

  1. Ant-lepidopteran associations along African forest edges

    Science.gov (United States)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  2. Poneromorph Ants Associated with Parasitoid Wasps of the Genus Kapala Cameron (Hymenoptera: Eucharitidae in French Guiana

    Directory of Open Access Journals (Sweden)

    Jean-Paul Lachaud

    2012-01-01

    Full Text Available Eucharitid wasps are specific, specialized parasitoids of ants. The genus Kapala Cameron is the most common in the Neotropics but few species are described, and information dealing with their biology, behavior and host associations is scarce. Numerous poneromorph ant colonies were inspected over 4 collection surveys in French Guiana. A diverse fauna of parasites and parasitoids was found, including mermithid nematodes, flies, eucharitids, and another gregarious endoparasitoid wasp. Five new host associations for Kapala are reported, all of them involving medium- to large-size poneromorph ant species from 4 genera: Ectatomma brunneum Fr. Smith, Gnamptogenys tortuolosa (Fr. Smith, Odontomachus haematodus (L., O. mayi Mann, and Pachycondyla verenae (Forel. Three other associations involving O. hastatus (Fabr., P. apicalis (Latreille, and P. stigma (Fabr., already reported for other countries but new for French Guiana, are confirmed. The data extend the number of hosts for Kapala to 24 ant species from 7 genera. The high diversity of the ant host genera associated with Kapala, combined with the fact that these ant genera are the most widely distributed among Neotropical poneromorph ants, could account for the dominant status of the genus Kapala among the eucharitine wasps of Central and South America.

  3. An ant-plant mutualism through the lens of cGMP-dependent kinase genes.

    Science.gov (United States)

    Malé, Pierre-Jean G; Turner, Kyle M; Doha, Manjima; Anreiter, Ina; Allen, Aaron M; Sokolowski, Marla B; Frederickson, Megan E

    2017-09-13

    In plant-animal mutualisms, how an animal forages often determines how much benefit its plant partner receives. In many animals, foraging behaviour changes in response to foraging gene expression or activation of the cGMP-dependent protein kinase (PKG) that foraging encodes. Here, we show that this highly conserved molecular mechanism affects the outcome of a plant-animal mutualism. We studied the two PKG genes of Allomerus octoarticulatus, an Amazonian ant that defends the ant-plant Cordia nodosa against herbivores. Some ant colonies are better 'bodyguards' than others. Working in the field in Peru, we found that colonies fed with a PKG activator recruited more workers to attack herbivores than control colonies. This resulted in less herbivore damage. PKG gene expression in ant workers correlated with whether an ant colony discovered an herbivore and how much damage herbivores inflicted on leaves in a complex way; natural variation in expression levels of the two genes had significant interaction effects on ant behaviour and herbivory. Our results suggest a molecular basis for ant protection of plants in this mutualism. © 2017 The Author(s).

  4. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Van Bael Sunshine A

    2012-11-01

    Full Text Available Abstract Background Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants’ defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Results Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Conclusions Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest.

  5. Laccase detoxification mediates the nutritional alliance between leaf-cutting ants and fungus-garden symbionts.

    Science.gov (United States)

    De Fine Licht, Henrik H; Schiøtt, Morten; Rogowska-Wrzesinska, Adelina; Nygaard, Sanne; Roepstorff, Peter; Boomsma, Jacobus J

    2013-01-08

    Leaf-cutting ants combine large-scale herbivory with fungus farming to sustain advanced societies. Their stratified colonies are major evolutionary achievements and serious agricultural pests, but the crucial adaptations that allowed this mutualism to become the prime herbivorous component of neotropical ecosystems has remained elusive. Here we show how coevolutionary adaptation of a specific enzyme in the fungal symbiont has helped leaf-cutting ants overcome plant defensive phenolic compounds. We identify nine putative laccase-coding genes in the fungal genome of Leucocoprinus gongylophorus cultivated by the leaf-cutting ant Acromyrmex echinatior. One of these laccases (LgLcc1) is highly expressed in the specialized hyphal tips (gongylidia) that the ants preferentially eat, and we confirm that these ingested laccase molecules pass through the ant guts and remain active when defecated on the leaf pulp that the ants add to their gardens. This accurate deposition ensures that laccase activity is highest where new leaf material enters the fungus garden, but where fungal mycelium is too sparse to produce extracellular enzymes in sufficient quantities to detoxify phenolic compounds. Phylogenetic analysis of LgLcc1 ortholog sequences from symbiotic and free-living fungi revealed significant positive selection in the ancestral lineage that gave rise to the gongylidia-producing symbionts of leaf-cutting ants and their non-leaf-cutting ant sister group. Our results are consistent with fungal preadaptation and subsequent modification of a particular laccase enzyme for the detoxification of secondary plant compounds during the transition to active herbivory in the ancestor of leaf-cutting ants between 8 and 12 Mya.

  6. Urea in Weaver Ant Feces: Quantification and Investigation of the Uptake and Translocation of Urea in Coffea Arabica

    DEFF Research Database (Denmark)

    Vidkjær, Nanna Hjort; Wollenweber, Bernd; Jensen, Karl-Martin Vagn

    2016-01-01

    Weaver ants are tropical insects that nest in tree canopies, and for centuries these ants have been used for pest control in tropical orchards. Trees hosting weaver ants might benefit not only from the pest protective properties of these insects but also an additional supply of nutrients from ant...... investigate the interactions of weaver ants with the host plants with respect to plant nutrition. Here, we report the identification and quantification of urea, a highly effective foliar nutrient present in the fecal depositions of O. smaragdina. Feces samples obtained from six O. smaragdina colonies were....... The results clearly demonstrated that fecal urea was not only assimilated but also translocated within the plant. This evidence strongly supports the hypothesis that the fecal urea of weaver ants is a source of nitrogen for the host trees. Thus, weaver ant feces likely contribute to an improved nutritional...

  7. Colony structure and spatial partitioning of cavity dwelling ant species in nuts of eastern US forest floors

    Science.gov (United States)

    Nut-bearing trees create islands of high efficiency, low cost housing opportunities for ant colonies. Fallen nuts in leaf litter from previous seasons provide ready-made nest sites for cavity dwelling ant species, as well as affording protection from the elements. Suitable nuts for nests require an ...

  8. Egg-Laying Butterflies Distinguish Predaceous Ants by Sight

    OpenAIRE

    Sendoya, SF; Freitas, AVL; Oliveira, PS

    2009-01-01

    Information about predation risks is critical for herbivorous insects, and natural selection favors their ability to detect predators before oviposition and to select enemy-free foliage when offspring mortality risk is high. Food plants are selected by ovipositing butterflies, and offspring survival frequently varies among plants because of variation in the presence of predators. Eunica bechina butterflies oviposit on Caryocar brasiliense, an ant-defended plant. Experiments with dried Campono...

  9. Ants as tools in sustainable agriculture

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2015-01-01

    1. With an expanding human population placing increasing pressure on the environment, agriculture needs sustainable production that can match conventional methods. Integrated pest management (IPM) is more sustainable, but not necessarily as efficient as conventional non-sustainable measures. 2...... in multiple crops. Their efficiency is comparable to chemical pesticides or higher, while at lower costs. They provide a rare example of documented efficient conservation biological control. 3. Weaver ants share beneficial traits with almost 13 000 other ant species and are unlikely to be unique...... of agricultural systems, this review emphasizes the potential of managing ants to achieve sustainable pest management solutions. The synthesis suggests future directions and may catalyse a research agenda on the utilization of ants, not only against arthropod pests, but also against weeds and plant diseases...

  10. Kunstikriitik Ants Juske sai doktoriks / Neeme Korv

    Index Scriptorium Estoniae

    Korv, Neeme, 1974-

    2003-01-01

    Tartu Kõrgema Kunstikooli rektor Ants Juske kaitses 7. veebruaril Tallinnas Kunstiakadeemias edukalt doktoriväitekirja, juhendajaks oli professor Boris Bernštein ning oponeerisid doktor Altti Kuusamo Soomest ja professor Peeter Tulviste

  11. Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    the more basal attine genera use substrates such as flowers, plant debris, small twigs, insect feces and insect carcasses. This diverse array of fungal substrates across the attine lineage implies that the symbiotic fungus needs different enzymes to break down the plant material that the ants provide...... or different efficiencies of enzyme function. Fungal enzymes that degrade plant cell walls may have functionally co-evolved with the ants in this scenario. We explore this hypothesis with direct measurements of enzyme activity in fungus gardens in 12 species across 8 genera spanning the entire phylogeny...... and diversity of life-styles within the attine clade. We find significant differences in enzyme activity between different genera and life-styles of the ants. How these findings relate to attine ant coevolution and crop optimization are discussed....

  12. Polyacrylamide hydrogels: an effective tool for delivering liquid baits to pest ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Buczkowski, Grzegorz; Roper, Elray; Chin, Darren

    2014-04-01

    Ant management in urban and natural areas often relies on toxic baits. Liquid baits are highly attractive to pest ants because they mimic natural food sources such as honeydew and nectar, the principal dietary components of many ants. However, liquid bait use has been limited owing to the lack of bait dispensers that are effective, inexpensive, and easy to service. The current study evaluated the potential of water-storing crystals (polyacrylamide spheres) to effectively deliver liquid thiamethoxam baits to laboratory colonies of Argentine ants, Linepithema humile Mayr. Results of laboratory trials show that bait crystals saturated in 25% sucrose solution containing 0.007% thiamethoxam are highly attractive to Argentine ants and highly effective against all castes and life stages, including workers, queens, and brood. Fresh bait crystals were highly effective and required approximately 2 d to kill all workers and approximately 6 d to achieve complete mortality in queens and brood. Results of bait aging tests show that the crystals lose approximately 70% of moisture in 8 h and the duration of outdoor exposure has a significant effect on moisture loss and subsequently bait acceptance and bait efficacy. A gradual decrease in mortality was observed for all castes and life stages as bait age increased. In general, fresh baits and those aged for ants that obtain thiamethoxam by feeding on bait crystals effectively transfer it to untreated recipient ants. The level of secondary mortality depended on the donor:recipient ratio, with approximately 40% recipient worker mortality with the 1:5 ratio and 15% recipient worker mortality with 1:10 or 1:20 ratios. However, no queens died in any transfer tests, suggesting that multiple feedings from multiple donors may be necessary to produce queen mortality. The results of the transfer tests demonstrate the role of trophallaxis in the distribution of thiamethoxam and confirm that thiamethoxam is effectively transferred in Argentine

  13. Are ant assemblages of Brazilian veredas characterised by location or habitat type?

    Directory of Open Access Journals (Sweden)

    CB Costa-Milanez

    Full Text Available Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

  14. Are ant assemblages of Brazilian veredas characterised by location or habitat type?

    Science.gov (United States)

    Costa-Milanez, C B; Lourenço-Silva, G; Castro, P T A; Majer, J D; Ribeiro, S P

    2014-02-01

    Wetland areas in the Brazilian Cerrado, known as "veredas", represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted "veredas". Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

  15. Impacts of the Invasive European Red Ant (Myrmica rubra (L.): Hymenoptera; Formicidae) on a Myrmecochorous System in the Northeastern United States.

    Science.gov (United States)

    Gammans, Nicola; Drummond, Frank; Groden, Eleanor

    2018-05-16

    We investigated the impact of an invasive ant species from Europe, Myrmica rubra (L.), on a myrmecochorous system (seeds dispersed by ants) in its invaded range in North America. We assessed: 1) how M. rubra process the myrmecochorous diapsores (seeds and elaiosome as a single dispersal unit transported by ants) in comparison with native ants; 2) its preference for common native and invasive diaspore species relative to native ants; 3) how far they disperse diaspores in the field; and 4) the diaspore removal rate by invertebrates and vertebrates in infested areas compared to noninvaded sites. Field experiments demonstrated higher diaspore removal rates over a 10-min and 24-h period by M. rubra compared to native ants. M. rubra's diaspore dispersal distance was 40% greater compared to native ants. In two of three laboratory studies and one field study, there was no significant difference between the seed species which M. rubra and native ants selected. Our data suggest no long-term deleterious effects of M. rubra's invasion on diaspore dispersal in the Maine plant community that is comprised of both native and invasive species. This implies that M. rubra benefits from the myrmechorous plant species' diaspores by increasing their dispersal range away from the parent plant and potentially reducing seed predation. However, it is not known whether the fact that the native ant fauna and M. rubra are attracted to the same plant species' diaspores creates a high level of competition between the ants with deleterious effects on the native ant community.

  16. Exotic ants (Hymenoptera, Formicidae) of Ohio

    OpenAIRE

    Ivanov,Kal

    2016-01-01

    The worldwide transfer of plants and animals outside their native ranges is an ever increasing problem for global biodiversity. Ants are no exception and many species have been transported to new locations often with profound negative impacts on local biota. The current study is based on data gathered since the publication of the “Ants of Ohio” in 2005. Here I expand on our knowledge of Ohio’s myrmecofauna by contributing new records, new distributional information and natural history notes. ...

  17. Improving Emergency Management by Modeling Ant Colonies

    Science.gov (United States)

    2015-03-01

    perform functions such as nursing the brood or maintaining the nest. The more mature workers will begin to travel outside the nest to perform foraging...small sized ants predominantly act in functional roles such as nurses or transport services within the nest. The larger sizes predominantly function...stages: the founding stage, the ergonomic stage, and the reproductive stage. The founding stage is marked by a queen ant successful mating and laying

  18. Extrafloral nectar fuels ant life in deserts

    OpenAIRE

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal dese...

  19. Chemically armed mercenary ants protect fungus-farming societies

    DEFF Research Database (Denmark)

    Adams, Rachelle Martha Marie; Liberti, Joanito; Illum, Anders A.

    2013-01-01

    guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit......The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated...... parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few...

  20. Chemical and behavioral integration of army ant-associated rove beetles - a comparison between specialists and generalists.

    Science.gov (United States)

    von Beeren, Christoph; Brückner, Adrian; Maruyama, Munetoshi; Burke, Griffin; Wieschollek, Jana; Kronauer, Daniel J C

    2018-01-01

    Host-symbiont interactions are embedded in ecological communities and range from unspecific to highly specific relationships. Army ants and their arthropod guests represent a fascinating example of species-rich host-symbiont associations where host specificity ranges across the entire generalist - specialist continuum. In the present study, we compared the behavioral and chemical integration mechanisms of two extremes of the generalist - specialist continuum: generalist ant-predators in the genus Tetradonia (Staphylinidae: Aleocharinae: Athetini), and specialist ant-mimics in the genera Ecitomorpha and Ecitophya (Staphylinidae: Aleocharinae: Ecitocharini). Similar to a previous study of Tetradonia beetles, we combined DNA barcoding with morphological studies to define species boundaries in ant-mimicking beetles. This approach found four ant-mimicking species at our study site at La Selva Biological Station in Costa Rica. Community sampling of Eciton army ant parasites revealed that ant-mimicking beetles were perfect host specialists, each beetle species being associated with a single Eciton species. These specialists were seamlessly integrated into the host colony, while generalists avoided physical contact to host ants in behavioral assays. Analysis of the ants' nestmate recognition cues, i.e. cuticular hydrocarbons (CHCs), showed close similarity in CHC composition and CHC concentration between specialists and Eciton burchellii foreli host ants. On the contrary, the chemical profiles of generalists matched host profiles less well, indicating that high accuracy in chemical host resemblance is only accomplished by socially integrated species. Considering the interplay between behavior, morphology, and cuticular chemistry, specialists but not generalists have cracked the ants' social code with respect to various sensory modalities. Our results support the long-standing idea that the evolution of host-specialization in parasites is a trade-off between the range of

  1. Congestion and communication in confined ant traffic

    Science.gov (United States)

    Gravish, Nick; Gold, Gregory; Zangwill, Andrew; Goodisman, Michael A. D.; Goldman, Daniel I.

    2014-03-01

    Many social animals move and communicate within confined spaces. In subterranean fire ants Solenopsis invicta, mobility within crowded nest tunnels is important for resource and information transport. Within confined tunnels, communication and traffic flow are at odds: trafficking ants communicate through tactile interactions while stopped, yet ants that stop to communicate impose physical obstacles on the traffic. We monitor the bi-directional flow of fire ant workers in laboratory tunnels of varied diameter D. The persistence time of communicating ant aggregations, τ, increases approximately linearly with the number of participating ants, n. The sensitivity of traffic flow increases as D decreases and diverges at a minimum diameter, Dc. A cellular automata model incorporating minimal traffic features--excluded volume and communication duration--reproduces features of the experiment. From the model we identify a competition between information transfer and the need to maintain jam-free traffic flow. We show that by balancing information transfer and traffic flow demands, an optimum group strategy exists which maximizes information throughput. We acknowledge funding from NSF PoLS #0957659 and #PHY-1205878.

  2. Evolutionarily advanced ant farmers rear polyploid fungal crops

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus; Aanen, D.K.; Schiøtt, Morten

    2015-01-01

    to be lowly and facultatively polyploid (just over two haplotypes on average), whereas Atta and Acromyrmex symbionts are highly and obligatorily polyploid (ca. 5-7 haplotypes on average). This stepwise transition appears analogous to ploidy variation in plants and fungi domesticated by humans and in fungi...... the number of nuclei per fungal cell for 42 symbionts reared by 14 species of Panamanian fungus-growing ants. This showed that domesticated symbionts of higher attine ants are polykaryotic with 7-17 nuclei per cell, whereas nonspecialized crops of lower attines are dikaryotic similar to most free...... domesticated by termites and plants, where gene or genome duplications were typically associated with selection for higher productivity, but allopolyploid chimerism was incompatible with sexual reproduction....

  3. Nasa's Ant-Inspired Swarmie Robots

    Science.gov (United States)

    Leucht, Kurt W.

    2016-01-01

    As humans push further beyond the grasp of earth, robotic missions in advance of human missions will play an increasingly important role. These robotic systems will find and retrieve valuable resources as part of an in-situ resource utilization (ISRU) strategy. They will need to be highly autonomous while maintaining high task performance levels. NASA Kennedy Space Center has teamed up with the Biological Computation Lab at the University of New Mexico to create a swarm of small, low-cost, autonomous robots to be used as a ground-based research platform for ISRU missions. The behavior of the robot swarm mimics the central-place foraging strategy of ants to find and collect resources in a previously unmapped environment and return those resources to a central site. This talk will guide the audience through the Swarmie robot project from its conception by students in a New Mexico research lab to its robot trials in an outdoor parking lot at NASA. The software technologies and techniques used on the project will be discussed, as well as various challenges and solutions that were encountered by the development team along the way.

  4. The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens

    DEFF Research Database (Denmark)

    Moller, Isabel Eva; de Fine Licht, Henrik Hjarvard; Harholt, Jesper

    2011-01-01

    communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated......The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus......, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste...

  5. Distribution, spread, and ecological associations of the introduced ant Pheidole obscurithorax in the southeastern United States

    Directory of Open Access Journals (Sweden)

    Shonna R. Storz

    2004-04-01

    Full Text Available A field survey of the southeastern United States showed that Pheidole obscurithorax Naves, an ant introduced from South America, inhabits a 80-km-wide band along the coast between Mobile, Alabama, and Tallahassee, Florida, and is continuing to increase its range. In Tallahassee P. obscurithorax is rapidly spreading, and its nest density increased by a factor of 6.4 over a two-year period. Evidence suggests that P. obscurithorax has spread gradually by natural means. It coexists with the fire ant Solenopsis invicta Buren, appears to be part of a largely exotic community of ants that are tolerant of highly disturbed habitats, and seems to have little negative effect on the ant communities that it invades.

  6. Modeling no-jam traffic in ant trails: a pheromone-controlled approach

    Science.gov (United States)

    Guo, Ning; Hu, Mao-Bin; Jiang, Rui; Ding, Jianxun; Ling, Xiang

    2018-05-01

    The experiment in John et al (2009 Phys. Rev. Lett. 102 108001) shows that when ants move in a single-file trail, no jam emerges even at very high densities. We propose a self-propelled model of ant traffic to reproduce the fundamental diagram without a jammed branch. In this model, ants can adjust their desired velocities actively by perceiving pheromone concentration near the front of the trail. Moreover, ants will bear the repulsive force when they have physical contact with neighbors. The velocity in the simulation decreases slightly with increasing density, which captures the main feature observed in the experiment. Distributions of velocity and distance headway basically also conform to the experimental ones.

  7. External immunity in ant societies: sociality and colony size do not predict investment in antimicrobials

    Science.gov (United States)

    Halawani, Omar; Pearson, Bria; Mathews, Stephanie; López-Uribe, Margarita M.; Dunn, Robert R.; Smith, Adrian A.

    2018-01-01

    Social insects live in dense groups with a high probability of disease transmission and have therefore faced strong pressures to develop defences against pathogens. For this reason, social insects have been hypothesized to invest in antimicrobial secretions as a mechanism of external immunity to prevent the spread of disease. However, empirical studies linking the evolution of sociality with increased investment in antimicrobials have been relatively few. Here we quantify the strength of antimicrobial secretions among 20 ant species that cover a broad spectrum of ant diversity and colony sizes. We extracted external compounds from ant workers to test whether they inhibited the growth of the bacterium Staphylococcus epidermidis. Because all ant species are highly social, we predicted that all species would exhibit some antimicrobial activity and that species that form the largest colonies would exhibit the strongest antimicrobial response. Our comparative approach revealed that strong surface antimicrobials are common to particular ant clades, but 40% of species exhibited no antimicrobial activity at all. We also found no correlation between antimicrobial activity and colony size. Rather than relying on antimicrobial secretions as external immunity to control pathogen spread, many ant species have probably developed alternative strategies to defend against disease pressure. PMID:29515850

  8. Disentangling the diversity of arboreal ant communities in tropical forest trees.

    Science.gov (United States)

    Klimes, Petr; Fibich, Pavel; Idigel, Cliffson; Rimandai, Maling

    2015-01-01

    Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

  9. Ant brood function as life preservers during floods.

    Directory of Open Access Journals (Sweden)

    Jessica Purcell

    Full Text Available Social organisms can surmount many ecological challenges by working collectively. An impressive example of such collective behavior occurs when ants physically link together into floating 'rafts' to escape from flooded habitat. However, raft formation may represent a social dilemma, with some positions posing greater individual risks than others. Here, we investigate the position and function of different colony members, and the costs and benefits of this functional geometry in rafts of the floodplain-dwelling ant Formica selysi. By causing groups of ants to raft in the laboratory, we observe that workers are distributed throughout the raft, queens are always in the center, and 100% of brood items are placed on the base. Through a series of experiments, we show that workers and brood are extremely resistant to submersion. Both workers and brood exhibit high survival rates after they have rafted, suggesting that occupying the base of the raft is not as costly as expected. The placement of all brood on the base of one cohesive raft confers several benefits: it preserves colony integrity, takes advantage of brood buoyancy, and increases the proportion of workers that immediately recover after rafting.

  10. ANTS/PAM: Future Exploration of the Asteroid Belt

    Science.gov (United States)

    Clark, P. E.; Curtis, S. A.; Rilee, M. L.; Cheung, C. Y.

    2004-05-01

    The Autonomous Nano-Technology Swarm (ANTS) is applied to the Prospecting Asteroid Mission (PAM) concept, as part of a NASA RASC study. The ANTS architecture is inspired by success of social insect colonies, based on the division of labor within the colonies: 1) within their specialties, individual specialists generally outperform general-ists, and 2) with sufficiently efficient social interaction and coordination, the group of specialists generally outper-forms the group of generalists. ANTS as applied to PAM involves a thousand individual specialist `sciencecraft', one subswarm per target, in an environment where detection and tracking of irregular, infrequent targets is a major chal-lenge. Workers, carry and operate eight to nine different scientific instruments, including spectrometers, ranging and radio science devices, imagers. The remaining specialists, Messenger/Rulers, provide communication and coordina-tion. The non-expendable propulsion system is based on autonomously deployable and configurable solar sails, a system suitable to a low gravity environment. The design of the neural basis function requires a minimum of 4 or 5 specialists for collective decision making. Allowing for ten instrument specialist teams and compensating for antici-pated high attrition, we calculate an initial minimum of 100 per subswarm should allow characterization of hundreds of asteroids. The difficulty in observing irregular, rapidly moving, poorly illuminated objects is largely overcome by the ANT sciencecraft capability to optimize conditions for each instrument. Components are composed of carbon nanotubules reversibly deployable from NEMS nodes, allowing 100 times decrease in packaging volume. 1000 smart 10 centimeter, 1 kg cubic boxes create a 1000 kg 1 meter cube.

  11. Determining the most effective concentration of cypermethrin and the appropriate carrier particle size for fire ant (Hymenoptera: Formicidae) bait.

    Science.gov (United States)

    Kafle, Lekhnath; Shih, Cheng-Jen

    2012-03-01

    The purpose of this study was to determine the most effective particle size of DDGS (distiller's dried grains with solubles) as fire ant bait carrier, as well as the most effective concentration of cypermethrin as a toxicant against the red imported fire ant (RIFA) Solenopsis invicta Buren under laboratory conditions. The DDGS particle size did not affect the fire ant's preference for the bait, but it did affect the mass of DDGS being carried back to the nest. The size of the DDGS particles and the mass of DDGS being carried back to the nest were positively correlated. The most efficient particle size of DDGS was 0.8-2 mm. The concentration of cypermethrin has a specific range for killing fire ants in an efficient manner. Neither a very low nor a very high concentration of cypermethrin was able to kill fire ants efficiently. The most effective concentration of cypermethrin was 0.13% in DDGS when mixed with 15% shrimp shell powders and 11% soybean oil. Based on its ability to kill fire ants when mixed with cypermethrin, as well as the advantage of having a larger area coverage when sprayed in the field, DDGS as the carrier and cypermethrin as the toxicant can be considered to be an efficient way to prepare fire ant bait for controlling fire ants in infested areas. Copyright © 2012 Society of Chemical Industry.

  12. Geographic mosaic of plant evolution: extrafloral nectary variation mediated by ant and herbivore assemblages.

    Directory of Open Access Journals (Sweden)

    Anselmo Nogueira

    with abundant and highly detrimental herbivores. Our findings provide insights on the ecology and evolution of plant-ant guarding systems, and suggest new directions to research on facultative mutualistic interactions at wide geographic scales.

  13. Fuzzy Rules for Ant Based Clustering Algorithm

    Directory of Open Access Journals (Sweden)

    Amira Hamdi

    2016-01-01

    Full Text Available This paper provides a new intelligent technique for semisupervised data clustering problem that combines the Ant System (AS algorithm with the fuzzy c-means (FCM clustering algorithm. Our proposed approach, called F-ASClass algorithm, is a distributed algorithm inspired by foraging behavior observed in ant colonyT. The ability of ants to find the shortest path forms the basis of our proposed approach. In the first step, several colonies of cooperating entities, called artificial ants, are used to find shortest paths in a complete graph that we called graph-data. The number of colonies used in F-ASClass is equal to the number of clusters in dataset. Hence, the partition matrix of dataset founded by artificial ants is given in the second step, to the fuzzy c-means technique in order to assign unclassified objects generated in the first step. The proposed approach is tested on artificial and real datasets, and its performance is compared with those of K-means, K-medoid, and FCM algorithms. Experimental section shows that F-ASClass performs better according to the error rate classification, accuracy, and separation index.

  14. Autonomous Agents on Expedition: Humans and Progenitor Ants and Planetary Exploration

    Science.gov (United States)

    Rilee, M. L.; Clark, P. E.; Curtis, S. A.; Truszkowski, W. F.

    2002-01-01

    The Autonomous Nano-Technology Swarm (ANTS) is an advanced mission architecture based on a social insect analog of many specialized spacecraft working together to achieve mission goals. The principal mission concept driving the ANTS architecture is a Main Belt Asteroid Survey in the 2020s that will involve a thousand or more nano-technology enabled, artificially intelligent, autonomous pico-spacecraft (architecture. High level, mission-oriented behaviors are to be managed by a control / communications layer of the swarm, whereas common low level functions required of all spacecraft, e.g. attitude control and guidance and navigation, are handled autonomically on each spacecraft. At the higher levels of mission planning and social interaction deliberative techniques are to be used. For the asteroid survey, ANTS acts as a large community of cooperative agents while for precursor missions there arises the intriguing possibility of Progenitor ANTS and humans acting together as agents. For optimal efficiency and responsiveness for individual spacecraft at the lowest levels of control we have been studying control methods based on nonlinear dynamical systems. We describe the critically important autonomous control architecture of the ANTS mission concept and a sequence of partial implementations that feature increasingly autonomous behaviors. The scientific and engineering roles that these Progenitor ANTS could play in human missions or remote missions with near real time human interactions, particularly to the Moon and Mars, will be discussed.

  15. Evaluation of Liquid and Bait Insecticides against the Dark Rover Ant (Brachymyrmex patagonicus

    Directory of Open Access Journals (Sweden)

    Javier G. Miguelena

    2014-11-01

    Full Text Available Dark rover ants (Brachymyrmex patagonicus, Mayr are an exotic ant species native to South America that has recently spread through the southern US. We evaluated the residual activity of three liquid insecticides (indoxacarb, fipronil and lambda-cyhalothrin as potential barrier treatments against these ants. The factors we considered include the use of a porous or non-porous surface, a short or long exposure time and the changes in insecticide activity after treatment during a 90 day period. We also tested the effect of baits containing three different active ingredients (imidacloprid, sodium tetraborate and indoxacarb on colony fragments of this species for a 15 day period. Both lambda-cyhalothrin® and indoxacarb® resulted in high levels of ant mortality up to 90 days after application. The results of exposure to fipronil® resembled those from the control treatment. Application of insecticides on a porous surface and the shorter exposure time generally resulted in greater ant survival. Of the baits tested, only the imidacloprid based one decreased ant survival significantly during the evaluation period. Within three days, the imidacloprid bait produced over 50% mortality which increased to over 95% by the end of the experiment. Results from the other two bait treatments were not significantly different from the control.

  16. Compound eye adaptations for diurnal and nocturnal lifestyle in the intertidal ant, Polyrhachis sokolova.

    Directory of Open Access Journals (Sweden)

    Ajay Narendra

    Full Text Available The Australian intertidal ant, Polyrhachis sokolova lives in mudflat habitats and nests at the base of mangroves. They are solitary foraging ants that rely on visual cues. The ants are active during low tides at both day and night and thus experience a wide range of light intensities. We here ask the extent to which the compound eyes of P. sokolova reflect the fact that they operate during both day and night. The ants have typical apposition compound eyes with 596 ommatidia per eye and an interommatidial angle of 6.0°. We find the ants have developed large lenses (33 µm in diameter and wide rhabdoms (5 µm in diameter to make their eyes highly sensitive to low light conditions. To be active at bright light conditions, the ants have developed an extreme pupillary mechanism during which the primary pigment cells constrict the crystalline cone to form a narrow tract of 0.5 µm wide and 16 µm long. This pupillary mechanism protects the photoreceptors from bright light, making the eyes less sensitive during the day. The dorsal rim area of their compound eye has specialised photoreceptors that could aid in detecting the orientation of the pattern of polarised skylight, which would assist the animals to determine compass directions required while navigating between nest and food sources.

  17. Repeated evolution of fungal cultivar specificity in independently evolved ant-plant-fungus symbioses.

    Science.gov (United States)

    Blatrix, Rumsaïs; Debaud, Sarah; Salas-Lopez, Alex; Born, Céline; Benoit, Laure; McKey, Doyle B; Attéké, Christiane; Djiéto-Lordon, Champlain

    2013-01-01

    Some tropical plant species possess hollow structures (domatia) occupied by ants that protect the plant and in some cases also provide it with nutrients. Most plant-ants tend patches of chaetothyrialean fungi within domatia. In a few systems it has been shown that the ants manure the fungal patches and use them as a food source, indicating agricultural practices. However, the identity of these fungi has been investigated only in a few samples. To examine the specificity and constancy of ant-plant-fungus interactions we characterised the content of fungal patches in an extensive sampling of three ant-plant symbioses (Petalomyrmex phylax/Leonardoxa africana subsp. africana, Aphomomyrmex afer/Leonardoxa africana subsp. letouzeyi and Tetraponera aethiops/Barteria fistulosa) by sequencing the Internal Transcribed Spacers of ribosomal DNA. For each system the content of fungal patches was constant over individuals and populations. Each symbiosis was associated with a specific, dominant, primary fungal taxon, and to a lesser extent, with one or two specific secondary taxa, all of the order Chaetothyriales. A single fungal patch sometimes contained both a primary and a secondary taxon. In one system, two founding queens were found with the primary fungal taxon only, one that was shown in a previous study to be consumed preferentially. Because the different ant-plant symbioses studied have evolved independently, the high specificity and constancy we observed in the composition of the fungal patches have evolved repeatedly. Specificity and constancy also characterize other cases of agriculture by insects.

  18. Repeated evolution of fungal cultivar specificity in independently evolved ant-plant-fungus symbioses.

    Directory of Open Access Journals (Sweden)

    Rumsaïs Blatrix

    Full Text Available Some tropical plant species possess hollow structures (domatia occupied by ants that protect the plant and in some cases also provide it with nutrients. Most plant-ants tend patches of chaetothyrialean fungi within domatia. In a few systems it has been shown that the ants manure the fungal patches and use them as a food source, indicating agricultural practices. However, the identity of these fungi has been investigated only in a few samples. To examine the specificity and constancy of ant-plant-fungus interactions we characterised the content of fungal patches in an extensive sampling of three ant-plant symbioses (Petalomyrmex phylax/Leonardoxa africana subsp. africana, Aphomomyrmex afer/Leonardoxa africana subsp. letouzeyi and Tetraponera aethiops/Barteria fistulosa by sequencing the Internal Transcribed Spacers of ribosomal DNA. For each system the content of fungal patches was constant over individuals and populations. Each symbiosis was associated with a specific, dominant, primary fungal taxon, and to a lesser extent, with one or two specific secondary taxa, all of the order Chaetothyriales. A single fungal patch sometimes contained both a primary and a secondary taxon. In one system, two founding queens were found with the primary fungal taxon only, one that was shown in a previous study to be consumed preferentially. Because the different ant-plant symbioses studied have evolved independently, the high specificity and constancy we observed in the composition of the fungal patches have evolved repeatedly. Specificity and constancy also characterize other cases of agriculture by insects.

  19. Macrodinychus mites as parasitoids of invasive ants: an overlooked parasitic association.

    Science.gov (United States)

    Lachaud, Jean-Paul; Klompen, Hans; Pérez-Lachaud, Gabriela

    2016-07-21

    Mites are frequent ant symbionts, yet the exact nature of their interactions with their hosts is poorly known. Generally, myrmecophilous mites show adaptations for dispersal through phoresis, but species that lack such an adaptation may have evolved unusual specialized relationships with their hosts. The immature stages of Macrodinychus multispinosus develop as ectoparasitoids of pupae of the invasive ant Paratrechina longicornis. Feeding stages show regressed locomotor appendages. These mites complete their development on a single host, sucking all of its body content and therefore killing it. Locally high proportions of parasitized host pupae suggest that M. multispinosus could serve as a biological control agent. This is the ninth species of Macrodinychus reported as ant parasite, and the third known as parasitoid of invasive ants, confirming a unique habit in the evolution of mite feeding strategies and suggesting that the entire genus might be parasitic on ants. Several mites' characteristics, such as their protective morphology, possible viviparity, lack of a specialized stage for phoretic dispersal, and low host specificity, combined with both the general low aggressiveness of invasive P. longicornis towards other ants and its possible susceptibility to generalist ectoparasites would account for the host shift in native macrodinychid mites.

  20. Spider diversity in coffee agroecosystems: the influence of agricultural intensification and aggressive ants.

    Science.gov (United States)

    Marín, Linda; Perfecto, Ivette

    2013-04-01

    Spiders are a very diverse group of invertebrate predators found in agroecosystems and natural systems. However, spider distribution, abundance, and eventually their ecological function in ecosystems can be influenced by abiotic and biotic factors such as agricultural intensification and dominant ants. Here we explore the influence of both agricultural intensification and the dominant arboreal ant Azteca instabilis on the spider community in coffee agroecosystems in southern Mexico. To measure the influence of the arboreal ant Azteca instabilis (F. Smith) on the spider community inhabiting the coffee layer of coffee agroecosystems, spiders were collected from coffee plants that were and were not patrolled by the ant in sites differing in agricultural intensification. For 2008, generalized linear mixed models showed that spider diversity was affected positively by agricultural intensification but not by the ant. However, results suggested that some spider species were associated with A. instabilis. Therefore, in 2009 we concentrated our research on the effect of A. instabilis on spider diversity and composition. For 2009, generalized linear mixed models show that spider richness and abundance per plant were significantly higher in the presence of A. instabilis. In addition, analyses of visual counts of insects and sticky traps data show that more resources were present in plants patrolled by the ant. The positive effect of A. instabilis on spiders seems to be caused by at least two mechanisms: high abundance of insects and protection against predators.

  1. Ant parasite queens revert to mating singly

    DEFF Research Database (Denmark)

    Sumner, Seirian; Hughes, William Owen Hamar; Pedersen, Jes Søe

    2004-01-01

    quantified and they tend to be similar in related species. Here we compare the mating strategies of the leaf-cutting ant Acromyrmex echinatior and its recently derived social parasite Acromyrmex insinuator, which is also its closest relative 2 (see Fig. 1 ). We find that although the host queens mate with up......A parasitic ant has abandoned the multiple mating habit of the queens of its related host. Multiple mating (polyandry) is widespread among animal groups, particularly insects 1 . But the factors that maintain it and underlie its evolution are hard to verify because benefits and costs are not easily...... to a dozen different males, the social parasite mates only singly. This rapid and surprising reversion to single mating in a socially parasitic ant indicates that the costs of polyandry are probably specific to a free-living lifestyle....

  2. The worldwide expansion of the Argentine ant

    DEFF Research Database (Denmark)

    Vogel, Valerie; Pedersen, Jes Søe; Giraud, Tatiana

    2010-01-01

    Aim The aim of this study was to determine the number of successful establishments of the invasive Argentine ant outside native range and to see whether introduced supercolonies have resulted from single or multiple introductions. We also compared the genetic diversity of native versus introduced...... supercolonies to assess the size of the propagules (i.e. the number of founding individuals) at the origin of the introduced supercolonies. Location Global. Methods We used mitochondrial DNA (mtDNA) markers and microsatellite loci to study 39 supercolonies of the Argentine ant Linepithema humile covering both......) and secondary introductions (from sites with established invasive supercolonies) were important in the global expansion of the Argentine ant. In combination with the similar social organization of colonies in the native and introduced range, this indicates that invasiveness did not evolve recently as a unique...

  3. Desert ants learn vibration and magnetic landmarks.

    Directory of Open Access Journals (Sweden)

    Cornelia Buehlmann

    Full Text Available The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks are usually provided by the ants' habitat as nest-defining cues. However, our results point to the flexibility of the ants' navigational system, which even makes use of cues that are probably most often sensed in a different context.

  4. Ant-plants and fungi: a new threeway symbiosis.

    Science.gov (United States)

    Defossez, Emmanuel; Selosse, Marc-André; Dubois, Marie-Pierre; Mondolot, Laurence; Faccio, Antonella; Djieto-Lordon, Champlain; McKey, Doyle; Blatrix, Rumsaïs

    2009-06-01

    Symbioses between plants and fungi, fungi and ants, and ants and plants all play important roles in ecosystems. Symbioses involving all three partners appear to be rare. Here, we describe a novel tripartite symbiosis in which ants and a fungus inhabit domatia of an ant-plant, and present evidence that such interactions are widespread. We investigated 139 individuals of the African ant-plant Leonardoxa africana for occurrence of fungus. Behaviour of mutualist ants toward the fungus within domatia was observed using a video camera fitted with an endoscope. Fungi were identified by sequencing a fragment of their ribosomal DNA. Fungi were always present in domatia occupied by mutualist ants but never in domatia occupied by opportunistic or parasitic ants. Ants appear to favour the propagation, removal and maintenance of the fungus. Similar fungi were associated with other ant-plants in Cameroon. All belong to the ascomycete order Chaetothyriales; those from L. africana formed a monophyletic clade. These new plant-ant-fungus associations seem to be specific, as demonstrated within Leonardoxa and as suggested by fungal phyletic identities. Such tripartite associations are widespread in African ant-plants but have long been overlooked. Taking fungal partners into account will greatly enhance our understanding of symbiotic ant-plant mutualisms.

  5. Ants of the Peloponnese, Greece (Hymenoptera: Formicidae

    Directory of Open Access Journals (Sweden)

    Borowiec Lech

    2017-09-01

    Full Text Available This paper relates to material obtained during two field trips to the Peloponnese in 2013 and 2016. With the inclusion of some hitherto unpublished ant material, it gives new records from a total of 92 sampling localities. 129 species (including morphospecies not attributed to any known taxon of ants have been recorded from the Peloponnese (southern Greece, 27 of which have been recorded from this region for the first time. Lasius reginae and 5 other morphospecies attributed only to species complexes are new to Greece.

  6. Image Edge Tracking via Ant Colony Optimization

    Science.gov (United States)

    Li, Ruowei; Wu, Hongkun; Liu, Shilong; Rahman, M. A.; Liu, Sanchi; Kwok, Ngai Ming

    2018-04-01

    A good edge plot should use continuous thin lines to describe the complete contour of the captured object. However, the detection of weak edges is a challenging task because of the associated low pixel intensities. Ant Colony Optimization (ACO) has been employed by many researchers to address this problem. The algorithm is a meta-heuristic method developed by mimicking the natural behaviour of ants. It uses iterative searches to find the optimal solution that cannot be found via traditional optimization approaches. In this work, ACO is employed to track and repair broken edges obtained via conventional Sobel edge detector to produced a result with more connected edges.

  7. Effect of perceived stress on depression of Chinese "Ant Tribe" and the moderating role of dispositional optimism.

    Science.gov (United States)

    Liu, Bo; Pu, Jun; Hou, Hanpo

    2015-05-08

    This study examines the moderating role of dispositional optimism on the relationship between perceived stress and depression of the Chinese "Ant Tribe." A total of 427 participants from an Ant Tribe community completed the measures of perceived stress, optimism, and depression. The structural equation modeling (SEM) analysis showed that dispositional optimism moderated the association between perceived stress and depression. The Ant Tribe with high perceived stress reported higher scores in depression than those with low perceived stress at low dispositional optimism level. However, the impact of perceived stress on depression was insignificant in the high dispositional optimism group. © The Author(s) 2015.

  8. Hybrid Bee Ant Colony Algorithm for Effective Load Balancing And ...

    African Journals Online (AJOL)

    PROF. OLIVER OSUAGWA

    Ant Colony algorithm is used in this hybrid Bee Ant Colony algorithm to solve load balancing issues ... Genetic Algorithm (MO-GA) for dynamic job scheduling that .... Information Networking and Applications Workshops. [7]. M. Dorigo & T.

  9. Thermoregulation strategies in ants in comparison to other social insects, with a focus on red wood ants (Formica rufa group [v2; ref status: indexed, http://f1000r.es/35p

    Directory of Open Access Journals (Sweden)

    Štěpánka Kadochová

    2014-03-01

    Full Text Available Temperature influences every aspect of ant biology, especially metabolic rate, growth and development. Maintenance of high inner nest temperature increases the rate of sexual brood development and thereby increases the colony fitness. Insect societies can achieve better thermoregulation than solitary insects due to the former’s ability to build large and elaborated nests and display complex behaviour. In ants and termites the upper part of the nest, the mound, often works as a solar collector and can also have an efficient ventilation system. Two thermoregulatory strategies could be applied. Firstly the ants use an increased thermal gradient available in the mound for brood relocation. Nurse workers move the brood according to the thermal gradients to ensure the ideal conditions for development. A precise perception of temperature and evolution of temperature preferences are needed to make the correct choices. A second thermoregulatory strategy used by mound nesting ants is keeping a high temperature inside large nests. The unique thermal and insulation properties of the nest material help to maintain stable conditions, which is the case of the Wood ant genus Formica. Ants can regulate thermal loss by moving nest aggregation and alternating nest ventilation. Metabolic heat produced by ant workers or associated micro organisms is an important additional source of heat which helps to maintain thermal homeostasis in the nest.

  10. Dealing with water deficit in Atta ant colonies: large ants scout for water while small ants transport it

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Da-Silva

    2012-07-01

    Leafcutter ants (Atta sexdens rubropilosa (Forel 1908 have an elaborate social organization, complete with caste divisions. Activities carried out by specialist groups contribute to the overall success and survival of the colony when it is confronted with environmental challenges such as dehydration. Ants detect variations in humidity inside the nest and react by activating several types of behavior that enhance water uptake and decrease water loss, but it is not clear whether or not a single caste collects water regardless of the cost of bringing this resource back to the colony. Accordingly, we investigated water collection activities in three colonies of Atta sexdens rubropilosa experimentally exposed to water stress. Specifically, we analyzed whether or not the same ant caste foraged for water, regardless of the absolute energetic cost (distance of transporting this resource back to the colony. Our experimental design offered water sources at 0 m, 1 m and 10 m from the nest. We studied the body size of ants near the water sources from the initial offer of water (time  =  0 to 120 min, and tested for specialization. We observed a reduction in the average size and variance of ants that corroborated the specialization hypothesis. Although the temporal course of specialization changed with distance, the final outcome was similar among distances. Thus, we conclude that, for this species, a specialist (our use of the word “specialist” does not mean exclusive task force is responsible for collecting water, regardless of the cost of transporting water back to the colony.

  11. Specificity of the mutualistic association between actinomycete bacteria and two sympatric species of Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Poulsen, M; Cafaro, M; Boomsma, J J

    2005-01-01

    Acromyrmex leaf-cutting ants maintain two highly specialized, vertically transmitted mutualistic ectosymbionts: basidiomycete fungi that are cultivated for food in underground gardens and actinomycete Pseudonocardia bacteria that are reared on the cuticle to produce antibiotics that suppress...

  12. Extended phenotype: nematodes turn ants into bird-dispersed fruits

    DEFF Research Database (Denmark)

    Hughes, D P; Kronauer, D J C; Boomsma, J J

    2008-01-01

    A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs.......A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs....

  13. Histrionicotoxin alkaloids finally detected in an ant

    DEFF Research Database (Denmark)

    Jones, Tappey H.; Adams, Rachelle Martha Marie; Spande, Thomas F.

    2012-01-01

    Workers of the ant Carebarella bicolor collected in Panama were found to have two major poison-frog alkaloids, cis- and trans-fused decahydroquinolines (DHQs) of the 269AB type, four minor 269AB isomers, two minor 269B isomers, and three isomers of DHQ 271D. For the first time in an ant, however......) sp., were found to have a very similar DHQ complex but failed to show HTXs. Several new DHQ alkaloids of MW 271 (named in the frog as 271G) are reported from the above ants that have both m/z 202 and 204 as major fragment ions, unlike the spectrum seen for the poison-frog alkaloid 271D, which has...... only an m/z 204 base peak. Found also for the first time in skin extracts from the comparison frog Oophaga granulifera of Costa Rica is a trace DHQ of MW 273. It is coded as 273F in the frog; a different isomer is found in the ant....

  14. Ants, rodents and seed predation in Proteaceae

    African Journals Online (AJOL)

    ... their nests extremely rapidly. One benefit of the ant-plant interaction may be seed escape ... (odourless to humans when dry) household glue or, b) placing seed in a Petri dish ... the layout of exclosures was completed. Response was not as.

  15. The evolution of invasiveness in garden ants

    DEFF Research Database (Denmark)

    Cremer, Sylvia; Ugelvig, Line Vej; Drijfhout, Falko P

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its ra...

  16. The ejaculatory biology of leafcutter ants

    DEFF Research Database (Denmark)

    den Boer, Susanne; Stürup, Marlene; Boomsma, Jacobus Jan

    2015-01-01

    understanding of the fundamental biology of ejaculate production, transfer and physiological function remains extremely limited. We studied the ejaculation process in the leafcutter ant Atta colombica and found that it starts with the appearance of a clear pre-ejaculatory fluid (PEF) at the tip...

  17. Mating, hybridisation and introgression in Lasius ants

    NARCIS (Netherlands)

    Have, van der T.M.; Pedersen, J.S.; Boomsma, J.J.

    2011-01-01

    Recent reviews have shown that hybridisation among ant species is likely to be more common than previously appreciated. but that documented cases of introgression remain rare. After molecular phylogenetic work had shown that European Lasius niger (LINNAEUS, 1758) and L. psammophilus SEIFERT, 1992

  18. Ants recognize foes and not friends

    Science.gov (United States)

    Guerrieri, Fernando J.; Nehring, Volker; Jørgensen, Charlotte G.; Nielsen, John; Galizia, C. Giovanni; d'Ettorre, Patrizia

    2009-01-01

    Discriminating among individuals and rejecting non-group members is essential for the evolution and stability of animal societies. Ants are good models for studying recognition mechanisms, because they are typically very efficient in discriminating ‘friends’ (nest-mates) from ‘foes’ (non-nest-mates). Recognition in ants involves multicomponent cues encoded in cuticular hydrocarbon profiles. Here, we tested whether workers of the carpenter ant Camponotus herculeanus use the presence and/or absence of cuticular hydrocarbons to discriminate between nest-mates and non-nest-mates. We supplemented the cuticular profile with synthetic hydrocarbons mixed to liquid food and then assessed behavioural responses using two different bioassays. Our results show that (i) the presence, but not the absence, of an additional hydrocarbon elicited aggression and that (ii) among the three classes of hydrocarbons tested (unbranched, mono-methylated and dimethylated alkanes; for mono-methylated alkanes, we present a new synthetic pathway), only the dimethylated alkane was effective in eliciting aggression. Our results suggest that carpenter ants use a fundamentally different mechanism for nest-mate recognition than previously thought. They do not specifically recognize nest-mates, but rather recognize and reject non-nest-mates bearing odour cues that are novel to their own colony cuticular hydrocarbon profile. This begs for a reappraisal of the mechanisms underlying recognition systems in social insects. PMID:19364750

  19. Recognition of social identity in ants

    DEFF Research Database (Denmark)

    Bos, Nick; d'Ettorre, Patrizia

    2012-01-01

    Recognizing the identity of others, from the individual to the group level, is a hallmark of society. Ants, and other social insects, have evolved advanced societies characterized by efficient social recognition systems. Colony identity is mediated by colony specific signature mixtures, a blend...

  20. Plasmodium parasitaemia among pregnant women attending ante ...

    African Journals Online (AJOL)

    ... Ante-Natal Clinic at Military Hospital Port Harcourt, Rivers State, Nigeria using the Standard parasitological technique. Venous blood was collected from 200 pregnant women, both thick and thin blood films were made on clean greese-free glass slide and stained with 10% Giemsa stains diluted with 7.2 buffered water for ...

  1. Operant conditioning in the ant Myrmica sabuleti.

    Science.gov (United States)

    Cammaerts, M C

    2004-11-30

    Operant conditioning could be obtained in the ant Myrmica sabuleti by presenting to the workers, during a six-day period, an apparatus containing either sugared water or meat as a reward. The conditioning obtained using sugared water as a reward was short lasting. A reconditioning was more persistent and lasted four hours. The ants' response was very precise, since they exhibited it only in front of an apparatus identical to that used during the training phase. Operant conditioning obtained using meat as a reward was more pronounced than that obtained by using sugared water, probably because meat is more valuable as a reward than sugar for the species studied, which is essentially a carnivorous one. Such a conditioning was rather persistent. Indeed, a first operant conditioning obtained by using meat as a reward could still be detected after seven hours, and a reconditioning was still significant after eight hours. One day after this eight-hour period without rewarding the ants, the response was higher again and a further day later, it was still significant. Since the operant conditioning is easy to perform and quantify and since the ants' response is very precise, such a conditioning can be used for further studying M. sabuleti workers' visual perception.

  2. A global database of ant species abundances

    Science.gov (United States)

    Gibb, Heloise; Dunn, Rob R.; Sanders, Nathan J.; Grossman, Blair F.; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N.; Angulo, Elena; Armbrecht, Ingre; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Bruhl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Ellison, Aaron M.; Enriquez, Martha L.; Fayle, Tom M.; Feener Jr., Donald H.; Fisher, Brian L.; Fisher, Robert N.; Fitpatrick, Matthew C.; Gomez, Cristanto; Gotelli, Nicholas J.; Gove, Aaron; Grasso, Donato A.; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H.; Majer, Jonathan; McGlynn, Terrence P.; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; Resasco, Julian; Retana, Javier; Silva, Rogerio R.; Sorger, Magdalena D.; Souza, Jorge; Suarez, Andrew V.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Weiser, Michael D.; Yates, Michelle; Parr, Catherine L.

    2017-01-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardised methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing dataset.

  3. Community Structure of Leaf-Litter Ants in a Neotropical Dry Forest: A Biogeographic Approach to Explain Betadiversity

    Directory of Open Access Journals (Sweden)

    Rogério Silvestre

    2012-01-01

    Full Text Available This paper describes habitat and geographic correlates of ant diversity in Serra da Bodoquena, a poorly surveyed region of central-western Brazil. We discuss leaf-litter ant diversity on a regional scale, with emphasis on the contribution of each of the processes that form the evolutionary basis of contemporary beta diversity. The diversity of leaf-litter ants was assessed from a series of 262 Winkler samples conducted in two microbasins within a deciduous forest domain. A total of 170 litter-dwelling ant species in 45 genera and 11 subfamilies was identified. The data showed that the study areas exhibited different arrangements of ant fauna, with a high turnover in species composition between sites, indicating high beta diversity. Our analysis suggests that the biogeographic history of this tropical dry forest in the centre of South America could explain ant assemblage structure more than competitive dominance. The co-occurrence analysis showed that species co-occur less often than expected by chance in only two of the localities, suggesting that, for most of the species, co-occurrences are random. The assessment of the structure of the diversity of litter-dwelling ants is the first step in understanding the beta diversity patterns in this region of great biogeographic importance.

  4. Vegetation structure of plantain-based agrosystems determines numerical dominance in community of ground-dwelling ants.

    Science.gov (United States)

    Dassou, Anicet Gbéblonoudo; Tixier, Philippe; Dépigny, Sylvain; Carval, Dominique

    2017-01-01

    In tropics, ants can represent an important part of animal biomass and are known to be involved in ecosystem services, such as pest regulation. Understanding the mechanisms underlying the structuring of local ant communities is therefore important in agroecology. In the humid tropics of Africa, plantains are cropped in association with many other annual and perennial crops. Such agrosystems differ greatly in vegetation diversity and structure and are well-suited for studying how habitat-related factors affect the ant community. We analysed abundance data for the six numerically dominant ant taxa in 500 subplots located in 20 diversified, plantain-based fields. We found that the density of crops with foliage at intermediate and high canopy strata determined the numerical dominance of species. We found no relationship between the numerical dominance of each ant taxon with the crop diversity. Our results indicate that the manipulation of the densities of crops with leaves in the intermediate and high strata may help maintain the coexistence of ant species by providing different habitat patches. Further research in such agrosystems should be performed to assess if the effect of vegetation structure on ant abundance could result in efficient pest regulation.

  5. Cloning and sequencing of wsp encoding gene fragments reveals a diversity of co-infecting Wolbachia strains in Acromyrmex leafcutter ants

    DEFF Research Database (Denmark)

    van Borm, S.; Wenseleers, T.; Billen, J.

    2003-01-01

    Acromyrmex insinuator hosted two additional infections. The multiple Wolbachia strains may influence the expression of reproductive conflicts in leafcutter ants, but the expected turnover of infections may make the cumulative effects on host ant reproduction complex. The additional Wolbachia infections......By sequencing part of the wsp gene of a series of clones, we detected an unusually high diversity of nine Wolbachia strains in queens of three species of leafcutter ants. Up to four strains co-occurred in a single ant. Most strains occurred in two clusters (InvA and InvB), but the social parasite...

  6. ANTS-anchored Zn-Al-CO3-LDH particles as fluorescent probe for sensing of folic acid

    International Nuclear Information System (INIS)

    Liu, Pengfei; Liu, Dan; Liu, Yanhuan; Li, Lei

    2016-01-01

    A novel fluorescent nanosensor for detecting folic acid (FA) in aqueous media has been developed based on 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) anchored to the surface of Zn-Al-CO 3 -layered double hydroxides (LDH) particles. The nanosensor showed high fluorescence intensity and good photostability due to a strong coordination interaction between surface Zn 2+ ions of Zn-Al-CO 3 -LDH and N atoms of ANTS, which were verified by result of X-ray photoelectron spectroscopy (XPS). ANTS-anchored on the surface of Zn-Al-CO 3 -LDH restricted the intra-molecular rotation leading to ANTS-anchored J-type aggregation emission enhancement. ANTS-anchored Zn-Al-CO 3 -LDH particles exhibited highly sensitive and selective response to FA over other common metal ions and saccharides present in biological fluids. The proposed mechanism was that oxygen atoms of -SO 3 groups in ANTS-anchored on the surface of Zn-Al-CO 3 -LDH were easily collided by FA molecules to form potential hydrogen bonds between ANTS-anchored and FA molecules, which could effectively quench the ANTS-anchored fluorescence. Under the simulated physiological conditions (pH of 7.4), the fluorescence quenching was fitted to Stern-Volmer equation with a linear response in the concentration range of 1 μM to 200 μM with a limit of detection of 0.1 μM. The results indicate that ANTS-anchored Zn-Al-CO 3 -LDH particles can afford a very sensitive system for the sensing FA in aqueous solution. - Highlights: • A novel fluorescent nanosensor has been developed. • The sensor exhibited highly sensitive and selective response to FA. • The fluorescence quenching was fitted to Stern–Volmer equation. • The linear response range was 1–200 μM with a limit of detection of 0.1 μM.

  7. Studies on the environmental implications of ants (Hymenoptera ...

    African Journals Online (AJOL)

    A study of ants associated wh two synanthropcenvironments in Awka was carried out in 2008 using pitfall and bait traps. The study yelded a total of 561 ants wth 409 obtaned from the hemisynanthrophic environment while 192 ants were collected from the endophilic environment. The percentage occurrence, total dstribution ...

  8. Dynamics of an ant-plant-pollinator model

    Science.gov (United States)

    Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.

    2015-03-01

    In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.

  9. Ants Orasest ja Anne Lange monograafiast / Jüri Talvet

    Index Scriptorium Estoniae

    Talvet, Jüri, 1945-

    2005-01-01

    Arvustus: Oras, Ants. Luulekool. I, Apoloogia / koostajad Hando Runnel ja Jaak Rähesoo. Tartu : Ilmamaa, 2003 ; Oras, Ants. Luulekool II, Meistriklass. Tartu : Ilmamaa, 2004 ; Lange, Anne. Ants Oras : [kirjandusteadlane, -kriitik ja tõlkija (1900-1982)]. Tartu : Ilmamaa, 2004

  10. Plant lock and ant key: pairwise coevolution of an exclusion filter in an ant-plant mutualism.

    Science.gov (United States)

    Brouat, C; Garcia, N; Andary, C; McKey, D

    2001-10-22

    Although observations suggest pairwise coevolution in specific ant-plant symbioses, coevolutionary processes have rarely been demonstrated. We report on, what is to the authors' knowledge, the strongest evidence yet for reciprocal adaptation of morphological characters in a species-specific ant-plant mutualism. The plant character is the prostoma, which is a small unlignified organ at the apex of the domatia in which symbiotic ants excavate an entrance hole. Each myrmecophyte in the genus Leonardoxa has evolved a prostoma with a different shape. By performing precise measurements on the prostomata of three related myrmecophytes, on their specific associated ants and on the entrance holes excavated by symbiotic ants at the prostomata, we showed that correspondence of the plant and ant traits forms a morphological and behavioural filter. We have strong evidence for coevolution between the dimensions and shape of the symbiotic ants and the prostoma in one of the three ant-Leonardoxa associations.

  11. Inflorescences of the Bromeliad Vriesea friburgensis as Nest Sites and Food Resources for Ants and Other Arthropods in Brazil

    OpenAIRE

    Schmid, Volker S.; Langner, Simone; Steiner, Josefina; Zillikens, Anne

    2014-01-01

    For the first time, the usage of bromeliad inflorescences as nesting sites for ants and other arthropods was studied. Frequencies of occurrence of nests were recorded from hollow stems of dried infructescences of the bromeliad Vriesea friburgensis on Santa Catarina Island, southern Brazil. Three habitat types were studied: miconietum and two types of restinga, one with low (restinga-low) and one with high vegetation cover (restinga-high). Additionally, flower visitation by ants was examined i...

  12. Hidden diversity behind the zombie-ant fungus Ophiocordyceps unilateralis: four new species described from carpenter ants in Minas Gerais, Brazil.

    Directory of Open Access Journals (Sweden)

    Harry C Evans

    Full Text Available BACKGROUND: Ophiocordyceps unilateralis (Clavicipitaceae: Hypocreales is a fungal pathogen specific to ants of the tribe Camponotini (Formicinae: Formicidae with a pantropical distribution. This so-called zombie or brain-manipulating fungus alters the behaviour of the ant host, causing it to die in an exposed position, typically clinging onto and biting into the adaxial surface of shrub leaves. We (HCE and DPH are currently undertaking a worldwide survey to assess the taxonomy and ecology of this highly variable species. METHODS: We formally describe and name four new species belonging to the O. unilateralis species complex collected from remnant Atlantic rainforest in the south-eastern region (Zona da Mata of the State of Minas Gerais, Brazil. Fully illustrated descriptions of both the asexual (anamorph and sexual (teleomorph stages are provided for each species. The new names are registered in Index Fungorum (registration.indexfungorum.org and have received IF numbers. This paper is also a test case for the electronic publication of new names in mycology. CONCLUSIONS: We are only just beginning to understand the taxonomy and ecology of the Ophiocordyceps unilateralis species complex associated with carpenter ants; macroscopically characterised by a single stalk arising from the dorsal neck region of the ant host on which the anamorph occupies the terminal region and the teleomorph occurs as lateral cushions or plates. Each of the four ant species collected--Camponotus rufipes, C. balzani, C. melanoticus and C. novogranadensis--is attacked by a distinct species of Ophiocordyceps readily separated using traditional micromorphology. The new taxa are named according to their ant host.

  13. Species-specific ant brain manipulation by a specialized fungal parasite.

    Science.gov (United States)

    de Bekker, Charissa; Quevillon, Lauren E; Smith, Philip B; Fleming, Kimberly R; Ghosh, Debashis; Patterson, Andrew D; Hughes, David P

    2014-08-29

    A compelling demonstration of adaptation by natural selection is the ability of parasites to manipulate host behavior. One dramatic example involves fungal species from the genus Ophiocordyceps that control their ant hosts by inducing a biting behavior. Intensive sampling across the globe of ants that died after being manipulated by Ophiocordyceps suggests that this phenomenon is highly species-specific. We advance our understanding of this system by reconstructing host manipulation by Ophiocordyceps parasites under controlled laboratory conditions and combining this with field observations of infection rates and a metabolomics survey. We report on a newly discovered species of Ophiocordyceps unilateralis sensu lato from North America that we use to address the species-specificity of Ophiocordyceps-induced manipulation of ant behavior. We show that the fungus can kill all ant species tested, but only manipulates the behavior of those it infects in nature. To investigate if this could be explained at the molecular level, we used ex vivo culturing assays to measure the metabolites that are secreted by the fungus to mediate fungus-ant tissue interactions. We show the fungus reacts heterogeneously to brains of different ant species by secreting a different array of metabolites. By determining which ion peaks are significantly enriched when the fungus is grown alongside brains of its naturally occurring host, we discovered candidate compounds that could be involved in behavioral manipulation by O. unilateralis s.l.. Two of these candidates are known to be involved in neurological diseases and cancer. The integrative work presented here shows that ant brain manipulation by O. unilateralis s.l. is species-specific seemingly because the fungus produces a specific array of compounds as a reaction to the presence of the host brain it has evolved to manipulate. These studies have resulted in the discovery of candidate compounds involved in establishing behavioral manipulation

  14. Saving the injured: Rescue behavior in the termite-hunting ant Megaponera analis.

    Science.gov (United States)

    Frank, Erik Thomas; Schmitt, Thomas; Hovestadt, Thomas; Mitesser, Oliver; Stiegler, Jonas; Linsenmair, Karl Eduard

    2017-04-01

    Predators of highly defensive prey likely develop cost-reducing adaptations. The ant Megaponera analis is a specialized termite predator, solely raiding termites of the subfamily Macrotermitinae (in this study, mostly colonies of Pseudocanthotermes sp.) at their foraging sites. The evolutionary arms race between termites and ants led to various defensive mechanisms in termites (for example, a caste specialized in fighting predators). Because M. analis incurs high injury/mortality risks when preying on termites, some risk-mitigating adaptations seem likely to have evolved. We show that a unique rescue behavior in M. analis , consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest. Injured ants that are forced experimentally to return without help, die in 32% of the cases. Behavioral experiments show that two compounds, dimethyl disulfide and dimethyl trisulfide, present in the mandibular gland reservoirs, trigger the rescue behavior. A model accounting for this rescue behavior identifies the drivers favoring its evolution and estimates that rescuing enables maintenance of a 28.7% larger colony size. Our results are the first to explore experimentally the adaptive value of this form of rescue behavior focused on injured nestmates in social insects and help us to identify evolutionary drivers responsible for this type of behavior to evolve in animals.

  15. Interactive effects of soil-dwelling ants, ant mounds and simulated grazing on local plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Olff, H.

    2011-01-01

    Interactions between aboveground vertebrate herbivores and subterranean yellow meadow ants (Lasius flavus) can drive plant community patterns in grassland ecosystems. Here, we study the relative importance of the presence of ants (L. flavus) and ant mounds under different simulated grazing regimes

  16. Edge detection in digital images using Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Marjan Kuchaki Rafsanjani

    2015-11-01

    Full Text Available Ant Colony Optimization (ACO is an optimization algorithm inspired by the behavior of real ant colonies to approximate the solutions of difficult optimization problems. In this paper, ACO is introduced to tackle the image edge detection problem. The proposed approach is based on the distribution of ants on an image; ants try to find possible edges by using a state transition function. Experimental results show that the proposed method compared to standard edge detectors is less sensitive to Gaussian noise and gives finer details and thinner edges when compared to earlier ant-based approaches.

  17. The Pied Piper: A Parasitic Beetle's Melodies Modulate Ant Behaviours.

    Directory of Open Access Journals (Sweden)

    Andrea Di Giulio

    Full Text Available Ants use various communication channels to regulate their social organisation. The main channel that drives almost all the ants' activities and behaviours is the chemical one, but it is long acknowledged that the acoustic channel also plays an important role. However, very little is known regarding exploitation of the acoustical channel by myrmecophile parasites to infiltrate the ant society. Among social parasites, the ant nest beetles (Paussus are obligate myrmecophiles able to move throughout the colony at will and prey on the ants, surprisingly never eliciting aggression from the colonies. It has been recently postulated that stridulatory organs in Paussus might be evolved as an acoustic mechanism to interact with ants. Here, we survey the role of acoustic signals employed in the Paussus beetle-Pheidole ant system. Ants parasitised by Paussus beetles produce caste-specific stridulations. We found that Paussus can "speak" three different "languages", each similar to sounds produced by different ant castes (workers, soldiers, queen. Playback experiments were used to test how host ants respond to the sounds emitted by Paussus. Our data suggest that, by mimicking the stridulations of the queen, Paussus is able to dupe the workers of its host and to be treated as royalty. This is the first report of acoustic mimicry in a beetle parasite of ants.

  18. The interactions of ants with their biotic environment.

    Science.gov (United States)

    Chomicki, Guillaume; Renner, Susanne S

    2017-03-15

    This s pecial feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this s pecial feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication. © 2017 The Author(s).

  19. Ant species confer different partner benefits on two neotropical myrmecophytes.

    Science.gov (United States)

    Frederickson, Megan E

    2005-04-01

    The dynamics of mutualistic interactions involving more than a single pair of species depend on the relative costs and benefits of interaction among alternative partners. The neotropical myrmecophytes Cordia nodosa and Duroia hirsuta associate with several species of obligately symbiotic ants. I compared the ant partners of Cordia and Duroia with respect to two benefits known to be important in ant-myrmecophyte interactions: protection against herbivores provided by ants, and protection against encroaching vegetation provided by ants. Azteca spp., Myrmelachista schumanni, and Allomerus octoarticulatus demerarae ants all provide the leaves of Cordia and Duroia some protection against herbivores. However, Azteca and Allomerus provide more protection than does Myrmelachista to the leaves of their host plants. Although Allomerus protects the leaves of its hosts, plants occupied by Allomerus suffer more attacks by herbivores to their stems than do plants occupied by other ants. Relative to Azteca or Allomerus, Myrmelachista ants provide better protection against encroaching vegetation, increasing canopy openness over their host plants. These differences in benefits among the ant partners of Cordia and Duroia are reflected in the effect of each ant species on host plant size, growth rate, and reproduction. The results of this study show how mutualistic ant partners can differ with respect to both the magnitude and type of benefits they provide to the same species of myrmecophytic host.

  20. Fast and flexible: argentine ants recruit from nearby trails.

    Directory of Open Access Journals (Sweden)

    Tatiana P Flanagan

    Full Text Available Argentine ants (Linepithema humile live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  1. Host ant independent oviposition in the parasitic butterfly Maculinea alcon

    DEFF Research Database (Denmark)

    Fürst, Matthias A; Nash, David Richard

    2010-01-01

    to host-ant nests and non-host-ant nests, and the number and position of eggs attached were assessed. Our results show no evidence for host-ant-based oviposition in M. alcon, but support an oviposition strategy based on plant characteristics. This suggests that careful management of host-ant distribution......Parasitic Maculinea alcon butterflies can only develop in nests of a subset of available Myrmica ant species, so female butterflies have been hypothesized to preferentially lay eggs on plants close to colonies of the correct host ants. Previous correlational investigations of host......-ant-dependent oviposition in this and other Maculinea species have, however, shown equivocal results, leading to a long-term controversy over support for this hypothesis. We therefore conducted a controlled field experiment to study the egg-laying behaviour of M. alcon. Matched potted Gentiana plants were set out close...

  2. Exploring with PAM: Prospecting ANTS Missions for Solar System Surveys

    Science.gov (United States)

    Clark, P. E.; Rilee, M. L.; Curtis, S. A.

    2003-01-01

    ANTS (Autonomous Nano-Technology Swarm), a large (1000 member) swarm of nano to picoclass (10 to 1 kg) totally autonomous spacecraft, are being developed as a NASA advanced mission concept. ANTS, based on a hierarchical insect social order, use an evolvable, self-similar, hierarchical neural system in which individual spacecraft represent the highest level nodes. ANTS uses swarm intelligence attained through collective, cooperative interactions of the nodes at all levels of the system. At the highest levels this can take the form of cooperative, collective behavior among the individual spacecraft in a very large constellation. The ANTS neural architecture is designed for totally autonomous operation of complex systems including spacecraft constellations. The ANTS (Autonomous Nano Technology Swarm) concept has a number of possible applications. A version of ANTS designed for surveying and determining the resource potential of the asteroid belt, called PAM (Prospecting ANTS Mission), is examined here.

  3. Fast and flexible: argentine ants recruit from nearby trails.

    Science.gov (United States)

    Flanagan, Tatiana P; Pinter-Wollman, Noa M; Moses, Melanie E; Gordon, Deborah M

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  4. Chemical camouflage--a frog's strategy to co-exist with aggressive ants.

    Directory of Open Access Journals (Sweden)

    Mark-Oliver Rödel

    Full Text Available Whereas interspecific associations receive considerable attention in evolutionary, behavioural and ecological literature, the proximate bases for these associations are usually unknown. This in particular applies to associations between vertebrates with invertebrates. The West-African savanna frog Phrynomantis microps lives in the underground nest of ponerine ants (Paltothyreus tarsatus. The ants usually react highly aggressively when disturbed by fiercely stinging, but the frog is not attacked and lives unharmed among the ants. Herein we examined the proximate mechanisms for this unusual association. Experiments with termites and mealworms covered with the skin secretion of the frog revealed that specific chemical compounds seem to prevent the ants from stinging. By HPLC-fractionation of an aqueous solution of the frogs' skin secretion, two peptides of 1,029 and 1,143 Da were isolated and found to inhibit the aggressive behaviour of the ants. By de novo sequencing using tandem mass spectrometry, the amino acid sequence of both peptides consisting of a chain of 9 and 11 residues, respectively, was elucidated. Both peptides were synthesized and tested, and exhibited the same inhibitory properties as the original frog secretions. These novel peptides most likely act as an appeasement allomone and may serve as models for taming insect aggression.

  5. A preliminary checklist of the ants (Hymenoptera, Formicidae of Andorra

    Directory of Open Access Journals (Sweden)

    Abel Bernadou

    2013-03-01

    Full Text Available Within the last decade, checklists of the ant fauna of several European countries have been published or updated. Nevertheless, no ant checklists have hitherto been published for the principality of Andorra, a small landlocked country located in the eastern part of the Pyrenees. This work presents a critical list of the ant species of Andorra based on a review of the literature and on the biological material we collected during several field campaigns conducted in Andorra since the year 2005. Seventy-five species belonging to 21 genera of Formicidae were recorded. Nine species were recorded for the first time in Andorra: Aphaenogaster gibbosa (Latreille, 1798, Camponotus lateralis (Olivier, 1792, Camponotus piceus (Leach, 1825, Formica exsecta Nylander, 1846, Lasius piliferus Seifert, 1992, Tapinoma madeirense Forel, 1895, Temnothorax lichtensteini (Bondroit, 1918, Temnothorax niger (Forel, 1894, Temnothorax nigriceps (Mayr, 1855. The most speciose genera were Formica Linnaeus, 1758 and Temnothorax Forel, 1890 with 14 and 12 species, respectively. The ant fauna of Andorra is mostly dominated by Central European species (some are typical cold climate specialists; however species belonging to the Mediterranean ant fauna were also found. This can be explained by the particular geographic situation of Andorra which is characterized by a high mountain Mediterranean climate.

  6. AntBot: Anti-pollution peer-to-peer botnets

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Guanhua [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Ha, Duc T [UNIV. AT BUFFALO

    2009-01-01

    Botnets, which are responsible for many email sparnming and DDoS (Distributed Denial of Service) attacks in the current Internet, have emerged as one of most severe cyber-threats in recent years. To evade detection and improve resistance against countermeasures, botnets have evolved from the first generation that relies on IRC chat channels to deliver commands to the current generation that uses highly resilient P2P (Peer-to-Peer) protocols to spread their C&C (Command and Control) information. It is, however, revealed that P2P botnets, although relieved from the single point of failure that IRC botnets suffer, can be easily disrupted using pollution-based mitigation schemes [15]. In this paper, we play the devil's advocate and propose a new type of hypothetical botnets called AntBot, which aim to propagate their C&C information to individual bots even though there exists an adversary that persistently pollutes keys used by seized bots to search the command information. The key idea of AntBot is a tree-like structure that bots use to deliver the command so that captured bots reveal only limited information. To evaluate effectiveness of AntBot against pollution-based mitigation in a virtual environment, we develop a distributed P2P botnet simulator. Using extensive experiments, we demonstrate that AntBot operates resiliently against pollution-based mitigation. We further present a few potential defense schemes that could effectively disrupt AntBot operations.

  7. Genetic transformation of midgut bacteria from the red imported fire ant (Solenopsis invicta).

    Science.gov (United States)

    Medina, Freder; Li, Haiwen; Vinson, S Bradleigh; Coates, Craig J

    2009-05-01

    In our previous study we isolated 10 bacterial species from fourth-instar larval midguts of the red imported fire ant, Solenopsis invicta. Here we report the genetic transformation and reintroduction of three species (Kluyvera cryocrescens, Serratia marcescens, and isolate 38) into the fire ant host. All three species were transformed with the plasmid vector, pZeoDsRed. High expression levels of DsRed were observed and the plasmid is maintained in these bacteria at 37 degrees C in the absence of antibiotic selection for at least 9 days of subculturing. The transformed bacteria were successfully reintroduced into fire ant larvae and survived in the fire ant gut for at least 7 days. Upon pupal emergence, 7 days after reintroduction, transformed bacteria can still be isolated, however, most were passed out in the meconium. We further demonstrated that the engineered bacteria could be spread within the colony by feeding this meconium to naive larvae with the aid of worker fire ants.

  8. Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

    Science.gov (United States)

    Bagny Beilhe, Leïla; Piou, Cyril; Tadu, Zéphirin; Babin, Régis

    2018-06-06

    The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.

  9. New evidences supporting trophobiosis between populations of Edessa rufomarginata (Heteroptera: Pentatomidae and Camponotus (Hymenoptera: Formicidae ants

    Directory of Open Access Journals (Sweden)

    Daniel Paiva Silva

    2016-06-01

    Full Text Available ABSTRACT Despite its important effect on the maintenance of tritrophic interactions among plants, insect herbivores, and ants, there is still a paucity of natural history and basic biology information involving trophobiosis among Heteroptera stink bugs. Here, based on previous observations of a new trophobiotic interaction between Edessa rufomarginata (De Geer, 1773 and Camponotus rufipes (Fabricius, 1775 ants, we describe the chemical profile of the honeydew obtained by Gas Chromatography–Mass Spectrometry. There were mainly three different sugars (trehalose, glucose, and sorbose within our samples. The extrafloral nectaries of Caryocar brasiliense Camb., the host plant of E. rufomarginata, attracts a wide assemblage of Cerrado ants with varying aggressiveness toward herbivores. Therefore, this facultative trophobiotic interaction may allow the survival of the stink bug while feeding on the risky, highly ant-visited plant. Given the rarity of trophobiotic interactions between Pentatomidae species and ants and considering a zoological perspective within this family, here we discuss the ecological and evolutionary routes that may allow the rise of these interactions.

  10. Ants swimming in pitcher plants: kinematics of aquatic and terrestrial locomotion in Camponotus schmitzi.

    Science.gov (United States)

    Bohn, Holger Florian; Thornham, Daniel George; Federle, Walter

    2012-06-01

    Camponotus schmitzi ants live in symbiosis with the Bornean pitcher plant Nepenthes bicalcarata. Unique among ants, the workers regularly dive and swim in the pitcher's digestive fluid to forage for food. High-speed motion analysis revealed that C. schmitzi ants swim at the surface with all legs submerged, with an alternating tripod pattern. Compared to running, swimming involves lower stepping frequencies and larger phase delays within the legs of each tripod. Swimming ants move front and middle legs faster and keep them more extended during the power stroke than during the return stroke. Thrust estimates calculated from three-dimensional leg kinematics using a blade-element approach confirmed that forward propulsion is mainly achieved by the front and middle legs. The hind legs move much less, suggesting that they mainly serve for steering. Experiments with tethered C. schmitzi ants showed that characteristic swimming movements can be triggered by submersion in water. This reaction was absent in another Camponotus species investigated. Our study demonstrates how insects can use the same locomotory system and similar gait patterns for moving on land and in water. We discuss insect adaptations for aquatic/amphibious lifestyles and the special adaptations of C. schmitzi to living on an insect-trapping pitcher plant.

  11. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host.

    Science.gov (United States)

    Konrad, Matthias; Grasse, Anna V; Tragust, Simon; Cremer, Sylvia

    2015-01-22

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  12. Anti-pathogen protection versus survival costs mediated by an ectosymbiont in an ant host

    Science.gov (United States)

    Konrad, Matthias; Grasse, Anna V.; Tragust, Simon; Cremer, Sylvia

    2015-01-01

    The fitness effects of symbionts on their hosts can be context-dependent, with usually benign symbionts causing detrimental effects when their hosts are stressed, or typically parasitic symbionts providing protection towards their hosts (e.g. against pathogen infection). Here, we studied the novel association between the invasive garden ant Lasius neglectus and its fungal ectosymbiont Laboulbenia formicarum for potential costs and benefits. We tested ants with different Laboulbenia levels for their survival and immunity under resource limitation and exposure to the obligate killing entomopathogen Metarhizium brunneum. While survival of L. neglectus workers under starvation was significantly decreased with increasing Laboulbenia levels, host survival under Metarhizium exposure increased with higher levels of the ectosymbiont, suggesting a symbiont-mediated anti-pathogen protection, which seems to be driven mechanistically by both improved sanitary behaviours and an upregulated immune system. Ants with high Laboulbenia levels showed significantly longer self-grooming and elevated expression of immune genes relevant for wound repair and antifungal responses (β-1,3-glucan binding protein, Prophenoloxidase), compared with ants carrying low Laboulbenia levels. This suggests that the ectosymbiont Laboulbenia formicarum weakens its ant host by either direct resource exploitation or the costs of an upregulated behavioural and immunological response, which, however, provides a prophylactic protection upon later exposure to pathogens. PMID:25473011

  13. Using pleometrosis (multiple queens) and pupae transplantation to boost weaver ant (Oecophylla smaragdina) colony growth in ant nurseries

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Nielsen, Mogens Gissel; Peng, Renkang

    2011-01-01

    Weaver ants (Oecophylla spp.) are increasingly being used for biocontrol and are targeted for future production of insect protein in ant farms. An efficient production of live ant colonies may facilitate the utilization of these ants but the production of mature colonies is hampered by the long...... and no transplantation. Thus, in ant nurseries the use of multiple queens during nest founding as well as transplantation of pupae from foreign colonies may be utilised to decrease the time it takes to produce a colony ready for implementation....

  14. Optic disc detection using ant colony optimization

    Science.gov (United States)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  15. Efficient distribution of toy products using ant colony optimization algorithm

    Science.gov (United States)

    Hidayat, S.; Nurpraja, C. A.

    2017-12-01

    CV Atham Toys (CVAT) produces wooden toys and furniture, comprises 13 small and medium industries. CVAT always attempt to deliver customer orders on time but delivery costs are high. This is because of inadequate infrastructure such that delivery routes are long, car maintenance costs are high, while fuel subsidy by the government is still temporary. This study seeks to minimize the cost of product distribution based on the shortest route using one of five Ant Colony Optimization (ACO) algorithms to solve the Vehicle Routing Problem (VRP). This study concludes that the best of the five is the Ant Colony System (ACS) algorithm. The best route in 1st week gave a total distance of 124.11 km at a cost of Rp 66,703.75. The 2nd week route gave a total distance of 132.27 km at a cost of Rp 71,095.13. The 3rd week best route gave a total distance of 122.70 km with a cost of Rp 65,951.25. While the 4th week gave a total distance of 132.27 km at a cost of Rp 74,083.63. Prior to this study there was no effort to calculate these figures.

  16. Analysis of ante-partum maternal morbidity in rural Bangladesh.

    Science.gov (United States)

    Chakraborty, Nitai; Islam, M Ataharul; Chowdhury, Rafiqul Islam; Bari, Wasimul

    2003-01-01

    This paper presents the results of a prospective study of maternal morbidity during the ante-partum period in rural areas of Bangladesh. The data came from a survey of Maternal Morbidity in Bangladesh, conducted by the Bangladesh Institute of Research for Promotion of Essential and Reproductive Health and Technologies (BIRPERHT) during the period from November 1992 to December 1993. Since then no such national level survey has been conducted in Bangladesh. This paper employs multiple-decrement life table technique, a convenient way of analysing the risks of different types of disease conditions that women experience during the antenatal period for different age categories. The high-risk complications such as ante-partum haemorrhage, excessive vomiting, fits/convulsion and oedema were considered in this study. In this study a cause specific model was applied to explore the differences in the risks exerted at different ages of reproductive life attributable to some selected complications of pregnancy. The results of this study indicate that women of age 25-29 years are less susceptible to most of the selected life-threatening and high-risk complications during pregnancy such as haemorrhage, fits/convulsion and oedema. However, younger women (age or = 30 years) are at greater risk of haemorrhage, fits/convulsion and oedema.

  17. A global database of ant species abundances

    Czech Academy of Sciences Publication Activity Database

    Gibb, H.; Dunn, R. R.; Sanders, N. J.; Grossman, B. F.; Photakis, M.; Abril, S.; Agosti, D.; Andersen, A. N.; Angulo, E.; Armbrecht, I.; Arnan, X.; Baccaro, F. B.; Bishop, T. R.; Boulay, R.; Brühl, C.; Castracani, C.; Cerdá, X.; Del Toro, I.; Delsinne, T.; Diaz, M.; Donoso, D. A.; Ellison, A. M.; Enríquez, M. L.; Fayle, Tom Maurice; Feener, D. H.; Fisher, B. L.; Fisher, R. N.; Fitzpatrick, M. C.; Gómez, C.; Gotelli, N. J.; Gove, A.; Grasso, D. A.; Groc, S.; Guenard, B.; Gunawardene, N.; Heterick, B.; Hoffmann, B.; Janda, Milan; Jenkins, C.; Kaspari, M.; Klimeš, Petr; Lach, L.; Laeger, T.; Lattke, J.; Leponce, M.; Lessard, J.-P.; Longino, J.; Lucky, A.; Luke, S. H.; Majer, J.; McGlynn, T. P.; Menke, S.; Mezger, D.; Mori, A.; Moses, Jimmy; Munyai, T. C.; Pacheco, R.; Paknia, O.; Pearce-Duvet, J.; Pfeiffer, M.; Philpott, S. M.; Resasco, J.; Retana, J.; Silva, R. R.; Sorger, M. D.; Souza, J.; Suarez, A.; Tista, M.; Vasconcelos, H. L.; Vonshak, M.; Weisser, M. D.; Yates, M.; Parr, C. L.

    2017-01-01

    Roč. 98, č. 3 (2017), s. 883-884 ISSN 0012-9658 R&D Projects: GA ČR GB14-36098G; GA ČR GAP505/12/2467; GA ČR GPP505/12/P875 Institutional support: RVO:60077344 Keywords : abundance * ants * database Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.809, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/ecy.1682/abstract

  18. Public goods dilemma in asexual ant societies

    OpenAIRE

    Dobata, Shigeto; Tsuji, Kazuki

    2013-01-01

    This study reports experimental evidence for the “public goods dilemma” between cooperators and cheaters in an asexual ant society, in which cheating is always more rewarding for individuals but cooperation at the cost of individual fitness leads to better performance of groups. Although this dilemma provides the basic principle of social evolution, its experimental demonstration with underlying genetics and fitness evaluation for both cooperators and cheaters still lacks in societies other t...

  19. Precision Rescue Behavior in North American Ants

    Directory of Open Access Journals (Sweden)

    Katherine Taylor

    2013-07-01

    Full Text Available Altruistic behavior, in which one individual provides aid to another at some cost to itself, is well documented. However, some species engage in a form of altruism, called rescue, that places the altruist in immediate danger. Here we investigate one such example, namely rescuing victims captured by predators. In a field experiment with two North American ant species, Tetramorium sp. E and Prenolepis imparis, individuals were held in artificial snares simulating capture. T. sp. E, but not P. imparis, exhibited digging, pulling, and snare biting, the latter precisely targeted to the object binding the victim. These results are the first to document precision rescue in a North American ant species; moreover, unlike rescue in other ants, T. sp. E rescues conspecifics from different colonies, mirroring their atypical social behavior, namely the lack of aggression between non-nestmate (heterocolonial conspecifics. In a second, observational study designed to demonstrate rescue from an actual predator, T. sp. E victims were dropped into an antlion's pit and the behavior of a single rescuer was observed. Results showed that T. sp. E not only attempted to release the victim, but also risked attacking the predator, suggesting that precision rescue may play an important role in this species' antipredator behavior.

  20. El periodista, ante la espiral de silencio

    Directory of Open Access Journals (Sweden)

    Dr. Fermín Galindo Arranz

    1998-01-01

    Full Text Available La percepción de la profesión periodística y de su influencia cambia mucho a lo largo del tiempo, de las coyunturas históricas y de los diferentes países y sociedades en los que desempeñan su labor. En un contexto mundial, la gravedad de las situaciones de riesgo periodístico se encuadran en situaciones políticas, económicas o sociales también conflictivas; es entonces cuando se suele reproducir con facilidad en la opinión pública el fenómeno de la espiral del silencio, ante el que inevitablemente se sitúa el periodista. Por definición, el trabajo del periodista consiste en ser portavoz de las novedades que se producen, en dar informaciones y emitir opiniones en la esfera pública, se tiene que situar, por tanto, de forma individual y notoriamente pública ante los fenómenos de espiral de silencio que puedan producirse en la opinión pública. Antonio Tabucchi nos presenta en su novela "Sostiene Pereira" un ejemplo magnífico del dilema del periodista ante este tipo de situaciones.

  1. Recognition of social identity in ants

    Directory of Open Access Journals (Sweden)

    Nick eBos

    2012-03-01

    Full Text Available Recognizing the identity of others, from the individual to the group level, is a hallmark of society. Ants, and other social insects, have evolved advanced societies characterized by efficient social recognition systems. Colony identity is mediated by colony specific signature mixtures, a blend of hydrocarbons present on the cuticle of every individual (the label. Recognition occurs when an ant encounters another individual, and compares the label it perceives to an internal representation of its own colony odor (the template. A mismatch between label and template leads to rejection of the encountered individual. Although advances have been made in our understanding of how the label is produced and acquired, contradictory evidence exists about information processing of recognition cues. Here, we review the literature on template acquisition in ants and address how and when the template is formed, where in the nervous system it is localized, and the possible role of learning. We combine seemingly contradictory evidence in to a novel, parsimonious theory for the information processing of nestmate recognition cues.

  2. Reproduction and dispersal in an ant-associated root aphid community

    DEFF Research Database (Denmark)

    Ivens, A.B.F.; Kronauer, Daniel Jan Christoph; Pen, I.

    2012-01-01

    viscosity is high and winged aphids rare, consistent with infrequent horizontal transmission between ant host colonies. The absence of the primary host shrub (Pistacia) may explain the absence of sex in three of the studied species, but elm trees (Ulmus) that are primary hosts of the fourth species (T...... above ground, whereas dispersal constraints and dependence on ant-tending may differentially affect the costs and benefits of sex in subterranean aphids. Here, we studied reproductive mode and dispersal in a community of root aphids that are obligately associated with the ant Lasius flavus. We assessed...... the genetic population structure of four species (Geoica utricularia, Tetraneura ulmi, Forda marginata and Forda formicaria) in a Dutch population and found that all species reproduce predominantly if not exclusively asexually, so that populations consist of multiple clonal lineages. We show that population...

  3. Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.

    Science.gov (United States)

    Hölldobler, Bert

    2016-01-01

    The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.

  4. Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.

    Directory of Open Access Journals (Sweden)

    Bert Hölldobler

    Full Text Available The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.

  5. Fungus-growing ants (Hymenoptera: Formicidae on Santa Catarina Island, Brazil: patterns of occurrence

    Directory of Open Access Journals (Sweden)

    Benedito Cortês Lopes

    2000-06-01

    Full Text Available A taxonomic survey on fungus-growing ants (Attini was made at 14 beaches on Santa Catarina Island (SC, Brazil. The samplings were manual, in soil or litterfall, in the following habitats: sandy beach, herbaceous vegetation and shrubby vegetation. From 12 species of Attini (ten of Acromyrmex Mayr and two of Cyphomyrmex Mayr, the most frequent were Cyphomyrmex morschi Emery and Acromyrmex crassispinus Forel, collected, respectively, on eight and ten of the monitored beaches. Altogether, Sorensen’s similarity coefficients were high (range: 0.59-0.80, in spite of the lower numbers of ant species on sandy beaches

  6. A reassessment of the mating system characteristics of the army ant Eciton burchellii

    DEFF Research Database (Denmark)

    Kronauer, Daniel Jan Christoph; Berghoff, Stefanie M.; Powell, Scott

    2006-01-01

    In a recent study, Denny et al. (2004a) showed that queens of the army ant, Eciton burchellii, mate with multiple males and presented estimates suggesting that they mate with more males than queens of any other ant species so far investigated. They also inferred that data were consistent...... colonies of the same species. Mating frequencies in E. burchellii are indeed very high (mean observed and effective queen-mating frequencies of 12.9 each) but considerably lower than the previous estimates. We show that the number of patrilines represented in the first worker offspring of a young queen...

  7. Nest Relocation and Colony Founding in the Australian Desert Ant, Melophorus bagoti Lubbock (Hymenoptera: Formicidae

    Directory of Open Access Journals (Sweden)

    Patrick Schultheiss

    2010-01-01

    Full Text Available Even after years of research on navigation in the Red Honey Ant, Melophorus bagoti, much of its life history remains elusive. Here, we present observations on nest relocation and the reproductive and founding stages of colonies. Nest relocation is possibly aided by trail laying behaviour, which is highly unusual for solitary foraging desert ants. Reproduction occurs in synchronised mating flights, which are probably triggered by rain. Queens may engage in multiple matings, and there is circumstantial evidence that males are chemically attracted to queens. After the mating flight, the queens found new colonies independently and singly. Excavation of these founding colonies reveals first insights into their structure.

  8. Evidences that human disturbance simplify the ant fauna associated a Stachytarpheta glabra Cham. (Verbenaceae compromising the benefits of ant-plant mutualism

    Directory of Open Access Journals (Sweden)

    BC. Barbosa

    Full Text Available Interaction among species, like ants and plants through extrafloral nectaries (EFNs, are important components of ecological communities’ evolution. However, the effect of human disturbance on such specific interactions and its ecological consequences is poorly understood. This study evaluated the outcomes of mutualism between ants and the EFN-bearing plant Stachytarpheta glabra under anthropogenic disturbance. We compared the arthropod fauna composition between two groups of twenty plant individuals, one in an area disturbed by human activities and one in a preserved area. We also check the plant investment in herbivory defense and the consequential leaf damage by herbivore. Our results indicate that such disturbances cause simplification of the associated fauna and lack of proper ant mutualist. This led to four times more herbivory on plants of disturbed areas, despite the equal amount of EFN and ant visitors and low abundance of herbivores. The high pressure of herbivory may difficult the re-establishment of S. glabra, an important pioneer species in ferruginous fields, therefore it may affect resilience of this fragile ecological community.

  9. Traumatic brain injury: Comparison between autopsy and ante-mortem CT.

    Science.gov (United States)

    Panzer, Stephanie; Covaliov, Lidia; Augat, Peter; Peschel, Oliver

    2017-11-01

    The aim of this study was to compare pathological findings after traumatic brain injury between autopsy and ante-mortem computed tomography (CT). A second aim was to identify changes in these findings between the primary posttraumatic CT and the last follow-up CT before death. Through the collaboration between clinical radiology and forensic medicine, 45 patients with traumatic brain injury were investigated. These patients had undergone ante-mortem CT as well as autopsy. During autopsy, the brain was cut in fronto-parallel slices directly after removal without additional fixation or subsequent histology. Typical findings of traumatic brain injury were compared between autopsy and radiology. Additionally, these findings were compared between the primary CT and the last follow-up CT before death. The comparison between autopsy and radiology revealed a high specificity (≥80%) in most of the findings. Sensitivity and positive predictive value were high (≥80%) in almost half of the findings. Sixteen patients had undergone craniotomy with subsequent follow-up CT. Thirteen conservatively treated patients had undergone a follow-up CT. Comparison between the primary CT and the last ante-mortem CT revealed marked changes in the presence and absence of findings, especially in patients with severe traumatic brain injury requiring decompression craniotomy. The main pathological findings of traumatic brain injury were comparable between clinical ante-mortem CT examinations and autopsy. Comparison between the primary CT after trauma and the last ante-mortem CT revealed marked changes in the findings, especially in patients with severe traumatic brain injury. Hence, clinically routine ante-mortem CT should be included in the process of autopsy interpretation. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  10. The invasive ant, Solenopsis invicta, reduces herpetofauna richness and abundance

    Science.gov (United States)

    Allen, Craig R.; Birge, Hannah E.; Slater, J.; Wiggers, E.

    2017-01-01

    Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta. Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.

  11. Predaceous ants, beach replenishment, and nest placement by sea turtles.

    Science.gov (United States)

    Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

    2007-10-01

    Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

  12. Chemically armed mercenary ants protect fungus-farming societies

    Science.gov (United States)

    Adams, Rachelle M. M.; Liberti, Joanito; Illum, Anders A.; Jones, Tappey H.; Nash, David R.; Boomsma, Jacobus J.

    2013-01-01

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies. PMID:24019482

  13. Chemically armed mercenary ants protect fungus-farming societies.

    Science.gov (United States)

    Adams, Rachelle M M; Liberti, Joanito; Illum, Anders A; Jones, Tappey H; Nash, David R; Boomsma, Jacobus J

    2013-09-24

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies.

  14. Efforts to eradicate yellow crazy ants on Johnston Atoll: Results from Crazy Ant Strike Team IX, December 2014-June 2015

    Science.gov (United States)

    Banko, Paul C.; Peck, Robert W.; Donmoyer, Kevin; Kropidlowski, Stephan; Pollock, Amanda

    2015-01-01

    The ecologically destructive yellow crazy ant (YCA; Anoplolepis gracilipes) was first detected on Johnston Atoll in January 2010. Within eight months, the U.S. Fish and Wildlife Service had mobilized its first crazy ant strike team (CAST), a group of biologists dedicated to testing and identifying insecticidal baits to be used to eradicate the ant on the atoll. During December 2014‒May 2015 CAST IX focused on testing hydrogel crystals saturated with sucrose solution (25%) carrying the insecticides thiamethoxam and dinotefuran against YCA. A series of experiments, including artificial nest box trials, and field-based palatability trials and eradication tests on small (500 m2 or 0.05 ha) and large plots (2500 m2 or 0.25 ha), were conducted to test concentrations of thiamethoxam ranging from 0.0005% to 0.01%, and dinotefuran at 0.05%. Additionally, the cat food-based matrix containing dinotefuran (0.05%), the standard bait used to suppress YCA on Johnston since 2011, and textured vegetable protein (TVP) carrying dinotefuran at 0.1% and 0.05% were included in large plot tests. Nest box trials were inconclusive due to a consistent loss of queen and worker ants in control boxes, so they were discontinued. Palatability trials suggested higher dosages of thiamethoxam (0.005 and 0.01%) were less attractive than lower dosages (0.0005 and 0.001%) and controls (sucrose only), but small and large plot experiments failed to identify a thiamethoxam concentration that was consistently effective at killing YCA. In contrast, hydrogel containing dinotefuran was consistently effective, killing >95% of YCA on small and large plots. As expected, the cat food bait effectively reduced YCA abundances, but was slightly less effective than hydrogel containing dinotefuran over time. Three successive, approximately weekly treatments of large plots with hydrogel bait, or other baits followed by hydrogel bait, suggest an increasing overall effectiveness, with no aversion of YCA to the bait

  15. Social influences on ant-dipping acquisition in the wild chimpanzees (Pan troglodytes verus) of Bossou, Guinea, West Africa.

    Science.gov (United States)

    Humle, Tatyana; Snowdon, Charles T; Matsuzawa, Tetsuro

    2009-10-01

    We currently have little understanding of the influence of learning opportunity, whether social or environmental, and maternal role on tool-use acquisition in young wild chimpanzees. This study aims to fill this gap by focusing on the acquisition of ant-dipping among chimpanzees of Bossou, Guinea. Ant-dipping is a hazardous tool-use behaviour aimed at army ants (Dorylus spp.). Bossou chimpanzees target these ants both at nests (high risk) and trails (low risk) and employ two techniques to consume them: direct mouthing and pull-through. We present data for 13 mother-offspring pairs (1-10 years old). Mothers with young chimpanzee material culture is a product of a complex interaction between social processes and ecological factors.

  16. When invasive ants meet: effects of outbreeding on queen performance in the tramp ant Cardiocondyla itsukii.

    Science.gov (United States)

    Heinze, Jürgen; Frohschammer, Sabine; Bernadou, Abel

    2017-08-18

    Most disturbed habitats in the tropics and subtropics harbor numerous species of invasive ants, and occasionally the same species has been introduced repeatedly from multiple geographical sources. We examined how experimental crossbreeding between sexuals from different populations affects the fitness of queens of the tramp ant Cardiocondyla itsukii, which is widely distributed in Asia and the Pacific Islands. Eggs laid by queens that mated with nestmate males had a higher hatching rate than eggs laid by queens mated to males from neighboring (Hawaii × Kauai) or distant introduced populations (Hawaii/Kauai × Okinawa). Furthermore, inbreeding queens had a longer lifespan and produced a less female-biased offspring sex ratio than queens from allopatric mating. This suggests that the genetic divergence between different source populations may already be so large that in case of multiple invasions eventual crossbreeding might negatively affect the fitness of tramp ants. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  17. Dynamic Vehicle Routing Problems with Enhanced Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Haitao Xu

    2018-01-01

    Full Text Available As we all know, there are a great number of optimization problems in the world. One of the relatively complicated and high-level problems is the vehicle routing problem (VRP. Dynamic vehicle routing problem (DVRP is a major variant of VRP, and it is closer to real logistic scene. In DVRP, the customers’ demands appear with time, and the unserved customers’ points must be updated and rearranged while carrying out the programming paths. Owing to the complexity and significance of the problem, DVRP applications have grabbed the attention of researchers in the past two decades. In this paper, we have two main contributions to solving DVRP. Firstly, DVRP is solved with enhanced Ant Colony Optimization (E-ACO, which is the traditional Ant Colony Optimization (ACO fusing improved K-means and crossover operation. K-means can divide the region with the most reasonable distance, while ACO using crossover is applied to extend search space and avoid falling into local optimum prematurely. Secondly, several new evaluation benchmarks are proposed, which can objectively and comprehensively estimate the proposed method. In the experiment, the results for different scale problems are compared to those of previously published papers. Experimental results show that the algorithm is feasible and efficient.

  18. Study of heuristics in ant system for nuclear reload optimisation

    International Nuclear Information System (INIS)

    Lima, Alan M.M. de; Schirru, Roberto; Silva, Fernando C. da; Machado, Marcelo D.; Medeiros, Jose A.C.C.

    2007-01-01

    A Pressurized Water Reactor core must be reloaded every time the fuel burnup reaches a level when it is not possible to sustain nominal power operation. The nuclear core fuel reload optimization consists in finding a burned-up and fresh-fuel-assembly loading pattern that maximizes the number of effective full power days, minimizing the relationship cost/benefit. This problem is NP-hard, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Besides that, the problem is non-linear and its search space is highly discontinual and multimodal. In this work a parallel computational system based on Ant Colony System (ACS) called Artificial-Ant-Colony Networks is used to solve the nuclear reactor core fuel reload optimization problem, with compatibles heuristics. ACS is a system based on artificial agents that uses the reinforcement learning technique and was originally developed to solve the Traveling Salesman Problem, which is conceptually similar to the nuclear fuel reload problem. (author)

  19. The expression and impact of antifungal grooming in ants.

    Science.gov (United States)

    Reber, A; Purcell, J; Buechel, S D; Buri, P; Chapuisat, M

    2011-05-01

    Parasites can cause extensive damage to animal societies in which many related individuals frequently interact. In response, social animals have evolved diverse individual and collective defences. Here, we measured the expression and efficiency of self-grooming and allo-grooming when workers of the ant Formica selysi were contaminated with spores of the fungal entomopathogen Metarhizium anisopliae. The amount of self-grooming increased in the presence of fungal spores, which shows that the ants are able to detect the risk of infection. In contrast, the amount of allo-grooming did not depend on fungal contamination. Workers groomed all nestmate workers that were re-introduced into their groups. The amount of allo-grooming towards noncontaminated individuals was higher when the group had been previously exposed to the pathogen. Allo-grooming decreased the number of fungal spores on the surface of contaminated workers, but did not prevent infection in the conditions tested (high dose of spores and late allo-grooming). The rate of disease transmission to groomers and other nestmates was extremely low. The systematic allo-grooming of all individuals returning to the colony, be they contaminated or not, is probably a simple but robust prophylactic defence preventing the spread of fungal diseases in insect societies. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  20. Study of heuristics in ant system for nuclear reload optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alan M.M. de; Schirru, Roberto; Silva, Fernando C. da; Machado, Marcelo D.; Medeiros, Jose A.C.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mail: alan@lmp.ufrj.br; schirru@lmp.ufrj.br; fernando@con.ufrj.br; marcelo@lmp.ufrj.br; canedo@lmp.ufrj.br

    2007-07-01

    A Pressurized Water Reactor core must be reloaded every time the fuel burnup reaches a level when it is not possible to sustain nominal power operation. The nuclear core fuel reload optimization consists in finding a burned-up and fresh-fuel-assembly loading pattern that maximizes the number of effective full power days, minimizing the relationship cost/benefit. This problem is NP-hard, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Besides that, the problem is non-linear and its search space is highly discontinual and multimodal. In this work a parallel computational system based on Ant Colony System (ACS) called Artificial-Ant-Colony Networks is used to solve the nuclear reactor core fuel reload optimization problem, with compatibles heuristics. ACS is a system based on artificial agents that uses the reinforcement learning technique and was originally developed to solve the Traveling Salesman Problem, which is conceptually similar to the nuclear fuel reload problem. (author)

  1. Reproductive conflict in social insects: Male production by workers in a slave-making ant

    DEFF Research Database (Denmark)

    Brunner, Elizabeth; Trindl, Andreas; Falk, Karl H.

    2005-01-01

    by producing their own sons than workers in nonparasitic species. In this study we investigated worker reproduction in four natural colonies of the slave-making ant Polyergus rufescens, using highly variable microsatellite markers. Our results show that workers produce up to 100% of the males. This study thus...

  2. Just follow your nose: homing by olfactory cues in ants.

    Science.gov (United States)

    Steck, Kathrin

    2012-04-01

    How is an ant-equipped with a brain that barely exceeds the size of a pinhead-capable of achieving navigational marvels? Even though evidences suggest that navigation is a multimodal process, ants heavily depend on olfactory cues-of pheromonal and non-pheromonal nature-for foraging and orientation. Recent studies have directed their attention to the efficiency of pheromone trail networks. Advances in neurophysiological techniques make it possible to investigate trail pheromone processing in the ant's brain. In addition to relying on pheromone odours, ants also make use of volatiles emanating from the nest surroundings. Deposited in the vicinity of the nest, these home-range markings help the ants to home after a foraging run. Furthermore, olfactory landmarks associated with the nest enhance ants' homing abilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Ant tending influences soldier production in a social aphid.

    Science.gov (United States)

    Shingleton, A W; Foster, W A

    2000-09-22

    The aphid Pseudoregma sundanica (Van der Goot) (Homoptera: Aphididae) has two defence strategies. It is obligatorily tended by various species of ant and also produces sterile soldiers. We investigated how they allocate their investment in these two strategies. We measured the size, number of soldiers, number and species of tending ant, and number and species of predators in P. sundanica populations. We found that the level of ant tending correlated negatively with soldier investment in P. sundanica. The species of tending ant also influenced soldier investment. We excluded ants from aphid populations and recorded changes in population size and structure over four weeks. Ant exclusion led to population decline and extinction. At the same time, surviving populations showed a significant increase in soldier investment. The data demonstrate that social aphids can adjust their investment in soldiers in direct response to environmental change.

  4. Time optimized path-choice in the termite hunting ant Megaponera analis.

    Science.gov (United States)

    Frank, Erik T; Hönle, Philipp O; Linsenmair, K Eduard

    2018-05-10

    Trail network systems among ants have received a lot of scientific attention due to their various applications in problem solving of networks. Recent studies have shown that ants select the fastest available path when facing different velocities on different substrates, rather than the shortest distance. The progress of decision-making by these ants is determined by pheromone-based maintenance of paths, which is a collective decision. However, path optimization through individual decision-making remains mostly unexplored. Here we present the first study of time-optimized path selection via individual decision-making by scout ants. Megaponera analis scouts search for termite foraging sites and lead highly organized raid columns to them. The path of the scout determines the path of the column. Through installation of artificial roads around M. analis nests we were able to influence the pathway choice of the raids. After road installation 59% of all recorded raids took place completely or partly on the road, instead of the direct, i.e. distance-optimized, path through grass from the nest to the termites. The raid velocity on the road was more than double the grass velocity, the detour thus saved 34.77±23.01% of the travel time compared to a hypothetical direct path. The pathway choice of the ants was similar to a mathematical model of least time allowing us to hypothesize the underlying mechanisms regulating the behavior. Our results highlight the importance of individual decision-making in the foraging behavior of ants and show a new procedure of pathway optimization. © 2018. Published by The Company of Biologists Ltd.

  5. Positive interactions between desert granivores: localized facilitation of harvester ants by kangaroo rats.

    Directory of Open Access Journals (Sweden)

    Andrew J Edelman

    Full Text Available Facilitation, when one species enhances the environment or performance of another species, can be highly localized in space. While facilitation in plant communities has been intensely studied, the role of facilitation in shaping animal communities is less well understood. In the Chihuahuan Desert, both kangaroo rats and harvester ants depend on the abundant seeds of annual plants. Kangaroo rats, however, are hypothesized to facilitate harvester ants through soil disturbance and selective seed predation rather than competing with them. I used a spatially explicit approach to examine whether a positive or negative interaction exists between banner-tailed kangaroo rat (Dipodomys spectabilis mounds and rough harvester ant (Pogonomyrmex rugosus colonies. The presence of a scale-dependent interaction between mounds and colonies was tested by comparing fitted spatial point process models with and without interspecific effects. Also, the effect of proximity to a mound on colony mortality and spatial patterns of surviving colonies was examined. The spatial pattern of kangaroo rat mounds and harvester ant colonies was consistent with a positive interspecific interaction at small scales (<10 m. Mortality risk of vulnerable, recently founded harvester ant colonies was lower when located close to a kangaroo rat mound and proximity to a mound partly predicted the spatial pattern of surviving colonies. My findings support localized facilitation of harvester ants by kangaroo rats, likely mediated through ecosystem engineering and foraging effects on plant cover and composition. The scale-dependent effect of kangaroo rats on abiotic and biotic factors appears to result in greater founding and survivorship of young colonies near mounds. These results suggest that soil disturbance and foraging by rodents can have subtle impacts on the distribution and demography of other species.

  6. Consuming fire ants reduces northern bobwhite survival and weight gain

    Science.gov (United States)

    Myers, P.E.; Allen, Craig R.; Birge, Hannah E.

    2014-01-01

    Northern bobwhite quail, Colinus virginianus (L.) (Galliformes: Odontophoridae), population declines are well documented, but pinpointing the reasons for these decreases has proven elusive. Bobwhite population declines are attributed primarily to loss of habitat and land use changes. This, however, does not entirely explain population declines in areas intensively managed for bobwhites. Although previous research demonstrates the negative impact of red imported fire ant (Solenopsis invicta Buren) (Hymenoptera: Formicidae) on northern bobwhites, the mechanisms underlying this effect are largely unknown. To meet the protein demands of early growth and development, bobwhite chicks predominantly consume small insects, of which ants are a substantial proportion. Fire ants alter ant community dynamics by often reducing native ant diversity and abundance while concurrently increasing the abundance of individuals. Fire ants have negative effects on chicks, but they are also a large potential protein source, making it difficult to disentangle their net effect on bobwhite chicks. To help investigate these effects, we conducted a laboratory experiment to understand (1) whether or not bobwhites consume fire ants, and (2) how the benefits of this consumption compare to the deleterious impacts of bobwhite chick exposure to fire ants. Sixty bobwhite chicks were separated into two groups of 30; one group was provided with starter feed only and the second group was provided with feed and fire ants. Bobwhite chicks were observed feeding on fire ants. Chicks that fed on fire ants had reduced survival and weight gain. Our results show that, while fire ants increase potential food sources for northern bobwhite, their net effect on bobwhite chicks is deleterious. This information will help inform land managers and commercial bobwhite rearing operations.

  7. Cercomacra and related antbirds (Aves, Formicariidae as army ant followers

    Directory of Open Access Journals (Sweden)

    Edwin O. Willis

    1984-01-01

    Full Text Available Cercomacra and Schistocichla antbirds (Formicariidae favor dense foliage and seldom follow army ants for flushed prey, since the ants move through open forest understory as well as through dense zones. Two other lineages, the Drymophila-Hypocnemis lineage (of dense woodland understory and the Formicivora lineage (of dense bushes in dry or semiopen zones, also cannot follow ants regularly through open forest understory.

  8. Do herbivores eavesdrop on ant chemical communication to avoid predation?

    Directory of Open Access Journals (Sweden)

    David J Gonthier

    Full Text Available Strong effects of predator chemical cues on prey are common in aquatic and marine ecosystems, but are thought to be rare in terrestrial systems and specifically for arthropods. For ants, herbivores are hypothesized to eavesdrop on ant chemical communication and thereby avoid predation or confrontation. Here I tested the effect of ant chemical cues on herbivore choice and herbivory. Using Margaridisa sp. flea beetles and leaves from the host tree (Conostegia xalapensis, I performed paired-leaf choice feeding experiments. Coating leaves with crushed ant liquids (Azteca instabilis, exposing leaves to ant patrolling prior to choice tests (A. instabilis and Camponotus textor and comparing leaves from trees with and without A. instabilis nests resulted in more herbivores and herbivory on control (no ant-treatment relative to ant-treatment leaves. In contrast to A. instabilis and C. textor, leaves previously patrolled by Solenopsis geminata had no difference in beetle number and damage compared to control leaves. Altering the time A. instabilis patrolled treatment leaves prior to choice tests (0-, 5-, 30-, 90-, 180-min. revealed treatment effects were only statistically significant after 90- and 180-min. of prior leaf exposure. This study suggests, for two ecologically important and taxonomically diverse genera (Azteca and Camponotus, ant chemical cues have important effects on herbivores and that these effects may be widespread across the ant family. It suggests that the effect of chemical cues on herbivores may only appear after substantial previous ant activity has occurred on plant tissues. Furthermore, it supports the hypothesis that herbivores use ant chemical communication to avoid predation or confrontation with ants.

  9. A Theoretic Basis for IS? The Contribution of ANT

    Directory of Open Access Journals (Sweden)

    Jim Underwood

    2002-11-01

    Full Text Available Representation is a key issue of IS design and operation that is often ignored. Actor-network theory (ANT, a semiotic theory of stakeholders, provides a way of dealing with representation. Combining aspects of ANT and Foucault's discourse theory allows us to include concepts as actors and promises a flexible and durable foundation for IS practice, but ANT itself indicates that the search for a purely theoretical foundation for IS is misguided.

  10. Insecticide transfer efficiency and lethal load in Argentine ants

    Energy Technology Data Exchange (ETDEWEB)

    Hooper-Bui, L.M. [Department of Environmental Science, Louisiana State University, Baton Rouge, LA 70803 (United States); Department of Entomology, University of California, Riverside, CA 92521 (United States); Kwok, E.S.C. [Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521 (United States); Buchholz, B.A., E-mail: buchholz2@llnl.gov [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Department of Environmental Toxicology, University of California, Davis, CA 95616 (United States); Rust, M.K. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Eastmond, D.A. [Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521 (United States); Vogel, J.S. [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

    2015-10-15

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of {sup 14}C-sucrose, {sup 14}C-hydramethylnon, and {sup 14}C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  11. Improved Ant Colony Clustering Algorithm and Its Performance Study

    Science.gov (United States)

    Gao, Wei

    2016-01-01

    Clustering analysis is used in many disciplines and applications; it is an important tool that descriptively identifies homogeneous groups of objects based on attribute values. The ant colony clustering algorithm is a swarm-intelligent method used for clustering problems that is inspired by the behavior of ant colonies that cluster their corpses and sort their larvae. A new abstraction ant colony clustering algorithm using a data combination mechanism is proposed to improve the computational efficiency and accuracy of the ant colony clustering algorithm. The abstraction ant colony clustering algorithm is used to cluster benchmark problems, and its performance is compared with the ant colony clustering algorithm and other methods used in existing literature. Based on similar computational difficulties and complexities, the results show that the abstraction ant colony clustering algorithm produces results that are not only more accurate but also more efficiently determined than the ant colony clustering algorithm and the other methods. Thus, the abstraction ant colony clustering algorithm can be used for efficient multivariate data clustering. PMID:26839533

  12. Insecticide transfer efficiency and lethal load in Argentine ants

    International Nuclear Information System (INIS)

    Hooper-Bui, L.M.; Kwok, E.S.C.; Buchholz, B.A.; Rust, M.K.; Eastmond, D.A.; Vogel, J.S.

    2015-01-01

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14 C-sucrose, 14 C-hydramethylnon, and 14 C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), but dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). The distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. Bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.

  13. Disease dynamics in a specialized parasite of ant societies

    DEFF Research Database (Denmark)

    Andersen, Sandra Breum; Ferrari, Matthew; Evans, Harry C.

    2012-01-01

    Coevolution between ant colonies and their rare specialized parasites are intriguing, because lethal infections of workers may correspond to tolerable chronic diseases of colonies, but the parasite adaptations that allow stable coexistence with ants are virtually unknown. We explore the trade......-offs experienced by Ophiocordyceps parasites manipulating ants into dying in nearby graveyards. We used field data from Brazil and Thailand to parameterize and fit a model for the growth rate of graveyards. We show that parasite pressure is much lower than the abundance of ant cadavers suggests...

  14. [Syagrus romanzoffiana (Arecaceae) seed utilization by ants in a secondary forest in South Brazil].

    Science.gov (United States)

    Silva, Fernanda R; Begnini, Romualdo M; Klier, Vinícius A; Scherer, Karla Z; Lopes, Benedito C; Castellani, Tânia T

    2009-01-01

    Ants can nest in a wide variety of substracts. This paper shows Syagrus romanzoffiana seed utilization by ants in an Atlantic secondary forest. We report 29 seeds occupied by small-bodied ants, with 27 of them showing at least two ant development stages. Although a large number of seeds were sampled, a low level of ant occupation was observed.

  15. Invasion risk of the yellow crazy ant (Anoplolepis gracilipes under the Representative Concentration Pathways 8.5 climate change scenario in South Korea

    Directory of Open Access Journals (Sweden)

    Jae-Min Jung

    2017-12-01

    Full Text Available The yellow crazy ant (Anoplolepis gracilipes has destroyed local ecosystems in numerous countries, and their population sizes and distribution are likely to increase under global warming. To evaluate the risk of invasion by yellow crazy ant in South Korea, this study identified their potential habitats and predicted their future global distribution by modeling various climate change scenarios using CLIMEX software. Our modeling predicted that future climate conditions in South Korea will be favorable for the yellow crazy ant, and they could invade by the mid-21st century. We highlight the use of predictive algorithms to establish geographical areas with a high risk of yellow crazy ant invasion under Representative Concentration Pathways (RCP 8.5 climate scenarios. Keywords: Anoplolepis gracilipes, climate change scenario, CLIMEX, invasive species, yellow crazy ant

  16. Relative effects of disturbance on red imported fire ants and native ant species in a longleaf pine ecosystem

    DEFF Research Database (Denmark)

    Stuble, Katharine L.; Kirkman, L. Katherine; Carroll, C. Ronald

    2011-01-01

    and cases in which non-native species become established in intact (lacking extensive anthropogenic soil disturbance) communities and subsequently diminish the abundance and richness of native species is challenging on the basis of observation alone. The red imported fire ant (Solenopsis invicta......), an invasive species that occurs throughout much of the southeastern United States, is such an example. Rather than competitively displacing native species, fire ants may become established only in disturbed areas in which native species richness and abundance are already reduced. We used insecticide to reduce......, the abundance of native ants increased to levels comparable to those in control plots after 1 year. Our findings suggest that factors other than large reductions in ant abundance and species density (number of species per unit area) may affect the establishment of fire ants and that the response of native ants...

  17. A Keystone Ant Species Provides Robust Biological Control of the Coffee Berry Borer Under Varying Pest Densities.

    Science.gov (United States)

    Morris, Jonathan R; Vandermeer, John; Perfecto, Ivette

    2015-01-01

    Species' functional traits are an important part of the ecological complexity that determines the provisioning of ecosystem services. In biological pest control, predator response to pest density variation is a dynamic trait that impacts the provision of this service in agroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need to know how natural enemies respond to these changes. Here we test the effect of variation in coffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Azteca sericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure the infestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored into fruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBB removed by ants, and estimated functional response from ant attack rates, measured as the difference in CBB infestation between branches. Infestation rates of CBB on branches with ants were significantly lower (71%-82%) than on those without ants across all density levels. Additionally, biocontrol efficiency was generally high and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. These results demonstrate that ants can provide robust biological control of CBB, despite variation in pest density, and that the response of predators to pest density variation is an important factor in the provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management of this ecosystem service in agroecosystems.

  18. La escritura como espada ante el machismo

    OpenAIRE

    Rottoli, Sofía

    2016-01-01

    Cuando se trata de expresar una postura que abarque una temática demasiado amplia o controversial, recurrir a la escritura puede ser una buena opción de abordaje. Sobre todo cuando son discusiones que llevan años de vigencia. Las luchas feministas ante la violencia de género no son una excepción. Sus discusiones siempre tuvieron presencia en diversos campos, uno de ellos es la ya mencionada escritura. Centro de Investigación en Lectura y Escritura (CILE)

  19. Ecology: 'Devil's gardens' bedevilled by ants.

    Science.gov (United States)

    Frederickson, Megan E; Greene, Michael J; Gordon, Deborah M

    2005-09-22

    'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites--a long-lasting benefit as colonies can live for 800 years.

  20. Ante-natal ionising radiation and cancer

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This editorial comments on the latest reports of the Oxford Survey of Childhood Cancer (now based on Birmingham). With 14759 pairs, the latest survey is over 10-fold larger than the 1958 report and the calculation of fatal childhood cancer rate at one case in 990 ante-natal radiographic examinations is rather larger than the early estimates, in spite of the fetal radiation dose having been halved and the cure rate for childhood leukemia being much improved. Comments are made on the comparisons with bomb survivors, and on the much increased fatal cancer incidence after first trimester radiography. (UK)

  1. Ant Systems for a Dynamic TSP - Ants Caught in a Traffic Jam

    NARCIS (Netherlands)

    Eyckelhof, C.J.; Dorigo, M.; Caro Di, G.; Snoek, M.; Sampels, M.

    2002-01-01

    In this paper we present a new Ants System approach to a dynamic Travelling Salesman Problem. Here the travel times between the cities are subject to change. To handle this dynamism several ways of adapting the pheromone matrix both locally and globally are considered. We show that the strategy of

  2. Chemical camouflage: a key process in shaping an ant-treehopper and fig-fig wasp mutualistic network.

    Science.gov (United States)

    Wang, Bo; Lu, Min; Cook, James M; Yang, Da-Rong; Dunn, Derek W; Wang, Rui-Wu

    2018-01-30

    Different types of mutualisms may interact, co-evolve and form complex networks of interdependences, but how species interact in networks of a mutualistic community and maintain its stability remains unclear. In a mutualistic network between treehoppers-weaver ants and fig-pollinating wasps, we found that the cuticular hydrocarbons of the treehoppers are more similar to the surface chemical profiles of fig inflorescence branches (FIB) than the cuticular hydrocarbons of the fig wasps. Behavioral assays showed that the cuticular hydrocarbons from both treehoppers and FIBs reduce the propensity of weaver ants to attack treehoppers even in the absence of honeydew rewards, suggesting that chemical camouflage helps enforce the mutualism between weaver ants and treehoppers. High levels of weaver ant and treehopper abundances help maintain the dominance of pollinating fig wasps in the fig wasp community and also increase fig seed production, as a result of discriminative predation and disturbance by weaver ants of ovipositing non-pollinating fig wasps (NPFWs). Ants therefore help preserve this fig-pollinating wasp mutualism from over exploitation by NPFWs. Our results imply that in this mutualistic network chemical camouflage plays a decisive role in regulating the behavior of a key species and indirectly shaping the architecture of complex arthropod-plant interactions.

  3. Cuticular hydrocarbons correlate with queen reproductive status in native and invasive Argentine ants (Linepithema humile, Mayr)

    Science.gov (United States)

    Diaz, Mireia; Lenoir, Alain; Ivon Paris, Carolina; Boulay, Raphaël; Gómez, Crisanto

    2018-01-01

    In insect societies, chemical communication plays an important role in colony reproduction and individual social status. Many studies have indicated that cuticular hydrocarbons (CHCs) are the main chemical compounds encoding reproductive status. However, these studies have largely focused on queenless or monogynous species whose workers are capable of egg laying and have mainly explored the mechanisms underlying queen-worker or worker-worker reproductive conflicts. Less is known about what occurs in highly polygynous ant species with permanently sterile workers. Here, we used the Argentine ant as a model to examine the role of CHCs in communicating reproductive information in such insect societies. The Argentine ant is unicolonial, highly polygynous, and polydomous. We identified several CHCs whose presence and levels were correlated with queen age, reproductive status, and fertility. Our results also provide new insights into queen executions in the Argentine ant, a distinctive feature displayed by this species in its introduced range. Each spring, just before new sexuals appear, workers eliminate up to 90% of the mated queens in their colonies. We discovered that queens that survived execution had different CHC profiles from queens present before and during execution. More specifically, levels of some CHCs were higher in the survivors, suggesting that workers could eliminate queens based on their chemical profiles. In addition, queen CHC profiles differed based on season and species range (native vs. introduced). Overall, the results of this study provide new evidence that CHCs serve as queen signals and do more than just regulate worker reproduction. PMID:29470506

  4. Invasive acacias experience higher ant seed removal rates at the invasion edges

    Directory of Open Access Journals (Sweden)

    D. Montesinos

    2012-06-01

    Full Text Available Seed dispersal is a key process for the invasion of new areas by exotic species. Introduced plants often take advantage of native generalist dispersers. Australian acacias are primarily dispersed by ants in their native range and produce seeds bearing a protein and lipid rich reward for ant mutualists (elaiosome. Nevertheless, the role of myrmecochory in the expansion of Australian acacias in European invaded areas is still not clear. We selected one European population of Acacia dealbata and another of A. longifolia and offered elaiosome-bearing and elaiosome-removed seeds to local ant communities. For each species, seeds were offered both in high-density acacia stands and in low-density invasion edges. For both acacia species, seed removal was significantly higher at the low-density edges. For A. longifolia, manual elimination of elaiosomes reduced the chance of seed removal by 80% in the low-density edges, whereas it made no difference on the high-density stands. For A. dealbata, the absence of elaiosome reduced seed removal rate by 52%, independently of the acacia density. Our data suggests that invasive acacias have found effective ant seed dispersers in Europe and that the importance of such dispersers is higher at the invasion edges.

  5. Nectar Theft and Floral Ant-Repellence: A Link between Nectar Volume and Ant-Repellent Traits?

    Science.gov (United States)

    Ballantyne, Gavin; Willmer, Pat

    2012-01-01

    As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were ant-repellent at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that ant-repellent floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost of nectar production in future studies into ant-flower interactions. PMID:22952793

  6. Partial incompatibility between ants and symbiotic fungi in two sympatric species of Acromyrmex leaf-cutting ants.

    Science.gov (United States)

    Bot, A N; Rehner, S A; Boomsma, J J

    2001-10-01

    We investigate the nature and duration of incompatibility between certain combinations of Acromyrmex leaf-cutting ants and symbiotic fungi, taken from sympatric colonies of the same or a related species. Ant-fungus incompatibility appeared to be largely independent of the ant species involved, but could be explained partly by genetic differences among the fungus cultivars. Following current theoretical considerations, we develop a hypothesis, originally proposed by S. A. Frank, that the observed incompatibilities are ultimately due to competitive interactions between genetically different fungal lineages, and we predict that the ants should have evolved mechanisms to prevent such competition between cultivars within a single garden. This requires that the ants are able to recognize unfamiliar fungi, and we show that this is indeed the case. Amplified fragment length polymorphism genotyping further shows that the two sympatric Acromyrmex species share each other's major lineages of cultivar, confirming that horizontal transfer does occasionally take place. We argue and provide some evidence that chemical substances produced by the fungus garden may mediate recognition of alien fungi by the ants. We show that incompatibility between ants and transplanted, genetically different cultivars is indeed due to active killing of the novel cultivar by the ants. This incompatibility disappears when ants are force-fed the novel cultivar for about a week, a result that is consistent with our hypothesis of recognition induced by the resident fungus and eventual replacement of incompatibility compounds during force-feeding.

  7. The importance of ants in cave ecology, with new records and behavioral observations of ants in Arizona caves

    Directory of Open Access Journals (Sweden)

    Robert B. Pape

    2016-09-01

    Full Text Available The importance of ants as elements in cave ecology has been mostly unrecognized. A global list of ant species recorded from caves, compiled from a review of existing literature, is presented. This paper also reviews what is currently known about ants occurring in Arizona (USA caves. The diversity and distribution represented in these records suggests ants are relatively common cave visitors (trogloxenes. A general utilization of caves by ants within both temperate and tropical latitudes may be inferred from this combined evidence. Observations of ant behavior in Arizona caves demonstrate a low level and sporadic, but persistent, use of these habitats and their contained resources by individual ant colonies. Documentation of Neivamyrmex sp. preying on cave-inhabiting arthropods is reported here for the first time. Observations of hypogeic army ants in caves suggests they may not penetrate to great vertical depth in search of prey, but can be persistent occupants in relatively shallow, horizontal sections of caves where they may prey on endemic cave animals. First cave records for ten ant species are reported from Arizona caves. These include two species of Neivamyrmex (N. nigrescens Cresson and Neivamyrmex sp.; Formicidae: Dorylinae, four myrmicines (Pheidole portalensis Wilson, Pheidole cf. porcula Wheeler, Solenopsis aurea Wheeler and Stenamma sp. Westwood, one dolichoderine (Forelius keiferi Wheeler and three formicines (Lasius arizonicus Wheeler, L. sitiens Wilson, and Camponotus sp. Mayr.

  8. Loading pattern optimization using ant colony algorithm

    International Nuclear Information System (INIS)

    Hoareau, Fabrice

    2008-01-01

    Electricite de France (EDF) operates 58 nuclear power plants (NPP), of the Pressurized Water Reactor type. The loading pattern optimization of these NPP is currently done by EDF expert engineers. Within this framework, EDF R and D has developed automatic optimization tools that assist the experts. LOOP is an industrial tool, developed by EDF R and D and based on a simulated annealing algorithm. In order to improve the results of such automatic tools, new optimization methods have to be tested. Ant Colony Optimization (ACO) algorithms are recent methods that have given very good results on combinatorial optimization problems. In order to evaluate the performance of such methods on loading pattern optimization, direct comparisons between LOOP and a mock-up based on the Max-Min Ant System algorithm (a particular variant of ACO algorithms) were made on realistic test-cases. It is shown that the results obtained by the ACO mock-up are very similar to those of LOOP. Future research will consist in improving these encouraging results by using parallelization and by hybridizing the ACO algorithm with local search procedures. (author)

  9. Ant Foraging Behavior for Job Shop Problem

    Directory of Open Access Journals (Sweden)

    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.

  10. The effect of diet and opponent size on aggressive interactions involving caribbean crazy ants (Nylanderia fulva.

    Directory of Open Access Journals (Sweden)

    Katherine C Horn

    Full Text Available Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants.

  11. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    Science.gov (United States)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  12. Ultrastructure of antennal sensillae of the samsum ant ...

    African Journals Online (AJOL)

    Black ant (Samsum), Pachycodyla sennarrensis, stings and injects venom and inflicts allergy (a rare clinical problem) due to its local and systemic reaction, which is considered as a health hazard amongst Saudi society. Thus, black ant is a source of serious concern for the government and experts as well.

  13. Development of a Bait System for the Pharaoh's Ant, Monomorium ...

    African Journals Online (AJOL)

    The infestation of the Pharaoh's ant, Monomorium pharaonis L. is widespread and, sometimes, very serious in homes, hospitals, restaurants, factories, etc. People are helpless because effective baited traps are not available locally, and little has been done locally to develop effective control strategies for these ants.

  14. A preliminary checklist of the ants (Hymenoptera: Formicidae) of ...

    African Journals Online (AJOL)

    A preliminary species checklist of the ants (Hymenoptera: Formicidae) of. Kakamega Forest, Western Kenya, is presented. The species list is based on specimens sampled from 1999 until 2009, which are deposited in the ant collection of the Zoological Research Museum Koenig, Bonn, Germany, and the Natural History ...

  15. Ant species richness of fynbos and forest ecosystems in the ...

    African Journals Online (AJOL)

    The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in ...

  16. Volatile chemicals in glands of the carpenter ant, Camponotus ...

    African Journals Online (AJOL)

    Volatile chemicals in glands of the carpenter ant, Camponotus arminius. J.M. Brand, L.V. Mabinya, E.D. Morgan. Abstract. Camponotus arminius is a large black carpenter ant that occurs in tropical and sub-tropical Africa and has extensive foraging trails both in trees and on the ground. Analysis of excised mandibular glands ...

  17. Novel Phialophora species from leaf-cutting ants (tribe Attini)

    NARCIS (Netherlands)

    Attili-Angelis, D.; Duarte, A.P.M.; Pagnocca, F.C.; Nagamoto, N.S.; de Vries, M.; Stielow, J.B.; de Hoog, G.S.

    2014-01-01

    Ants in the tribe Attini (Hymenoptera, Formicidae) maintain a 50 million-year-old lifestyle of co-evolution with symbiotic basidiomycetous fungi which they cultivate as essential source of nutrition. However, other microorganisms have been reported from ant habitats indicating a higher diversity of

  18. Why do house-hunting ants recruit in both directions?

    NARCIS (Netherlands)

    Planqué, R.; Dechaume-Moncharmont, F.-X.; Franks, N.R.; Kovacs, T.; Marshall, J.A.R.

    2007-01-01

    To perform tasks, organisms often use multiple procedures. Explaining the breadth of such behavioural repertoires is not always straightforward. During house hunting, colonies of Temnothorax albipennis ants use a range of behaviours to organise their emigrations. In particular, the ants use tandem

  19. Tracing the rise of ants - out of the ground.

    Directory of Open Access Journals (Sweden)

    Andrea Lucky

    Full Text Available The evolution of ants (Hymenoptera: Formicidae is increasingly well-understood due to recent phylogenetic analyses, along with estimates of divergence times and diversification rates. Yet, leading hypotheses regarding the ancestral habitat of ants conflict with new findings that early ant lineages are cryptic and subterranean. Where the ants evolved, in respect to habitat, and how habitat shifts took place over time have not been formally tested. Here, we reconstruct the habitat transitions of crown-group ants through time, focusing on where they nest and forage (in the canopy, litter, or soil. Based on ancestral character reconstructions, we show that in contrast to the current consensus based on verbal arguments that ants evolved in tropical leaf litter, the soil is supported as the ancestral stratum of all ants. We also find subsequent movements up into the litter and, in some cases, into the canopy. Given the global importance of ants, because of their diversity, ecological influence and status as the most successful eusocial lineage on Earth, understanding the early evolution of this lineage provides insight into the factors that made this group so successful today.

  20. In vitro studies of ante-mortem proliferation kinetics

    International Nuclear Information System (INIS)

    McBride, W.H.; Withers, H.R.

    1986-01-01

    Using K562 human erythroblastoid cells, it was concluded that dose fractionation has no discrepant effect on the ante-mortem proliferation kinetics of doomed cells as opposed to clonogenic cell survival and that effects on ante-mortem proliferation kinetics cannot be solely responsible for the differences in fractionation response between early and late responding tissues. (UK)

  1. Reciprocal genomic evolution in the ant-fungus agricultural symbiosis

    DEFF Research Database (Denmark)

    Nygaard, Sanne; Hu, Haofu; Li, Cai

    2016-01-01

    The attine ant-fungus agricultural symbiosis evolved over tens of millions of years, producing complex societies with industrial-scale farming analogous to that of humans. Here we document reciprocal shifts in the genomes and transcriptomes of seven fungus-farming ant species and their fungal...

  2. Life-Histories of Sub-Arctic Ants

    OpenAIRE

    Heinze, Jürgen

    1993-01-01

    Ant species belonging to seven genera occur in habitats near the tree line in the Northern Hemisphere. An analysis of colony founding strategies suggests that in addition to physiological cold resistance, behavioral and sociometric adaptations might be important for survival and propagation of ants in subarctic biomes.

  3. Studies of laboulbeniales (Fungi, Ascomycota) on myrmica ants (II)

    NARCIS (Netherlands)

    Haelewaters, Danny; Boer, Peter; Gort, Gerrit; Noordijk, Jinze

    2015-01-01

    One group of important insect parasites are the Laboulbeniales (Ascomycota), microscopic fungi that live attached to the exterior of their hosts, mainly beetles, but also mites, millipedes, earwigs, and ants. Rickia wasmannii is a common fungus in Europe and is limited to the ant genus Myrmica

  4. ADAPTIVE ANT COLONY OPTIMIZATION BASED GRADIENT FOR EDGE DETECTION

    Directory of Open Access Journals (Sweden)

    Febri Liantoni

    2014-08-01

    Full Text Available Ant Colony Optimization (ACO is a nature-inspired optimization algorithm which is motivated by ants foraging behavior. Due to its favorable advantages, ACO has been widely used to solve several NP-hard problems, including edge detection. Since ACO initially distributes ants at random, it may cause imbalance ant distribution which later affects path discovery process. In this paper an adaptive ACO is proposed to optimize edge detection by adaptively distributing ant according to gradient analysis. Ants are adaptively distributed according to gradient ratio of each image regions. Region which has bigger gradient ratio, will have bigger number of ant distribution. Experiments are conducted using images from various datasets. Precision and recall are used to quantitatively evaluate performance of the proposed algorithm. Precision and recall of adaptive ACO reaches 76.98 % and 96.8 %. Whereas highest precision and recall for standard ACO are 69.74 % and 74.85 %. Experimental results show that the adaptive ACO outperforms standard ACO which randomly distributes ants.

  5. Patterns of male parentage in the fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Boomsma, JJ

    2003-01-01

    Ant queens from eight species, covering three genera of lower and two genera of higher attine ants, have exclusively or predominantly single mating. The ensuing full-sib colonies thus have a strong potential reproductive conflict between the queen and the workers over male production...

  6. Odorous house ants (Tapinoma sessile as back-seat drivers of localized ant decline in urban habitats.

    Directory of Open Access Journals (Sweden)

    Adam Salyer

    Full Text Available Invasive species and habitat disturbance threaten biodiversity worldwide by modifying ecosystem performance and displacing native organisms. Similar homogenization impacts manifest locally when urbanization forces native species to relocate or reinvade perpetually altered habitat. This study investigated correlations between ant richness and abundance in response to urbanization and the nearby presence of invasive ant species, odorous house ants (Tapinoma sessile, within its native region. Surveying localized ant composition within natural, semi-natural, and urban habitat supported efforts to determine whether T. sessile appear to be primary (drivers threats as instigators or secondary (passengers threats as inheritors of indigenous ant decline. Sampling 180 sites, evenly split between all habitats with and without T. sessile present, yielded 45 total species. Although urbanization and T. sessile presence factors were significantly linked to ant decline, their interaction correlated to the greatest reduction of total ant richness (74% and abundance (81%. Total richness appeared to decrease from 27 species to 18 when natural habitat is urbanized and from 18 species to 7 with T. sessile present in urban plots. Odorous house ant presence minimally influenced ant communities within natural and semi-natural habitat, highlighting the importance of habitat alteration and T. sessile presence interactions. Results suggest urbanization releases T. sessile from unknown constraints by decreasing ant richness and competition. Within urban environment, T. sessile are pre-adapted to quickly exploit new resources and grow to supercolony strength wherein T. sessile drive adjacent biodiversity loss. Odorous house ants act as passengers and drivers of ecological change throughout different phases of urban 'invasion'. This progression through surviving habitat alteration, exploiting new resources, thriving, and further reducing interspecific competition supports a

  7. An ant-plant by-product mutualism is robust to selective logging of rain forest and conversion to oil palm plantation.

    Science.gov (United States)

    Fayle, Tom M; Edwards, David P; Foster, William A; Yusah, Kalsum M; Turner, Edgar C

    2015-06-01

    Anthropogenic disturbance and the spread of non-native species disrupt natural communities, but also create novel interactions between species. By-product mutualisms, in which benefits accrue as side effects of partner behaviour or morphology, are often non-specific and hence may persist in novel ecosystems. We tested this hypothesis for a two-way by-product mutualism between epiphytic ferns and their ant inhabitants in the Bornean rain forest, in which ants gain housing in root-masses while ferns gain protection from herbivores. Specifically, we assessed how the specificity (overlap between fern and ground-dwelling ants) and the benefits of this interaction are altered by selective logging and conversion to an oil palm plantation habitat. We found that despite the high turnover of ant species, ant protection against herbivores persisted in modified habitats. However, in ferns growing in the oil palm plantation, ant occupancy, abundance and species richness declined, potentially due to the harsher microclimate. The specificity of the fern-ant interactions was also lower in the oil palm plantation habitat than in the forest habitats. We found no correlations between colony size and fern size in modified habitats, and hence no evidence for partner fidelity feedbacks, in which ants are incentivised to protect fern hosts. Per species, non-native ant species in the oil palm plantation habitat (18 % of occurrences) were as important as native ones in terms of fern protection and contributed to an increase in ant abundance and species richness with fern size. We conclude that this by-product mutualism persists in logged forest and oil palm plantation habitats, with no detectable shift in partner benefits. Such persistence of generalist interactions in novel ecosystems may be important for driving ecosystem functioning.

  8. Plant defences against ants provide a pathway to social parasitism in butterflies

    Science.gov (United States)

    Patricelli, Dario; Barbero, Francesca; Occhipinti, Andrea; Bertea, Cinzia M.; Bonelli, Simona; Casacci, Luca P.; Zebelo, Simon A.; Crocoll, Christoph; Gershenzon, Jonathan; Maffei, Massimo E.; Thomas, Jeremy A.; Balletto, Emilio

    2015-01-01

    Understanding the chemical cues and gene expressions that mediate herbivore–host-plant and parasite–host interactions can elucidate the ecological costs and benefits accruing to different partners in tight-knit community modules, and may reveal unexpected complexities. We investigated the exploitation of sequential hosts by the phytophagous–predaceous butterfly Maculinea arion, whose larvae initially feed on Origanum vulgare flowerheads before switching to parasitize Myrmica ant colonies for their main period of growth. Gravid female butterflies were attracted to Origanum plants that emitted high levels of the monoterpenoid volatile carvacrol, a condition that occurred when ants disturbed their roots: we also found that Origanum expressed four genes involved in monoterpene formation when ants were present, accompanied by a significant induction of jasmonates. When exposed to carvacrol, Myrmica workers upregulated five genes whose products bind and detoxify this biocide, and their colonies were more tolerant of it than other common ant genera, consistent with an observed ability to occupy the competitor-free spaces surrounding Origanum. A cost is potential colony destruction by Ma. arion, which in turn may benefit infested Origanum plants by relieving their roots of further damage. Our results suggest a new pathway, whereby social parasites can detect successive resources by employing plant volatiles to simultaneously select their initial plant food and a suitable sequential host. PMID:26156773

  9. Energy Efficiency Performance Improvements for Ant-Based Routing Algorithm in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Adamu Murtala Zungeru

    2013-01-01

    Full Text Available The main problem for event gathering in wireless sensor networks (WSNs is the restricted communication range for each node. Due to the restricted communication range and high network density, event forwarding in WSNs is very challenging and requires multihop data forwarding. Currently, the energy-efficient ant based routing (EEABR algorithm, based on the ant colony optimization (ACO metaheuristic, is one of the state-of-the-art energy-aware routing protocols. In this paper, we propose three improvements to the EEABR algorithm to further improve its energy efficiency. The improvements to the original EEABR are based on the following: (1 a new scheme to intelligently initialize the routing tables giving priority to neighboring nodes that simultaneously could be the destination, (2 intelligent update of routing tables in case of a node or link failure, and (3 reducing the flooding ability of ants for congestion control. The energy efficiency improvements are significant particularly for dynamic routing environments. Experimental results using the RMASE simulation environment show that the proposed method increases the energy efficiency by up to 9% and 64% in converge-cast and target-tracking scenarios, respectively, over the original EEABR without incurring a significant increase in complexity. The method is also compared and found to also outperform other swarm-based routing protocols such as sensor-driven and cost-aware ant routing (SC and Beesensor.

  10. Multi-view 3D scene reconstruction using ant colony optimization techniques

    International Nuclear Information System (INIS)

    Chrysostomou, Dimitrios; Gasteratos, Antonios; Nalpantidis, Lazaros; Sirakoulis, Georgios C

    2012-01-01

    This paper presents a new method performing high-quality 3D object reconstruction of complex shapes derived from multiple, calibrated photographs of the same scene. The novelty of this research is found in two basic elements, namely: (i) a novel voxel dissimilarity measure, which accommodates the elimination of the lighting variations of the models and (ii) the use of an ant colony approach for further refinement of the final 3D models. The proposed reconstruction procedure employs a volumetric method based on a novel projection test for the production of a visual hull. While the presented algorithm shares certain aspects with the space carving algorithm, it is, nevertheless, first enhanced with the lightness compensating image comparison method, and then refined using ant colony optimization. The algorithm is fast, computationally simple and results in accurate representations of the input scenes. In addition, compared to previous publications, the particular nature of the proposed algorithm allows accurate 3D volumetric measurements under demanding lighting environmental conditions, due to the fact that it can cope with uneven light scenes, resulting from the characteristics of the voxel dissimilarity measure applied. Besides, the intelligent behavior of the ant colony framework provides the opportunity to formulate the process as a combinatorial optimization problem, which can then be solved by means of a colony of cooperating artificial ants, resulting in very promising results. The method is validated with several real datasets, along with qualitative comparisons with other state-of-the-art 3D reconstruction techniques, following the Middlebury benchmark. (paper)

  11. Genetic evidence for intra- and interspecific slavery in honey ants (genus Myrmecocystus).

    Science.gov (United States)

    Kronauer, D J C; Gadau, J; Hölldobler, B

    2003-04-22

    The New World honey ant species Myrmecocystus mimicus is well known for its highly stereotyped territorial tournaments, and for the raids on conspecific nests that can lead to intraspecific slavery. Our results from mitochondrial and nuclear markers show that the raided brood emerges in the raiding colony and is subsequently incorporated into the colony's worker force. We also found enslaved conspecifics in a second honey ant species, M. depilis, the sister taxon of M. mimicus, which occurs in sympatry with M. mimicus at the study site. Colonies of this species furthermore contained raided M. mimicus workers. Both species have an effective mating frequency that is not significantly different from 1. This study provides genetic evidence for facultative intra- and interspecific slavery in the genus Myrmecocystus. Slavery in ants has evolved repeatedly and supposedly by different means. We propose that, in honey ants, secondary contact between two closely related species that both exhibit intraspecific slavery gave rise to an early form of facultative interspecific slavery.

  12. Paratrechina longicornis ants in a tropical dry forest harbor specific Actinobacteria diversity.

    Science.gov (United States)

    Reyes, Ruth D Hernández; Cafaro, Matías J

    2015-01-01

    The diversity of Actinobacteria associated with Paratrechina longicornis, an ant species that prefers a high protein diet, in a subtropical dry forest (Guánica, Puerto Rico) was determined by culture methods and by 16S rDNA clone libraries. The results of both methodologies were integrated to obtain a broader view of the diversity. Streptomyces, Actinomadura, Nocardia, Ornithinimicrobium, Tsukamurella, Brevibacterium, Saccharopolyspora, Nocardioides, Microbacterium, Leifsonia, Pseudonocardia, Corynebacterium, Geodermatophilus, Amycolatopsis, and Nonomuraea were found associated with the ants. The genera Streptomyces and Actinomadura were the most abundant. Also, the diversity of Actinobacteria associated with the soil surrounding the nest was determined using 16S rDNA clone libraries. In total, 27 genera of Actinobacteria were associated with the nest soils. A dominant genus was not observed in any of the soil samples. We compared statistically the Actinobacteria communities among P. longicornis nests and each nest with its surrounding soil using the clone libraries data. We established that the communities associated with the ants were consistent and significantly different from those found in the soil in which the ants live. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Weaver Ants to Control Fruit Fly Damage to Tanzanian Mangoes

    DEFF Research Database (Denmark)

    Kirkegaard, Nina

    in Australia and West Africa. In this study, small scale farmers did not think weaver ants protected their mangoes from fruit flies. Observational studies confirmed the farmers’ views. No volatile compounds, likely to be responsible for the weaver ants’ deterrent effect, were identified. This study focused...... mangoes varied a lot with zero infestation in some fruits and more than 100 pupae emerging from other fruits, indicating that other factors than the presence of weaver ants affect the fruit flies’ decision on where to oviposit. It was not uncommon for farmers to place newly harvested mangoes below mango...... not shown to be effectively deterring fruit flies, there is no great motivation for farmers to adopt weaver ants. Assuming the weaver ants could be managed in a way that made weaver ants deter fruit flies effectively there are still some economic aspects which should be studied further. It is necessary...

  14. Behind every great ant, there is a great gut

    DEFF Research Database (Denmark)

    Poulsen, Michael; Sapountzis, Panagiotis

    2012-01-01

    on the potential contribution of the ants’ gut symbionts. This issue of Molecular Ecology contains a study by Anderson et al. (2012), who take a comparative approach to explore the link between trophic levels and ant microbiomes, specifically, to address three main questions: (i) Do closely related herbivorous...... conserved gut microbiomes, suggesting symbiont functions that directly relate to dietary preference of the ant host. These findings suggest an ecological role of gut symbionts in ants, for example, in metabolism and/or protection, and the comparative approach taken supports a model of co-evolution between...... ant species and specific core symbiont microbiomes. This study, thereby, highlights the omnipresence and importance of gut symbioses—also in the Hymenoptera—and suggests that these hitherto overlooked microbes likely have contributed to the ecological success of the ants....

  15. Invasive ants compete with and modify the trophic ecology of hermit crabs on tropical islands.

    Science.gov (United States)

    McNatty, Alice; Abbott, Kirsti L; Lester, Philip J

    2009-05-01

    Invasive species can dramatically alter trophic interactions. Predation is the predominant trophic interaction generally considered to be responsible for ecological change after invasion. In contrast, how frequently competition from invasive species contributes to the decline of native species remains controversial. Here, we demonstrate how the trophic ecology of the remote atoll nation of Tokelau is changing due to competition between invasive ants (Anoplolepis gracilipes) and native terrestrial hermit crabs (Coenobita spp.) for carrion. A significant negative correlation was observed between A. gracilipes and hermit crab abundance. On islands with A. gracilipes, crabs were generally restricted to the periphery of invaded islands. Very few hermit crabs were found in central areas of these islands where A. gracilipes abundances were highest. Ant exclusion experiments demonstrated that changes in the abundance and distribution of hermit crabs on Tokelau are a result of competition. The ants did not kill the hermit crabs. Rather, when highly abundant, A. gracilipes attacked crabs by spraying acid and drove crabs away from carrion resources. Analysis of naturally occurring N and C isotopes suggests that the ants are effectively lowering the trophic level of crabs. According to delta(15) N values, hermit crabs have a relatively high trophic level on islands where A. gracilipes have not invaded. In contrast, where these ants have invaded we observed a significant decrease in delta(15) N for all crab species. This result concurs with our experiment in suggesting long-term exclusion from carrion resources, driving co-occurring crabs towards a more herbivorous diet. Changes in hermit crab abundance or distribution may have major ramifications for the stability of plant communities. Because A. gracilipes have invaded many tropical islands where the predominant scavengers are hermit crabs, we consider that their competitive effects are likely to be more prominent in

  16. Case series of ante-grade biliary stenting: An option during bile duct exploration

    Directory of Open Access Journals (Sweden)

    Qaiser Jalal

    Full Text Available Background: Managing choledochotomy after bile duct clearance is an ongoing debate. T-tube insertion is not without complication and morbidity, requires significant post-operative care. Primary closure alone can result in a high pressure biliary system and bile leak. The placement of an ante-grade stent through the choledochotomy prior to primary closure is an option for ensuring biliary drainage after bile duct exploration. We reviewed our series of open bile duct explorations, where an ante-grade stent was placed when managing choledochotomy. Methods: Patients who had ante-grade stent placement, all performed by same senior hepatobiliary surgeon, were identified retrospectively. Case note review was used to gather demographic, complication, length of stay, post-operative clinic visits and readmission data. Results: 22 (M:F, 7:15 patients with a median age of 64 years (22–82. The indication for surgical stone clearance was failed ERCP in 20.2 patients were not suitable for ERCP. The median post-operative stay was 8 days (379 with the abdominal drain remaining for a median of 4 days (137. 16 (73% patients had no complications. 4 (18% had bile leaks, 5 (22% wound infections, 1 (5% cholangitis and 1 (5% pancreatitis. All complications were Clavien-Dindo grade 3 or less. Conclusion: In situations where primary CBD closure is not safe due to concern over high pressure in the biliary tree the placement of ante-grade stent may be preferred to T-tube placement. Keywords: Choledocholithiasis, Ante-grade stenting, Choledochotomy

  17. ANT International chemistry update and best practices

    International Nuclear Information System (INIS)

    Nordmann, F.; Odar, S.; Venz, H.; Kysela, J.; Ruehle, W.; Riess, R.

    2010-01-01

    There is an increasing number of Nuclear Power Plants (NPP) in various countries. Their chemistry practices are different due to the variety of designs and experiences while in the past the view was more monolithic. This is allowing a very rich experience that is extremely difficult to fully be aware of. ANT International is now collecting and evaluating these data as well as related R and D Information. This allows interested parties to have an easier access to the various sources of information. The chemistry experts associated to ANT International have been gathering a comprehensive detailed view of: The numerous laboratory data gained all over the world during the past decades; The extensive plant operating experiences with various types of chemistry strategies, crosschecked for various types of reactors designs and materials; An experienced international knowledge able to give the comprehensive overview that young engineers now in charge of many other activities are unable to fully cover. This paper gives the core conclusions of the detailed ANT International reports and results that have recently been gathered in the area of chemistry. It particularly covers: The primary water chemistry and its relation with radionuclides, dose rates and fuel behaviour; The secondary water chemistry focusing on its rationale selection depending on materials, design and other constraints; The start up and shutdown chemistry with it large variety of practices hardly understandable even for some experts; and, The maintenance remedies such as decontamination, steam generator cleaning and its alternate options. Various types of Reactor designs (PWR, VVER, BWR, CANDU®) are considered. The different materials, for example the impact of steam generator tubing and its evolution on the secondary water chemistry rationale or on the radioactivity built-up in the primary coolant, are described. The ways to improve the plant operation with a long term reliability as well as the most

  18. 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.

  19. Immune defense in leaf-cutting ants

    DEFF Research Database (Denmark)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández

    2011-01-01

    To ameliorate the impact of disease, social insects combine individual innate immune defenses with collective social defenses. This implies that there are different levels of selection acting on investment in immunity, each with their own trade-offs. We present the results of a cross......-fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced...... both individual innate immunity (constitutive antibacterial activity) and the size of the metapleural gland, which secretes antimicrobial compounds and functions in individual and social defense, indicating multiple mating could have important consequences for both defense types. However, the primarily...

  20. Ex-ante Evaluation von Investitionsalternativen

    Directory of Open Access Journals (Sweden)

    Matthias Müller

    2017-12-01

    Full Text Available Der Beitrag zeigt, wie mit Hilfe der Methode der agentenbasierten Modellierung und Simulation (ABMS ein Beitrag zur ex-ante Policy-Beratung geleistet werden kann. Anhand eines exemplarischen Anwendungsfalls, der VISIBLE Simulationsumgebung („Virtual Simulation Lab for the Analysis of Investments in Learning and Education“, diskutieren wir die Konsequenzen unterschiedlicher Kooperationsförderinstrumente für Wissensdiffusionsprozesse in Netzwerken am Beispiel der Region Heilbronn-Franken. Die Simulationsergebnisse zeigen, dass die strukturelle Konfiguration eines regionalen Innovationssystems eine zentrale Bedeutung für die Gestaltung von Kooperationsfördermaßnahmen hat und dass Interventionen, die darauf abzielen, Wissenstransfer zwischen den Akteuren anzuregen, genau die entgegengesetzten Wirkungen entfalten können.

  1. Swarm controlled emergence for ant clustering

    DEFF Research Database (Denmark)

    Scheidler, Alexander; Merkle, Daniel; Middendorf, Martin

    2013-01-01

    .g. moving robots, and clustering algorithms. Design/methodology/approach: Different types of control agents for that ant clustering model are designed by introducing slight changes to the behavioural rules of the normal agents. The clustering behaviour of the resulting swarms is investigated by extensive...... for future research to investigate the application of the method in other swarm systems. Swarm controlled emergence might be applied to control emergent effects in computing systems that consist of many autonomous components which make decentralized decisions based on local information. Practical...... simulation studies. Findings: It is shown that complex behavior can emerge in systems with two types of agents (normal agents and control agents). For a particular behavior of the control agents, an interesting swarm size dependent effect was found. The behaviour prevents clustering when the number...

  2. Discrimination Behavior in the Supercolonial Pharaoh Ant

    DEFF Research Database (Denmark)

    Pontieri, Luigi

    The majority of eusocial insect species live in small, kin structured colonies that are mutually aggressive and rarely interact. By contrast, a restricted group of ant species show a peculiar social organization called unicoloniality, where colonies can grow to vast networks of geographically...... and genetic distance between colony pairs, further confirming the important role of endogenous cues in the nestmate recognition of this species. The third chapter presents a methodological study on the best procedures for identifying chemical compounds used for nestmate recognition in social insects. We first...... evaluated the power of different combinations of data transformation and chemical distance calculation in differentiating between true nestmate recognition (NMR) cues and other compounds. We found that particular combinations of statistical procedures are more effective in differentiating NMR cues from...

  3. Food resource and temporal partitioning amongst a guild of predatory agroecosystem - inhabiting ant species

    Directory of Open Access Journals (Sweden)

    Vivek Mohan AGARWAL, Neelkamal RASTOGI

    2009-10-01

    Full Text Available Prey diversity and temporal foraging patterns of six abundant, predatory ant species were investigated seasonally in an agroecosystem with two main vegetable crops. Pheidole sp. demonstrated the highest predation success and therefore appears to be the dominant species while Tapinoma melanocephalum showed the lowest success under the natural field conditions. Investigation of prey diversity and temporal activity patterns with the null model tests of niche overlap revealed a significant overlap indicating that the activity periods and prey diversity may not be solely influenced by interactions among the co-existing ant species. However, niche partitioning in the daily peak activity periods was demonstrated during all the three seasons (summer, rainy and winter particularly between Pheidole sp. and T. melanocephalum. Pheidole sp. exhibited a high intensity, broadly extended mono-modal foraging pattern. Camponotus compressus and C. paria showed bi-modality in their foraging activity during the rainy season and mono-modal patterns during summer and winter seasons. Pachycondyla tesserinoda, Tetramorium sp. and T. melanocephalum exhibited peak foraging activities in the morning hours during the summer and rainy seasons. The activity profiles of C. compressus and T. melanocephalum were skewed towards late afternoon hours during the winter season indicating avoidance of foraging activity during the favourable periods when the more aggressive Pheidole sp. is active. In the sponge gourd agroecosystem, the ants captured predominantly hymenopteran, orthopteran and coleopteran insects. While Pheidole sp. hunted mainly the large orthopteran prey, other ant species captured worker ants in the sponge gourd agroecosystem. In the cauliflower agroecosystem, while other species captured prey chiefly belonging to six orders, i.e., Lepidoptera, Hymenoptera, Coleoptera, Hemiptera, Isoptera and Diptera, Pheidole sp. was the only species to also hunt orthopteran prey

  4. Effect of post-fire resprouting on leaf fluctuating asymmetry, extrafloral nectar quality, and ant-plant-herbivore interactions

    Science.gov (United States)

    Alves-Silva, Estevão; Del-Claro, Kleber

    2013-06-01

    Fires in the Cerrado savanna are a severe form of disturbance, but some species are capable of resprouting afterwards. It is unknown, however, how and whether post-fire resprouting represents a stressful condition to plants and how their rapid re-growth influences both the production of biochemical compounds, and interactions with mutualistic ants. In this study, we examined the influence of post-fire resprouting on biotic interactions (ant-plant-herbivore relationships) and on plant stress. The study was performed on two groups of the extrafloral nectaried shrub Banisteriopsis campestris (Malpighiaceae); one group was recovering from fire while the other acted as control. With respect to biotic interactions, we examined whether resprouting influenced extrafloral nectar concentration (milligrams per microliter), the abundance of the ant Camponotus crassus and leaf herbivory rates. Plant stress was assessed via fluctuating asymmetry (FA) analysis, which refers to deviations from perfect symmetry in bilaterally symmetrical traits (e.g., leaves) and indicates whether species are under stress. Results revealed that FA, sugar concentration, and ant abundance were 51.7 %, 35.7 % and 21.7 % higher in resprouting plants. Furthermore, C. crassus was significantly associated with low herbivory rates, but only in resprouting plants. This study showed that post-fire resprouting induced high levels of plant stress and influenced extrafloral nectar quality and ant-herbivore relationships in B. campestris. Therefore, despite being a stressful condition to the plant, post-fire resprouting individuals had concentrated extrafloral nectar and sustained more ants, thus strengthening the outcomes of ant-plant mutualism.

  5. ANTS-anchored Zn-Al-CO{sub 3}-LDH particles as fluorescent probe for sensing of folic acid

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pengfei; Liu, Dan; Liu, Yanhuan [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Lei, E-mail: lilei@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China)

    2016-09-15

    A novel fluorescent nanosensor for detecting folic acid (FA) in aqueous media has been developed based on 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) anchored to the surface of Zn-Al-CO{sub 3}-layered double hydroxides (LDH) particles. The nanosensor showed high fluorescence intensity and good photostability due to a strong coordination interaction between surface Zn{sup 2+} ions of Zn-Al-CO{sub 3}-LDH and N atoms of ANTS, which were verified by result of X-ray photoelectron spectroscopy (XPS). ANTS-anchored on the surface of Zn-Al-CO{sub 3}-LDH restricted the intra-molecular rotation leading to ANTS-anchored J-type aggregation emission enhancement. ANTS-anchored Zn-Al-CO{sub 3}-LDH particles exhibited highly sensitive and selective response to FA over other common metal ions and saccharides present in biological fluids. The proposed mechanism was that oxygen atoms of -SO{sub 3} groups in ANTS-anchored on the surface of Zn-Al-CO{sub 3}-LDH were easily collided by FA molecules to form potential hydrogen bonds between ANTS-anchored and FA molecules, which could effectively quench the ANTS-anchored fluorescence. Under the simulated physiological conditions (pH of 7.4), the fluorescence quenching was fitted to Stern-Volmer equation with a linear response in the concentration range of 1 μM to 200 μM with a limit of detection of 0.1 μM. The results indicate that ANTS-anchored Zn-Al-CO{sub 3}-LDH particles can afford a very sensitive system for the sensing FA in aqueous solution. - Highlights: • A novel fluorescent nanosensor has been developed. • The sensor exhibited highly sensitive and selective response to FA. • The fluorescence quenching was fitted to Stern–Volmer equation. • The linear response range was 1–200 μM with a limit of detection of 0.1 μM.

  6. Entomopathogens Isolated from Invasive Ants and Tests of Their Pathogenicity

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Miori de Zarzuela

    2012-01-01

    Full Text Available Some ant species cause severe ecological and health impact in urban areas. Many attempts have been tested to control such species, although they do not always succeed. Biological control is an alternative to chemical control and has gained great prominence in research, and fungi and nematodes are among the successful organisms controlling insects. This study aimed to clarify some questions regarding the biological control of ants. Invasive ant species in Brazil had their nests evaluated for the presence of entomopathogens. Isolated entomopathogens were later applied in colonies of Monomorium floricola under laboratory conditions to evaluate their effectiveness and the behavior of the ant colonies after treatment. The entomopathogenic nematodes Heterorhabditis sp. and Steinernema sp. and the fungi Beauveria bassiana, Metarhizium anisopliae, and Paecilomyces sp. were isolated from the invasive ant nests. M. floricola colonies treated with Steinernema sp. and Heterorhabditis sp. showed a higher mortality of workers than control. The fungus Beauveria bassiana caused higher mortality of M. floricola workers. However, no colony reduction or elimination was observed in any treatment. The defensive behaviors of ants, such as grooming behavior and colony budding, must be considered when using fungi and nematodes for biological control of ants.

  7. 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.

  8. Evolution of Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    The attine ant symbiosis is characterized by ancient but varying degrees of diffuse co-evolution between the ants and their fungal cultivars. Domesticated fungi became dependent on vertical transmission by queens and the ant colonies came to rely on their symbiotic fungus for food and thus...... as garden substrate, whereas the more basal genera use leaf litter, insect feces and insect carcasses. We hypothesized that enzyme activity of fungal symbionts has co-evolved with substrate use and we measured enzyme activities of fungus gardens in the field to test this, focusing particularly on plant...... essential for the symbiosis in general, but have contributed specifically to the evolution of the symbiosis....

  9. Comparative studies of the secretome of fungus-growing ants

    DEFF Research Database (Denmark)

    Linde, Tore; Grell, Morten Nedergaard; Schiøtt, Morten

    2009-01-01

    Leafcutter ants of the species Acromyrmex echinatior live in symbiosis with the fungus Leucoagaricus gongylophorus. The ants harvest fragments of leaves and carry them to the nest where they place the material on the fungal colony. The fungus secretes a wide array of proteins to degrade the leaves...... into nutrients that the ants can feed on. The focus of this study is to discover, characterize and compare the secreted proteins. In order to do so cDNA libraries are constructed from mRNA extracted from the fungus material. The most efficient technology to screen cDNA libraries selectively for secreted...

  10. Warehouse stocking optimization based on dynamic ant colony genetic algorithm

    Science.gov (United States)

    Xiao, Xiaoxu

    2018-04-01

    In view of the various orders of FAW (First Automotive Works) International Logistics Co., Ltd., the SLP method is used to optimize the layout of the warehousing units in the enterprise, thus the warehouse logistics is optimized and the external processing speed of the order is improved. In addition, the relevant intelligent algorithms for optimizing the stocking route problem are analyzed. The ant colony algorithm and genetic algorithm which have good applicability are emphatically studied. The parameters of ant colony algorithm are optimized by genetic algorithm, which improves the performance of ant colony algorithm. A typical path optimization problem model is taken as an example to prove the effectiveness of parameter optimization.

  11. Ant colony algorithm for clustering in portfolio optimization

    Science.gov (United States)

    Subekti, R.; Sari, E. R.; Kusumawati, R.

    2018-03-01

    This research aims to describe portfolio optimization using clustering methods with ant colony approach. Two stock portfolios of LQ45 Indonesia is proposed based on the cluster results obtained from ant colony optimization (ACO). The first portfolio consists of assets with ant colony displacement opportunities beyond the defined probability limits of the researcher, where the weight of each asset is determined by mean-variance method. The second portfolio consists of two assets with the assumption that each asset is a cluster formed from ACO. The first portfolio has a better performance compared to the second portfolio seen from the Sharpe index.

  12. Automating ActionScript Projects with Eclipse and Ant

    CERN Document Server

    Koning, Sidney

    2011-01-01

    Automating repetitive programming tasks is easier than many Flash/AS3 developers think. With the Ant build tool, the Eclipse IDE, and this concise guide, you can set up your own "ultimate development machine" to code, compile, debug, and deploy projects faster. You'll also get started with versioning systems, such as Subversion and Git. Create a consistent workflow for multiple machines, or even complete departments, with the help of extensive Ant code samples. If you want to work smarter and take your skills to a new level, this book will get you on the road to automation-with Ant. Set up y

  13. The invasion biology and sociogenetics of pharaoh ants

    DEFF Research Database (Denmark)

    Schmidt, Anna Mosegaard

    Social insect colonies perform a number of tasks affecting the environments they live in. Some unintentionally introduced species have attracted the attention of scientists and general public alike when causing a number of changes to the composition and functioning of ecosystems. Such ?invaders...... laboratory lineages, thus building the foundation for future research on the species. In addition, I have started a selection experiment (still ongoing in collaboration with Dr. T. Linksvayer) using pharaoh ants, which is the first time artificial selection is attempted in an ant species. Pharaoh ants have...

  14. "Ant" and "grasshopper" life-history strategies in Saccharomyces cerevisiae.

    Science.gov (United States)

    Spor, Aymé; Wang, Shaoxiao; Dillmann, Christine; de Vienne, Dominique; Sicard, Delphine

    2008-02-13

    From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r), the carrying capacity (K), the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as "ant" and "grasshopper" strategies of resource utilization. Interestingly, a strain may be "ant" in one medium and "grasshopper" in another. These life-history strategies are discussed

  15. "Ant" and "grasshopper" life-history strategies in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Aymé Spor

    Full Text Available From the evolutionary and ecological points of view, it is essential to distinguish between the genetic and environmental components of the variability of life-history traits and of their trade-offs. Among the factors affecting this variability, the resource uptake rate deserves particular attention, because it depends on both the environment and the genetic background of the individuals. In order to unravel the bases of the life-history strategies in yeast, we grew a collection of twelve strains of Saccharomyces cerevisiae from different industrial and geographical origins in three culture media differing for their glucose content. Using a population dynamics model to fit the change of population size over time, we estimated the intrinsic growth rate (r, the carrying capacity (K, the mean cell size and the glucose consumption rate per cell. The life-history traits, as well as the glucose consumption rate, displayed large genetic and plastic variability and genetic-by-environment interactions. Within each medium, growth rate and carrying capacity were not correlated, but a marked trade-off between these traits was observed over the media, with high K and low r in the glucose rich medium and low K and high r in the other media. The cell size was tightly negatively correlated to carrying capacity in all conditions. The resource consumption rate appeared to be a clear-cut determinant of both the carrying capacity and the cell size in all media, since it accounted for 37% to 84% of the variation of those traits. In a given medium, the strains that consume glucose at high rate have large cell size and low carrying capacity, while the strains that consume glucose at low rate have small cell size but high carrying capacity. These two contrasted behaviors may be metaphorically defined as "ant" and "grasshopper" strategies of resource utilization. Interestingly, a strain may be "ant" in one medium and "grasshopper" in another. These life

  16. Symbiotic mutualism with a community of opportunistic ants: protection, competition, and ant occupancy of the myrmecophyte Barteria nigritana (Passifloraceae)

    Science.gov (United States)

    Djiéto-Lordon, Champlain; Dejean, Alain; Gibernau, Marc; Hossaert-McKey, Martine; McKey, Doyle

    2004-10-01

    Barteria nigritana is a myrmecophyte tree of Lower Guinea coastal vegetation. Unlike the more specialised B. fistulosa, which harbours a single host-specific mutualistic ant, B. nigritana is associated with several opportunistic ants. Such symbiotic, yet opportunistic, ant-plant associations have been little studied. On 113 clumps of B. nigritana, we censused ant associates and herbivores and compared herbivory on plants occupied by different ants. In addition to these correlative data, protection conferred by different ant species was compared by herbivore-placement experiments. Identity of ant associate changed predictably over plant ontogeny. Pheidole megacephala was restricted to very small plants; saplings were occupied by either Oecophylla longinoda or Crematogaster sp., and the latter species was the sole occupant of larger trees. Damage by caterpillars of the nymphalid butterfly Acraea zetes accounted for much of the herbivory to leaves. Ant species differed in the protection provided to hosts. While P. megacephala provided no significant protection, plants occupied by O. longinoda and Crematogaster sp. suffered less damage than did unoccupied plants or those occupied by P. megacephala. Furthermore, O. longinoda provided more effective protection than did Crematogaster sp. Herbivore-placement experiments confirmed these results. Workers of O. longinoda killed or removed all larval instars of A. zetes. Crematogaster preyed on only the two first larval instars, and P. megacephala preyed mainly on eggs, only rarely attacking the two first larval instars. Opportunistic ants provided significant protection to this relatively unspecialised myrmecophyte. The usual associate of mature trees was not the species that provided most protection.

  17. The organization of societal conflicts by pavement ants Tetramorium caespitum: an agent-based model of amine-mediated decision making.

    Science.gov (United States)

    Hoover, Kevin M; Bubak, Andrew N; Law, Isaac J; Yaeger, Jazmine D W; Renner, Kenneth J; Swallow, John G; Greene, Michael J

    2016-06-01

    Ant colonies self-organize to solve complex problems despite the simplicity of an individual ant's brain. Pavement ant Tetramorium caespitum colonies must solve the problem of defending the territory that they patrol in search of energetically rich forage. When members of 2 colonies randomly interact at the territory boundary a decision to fight occurs when: 1) there is a mismatch in nestmate recognition cues and 2) each ant has a recent history of high interaction rates with nestmate ants. Instead of fighting, some ants will decide to recruit more workers from the nest to the fighting location, and in this way a positive feedback mediates the development of colony wide wars. In ants, the monoamines serotonin (5-HT) and octopamine (OA) modulate many behaviors associated with colony organization and in particular behaviors associated with nestmate recognition and aggression. In this article, we develop and explore an agent-based model that conceptualizes how individual changes in brain concentrations of 5-HT and OA, paired with a simple threshold-based decision rule, can lead to the development of colony wide warfare. Model simulations do lead to the development of warfare with 91% of ants fighting at the end of 1 h. When conducting a sensitivity analysis, we determined that uncertainty in monoamine concentration signal decay influences the behavior of the model more than uncertainty in the decision-making rule or density. We conclude that pavement ant behavior is consistent with the detection of interaction rate through a single timed interval rather than integration of multiple interactions.

  18. Nest architecture, fungus gardens, queen, males and larvae of the fungus-growing ant Mycetagroicus inflatus Brandão & Mayhé-Nunes.

    Science.gov (United States)

    Jesovnik, A; Sosa-Calvo, J; Lopes, C T; Vasconcelos, H L; Schultz, T R

    2013-01-01

    All known fungus-growing ants (tribe Attini) are obligately symbiotic with their cultivated fungi. The fungal cultivars of "lower" attine ants are facultative symbionts, capable of living apart from ants, whereas the fungal cultivars of "higher" attine ants, including leaf-cutting genera Atta and Acromyrmex , are highly specialized, obligate symbionts. Since higher attine ants and fungi are derived from lower attine ants and fungi, understanding the evolutionary transition from lower to higher attine agriculture requires understanding the historical sequence of change in both ants and fungi. The biology of the poorly known ant genus Mycetagroicus is of special interest in this regard because it occupies a phylogenetic position intermediate between lower and higher ant agriculture. Here, based on the excavations of four nests in Pará, Brazil, we report the first biological data for the recently described species Mycetagroicus inflatus , including the first descriptions of Mycetagroicus males and larvae. Like M. cerradensis , the only other species in the genus for which nesting biology is known, the garden chambers of M. inflatus are unusually deep and the garden is most likely relocated vertically in rainy and dry seasons. Due to the proximity of nests to the Araguaia River, it is likely that even the uppermost chambers and nest entrances of M. inflatus are submerged during the rainy season. Most remarkably, all three examined colonies of M. inflatus cultivate the same fungal species as their congener, M. cerradensis , over 1,000 km away, raising the possibility of long-term symbiont fidelity spanning speciation events within the genus.

  19. Application of ground penetrating radar in detecting the hazards and risks of termites and ants in soil levees.

    Science.gov (United States)

    Yang, Xiuhao; Henderson, Gregg; Mao, Lixin; Evans, Ahmad

    2009-08-01

    A ground penetrating radar (GPR) technique was used to detect Formosan subterranean termite (Coptotermes formosanus) and red imported fire ant (Solenopsis invicta) hazards and risks (targets) in a soil levee at the London Avenue Canal in New Orleans, LA. To make this assessment, GPR signal scans were examined for features produced by termite or ant activities and potential sources of food and shelter such as nests, tree roots, and voids (tunnels). The total scanned length of the soil levee was 4,125 m. The average velocity and effective depth of the radar penetration was 0.080 m/ns and 0.61 m, respectively. Four hundred twenty-seven targets were identified. Tree roots (38), voids (31), fire ant nests (209), and metal objects (149) were detected, but no Formosan termite carton nests were identified. The lack of identified termite nests may be related to drowning events at the time to the flood. Based on the target density (TD), the two new floodwall and levee sections that were rebuilt or reinforced after they were destroyed by Hurricane Katrina in 2005 were determined to be at low potential risk from termites and ants. A merging target density (MTD) method indicated a high potential risk near one of the breached sections still remains. Foraging and nesting activity of Formosan subterranean termites and red imported fire ants may be a contributory factor to the levee failure at the London Avenue Canal.

  20. Evaluating effects of habitat loss and land-use continuity on ant species richness in seminatural grassland remnants.

    Science.gov (United States)

    Dauber, Jens; Bengtsson, Jan; Lenoir, Lisette

    2006-08-01

    Seminatural grasslands in Europe are susceptible to habitat destruction and fragmentation that result in negative effects on biodiversity because of increased isolation and area effects on extinction rate. However even small habitatpatches of seminatural grasslands might be of value for conservation and restoration of species richness in a landscape with a long history of management, which has been argued to lead to high species richness. We tested whether ant communities have been negatively affected by habitat loss and increased isolation of seminatural grasslands during the twentieth century. We examined species richness and community composition in seminatural grasslands of different size in a mosaic landscape in Central Sweden. Grasslands managed continuously over centuries harbored species-rich and ecologically diverse ant communities. Grassland remnant size had no effect on ant species richness. Small grassland remnants did not harbor a nested subset of the ant species of larger habitats. Community composition of ants was mainly affected by habitat conditions. Our results suggest that the abandonment of traditional land use and the encroachment of trees, rather than the effects of fragmentation, are important for species composition in seminatural grasslands. Our results highlight the importance of considering land-use continuity and dispersal ability of thefocal organisms when examining the effects of habitat loss and fragmentation on biodiversity. Landscape history should be considered in conservation programs focusing on effects of land-use change.

  1. The Ant Cardiocondyla elegans as Host of the Enigmatic Endoparasitic Fungus Myrmicinosporidium durum

    Directory of Open Access Journals (Sweden)

    Julia Giehr

    2015-01-01

    Full Text Available Data on host species and the distribution of the endoparasitic fungus Myrmicinosporidium durum increased continuously in recent decades. Here, we add the ant Cardiocondyla elegans as new host species. Colonies of the monogynous species were found infested in the region of Languedoc-Roussillon (South France. Samples from the nest indicate high infection rates. All castes and sexes were infected by the spores. Variations of infection rates between sampling methods and species are discussed.

  2. Feeding and stocking up: radio-labelled food reveals exchange patterns in ants.

    OpenAIRE

    Aurélie Buffin; Damien Denis; Gaetan Van Simaeys; Serge Goldman; Jean-Louis Deneubourg

    2009-01-01

    Food sharing is vital for a large number of species, either solitary or social, and is of particular importance within highly integrated societies, such as in colonial organisms and in social insects. Nevertheless, the mechanisms that govern the distribution of food inside a complex organizational system remain unknown. Using scintigraphy, a method developed for medical imaging, we were able to describe the dynamics of food-flow inside an ant colony. We monitored the sharing process of a radi...

  3. Coevolution in host-parasite systems: behavioural strategies of slave-making ants and their hosts.

    OpenAIRE

    Foitzik, S.; DeHeer, C. J.; Hunjan, D. N.; Herbers, J. M.

    2001-01-01

    Recently, avian brood parasites and their hosts have emerged as model systems for the study of host-parasite coevolution. However, empirical studies of the highly analogous social parasites, which use the workers of another eusocial species to raise their own young, have never explicitly examined the dynamics of these systems from a coevolutionary perspective. Here, we demonstrate interpopulational variation in behavioural interactions between a socially parasitic slave-maker ant and its host...

  4. Selenium exposure results in reduced reproduction in an invasive ant species and altered competitive behavior for a native ant species

    International Nuclear Information System (INIS)

    De La Riva, Deborah G.; Trumble, John T.

    2016-01-01

    Competitive ability and numerical dominance are important factors contributing to the ability of invasive ant species to establish and expand their ranges in new habitats. However, few studies have investigated the impact of environmental contamination on competitive behavior in ants as a potential factor influencing dynamics between invasive and native ant species. Here we investigated the widespread contaminant selenium to investigate its potential influence on invasion by the exotic Argentine ant, Linepithema humile, through effects on reproduction and competitive behavior. For the fecundity experiment, treatments were provided to Argentine ant colonies via to sugar water solutions containing one of three concentrations of selenium (0, 5 and 10 μg Se mL −1 ) that fall within the range found in soil and plants growing in contaminated areas. Competition experiments included both the Argentine ant and the native Dorymyrmex bicolor to determine the impact of selenium exposure (0 or 15 μg Se mL −1 ) on exploitation- and interference-competition between ant species. The results of the fecundity experiment revealed that selenium negatively impacted queen survival and brood production of Argentine ants. Viability of the developing brood was also affected in that offspring reached adulthood only in colonies that were not given selenium, whereas those in treated colonies died in their larval stages. Selenium exposure did not alter direct competitive behaviors for either species, but selenium exposure contributed to an increased bait discovery time for D. bicolor. Our results suggest that environmental toxins may not only pose problems for native ant species, but may also serve as a potential obstacle for establishment among exotic species. - Highlights: • Argentine ant colonies exposed to selenium had reduced fecundity compared to unexposed colonies. • Viability of offspring was negatively impacted by selenium. • Queen survival was reduced in colonies

  5. The introduction history of invasive garden ants in Europe: integrating genetic, chemical and behavioural approaches

    DEFF Research Database (Denmark)

    Ugelvig, Line; Drijfhout, Falko; Kronauer, Daniel

    2008-01-01

    BACKGROUND: The invasive garden ant, Lasius neglectus, is the most recently detected pest ant and the first known invasive ant able to become established and thrive in the temperate regions of Eurasia. In this study, we aim to reconstruct the invasion history of this ant in Europe analysing 14 po...

  6. Stealthy invaders: the biology of Cardiocondyla tramp ants

    DEFF Research Database (Denmark)

    Heinze, J.; Cremer, Sylvia; Eckl, N.

    2006-01-01

    Many invasive ant species, such as the Argentine ant or the red imported fire ant, have huge colonies with thousands of mass-foraging workers, which quickly monopolise resources and therefore represent a considerable threat to the native ant fauna. Cardiocondyla obscurior and several other specie...

  7. FMR measurements in fire ants: evidence of magnetic material

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Darci M.S.; Acosta-Avalos, Daniel; El-Jaick, Lea J.; Cunha, Alexandra D.M.; Malheiros, Maria G.; Wajnberg, Eliane [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Linhares, Marilia P. [Centro de Ciencias do Estado, do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    1998-01-01

    Based on the behavioral and the localization of iron-containing tissue fire ants were examined by EPR for magnetic material. Results suggest the presence of magnetite particles. (author) 12 refs., 1 fig.

  8. Myrmeciza and related antbirds (Aves, Formicariidae as army ant followers

    Directory of Open Access Journals (Sweden)

    Edwin O. Willis

    1984-01-01

    Full Text Available Antbirds of the genera Myrmeciza (including Sipia and Myrmoborus, Gymnocichla, and Sclateria hop near or on the ground in fairly dense vegetation, "pounding" their tails downward. Where dense understory vegetation is widespread and ants move in it for long distances, certain of these antbirds become regular ant followers: M. immaculata and M. fortis in cluttered moist foothill forest from Costa Rica to upper Amazonia; Gymnocichla nudiceps in moist cluttered second growth of Central America to Colombia. Where the forest understory is more open, Myrmeciza species follow ants mainly in cluttered patches: M. exsul in lowland forest west of the Andes, M. myotherina east of the Andes. Myrmeciza or relatives that specialize on water-edge or very dense zones rarely follow ants.

  9. Ants farm subterranean aphids mostly in single clone groups

    DEFF Research Database (Denmark)

    Ivens, Aniek B.F.; Kronauer, Daniel Jan Christoph; Pen, Ido

    2012-01-01

    mutualisms have been studied in sufficient genetic detail to address these issues, so we decided to characterize symbiont diversity in the complex mutualism between multiple root aphid species and Lasius flavus ants. After showing elsewhere that three of these aphid species have low dispersal and mostly...... if not exclusively asexual reproduction, we here investigate aphid diversity within and between ant nest mounds. Results The three focal species (Geoica utricularia, Forda marginata and Tetraneura ulmi) had considerable clonal diversity at the population level. Yet more than half of the ant mounds contained just....... The ants appear to eat most of the early instar aphids, so that adult aphids are unlikely to face limited phloem resources and scramble competition with other aphids. We suggest that such culling of carbohydrate-providing symbionts for protein ingestion may maintain maximal host yield per aphid while also...

  10. Ant groups optimally amplify the effect of transiently informed individuals

    Science.gov (United States)

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Ghosh, Abhijit; Gov, Nir; Feinerman, Ofer

    2015-07-01

    To cooperatively transport a large load, it is important that carriers conform in their efforts and align their forces. A downside of behavioural conformism is that it may decrease the group's responsiveness to external information. Combining experiment and theory, we show how ants optimize collective transport. On the single-ant scale, optimization stems from decision rules that balance individuality and compliance. Macroscopically, these rules poise the system at the transition between random walk and ballistic motion where the collective response to the steering of a single informed ant is maximized. We relate this peak in response to the divergence of susceptibility at a phase transition. Our theoretical models predict that the ant-load system can be transitioned through the critical point of this mesoscopic system by varying its size; we present experiments supporting these predictions. Our findings show that efficient group-level processes can arise from transient amplification of individual-based knowledge.

  11. Florida alternative NTCIP testing software (ANTS) for actuated signal controllers.

    Science.gov (United States)

    2009-01-01

    The scope of this research project did include the development of a software tool to test devices for NTCIP compliance. Development of the Florida Alternative NTCIP Testing Software (ANTS) was developed by the research team due to limitations found w...

  12. Ant colony search algorithm for optimal reactive power optimization

    Directory of Open Access Journals (Sweden)

    Lenin K.

    2006-01-01

    Full Text Available The paper presents an (ACSA Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents’ approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical test bus system. The proposed approach is tested and compared to genetic algorithm (GA, Adaptive Genetic Algorithm (AGA.

  13. application of ant colony optimisation in distribution transformer sizing

    African Journals Online (AJOL)

    HP

    Keywords: ant colony, optimization, transformer sizing, distribution transformer. 1. INTRODUCTION ... more intensive pheromone and higher probability to be chosen [12]. ..... pp.29-41, 1996. [7] EC global market place, “Technical Parameters”,.

  14. Structural and molecular basis for resistance to aminoglycoside antibiotics by the adenylyltransferase ANT(2″)-Ia.

    Science.gov (United States)

    Cox, Georgina; Stogios, Peter J; Savchenko, Alexei; Wright, Gerard D

    2015-01-06

    The aminoglycosides are highly effective broad-spectrum antimicrobial agents. However, their efficacy is diminished due to enzyme-mediated covalent modification, which reduces affinity of the drug for the target ribosome. One of the most prevalent aminoglycoside resistance enzymes in Gram-negative pathogens is the adenylyltransferase ANT(2″)-Ia, which confers resistance to gentamicin, tobramycin, and kanamycin. Despite the importance of this enzyme in drug resistance, its structure and molecular mechanism have been elusive. This study describes the structural and mechanistic basis for adenylylation of aminoglycosides by the ANT(2″)-Ia enzyme. ANT(2″)-Ia confers resistance by magnesium-dependent transfer of a nucleoside monophosphate (AMP) to the 2″-hydroxyl of aminoglycoside substrates containing a 2-deoxystreptamine core. The catalyzed reaction follows a direct AMP transfer mechanism from ATP to the substrate antibiotic. Central to catalysis is the coordination of two Mg(2+) ions, positioning of the modifiable substrate ring, and the presence of a catalytic base (Asp86). Comparative structural analysis revealed that ANT(2″)-Ia has a two-domain structure with an N-terminal active-site architecture that is conserved among other antibiotic nucleotidyltransferases, including Lnu(A), LinB, ANT(4')-Ia, ANT(4″)-Ib, and ANT(6)-Ia. There is also similarity between the nucleotidyltransferase fold of ANT(2″)-Ia and DNA polymerase β. This similarity is consistent with evolution from a common ancestor, with the nucleotidyltransferase fold having adapted for activity against chemically distinct molecules. IMPORTANCE  : To successfully manage the threat associated with multidrug-resistant infectious diseases, innovative therapeutic strategies need to be developed. One such approach involves the enhancement or potentiation of existing antibiotics against resistant strains of bacteria. The reduction in clinical usefulness of the aminoglycosides is a particular

  15. Fluid intake rates in ants correlate with their feeding habits.

    Science.gov (United States)

    Paul, J; Roces, F

    2003-04-01

    This study investigates the techniques of nectar feeding in 11 different ant species, and quantitatively compares fluid intake rates over a wide range of nectar concentrations in four species that largely differ in their feeding habits. Ants were observed to employ two different techniques for liquid food intake, in which the glossa works either as a passive duct-like structure (sucking), or as an up- and downwards moving shovel (licking). The technique employed for collecting fluids at ad libitum food sources was observed to be species-specific and to correlate with the presence or absence of a well-developed crop in the species under scrutiny. Workers of ponerine ants licked fluid food during foraging and transported it as a droplet between their mandibles, whereas workers of species belonging to phylogenetically more advanced subfamilies, with a crop capable of storing liquids, sucked the fluid food, such as formicine ants of the genus Camponotus. In order to evaluate the performance of fluid collection during foraging, intake rates for sucrose solutions of different concentrations were measured in four ant species that differ in their foraging ecology. Scaling functions between fluid intake rates and ant size were first established for the polymorphic species, so as to compare ants of different size across species. Results showed that fluid intake rate depended, as expected and previously reported in the literature, on sugar concentration and the associated fluid viscosity. It also depended on both the species-specific feeding technique and the extent of specialization on foraging on liquid food. For similarly-sized ants, workers of two nectar-feeding ant species, Camponotus rufipes (Formicinae) and Pachycondyla villosa (Ponerinae), collected fluids with the highest intake rates, while workers of the leaf-cutting ant Atta sexdens (Myrmicinae) and a predatory ant from the Rhytidoponera impressa-complex (Ponerinae) did so with the lowest rate. Calculating the

  16. Climatic warming destabilizes forest ant communities.

    Science.gov (United States)

    Diamond, Sarah E; Nichols, Lauren M; Pelini, Shannon L; Penick, Clint A; Barber, Grace W; Cahan, Sara Helms; Dunn, Robert R; Ellison, Aaron M; Sanders, Nathan J; Gotelli, Nicholas J

    2016-10-01

    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future may become increasingly fragile and unstable.

  17. Recognition in ants: social origin matters.

    Directory of Open Access Journals (Sweden)

    Joël Meunier

    Full Text Available The ability of group members to discriminate against foreigners is a keystone in the evolution of sociality. In social insects, colony social structure (number of queens is generally thought to influence abilities of resident workers to discriminate between nestmates and non-nestmates. However, whether social origin of introduced individuals has an effect on their acceptance in conspecific colonies remains poorly explored. Using egg-acceptance bioassays, we tested the influence of social origin of queen-laid eggs on their acceptance by foreign workers in the ant Formica selysi. We showed that workers from both single- and multiple-queen colonies discriminated against foreign eggs from single-queen colonies, whereas they surprisingly accepted foreign eggs from multiple-queen colonies. Chemical analyses then demonstrated that social origins of eggs and workers could be discriminated on the basis of their chemical profiles, a signal generally involved in nestmate discrimination. These findings provide the first evidence in social insects that social origins of eggs interfere with nestmate discrimination and are encoded by chemical signatures.

  18. Carbohydrate supply limits invasion of natural communities by Argentine ants.

    Science.gov (United States)

    Rowles, Alexei D; Silverman, Jules

    2009-08-01

    The ability of species to invade new habitats is often limited by various biotic and physical factors or interactions between the two. Invasive ants, frequently associated with human activities, flourish in disturbed urban and agricultural environments. However, their ability to invade and establish in natural habitats is more variable. This is particularly so for the invasive Argentine ant (Linepithema humile). While biotic resistance and low soil moisture limits their invasion of natural habitats in some instances, the effect of food availability has been poorly explored. We conducted field experiments to determine if resource availability limits the spread and persistence of Argentine ants in remnant natural forest in North Carolina. Replicated transects paired with and without sucrose solution feeding stations were run from invaded urban edges into forest remnants and compared over time using baits and direct counts at feeding stations. Repeated under different timing regimes in 2006 and 2007, access to sucrose increased local Argentine ant abundances (1.6-2.5 fold) and facilitated their progression into the forest up to 73 +/- 21% of 50-m transects. Resource removal caused an expected decrease in Argentine ant densities in 2006, in conjunction with their retreat to the urban/forest boundary. However, in 2007, Argentine ant numbers unexpectedly continued to increase in the absence of sugar stations, possibly through access to alternative resources or conditions not available the previous year such as honeydew-excreting Hemiptera. Our results showed that supplementing carbohydrate supply facilitates invasion of natural habitat by Argentine ants. This is particularly evident where Argentine ants continued to thrive following sugar station removal.

  19. Hybridization in East African swarm-raiding army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel Jc; Peters, Marcell K; Schöning, Caspar

    2011-01-01

    Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied...... hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites....

  20. An Improved Ant Colony Matching by Using Discrete Curve Evolution

    OpenAIRE

    Saadi, Younes; Sari, Eka,; Herawan, Tutut

    2014-01-01

    Part 1: Information & Communication Technology-EurAsia Conference 2014, ICT-EurAsia 2014; International audience; In this paper we present an improved Ant Colony Optimization (ACO) for contour matching, which can be used to match 2D shapes. Discrete Curve Evolution (DCE) technique is used to simplify the extracted contour. In order to find the best correspondence between shapes, the match process is formulated as a Quadratic Assignment Problem (QAP) and resolved by using Ant Colony Optimizati...

  1. Behavior of ergatoid males in the ant, Cardiocondyla nuda

    OpenAIRE

    Heinze, Jürgen; Künholz, S.; Schilder, K.; Hölldobler, B.

    1993-01-01

    Ergatoid males of the ant, Cardiocondyla nuda, attack and frequently kill young males during or shortly after eclosion. Smaller colonies therefore contain typically only one adult male, which may inseminate all alate queens which are reared in the colony over a few weeks. In larger colonies, several males may be present, however, fighting among adult males was not observed. We discuss the significance of male fighting behavior in ants.

  2. Aflatoxins produced by Aspergillus nomius ASR3, a pathogen isolated from the leaf-cutter ant Atta sexdens rubropilosa

    Directory of Open Access Journals (Sweden)

    Eduardo Afonso da Silva-Junior

    Full Text Available ABSTRACT Aspergillus spp. cause economic impacts due to aflatoxins production. Although the toxicity of aflatoxins is already known, little information about their ecological roles is available. Here we investigated the compounds produced by Aspergillus nomius ASR3 directly from a dead leaf-cutter queen ant Atta sexdens rubropilosa and the fungal axenic culture. Chemical analyses were carried out by high-resolution mass spectrometry and tandem mass spectrometry techniques. Aflatoxins B1 and G1 were detected in both the axenic culture and in the dead leaf-cutter queen ant. The presence of these mycotoxins in the dead leaf-cutter queen ant suggests that these compounds can be related to the insect pathogenicity of A. nomius against A. sexdens rubropilosa.

  3. Temporal polyethism, life expectancy, and entropy of workers of the ant Ectatomma vizottoi Almeida, 1987 (Formicidae: Ectatomminae).

    Science.gov (United States)

    Santana Vieira, Alexsandro; Desidério Fernandes, Wedson; Fernando Antonialli-Junior, William

    2010-05-01

    We investigated the changes in the behavioral repertoire over the course of life and determined the life expectancy and entropy of workers of the ant Ectatomma vizottoi. Newly emerged ants were individually marked with model airplane paint for observation of behaviors and determination of the age and life expectancy. Ants were divided into two groups: young and old workers. The 36 behaviors observed were divided into eight categories. Workers exhibit a clear division of tasks throughout their lives, with young workers performing more tasks inside the colony and old workers, outside, unlike species that have small colonies. This species also exhibits an intermediate life expectancy compared to workers of other species that are also intermediary in size. This supports the hypothesis of a relationship between size and maximum life expectancy, but it also suggests that other factors may also be acting in concert. Entropy value shows a high mortality rate during the first life intervals.

  4. Trail Pheromone Disruption of Argentine Ant Trail Formation and Foraging

    Science.gov (United States)

    Suckling, D.M.; Peck, R.W.; Stringer, L.D.; Snook, K.; Banko, P.C.

    2010-01-01

    Trail pheromone disruption of invasive ants is a novel tactic that builds on the development of pheromone-based pest management in other insects. Argentine ant trail pheromone, (Z)-9-hexadecenal, was formulated as a micro-encapsulated sprayable particle and applied against Argentine ant populations in 400 m2 field plots in Hawai'i Volcanoes National Park. A widely dispersed point source strategy for trail pheromone disruption was used. Traffic rates of ants in bioassays of treated filter paper, protected from rainfall and sunlight, indicated the presence of behaviorally significant quantities of pheromone being released from the formulation for up to 59 days. The proportion of plots, under trade wind conditions (2-3 m s-1), with visible trails was reduced for up to 14 days following treatment, and the number of foraging ants at randomly placed tuna-bait cards was similarly reduced. The success of these trail pheromone disruption trials in a natural ecosystem highlights the potential of this method for control of invasive ant species in this and other environments. ?? Springer Science+Business Media, LLC 2010.

  5. No sex in fungus-farming ants or their crops.

    Science.gov (United States)

    Himler, Anna G; Caldera, Eric J; Baer, Boris C; Fernández-Marín, Hermógenes; Mueller, Ulrich G

    2009-07-22

    Asexual reproduction imposes evolutionary handicaps on asexual species, rendering them prone to extinction, because asexual reproduction generates novel genotypes and purges deleterious mutations at lower rates than sexual reproduction. Here, we report the first case of complete asexuality in ants, the fungus-growing ant Mycocepurus smithii, where queens reproduce asexually but workers are sterile, which is doubly enigmatic because the clonal colonies of M. smithii also depend on clonal fungi for food. Degenerate female mating anatomy, extensive field and laboratory surveys, and DNA fingerprinting implicate complete asexuality in this widespread ant species. Maternally inherited bacteria (e.g. Wolbachia, Cardinium) and the fungal cultivars can be ruled out as agents inducing asexuality. M. smithii societies of clonal females provide a unique system to test theories of parent-offspring conflict and reproductive policing in social insects. Asexuality of both ant farmer and fungal crop challenges traditional views proposing that sexual farmer ants outpace coevolving sexual crop pathogens, and thus compensate for vulnerabilities of their asexual crops. Either the double asexuality of both farmer and crop may permit the host to fully exploit advantages of asexuality for unknown reasons or frequent switching between crops (symbiont reassociation) generates novel ant-fungus combinations, which may compensate for any evolutionary handicaps of asexuality in M. smithii.

  6. Species-Specific Effects of Ant Inhabitants on Bromeliad Nutrition.

    Directory of Open Access Journals (Sweden)

    Ana Z Gonçalves

    Full Text Available Predator activities may lead to the accumulation of nutrients in specific areas of terrestrial habitats where they dispose of prey carcasses. In their feeding sites, predators may increase nutrient availability in the soil and favor plant nutrition and growth. However, the translocation of nutrients from one habitat to another may depend on predator identity and diet, as well as on the amount of prey intake. Here we used isotopic (15N and physiological methods in greenhouse experiments to evaluate the effects of the identity of predatory ants (i.e., the consumption of prey and nest sites on the nutrition and growth of the bromeliad Quesnelia arvensis. We showed that predatory ants with protein-based nutrition (i.e., Odontomachus hastatus, Gnamptogenys moelleri improved the performance of their host bromeliads (i.e., increased foliar N, production of soluble proteins and growth. On the other hand, the contribution of Camponotus crassus for the nutritional status of bromeliads did not differ from bromeliads without ants, possibly because this ant does not have arthropod prey as a preferred food source. Our results show, for the first time, that predatory ants can translocate nutrients from one habitat to another within forests, accumulating nutrients in their feeding sites that become available to bromeliads. Additionally, we highlight that ant contribution to plant nutrition may depend on predator identity and its dietary requirements. Nest debris may be especially important for epiphytic and terrestrial bromeliads in nutrient-poor environments.

  7. Reaction of mutualistic and granivorous ants to ulex elaiosome chemicals.

    Science.gov (United States)

    Gammans, Nicola; Bullock, James M; Gibbons, Hannah; Schönrogge, Karsten

    2006-09-01

    It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.

  8. Competence of Litter Ants for Rapid Biodiversity Assessments

    Directory of Open Access Journals (Sweden)

    T. H. Saumya E. Silva

    2017-01-01

    Full Text Available Rapid Biodiversity Assessment approaches associated with focusing taxa have overcome many of the problems related to large scale surveys. This study examined the suitability of litter ants as a focusing taxon by checking whether diversity and species assemblages of litter ants reflect the overall picture of arthropod diversity and assemblages in leaf litter in two vegetation types: secondary forest and pine plantation in Upper Hanthana forest reserve, Sri Lanka. In each vegetation type, arthropods were sampled using three sampling methods (Winkler extraction, hand collection, and pitfall traps along three 100 m line transects. From the two sites, 1887 litter ants (34 species and 3488 litter arthropods (52 species were collected. Species assemblages composition of both ants and other arthropods differed significantly between the two sites (ANOSIM, p=0.001 with both groups generating distinct clusters for the two sites (SIMPROF, p=0.001. But there was no significant correlation (p>0.05 between abundance and richness of litter ants and those of other arthropods in both vegetation types. The overall finding suggests that the litter ants do not reflect the holistic picture of arthropod diversity and assemblages in leaf litter, but the quality of the habitat for the survival of all litter arthropods.

  9. Water stress strengthens mutualism among ants, trees, and scale insects.

    Directory of Open Access Journals (Sweden)

    Elizabeth G Pringle

    2013-11-01

    Full Text Available Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  10. An invasive slug exploits an ant-seed dispersal mutualism.

    Science.gov (United States)

    Meadley Dunphy, Shannon A; Prior, Kirsten M; Frederickson, Megan E

    2016-05-01

    Plant-animal mutualisms, such as seed dispersal, are often vulnerable to disruption by invasive species. Here, we show for the first time how a non-ant invasive species negatively affects seed dispersal by ants. We examined the effects of several animal species that co-occur in a temperate deciduous forest-including native and invasive seed-dispersing ants (Aphaenogaster rudis and Myrmica rubra, respectively), an invasive slug (Arion subfuscus), and native rodents-on a native myrmecochorous plant, Asarum canadense. We experimentally manipulated ant, slug, and rodent access to seed depots and measured seed removal. We also video-recorded depots to determine which other taxa interact with seeds. We found that A. rudis was the main disperser of seeds and that A. subfuscus consumed elaiosomes without dispersing seeds. Rodent visitation was rare, and rodent exclusion had no significant effect on seed or elaiosome removal. We then used data obtained from laboratory and field mesocosm experiments to determine how elaiosome robbing by A. subfuscus affects seed dispersal by A. rudis and M. rubra. We found that elaiosome robbing by slugs reduced seed dispersal by ants, especially in mesocosms with A. rudis, which picks up seeds more slowly than M. rubra. Taken together, our results show that elaiosome robbing by an invasive slug reduces seed dispersal by ants, suggesting that invasive slugs can have profound negative effects on seed dispersal mutualisms.

  11. Water stress strengthens mutualism among ants, trees, and scale insects.

    Science.gov (United States)

    Pringle, Elizabeth G; Akçay, Erol; Raab, Ted K; Dirzo, Rodolfo; Gordon, Deborah M

    2013-11-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  12. Response Analysis of eight native species of high Andean forest with two methods of propagation; Analisis de la respuesta de ocho especies nativas del bosque alto andino ante dos metodos de propagacion

    Energy Technology Data Exchange (ETDEWEB)

    Liliana, Castaneda Sandra; Ernesto, Garzon Alvaro; Angel, Cantillo Miguel; Patricia, Torres Monica; Jairo, Silva Luis

    2007-07-01

    The objective of this research was to generate information on the native tree species represent an alternative in the ecological restoration of the Colombian high Andean forests, according to its dynamo-genetic characteristics. We have chosen and spread the species: Baccharis latifolia (R and P), Bocconia frutescens L., Cordia cylindrostachya (R and P), Diplostephium rosmarinifolium (Benth), Drymis granadensis L f., Eupatorium angustifolium (Kunth), Palicourea vaginata Benth, and Palicourea linearifolia Wernham. The species include a morphological description of flowers, fruits and seeds, and ISTA tests. The spread experiments were made in the nurseries of the Universidad Distrital and La Florida park. For the sexual spread, we have used as treatments four gibberellins concentrations and three shadow conditions, while the vegetative spread consisted of two diameters and ive indol butiric acid (IBA) concentrations. Results have shown that pre-germination treatments are needed for Bocconia frutescens y Palicourea vaginata, in order to increase the probability and germination rate. On the other hand, shadow conditions are needed for Baccharis latifolia, Diplostephium rosmarinifolium, Drymis granadensis, Eupatorium angustifolium and Palicourea vaginata, as their seeds exhibit photoblastic characteristics. Due to the Cordia cylindrostachya and Palicourea linearifolia seed attack by insects (Lepidoptera and Hymenoptera) their sexual spread is highly limited. Finally, regarding the species response to the IBA and diameter combinations, each species responded in a different manner. Additionally, regarding the vegetative spread, the species Bocconia frutescens, Cordia cylindrostachya, Palicourea vaginata, Diplostephium rosmarinifolium and Drymis granadensis were very difficult to spread.

  13. Conducta ante la hemorragia digestiva alta por úlcera gastroduodenal en el anciano: consideraciones actuales Behavior in face of a high digestive hemorrhage from gastroduodenal ulcer in elderly: current considerations

    Directory of Open Access Journals (Sweden)

    Zenén Rodríguez Fernández

    2010-03-01

    Full Text Available La hemorragia digestiva alta reviste singular importancia en el anciano porque es un evento que puede rápidamente poner en peligro la vida. En el adulto mayor, la alta incidencia de enfermedades osteomioarticulares y cardiovasculares asociadas, que además condicionan la ingestión de medicamentos como los antiinflamatorios no esteroideos y aspirina, y los hábitos tóxicos frecuentes en la tercera edad, como el consumo de alcohol, café y tabaco, constituyen factores que ejercen efecto ulcerógeno sobre la mucosa del tracto digestivo superior. La causa más común de hemorragia es la úlcera gastroduodenal. En la actualidad se considera de importancia capital la realización precoz de la endoscopia para el diagnóstico y tratamiento médico consecuente, y se limita la cirugía sólo para los ancianos en los cuales, por su estado general y la cuantía o persistencia del sangrado, no sea posible la realización de aquella, cuando fracase el tratamiento endoscópico, el farmacológico o ambos.High digestive hemorrhage has a peculiar significance in elderly because of it is an event putting quickly at risk the life. In elderly, the high incidence of associated osteomyoarticular and cardiovascular diseases that also fitting the drugs ingestion, e.g. the non-steroid anti-inflammatory and the aspirin and the toxic habits frequent in third age, since the alcohol, coffee and tobacco consumption are factors having an ulcerative effect on the high digestive tract mucosa. The commonest cause of hemorrhage is the gastric ulcer. At present time we considered as of supreme significance the early carrying out of the endoscopy for the consequent medical treatment and diagnosis limiting surgery only for elderlies, who due to its general status and the bleeding extent or persistence be impossible its carrying out when there is a failure of endoscopic and/or pharmacologic treatment.

  14. Image Watermarking Algorithm Based on Multiobjective Ant Colony Optimization and Singular Value Decomposition in Wavelet Domain

    Directory of Open Access Journals (Sweden)

    Khaled Loukhaoukha

    2013-01-01

    Full Text Available We present a new optimal watermarking scheme based on discrete wavelet transform (DWT and singular value decomposition (SVD using multiobjective ant colony optimization (MOACO. A binary watermark is decomposed using a singular value decomposition. Then, the singular values are embedded in a detailed subband of host image. The trade-off between watermark transparency and robustness is controlled by multiple scaling factors (MSFs instead of a single scaling factor (SSF. Determining the optimal values of the multiple scaling factors (MSFs is a difficult problem. However, a multiobjective ant colony optimization is used to determine these values. Experimental results show much improved performances of the proposed scheme in terms of transparency and robustness compared to other watermarking schemes. Furthermore, it does not suffer from the problem of high probability of false positive detection of the watermarks.

  15. Ants of João da Cunha Island, SC, Brazil: composition and diversity

    Directory of Open Access Journals (Sweden)

    Ricardo Corbetta

    2005-05-01

    Full Text Available The ant species of João da Cunha Island, SC, were collected both manually and by the use of attractive baits of honey and sardine. The samples were taken at 10 sites, each having one bait of each type, totalling 20 samples in each collection. A total of 14 genera, 52 species and 5 subfamilies was sampled in one year of monthly sampling. The richest genera were Pheidole (16 species and Camponotus (9. The biological diversity values were high, and the ant fauna presented a strong seazonality on account of this diversity. The greatest similarity between seasons of the year was observed between spring and summer, followed by autumn and winter.

  16. Reliable Ant Colony Routing Algorithm for Dual-Channel Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    YongQiang Li

    2018-01-01

    Full Text Available For the problem of poor link reliability caused by high-speed dynamic changes and congestion owing to low network bandwidth in ad hoc networks, an ant colony routing algorithm, based on reliable path under dual-channel condition (DSAR, is proposed. First, dual-channel communication mode is used to improve network bandwidth, and a hierarchical network model is proposed to optimize the dual-layer network. Thus, we reduce network congestion and communication delay. Second, a comprehensive reliable path selection strategy is designed, and the reliable path is selected ahead of time to reduce the probability of routing restart. Finally, the ant colony algorithm is used to improve the adaptability of the routing algorithm to changes of network topology. Simulation results show that DSAR improves the reliability of routing, packet delivery, and throughput.

  17. A nuclear reactor core fuel reload optimization using Artificial-Ant-Colony Connective Networks

    International Nuclear Information System (INIS)

    Lima, Alan M.M. de; Schirru, Roberto

    2005-01-01

    A Pressurized Water Reactor core must be reloaded every time the fuel burnup reaches a level when it is not possible to sustain nominal power operation. The nuclear core fuel reload optimization consists in finding a burned-up and fresh-fuel-assembly pattern that maximizes the number of full operational days. This problem is NP-hard, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Besides that, the problem is non-linear and its search space is highly discontinual and multimodal. In this work a parallel computational system based on Ant Colony System (ACS) called Artificial-Ant-Colony Networks is introduced to solve the nuclear reactor core fuel reload optimization problem. ACS is a system based on artificial agents that uses the reinforcement learning technique and was originally developed to solve the Traveling Salesman Problem, which is conceptually similar to the nuclear fuel reload problem. (author)

  18. Experimental winter warming modifies thermal performance and primes acorn ants for warm weather

    DEFF Research Database (Denmark)

    MacLean, Heidi J.; Penick, Clint A.; Dunn, Robert R.

    2017-01-01

    The frequency of warm winter days is increasing under global climate change, but how organisms respond to warmer winters is not well understood. Most studies focus on growing season responses to warming. Locomotor performance is often highly sensitive to temperature, and can determine fitness...... outcomes through a variety of mechanisms including resource acquisition and predator escape. As a consequence, locomotor performance, and its impacts on fitness, may be strongly affected by winter warming in winter-active species. Here we use the acorn ant, Temnothorax curvispinosus, to explore how thermal...... performance (temperature-driven plasticity) in running speed is influenced by experimental winter warming of 3–5 °C above ambient in a field setting. We used running speed as a measure of performance as it is a common locomotor trait that influences acquisition of nest sites and food in acorn ants...

  19. Intersexual Trophic Niche Partitioning in an Ant-Eating spider (Araneae: Zodariidae)

    DEFF Research Database (Denmark)

    Pekár, Stanislav; Martisová, Martina; Bilde, T.

    2011-01-01

    lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants...... that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning. Methodology/Principal Findings Comparative analysis of trophic morphology (the chelicerae) and body size of males, females and juveniles...... demonstrated highly female biased SSD (Sexual Size Dimorphism) in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size...

  20. Formigas como veiculadoras de microrganismos em ambiente hospitalar Ants as carriers of microorganisms in hospital environments

    Directory of Open Access Journals (Sweden)

    Rogério dos Santos Pereira

    2008-10-01

    Full Text Available Existe preocupação sobre as reais possibilidades de agravos à saúde pública que possam ser causados pela veiculação de agentes patogênicos através de formigas urbanas. O presente trabalho teve por objetivo isolar e identificar os microrganismos associados às formigas em ambiente hospitalar. Foram coletadas 125 formigas, da mesma espécie, em diferentes unidades de um Hospital Universitário. Cada formiga foi coletada com swab embebido em solução fisiológica e transferida para um tubo com caldo Brain Heart Infusion e incubados 35ºC por 24 horas. A partir de cada tubo, com crescimento, foram realizadas inoculações, em meios específicos, para isolamento dos microrganismos. As formigas apresentaram alta capacidade de veiculação de grupos de microrganismos, sendo que 63,5% das cepas eram bacilos Gram positivos produtores de esporos, 6,3% eram bacilos Gram negativos, cocos Gram positivos corresponderam a 23,1% das cepas, 6,7% eram fungos filamentosos e 0,5% eram leveduras. Desta forma, pode-se inferir que as formigas podem ser um dos responsáveis pela disseminação de microrganismos em ambientes hospitalares.Concern exists regarding the real possibility of public health threats caused by pathogenic agents that are carried by urban ants. The present study had the objective of isolating and identifying the microorganisms that are associated with ants in hospital environments. One hundred and twenty-five ants of the same species were collected from different units of a university hospital. Each ant was collected using a swab soaked with physiological solution and was transferred to a tube containing brain heart infusion broth and incubated at 35ºC for 24 hours. From each tube, with growth, inoculations were made into specific culturing media, to isolate any microorganisms. The ants presented a high capacity for carrying microorganism groups: spore-producing Gram-positive bacilli 63.5%, Gram-negative bacilli 6.3%, Gram-positive cocci

  1. Does cooperation mean kinship between spatially discrete ant nests?

    Science.gov (United States)

    Procter, Duncan S; Cottrell, Joan E; Watts, Kevin; A'Hara, Stuart W; Hofreiter, Michael; Robinson, Elva J H

    2016-12-01

    Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.

  2. Co-founding ant queens prevent disease by performing prophylactic undertaking behaviour.

    Science.gov (United States)

    Pull, Christopher D; Cremer, Sylvia

    2017-10-13

    Social insects form densely crowded societies in environments with high pathogen loads, but have evolved collective defences that mitigate the impact of disease. However, colony-founding queens lack this protection and suffer high rates of mortality. The impact of pathogens may be exacerbated in species where queens found colonies together, as healthy individuals may contract pathogens from infectious co-founders. Therefore, we tested whether ant queens avoid founding colonies with pathogen-exposed conspecifics and how they might limit disease transmission from infectious individuals. Using Lasius niger queens and a naturally infecting fungal pathogen Metarhizium brunneum, we observed that queens were equally likely to found colonies with another pathogen-exposed or sham-treated queen. However, when one queen died, the surviving individual performed biting, burial and removal of the corpse. These undertaking behaviours were performed prophylactically, i.e. targeted equally towards non-infected and infected corpses, as well as carried out before infected corpses became infectious. Biting and burial reduced the risk of the queens contracting and dying from disease from an infectious corpse of a dead co-foundress. We show that co-founding ant queens express undertaking behaviours that, in mature colonies, are performed exclusively by workers. Such infection avoidance behaviours act before the queens can contract the disease and will therefore improve the overall chance of colony founding success in ant queens.

  3. Using ant-behavior-based simulation model AntWeb to improve website organization

    Science.gov (United States)

    Li, Weigang; Pinheiro Dib, Marcos V.; Teles, Wesley M.; Morais de Andrade, Vlaudemir; Alves de Melo, Alba C. M.; Cariolano, Judas T.

    2002-03-01

    Some web usage mining algorithms showed the potential application to find the difference among the organizations expected by visitors to the website. However, there are still no efficient method and criterion for a web administrator to measure the performance of the modification. In this paper, we developed an AntWeb, a model inspired by ants' behavior to simulate the sequence of visiting the website, in order to measure the efficient of the web structure. We implemented a web usage mining algorithm using backtrack to the intranet website of the Politec Informatic Ltd., Brazil. We defined throughput (the number of visitors to reach their target pages per time unit relates to the total number of visitors) as an index to measure the website's performance. We also used the link in a web page to represent the effect of visitors' pheromone trails. For every modification in the website organization, for example, putting a link from the expected location to the target object, the simulation reported the value of throughput as a quick answer about this modification. The experiment showed the stability of our simulation model, and a positive modification to the intranet website of the Politec.

  4. Intersexual trophic niche partitioning in an ant-eating spider (Araneae: Zodariidae.

    Directory of Open Access Journals (Sweden)

    Stano Pekár

    2011-01-01

    Full Text Available Divergence in trophic niche between the sexes may function to reduce competition between the sexes ("intersexual niche partitioning hypothesis", or may be result from differential selection among the sexes on maximizing reproductive output ("sexual selection hypothesis". The latter may lead to higher energy demands in females driven by fecundity selection, while males invest in mate searching. We tested predictions of the two hypotheses underlying intersexual trophic niche partitioning in a natural population of spiders. Zodarion jozefienae spiders specialize on Messor barbarus ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning.Comparative analysis of trophic morphology (the chelicerae and body size of males, females and juveniles demonstrated highly female biased SSD (Sexual Size Dimorphism in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size, and larger than ants captured by juveniles and males. Female fecundity was highly positively correlated with female body mass, which reflects foraging success during the adult stage. Females in laboratory experiments preferred the large ant sub-castes and displayed higher capture efficiency. In contrast, males occupied a different trophic niche and showed reduced foraging effort and reduced prey capture and feeding efficiency compared with females and juveniles.Our data indicate that female-biased dimorphism in trophic morphology and body size correlate with sex-specific reproductive strategies. We propose that intersexual trophic niche partitioning is shaped primarily by fecundity selection in females, and results from sex-differences in the route to successful reproduction where females are

  5. Feeding and stocking up: radio-labelled food reveals exchange patterns in ants.

    Science.gov (United States)

    Buffin, Aurélie; Denis, Damien; Van Simaeys, Gaetan; Goldman, Serge; Deneubourg, Jean-Louis

    2009-06-17

    Food sharing is vital for a large number of species, either solitary or social, and is of particular importance within highly integrated societies, such as in colonial organisms and in social insects. Nevertheless, the mechanisms that govern the distribution of food inside a complex organizational system remain unknown. Using scintigraphy, a method developed for medical imaging, we were able to describe the dynamics of food-flow inside an ant colony. We monitored the sharing process of a radio-labelled sucrose solution inside a nest of Formica fusca. Our results show that, from the very first load that enters the nest, food present within the colony acts as negative feedback to entering food. After one hour of the experiments, 70% of the final harvest has already entered the nest. The total foraged quantity is almost four times smaller than the expected storage capacity. A finer study of the spatial distribution of food shows that although all ants have been fed rapidly (within 30 minutes), a small area representing on average 8% of the radioactive surface holds more than 25% of the stored food. Even in rather homogeneous nests, we observed a strong concentration of food in few workers. Examining the position of these workers inside the nest, we found heavily loaded ants in the centre of the aggregate. The position of the centre of this high-intensity radioactive surface remained stable for the three consecutive hours of the experiments. We demonstrate that the colony simultaneously managed to rapidly feed all workers (200 ants fed within 30 minutes) and build up food stocks to prevent food shortage, something that occurs rather often in changing environments. Though we expected the colony to forage to its maximum capacity, the flow of food entering the colony is finely tuned to the colony's needs. Indeed the food-flow decreases proportionally to the food that has already been harvested, liberating the work-force for other tasks.

  6. Genetic clusters and sex-biased gene flow in a unicolonial Formica ant

    Directory of Open Access Journals (Sweden)

    Chapuisat Michel

    2009-03-01

    Full Text Available Abstract Background Animal societies are diverse, ranging from small family-based groups to extraordinarily large social networks in which many unrelated individuals interact. At the extreme of this continuum, some ant species form unicolonial populations in which workers and queens can move among multiple interconnected nests without eliciting aggression. Although unicoloniality has been mostly studied in invasive ants, it also occurs in some native non-invasive species. Unicoloniality is commonly associated with very high queen number, which may result in levels of relatedness among nestmates being so low as to raise the question of the maintenance of altruism by kin selection in such systems. However, the actual relatedness among cooperating individuals critically depends on effective dispersal and the ensuing pattern of genetic structuring. In order to better understand the evolution of unicoloniality in native non-invasive ants, we investigated the fine-scale population genetic structure and gene flow in three unicolonial populations of the wood ant F. paralugubris. Results The analysis of geo-referenced microsatellite genotypes and mitochondrial haplotypes revealed the presence of cryptic clusters of genetically-differentiated nests in the three populations of F. paralugubris. Because of this spatial genetic heterogeneity, members of the same clusters were moderately but significantly related. The comparison of nuclear (microsatellite and mitochondrial differentiation indicated that effective gene flow was male-biased in all populations. Conclusion The three unicolonial populations exhibited male-biased and mostly local gene flow. The high number of queens per nest, exchanges among neighbouring nests and restricted long-distance gene flow resulted in large clusters of genetically similar nests. The positive relatedness among clustermates suggests that kin selection may still contribute to the maintenance of altruism in unicolonial

  7. Conducta médica posnatal ante la dilatación del tracto urinario superior fetal Postnatal medical behavior in face a dilatation of fetal high urinary tract

    Directory of Open Access Journals (Sweden)

    Sandalio Durán Álvarez

    2012-03-01

    Full Text Available El seguimiento sistemático del embarazo normal mediante el estudio ultrasonográfico materno-fetal ha demostrado que por cada 500 embarazos debemos esperar una anomalía importante del tracto urinario. La anomalía detectada con mayor frecuencia es la dilatación del tracto urinario superior, que si bien la mayoría de las veces no se traduce en una alteración importante, obliga a su estudio posnatal para poder valorar su significación. Una dilatación del tracto urinario superior puede ser la traducción de una hidronefrosis obstructiva por estenosis ureteropiélica, una hidronefrosis no obstructiva, un reflujo vesicoureteral o una pielectasia, y menos frecuentemente, puede ser la imagen de un doble sistema excretor con el superior obstruido, un megauréter obstructivo o no obstructivo, o una valva de uretra posterior en el sexo masculino. En esta revisión se presentan los criterios diagnósticos y el tratamiento clínico de las hidronefrosis y pielectasias, así como el estudio de los casos en que se sospecha reflujo vesicoureteral, y se relatan las anomalías encontradas en 318 niños en que el ultrasonido materno-fetal detectó alguna alteración del tracto urinario. Aunque no tan frecuente como las pielectasias y las hidronefrosis no obstructivas, las estenosis pieloureterales que producen obstrucción, pueden traer serias consecuencias sobre la función renal, que obligan a tomar decisiones médicas, y, en ocasiones, quirúrgicas, para mejorar la calidad de vida de estos niños.The systematic follow-up of the normal pregnancy by means of a mother-fetus ultrasonography study has demonstrated that for each 500 pregnancies, we must to expect a significant anomaly of urinary tract. The more frequent anomaly detected is the high urinary tract dilatation, which if not always it is a significant alteration, leads to a postnatal study to assess its significance. A high urinary tract dilatation may to give rise to an obstructive hydronephrosis

  8. Self-restraint and sterility in workers of Acromyrmex and Atta leafcutter ants

    DEFF Research Database (Denmark)

    Dijkstra, Michiel Bendert; Nash, David Richard; Boomsma, Jacobus Jan

    2005-01-01

    Queens of leafcutter ants (Acromyrmex and Atta) are highly multiply mated, resulting in a potential queenworker and worker-worker conflict over who should produce the males in the colony. We studied whether this conflict is expressed, by determining the amount of reproductive egg-laying by worker...

  9. Population Development of Several Species of Ants on the Cocoa Trees in South Sulawesi

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    Fatahuddin Fatahuddin

    2010-08-01

    Full Text Available Several species of ants with different behavior have been found in cocoa plantations and their behavior is important to be considered because it might be correlated with the degree of protection of cocoa plant from cocoa pests. The aim of this research is to manipulate and to develop ants population in environment, so they are able to establish permanently in cocoa trees. This research was conducted in Papakaju Regions Luwu Regency in Juli to November 2009. In this study, 10 cocoa trees with ants were sampled (each species of ant in 10 cocoa trees. A control of 10 tree samples without ant was also taken. In order to assess the abundance of ant population, it was grouped based on scoring, which score 1 for less than 20 ants, score 2 for 21–50 ants, score 3 for 51–200 ants, score 4 for 201–1000 ants, and score 5 for more than 1000 per tree. The results indicated that average of population score of the three ants species reached the highest population for the Oecophylla. smaragdina with average score 4.85 (>1000 ants, Dolichoderus thoracicus, with average score 3.90 (> 200 ants and Crematogaster. difformis with average score 3.10 (>200 ants. This research indicated that three species of ants, Oecophylla smaragdina (weaver ant, Dolichoderus thoracicus (cocoa black ant and Crematogaster difformis (cracking ant. in farmer cocoa plantations in South Sulawesi giving better performance against major pests of cocoa in particular cocoa pod borer (CPB. Key words: Ant Population, Oecophylla smaragdina, Dolichoderus thoracicus, Crematogaster difformis, artificial nest, cocoa.

  10. The effects of biogeography on ant diversity and activity on the Boston Harbor Islands, Massachusetts, U.S.A.

    Science.gov (United States)

    Clark, Adam T; Rykken, Jessica J; Farrell, Brian D

    2011-01-01

    Many studies have examined how island biogeography affects diversity on the scale of island systems. In this study, we address how diversity varies over very short periods of time on individual islands. To do this, we compile an inventory of the ants living in the Boston Harbor Islands National Recreation Area, Boston, Massachusetts, USA using data from a five-year All Taxa Biodiversity Inventory of the region's arthropods. Consistent with the classical theory of island biogeography, species richness increased with island size, decreased with island isolation, and remained relatively constant over time. Additionally, our inventory finds that almost half of the known Massachusetts ant fauna can be collected in the BHI, and identifies four new species records for Massachusetts, including one new to the United States, Myrmica scabrinodis. We find that the number of species actually active on islands depended greatly on the timescale under consideration. The species that could be detected during any given week of sampling could by no means account for total island species richness, even when correcting for sampling effort. Though we consistently collected the same number of species over any given week of sampling, the identities of those species varied greatly between weeks. This variation does not result from local immigration and extinction of species, nor from seasonally-driven changes in the abundance of individual species, but rather from weekly changes in the distribution and activity of foraging ants. This variation can be upwards of 50% of ant species per week. This suggests that numerous ant species on the BHI share the same physical space at different times. This temporal partitioning could well explain such unexpectedly high ant diversity in an isolated, urban site.

  11. The effects of biogeography on ant diversity and activity on the Boston Harbor Islands, Massachusetts, U.S.A.

    Directory of Open Access Journals (Sweden)

    Adam T Clark

    Full Text Available Many studies have examined how island biogeography affects diversity on the scale of island systems. In this study, we address how diversity varies over very short periods of time on individual islands. To do this, we compile an inventory of the ants living in the Boston Harbor Islands National Recreation Area, Boston, Massachusetts, USA using data from a five-year All Taxa Biodiversity Inventory of the region's arthropods. Consistent with the classical theory of island biogeography, species richness increased with island size, decreased with island isolation, and remained relatively constant over time. Additionally, our inventory finds that almost half of the known Massachusetts ant fauna can be collected in the BHI, and identifies four new species records for Massachusetts, including one new to the United States, Myrmica scabrinodis. We find that the number of species actually active on islands depended greatly on the timescale under consideration. The species that could be detected during any given week of sampling could by no means account for total island species richness, even when correcting for sampling effort. Though we consistently collected the same number of species over any given week of sampling, the identities of those species varied greatly between weeks. This variation does not result from local immigration and extinction of species, nor from seasonally-driven changes in the abundance of individual species, but rather from weekly changes in the distribution and activity of foraging ants. This variation can be upwards of 50% of ant species per week. This suggests that numerous ant species on the BHI share the same physical space at different times. This temporal partitioning could well explain such unexpectedly high ant diversity in an isolated, urban site.

  12. Transcriptome characterisation of the ant Formica exsecta with new insights into the evolution of desaturase genes in social hymenoptera.

    Directory of Open Access Journals (Sweden)

    Hélène Badouin

    Full Text Available BACKGROUND: Despite the recent sequencing of seven ant genomes, no genomic data are available for the genus Formica, an important group for the study of eusocial traits. We sequenced the transcriptome of the ant Formica exsecta with the 454 FLX Titanium technology from a pooled sample of workers from 70 Finnish colonies. RESULTS: About 1,000,000 reads were obtained from a normalised cDNA library. We compared the assemblers MIRA3.0 and Newbler2.6 and showed that the latter performed better on this dataset due to a new option which is dedicated to improve contig formation in low depth portions of the assemblies. The 29,579 contigs represent 27 Mb. 50% showed similarity with known proteins and 25% could be assigned a category of gene ontology. We found more than 13,000 high-quality single nucleotide polymorphisms. The Δ9 desaturase gene family is an important multigene family involved in chemical communication in insects. We found six Δ9 desaturases in this Formica exsecta transcriptome dataset that were used to reconstruct a maximum-likelihood phylogeny of insect desaturases and to test for signatures of positive selection in this multigene family in ant lineages. We found differences with previous phylogenies of this gene family in ants, and found two clades potentially under positive selection. CONCLUSION: This first transcriptome reference sequence of Formica exsecta provided sequence and polymorphism data that will allow researchers working on Formica ants to develop studies to tackle the genetic basis of eusocial phenotypes. In addition, this study provided some general guidelines for de novo transcriptome assembly that should be useful for future transcriptome sequencing projects. Finally, we found potential signatures of positive selection in some clades of the Δ9 desaturase gene family in ants, which suggest the potential role of sequence divergence and adaptive evolution in shaping the large diversity of chemical cues in social insects.

  13. The nest architecture of the Florida harvester ant, Pogonomyrmex badius.

    Science.gov (United States)

    Tschinkel, Walter R

    2004-01-01

    The architecture of the subterranean nests of the Florida harvester ant, Pogonomyrmex badius, was studied through excavation and casting. Nests are composed of two basic units: descending shafts and horizontal chambers. Shafts form helices with diameters of 4 to 6 cm, and descend at an angle of about 15-20 degrees near the surface, increasing to about 70 degrees below about 50 cm in depth. Superficial chambers (engaging in digging, rather than an increase in their rate of work. All ages of workers produced similar top-heavy nests. When different ages of workers from different levels of a mature colony were allowed to re-assort themselves in a vertical test apparatus buried in the soil, older workers moved upward to assume positions in the upper parts of the nest, much as in the colonies from which they were taken. The vertical organization of workers based on age is therefore the product of active movement and choice. A possible template imparting information on depth is a carbon dioxide gradient. Carbon dioxide concentrations increased 5-fold between the surface and the depths of the nest. A preference of young workers for high carbon dioxide concentrations, and a tendency for workers to dig more under low carbon dioxide concentrations could explain both the vertical age-distribution of workers, and the top-heaviness of the nest's architecture.

  14. Solving optimum operation of single pump unit problem with ant colony optimization (ACO) algorithm

    International Nuclear Information System (INIS)

    Yuan, Y; Liu, C

    2012-01-01

    For pumping stations, the effective scheduling of daily pump operations from solutions to the optimum design operation problem is one of the greatest potential areas for energy cost-savings, there are some difficulties in solving this problem with traditional optimization methods due to the multimodality of the solution region. In this case, an ACO model for optimum operation of pumping unit is proposed and the solution method by ants searching is presented by rationally setting the object function and constrained conditions. A weighted directed graph was constructed and feasible solutions may be found by iteratively searching of artificial ants, and then the optimal solution can be obtained by applying the rule of state transition and the pheromone updating. An example calculation was conducted and the minimum cost was found as 4.9979. The result of ant colony algorithm was compared with the result from dynamic programming or evolutionary solving method in commercial software under the same discrete condition. The result of ACO is better and the computing time is shorter which indicates that ACO algorithm can provide a high application value to the field of optimal operation of pumping stations and related fields.

  15. Microbial Communities in Different Tissues of Atta sexdens rubropilosa Leaf-cutting Ants.

    Science.gov (United States)

    Vieira, Alexsandro S; Ramalho, Manuela O; Martins, Cintia; Martins, Vanderlei G; Bueno, Odair C

    2017-10-01

    Bacterial endosymbionts are common in all insects, and symbiosis has played an integral role in ant evolution. Atta sexdens rubropilosa leaf-cutting ants cultivate their symbiotic fungus using fresh leaves. They need to defend themselves and their brood against diseases, but they also need to defend their obligate fungus gardens, their primary food source, from infection, parasitism, and usurpation by competitors. This study aimed to characterize the microbial communities in whole workers and different tissues of A. sexdens rubropilosa queens using Ion Torrent NGS. Our results showed that the microbial community in the midgut differs in abundance and diversity from the communities in the postpharyngeal gland of the queen and in whole workers. The main microbial orders in whole workers were Lactobacillales, Clostridiales, Enterobacteriales, Actinomycetales, Burkholderiales, and Bacillales. In the tissues of the queens, the main orders were Burkholderiales, Clostridiales, Syntrophobacterales, Lactobacillales, Bacillales, and Actinomycetales (midgut) and Entomoplasmatales, unclassified γ-proteobacteria, and Actinomycetales (postpharyngeal glands). The high abundance of Entomoplasmatales in the postpharyngeal glands (77%) of the queens was an unprecedented finding. We discuss the role of microbial communities in different tissues and castes. Bacteria are likely to play a role in nutrition and immune defense as well as helping antimicrobial defense in this ant species.

  16. A nuclear reactor core fuel reload optimization using artificial ant colony connective networks

    International Nuclear Information System (INIS)

    Lima, Alan M.M. de; Schirru, Roberto; Carvalho da Silva, Fernando; Medeiros, Jose Antonio Carlos Canedo

    2008-01-01

    The core of a nuclear Pressurized Water Reactor (PWR) may be reloaded every time the fuel burn-up is such that it is not more possible to maintain the reactor operating at nominal power. The nuclear core fuel reload optimization problem consists in finding a pattern of burned-up and fresh-fuel assemblies that maximize the number of full operational days. This is an NP-Hard problem, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Moreover, the problem is non-linear and its search space is highly discontinuous and multi-modal. Ant Colony System (ACS) is an optimization algorithm based on artificial ants that uses the reinforcement learning technique. The ACS was originally developed to solve the Traveling Salesman Problem (TSP), which is conceptually similar to the nuclear core fuel reload problem. In this work a parallel computational system based on the ACS, called Artificial Ant Colony Networks is introduced to solve the core fuel reload optimization problem

  17. Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals.

    Science.gov (United States)

    Archibald, S Bruce; Johnson, Kirk R; Mathewes, Rolf W; Greenwood, David R

    2011-12-22

    Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20°C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene.

  18. Financing long-term care: ex ante, ex post or both?

    Science.gov (United States)

    Costa-Font, Joan; Courbage, Christophe; Swartz, Katherine

    2015-03-01

    This paper attempts to examine the heterogeneity in the public financing of long-term care (LTC) and the wide-ranging instruments in place to finance LTC services. We distinguish and classify the institutional responses to the need for LTC financing as ex ante (occurring prior to when the need arises, such as insurance) and ex post (occurring after the need arises, such as public sector and family financing). Then, we examine country-specific data to ascertain whether the two types of financing are complements or substitutes. Finally, we examine exploratory cross-national data on public expenditure determinants, specifically economic, demographic and social determinants. We show that although both ex ante and ex post mechanisms exist in all countries with advanced industrial economies and despite the fact that instruments are different across countries, ex ante and ex post instruments are largely substitutes for each other. Expenditure estimates to date indicate that the public financing of LTC is highly sensitive to a country's income, ageing of the population and the availability of informal caregiving. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Effects of heavy metal pollution on red wood ant (Formica s. str.) populations

    International Nuclear Information System (INIS)

    Eeva, T.; Sorvari, J.; Koivunen, V.

    2004-01-01

    We studied the species composition, mound population densities, relative abundance and colony sizes of red wood ants along a well known air pollution gradient of a copper smelter in Southwest Finland. The dominant species, Formica aquilonia, was further studied for heavy metal (Al, Cu, Cd, Ni, Zn, As, Pb, Hg) levels and morphological characters (body mass, head width, labial gland disease) of workers. We found five species belonging to Formica s. str., and two of them showed changes in their relative abundance, which could not be explained by natural habitat differences. Nest mound volumes were 34% smaller in the polluted area, suggesting that smaller colonies can be maintained there. The heavy metal levels in F. aquilonia workers were higher in the polluted area for all metals, except Hg. The largest relative differences between the study areas (polluted/unpolluted) were found for As (4.1), Ni (2.4), Cu (2.1) and Pb (1.8). Morphological characters of workers were not related to the heavy metal levels. Our data showed that red wood ants can tolerate relatively high amounts of heavy metals and maintain reproducing colonies even in a heavily polluted area, but on the basis of smaller colony sizes, pollution stress may also cause trade-offs in reproduction. - Capsule: Five species of red wood ants vary in their sensitivity to heavy metal pollution but all of them had smaller colonies in a polluted area

  20. Arthropods Associate with their Red Wood ant Host without Matching Nestmate Recognition Cues.

    Science.gov (United States)

    Parmentier, Thomas; Dekoninck, Wouter; Wenseleers, Tom

    2017-07-01

    Social insect colonies provide a valuable resource that attracts and offers shelter to a large community of arthropods. Previous research has suggested that many specialist parasites of social insects chemically mimic their host in order to evade aggression. In the present study, we carry out a systematic study to test how common such chemical deception is across a group of 22 arthropods that are associated with red wood ants (Formica rufa group). In contrast to the examples of chemical mimicry documented in some highly specialized parasites in previous studies, we find that most of the rather unspecialized red wood ant associates surveyed did not use mimicry of the cuticular hydrocarbon recognition cues to evade host detection. Instead, we found that myrmecophiles with lower cuticular hydrocarbon concentrations provoked less host aggression. Therefore, some myrmecophiles with low hydrocarbon concentrations appear to evade host detection via a strategy known as chemical insignificance. Others showed no chemical disguise at all and, instead, relied on behavioral adaptations such as particular defense or evasion tactics, in order to evade host aggression. Overall, this study indicates that unspecialized myrmecophiles do not require the matching of host recognition cues and advanced strategies of chemical mimicry, but can integrate in a hostile ant nest via either chemical insignificance or specific behavioral adaptations.

  1. Laboratory and Field Evaluations of Polyacrylamide Hydrogel Baits Against Argentine Ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Rust, Michael K; Soeprono, Andrew; Wright, Sarajean; Greenberg, Les; Choe, Dong-Hwan; Boser, Christina L; Cory, Coleen; Hanna, Cause

    2015-06-01

    The development of effective baits to control the Argentine ant, Linepithema humile (Mayr), has been problematic because foragers prefer sweet liquids, while many toxicants are insoluble in water and liquid baits are generally difficult to deliver. The incorporation of thiamethoxam and sucrose solutions into a water-absorbing polyacrylamide hydrogel provides a unique and novel carrier and method of application for liquid baits. Formulations of thiamethoxam affected the size of the hydrogels, and sucrose solutions containing 0.0003% technical thiamethoxam provided hydrogels as large as those made with 25% sucrose solution or deionized water. Concentrations of thiamethoxam as low as 0.000075% in the hydrogels provided 50% kill of workers within 3 d in a laboratory setting. In small colony studies, baiting with 0.00015 and 0.000075% thiamethoxam hydrogels provided 100% mortality of workers and queens within 8 d. An enzyme-linked immunosorbent assay indicated that thiamethoxam was absorbed into the interior of the polyacrylamide matrix. The water loss rates of the hydrogels were dependent upon the relative humidity. Polyacrylamide hydrogels with >50% water loss were less attractive to ants. Field studies in highly infested areas indicated that concentrations of 0.0006 or 0.0018% thiamethoxam were more effective than 0.00015%. Hydrogels may provide a cost-effective alternative to providing aqueous baits to control Argentine ants. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. A nuclear reactor core fuel reload optimization using artificial ant colony connective networks

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alan M.M. de [Universidade Federal do Rio de Janeiro, PEN/COPPE - UFRJ, Ilha do Fundao s/n, CEP 21945-970 Rio de Janeiro (Brazil)], E-mail: alanmmlima@yahoo.com.br; Schirru, Roberto [Universidade Federal do Rio de Janeiro, PEN/COPPE - UFRJ, Ilha do Fundao s/n, CEP 21945-970 Rio de Janeiro (Brazil)], E-mail: schirru@lmp.ufrj.br; Carvalho da Silva, Fernando [Universidade Federal do Rio de Janeiro, PEN/COPPE - UFRJ, Ilha do Fundao s/n, CEP 21945-970 Rio de Janeiro (Brazil)], E-mail: fernando@con.ufrj.br; Medeiros, Jose Antonio Carlos Canedo [Universidade Federal do Rio de Janeiro, PEN/COPPE - UFRJ, Ilha do Fundao s/n, CEP 21945-970 Rio de Janeiro (Brazil)], E-mail: canedo@lmp.ufrj.br

    2008-09-15

    The core of a nuclear Pressurized Water Reactor (PWR) may be reloaded every time the fuel burn-up is such that it is not more possible to maintain the reactor operating at nominal power. The nuclear core fuel reload optimization problem consists in finding a pattern of burned-up and fresh-fuel assemblies that maximize the number of full operational days. This is an NP-Hard problem, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Moreover, the problem is non-linear and its search space is highly discontinuous and multi-modal. Ant Colony System (ACS) is an optimization algorithm based on artificial ants that uses the reinforcement learning technique. The ACS was originally developed to solve the Traveling Salesman Problem (TSP), which is conceptually similar to the nuclear core fuel reload problem. In this work a parallel computational system based on the ACS, called Artificial Ant Colony Networks is introduced to solve the core fuel reload optimization problem.

  3. To drink or grasp? How bullet ants ( Paraponera clavata) differentiate between sugars and proteins in liquids

    Science.gov (United States)

    Jandt, Jennifer; Larson, Hannah K.; Tellez, Peter; McGlynn, Terrence P.

    2013-12-01

    Flexibility in behavior can increase the likelihood that a forager may respond optimally in a fluctuating environment. Nevertheless, physiological or neuronal constraints may result in suboptimal responses to stimuli. We observed foraging workers of the giant tropical ant (also referred to as the "bullet ant"), Paraponera clavata, as they reacted to liquid solutions with varying concentrations of sugar and protein. We show that when protein/sucrose concentration is high, many bullet ants will often try to grasp at the droplet, rather than gather it by drinking. Because P. clavata actively hunt for prey, fixed action patterns and rapid responses to protein may be adaptively important, regardless of the medium in which it is presented. We conclude that, in P. clavata, food-handling decisions are made in response to the nutrient content of the food rather than the texture of the food. Further, we suggest that colonies that maintain a mixture of individuals with consistent fixed or flexible behavioral responses to food-handling decisions may be better adapted to fluctuating environmental conditions, and we propose future studies that could address this.

  4. Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals

    Science.gov (United States)

    Archibald, S. Bruce; Johnson, Kirk R.; Mathewes, Rolf W.; Greenwood, David R.

    2011-01-01

    Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20°C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene. PMID:21543354

  5. Fumigant Activity of Sweet Orange Essential Oil Fractions Against Red Imported Fire Ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Hu, Wei; Zhang, Ning; Chen, Hongli; Zhong, Balian; Yang, Aixue; Kuang, Fan; Ouyang, Zhigang; Chun, Jiong

    2017-08-01

    Sweet orange oil fractions were prepared by molecular distillation of cold-pressed orange oil from sample A (Citrus sinensis (L.) 'Hamlin' from America) and sample B (Citrus sinensis Osbeck 'Newhall' from China) respectively, and their fumigant activities against medium workers of red imported fire ants (Solenopsis invicta Buren) were investigated. The volatile composition of the orange oil fractions was identified and quantified using GC-MS. Fractions from sample A (A1, A2, and A3) contained 23, 37, and 48 chemical constituents, and fractions from sample B (B1, B2, and B3) contained 18, 29, and 26 chemical constituents, respectively. Monoterpenes were the most abundant components, accounting for 73.56% to 94.86% of total orange oil fractions, among which D-limonene (65.28-80.18%), β-pinene (1.71-5.58%), 3-carene (0.41-4.01%), β-phellandrene (0.58-2.10%), and linalool (0.31-2.20%) were major constituents. Fumigant bioassay indicated that all orange oil fractions exerted good fumigant toxicity against workers of fire ants at 3, 5, 10, and 20 mg/centrifuge tubes, and B1 had the strongest insecticidal potential, followed by A1, B2, A2, B3, and A3. The fractions composed of more high volatile molecules (A1 and B1) showed greater fumigant effects than others. Compounds linalool and D-limonene, which were the constituents of the orange oil, exhibited excellent fumigant toxicity against red imported fire ant workers. Linalool killed red imported fire ant workers completely at 5, 10, and 20 mg/tube after 8 h of treatment, and D-limonene induced >86% mortality at 8 h of exposure. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. QTL Mapping of Sex Determination Loci Supports an Ancient Pathway in Ants and Honey Bees.

    Directory of Open Access Journals (Sweden)

    Misato O Miyakawa

    2015-11-01

    Full Text Available Sex determination mechanisms play a central role in life-history characteristics, affecting mating systems, sex ratios, inbreeding tolerance, etc. Downstream components of sex determination pathways are highly conserved, but upstream components evolve rapidly. Evolutionary dynamics of sex determination remain poorly understood, particularly because mechanisms appear so diverse. Here we investigate the origins and evolution of complementary sex determination (CSD in ants and bees. The honey bee has a well-characterized CSD locus, containing tandemly arranged homologs of the transformer gene [complementary sex determiner (csd and feminizer (fem]. Such tandem paralogs appear frequently in aculeate hymenopteran genomes. However, only comparative genomic, but not functional, data support a broader role for csd/fem in sex determination, and whether species other than the honey bee use this pathway remains controversial. Here we used a backcross to test whether csd/fem acts as a CSD locus in an ant (Vollenhovia emeryi. After sequencing and assembling the genome, we computed a linkage map, and conducted a quantitative trait locus (QTL analysis of diploid male production using 68 diploid males and 171 workers. We found two QTLs on separate linkage groups (CsdQTL1 and CsdQTL2 that jointly explained 98.0% of the phenotypic variance. CsdQTL1 included two tandem transformer homologs. These data support the prediction that the same CSD mechanism has indeed been conserved for over 100 million years. CsdQTL2 had no similarity to CsdQTL1 and included a 236-kb region with no obvious CSD gene candidates, making it impossible to conclusively characterize it using our data. The sequence of this locus was conserved in at least one other ant genome that diverged >75 million years ago. By applying QTL analysis to ants for the first time, we support the hypothesis that elements of hymenopteran CSD are ancient, but also show that more remains to be learned about the

  7. SeqAnt: A web service to rapidly identify and annotate DNA sequence variations

    Directory of Open Access Journals (Sweden)

    Patel Viren

    2010-09-01

    Full Text Available Abstract Background The enormous throughput and low cost of second-generation sequencing platforms now allow research and clinical geneticists to routinely perform single experiments that identify tens of thousands to millions of variant sites. Existing methods to annotate variant sites using information from publicly available databases via web browsers are too slow to be useful for the large sequencing datasets being routinely generated by geneticists. Because sequence annotation of variant sites is required before functional characterization can proceed, the lack of a high-throughput pipeline to efficiently annotate variant sites can act as a significant bottleneck in genetics research. Results SeqAnt (Sequence Annotator is an open source web service and software package that rapidly annotates DNA sequence variants and identifies recessive or compound heterozygous loci in human, mouse, fly, and worm genome sequencing experiments. Variants are characterized with respect to their functional type, frequency, and evolutionary conservation. Annotated variants can be viewed on a web browser, downloaded in a tab-delimited text file, or directly uploaded in a BED format to the UCSC genome browser. To demonstrate the speed of SeqAnt, we annotated a series of publicly available datasets that ranged in size from 37 to 3,439,107 variant sites. The total time to completely annotate these data completely ranged from 0.17 seconds to 28 minutes 49.8 seconds. Conclusion SeqAnt is an open source web service and software package that overcomes a critical bottleneck facing research and clinical geneticists using second-generation sequencing platforms. SeqAnt will prove especially useful for those investigators who lack dedicated bioinformatics personnel or infrastructure in their laboratories.

  8. Prospecting for viral natural enemies of the fire ant Solenopsis invicta in Argentina.

    Science.gov (United States)

    Valles, Steven M; Porter, Sanford D; Calcaterra, Luis A

    2018-01-01

    Metagenomics and next generation sequencing were employed to discover new virus natural enemies of the fire ant, Solenopsis invicta Buren in its native range (i.e., Formosa, Argentina) with the ultimate goal of testing and releasing new viral pathogens into U.S. S. invicta populations to provide natural, sustainable control of this ant. RNA was purified from worker ants from 182 S. invicta colonies, which was pooled into 4 groups according to location. A library was created from each group and sequenced using Illumina Miseq technology. After a series of winnowing methods to remove S. invicta genes, known S. invicta virus genes, and all other non-virus gene sequences, 61,944 unique singletons were identified with virus identity. These were assembled de novo yielding 171 contiguous sequences with significant identity to non-plant virus genes. Fifteen contiguous sequences exhibited very high expression rates and were detected in all four gene libraries. One contig (Contig_29) exhibited the highest expression level overall and across all four gene libraries. Random amplification of cDNA ends analyses expanded this contiguous sequence yielding a complete virus genome, which we have provisionally named Solenopsis invicta virus 5 (SINV-5). SINV-5 is a positive-sense, single-stranded RNA virus with genome characteristics consistent with insect-infecting viruses from the family Dicistroviridae. Moreover, the replicative genome strand of SINV-5 was detected in worker ants indicating that S. invicta serves as host for the virus. Many additional sequences were identified that are likely of viral origin. These sequences await further investigation to determine their origins and relationship with S. invicta. This study expands knowledge of the RNA virome diversity found within S. invicta populations.

  9. Prospecting for viral natural enemies of the fire ant Solenopsis invicta in Argentina.

    Directory of Open Access Journals (Sweden)

    Steven M Valles

    Full Text Available Metagenomics and next generation sequencing were employed to discover new virus natural enemies of the fire ant, Solenopsis invicta Buren in its native range (i.e., Formosa, Argentina with the ultimate goal of testing and releasing new viral pathogens into U.S. S. invicta populations to provide natural, sustainable control of this ant. RNA was purified from worker ants from 182 S. invicta colonies, which was pooled into 4 groups according to location. A library was created from each group and sequenced using Illumina Miseq technology. After a series of winnowing methods to remove S. invicta genes, known S. invicta virus genes, and all other non-virus gene sequences, 61,944 unique singletons were identified with virus identity. These were assembled de novo yielding 171 contiguous sequences with significant identity to non-plant virus genes. Fifteen contiguous sequences exhibited very high expression rates and were detected in all four gene libraries. One contig (Contig_29 exhibited the highest expression level overall and across all four gene libraries. Random amplification of cDNA ends analyses expanded this contiguous sequence yielding a complete virus genome, which we have provisionally named Solenopsis invicta virus 5 (SINV-5. SINV-5 is a positive-sense, single-stranded RNA virus with genome characteristics consistent with insect-infecting viruses from the family Dicistroviridae. Moreover, the replicative genome strand of SINV-5 was detected in worker ants indicating that S. invicta serves as host for the virus. Many additional sequences were identified that are likely of viral origin. These sequences await further investigation to determine their origins and relationship with S. invicta. This study expands knowledge of the RNA virome diversity found within S. invicta populations.

  10. Moving in Dim Light: Behavioral and Visual Adaptations in Nocturnal Ants.

    Science.gov (United States)

    Narendra, Ajay; Kamhi, J Frances; Ogawa, Yuri

    2017-11-01

    Visual navigation is a benchmark information processing task that can be used to identify the consequence of being active in dim-light environments. Visual navigational information that animals use during the day includes celestial cues such as the sun or the pattern of polarized skylight and terrestrial cues such as the entire panorama, canopy pattern, or significant salient features in the landscape. At night, some of these navigational cues are either unavailable or are significantly dimmer or less conspicuous than during the day. Even under these circumstances, animals navigate between locations of importance. Ants are a tractable system for studying navigation during day and night because the fine scale movement of individual animals can be recorded in high spatial and temporal detail. Ant species range from being strictly diurnal, crepuscular, and nocturnal. In addition, a number of species have the ability to change from a day- to a night-active lifestyle owing to environmental demands. Ants also offer an opportunity to identify the evolution of sensory structures for discrete temporal niches not only between species but also within a single species. Their unique caste system with an exclusive pedestrian mode of locomotion in workers and an exclusive life on the wing in males allows us to disentangle sensory adaptations that cater for different lifestyles. In this article, we review the visual navigational abilities of nocturnal ants and identify the optical and physiological adaptations they have evolved for being efficient visual navigators in dim-light. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  11. Various chemical strategies to deceive ants in three Arhopala species (lepidoptera: Lycaenidae exploiting Macaranga myrmecophytes.

    Directory of Open Access Journals (Sweden)

    Yoko Inui

    Full Text Available Macaranga myrmecophytes (ant-plants are generally well protected from herbivore attacks by their symbiotic ants (plant-ants. However, larvae of Arhopala (Lepidoptera: Lycaenidae species survive and develop on specific Macaranga ant-plant species without being attacked by the plant-ants of their host species. We hypothesized that Arhopala larvae chemically mimic or camouflage themselves with the ants on their host plant so that the larvae are accepted by the plant-ant species of their host. Chemical analyses of cuticular hydrocarbons showed that chemical congruency varied among Arhopala species; A. dajagaka matched well the host plant-ants, A. amphimuta did not match, and unexpectedly, A. zylda lacked hydrocarbons. Behaviorally, the larvae and dummies coated with cuticular chemicals of A. dajagaka were well attended by the plant-ants, especially by those of the host. A. amphimuta was often attacked by all plant-ants except for the host plant-ants toward the larvae, and those of A. zylda were ignored by all plant-ants. Our results suggested that conspicuous variations exist in the chemical strategies used by the myrmecophilous butterflies that allow them to avoid ant attack and be accepted by the plant-ant colonies.

  12. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants.

    Directory of Open Access Journals (Sweden)

    Andrew N Bubak

    Full Text Available Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context-isolation, nestmate interaction, or fighting non-nestmates-affects brain monoamine levels in pavement ants (Tetramorium caespitum. Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants.

  13. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants.

    Science.gov (United States)

    Bubak, Andrew N; Yaeger, Jazmine D W; Renner, Kenneth J; Swallow, John G; Greene, Michael J

    2016-01-01

    Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context-isolation, nestmate interaction, or fighting non-nestmates-affects brain monoamine levels in pavement ants (Tetramorium caespitum). Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants.

  14. PARAMETER ESTIMATION OF VALVE STICTION USING ANT COLONY OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    S. Kalaivani

    2012-07-01

    Full Text Available In this paper, a procedure for quantifying valve stiction in control loops based on ant colony optimization has been proposed. Pneumatic control valves are widely used in the process industry. The control valve contains non-linearities such as stiction, backlash, and deadband that in turn cause oscillations in the process output. Stiction is one of the long-standing problems and it is the most severe problem in the control valves. Thus the measurement data from an oscillating control loop can be used as a possible diagnostic signal to provide an estimate of the stiction magnitude. Quantification of control valve stiction is still a challenging issue. Prior to doing stiction detection and quantification, it is necessary to choose a suitable model structure to describe control-valve stiction. To understand the stiction phenomenon, the Stenman model is used. Ant Colony Optimization (ACO, an intelligent swarm algorithm, proves effective in various fields. The ACO algorithm is inspired from the natural trail following behaviour of ants. The parameters of the Stenman model are estimated using ant colony optimization, from the input-output data by minimizing the error between the actual stiction model output and the simulated stiction model output. Using ant colony optimization, Stenman model with known nonlinear structure and unknown parameters can be estimated.

  15. The cavity-nest ant Temnothorax crassispinus prefers larger nests.

    Science.gov (United States)

    Mitrus, S

    Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm 3 , respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger nests. Among queenright colonies, the ones which inhabited bigger nests had more workers. However, there was no relationship between volume of nest and number of workers for queenless colonies. Queenright colonies from bigger nests produced more sexual individuals, but there was no correlation between number of workers and sex allocation ratio, or between volume of nest and sex allocation ratio. In a laboratory experiment where ant colonies were kept in 470 and 860 mm 3 nests, larger colonies allocated more energy to produce sexual individuals. The results of this study show the selectivity of T. crassispinus ants regarding the size of nest cavity, and that the nest volume has an impact on life history parameters.

  16. Polarized light use in the nocturnal bull ant, Myrmecia midas.

    Science.gov (United States)

    Freas, Cody A; Narendra, Ajay; Lemesle, Corentin; Cheng, Ken

    2017-08-01

    Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas . We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1-2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

  17. DATA MINING UNTUK KLASIFIKASI PELANGGAN DENGAN ANT COLONY OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    Maulani Kapiudin

    2007-01-01

    Full Text Available In this research the system for potentially customer classification is designed by extracting rule based classification from raw data with certain criteria. The searching process uses customer database from a bank with data mining technic by using ant colony optimization. A test based on min_case_per_rule variety and phenomene updating were done on a certain period of time. The result are group of customer class which base on rules built by ant and by modifying the pheromone updating, the area of the case is getting bigger. Prototype of the software is coded with C++ 6 version. The customer database master is created by using Microsoft Access. This paper gives information about potential customer of bank that can be classified by prototype of the software. Abstract in Bahasa Indonesia : Pada penelitian untuk sistem klasifikasi potensial customer ini didesain dengan melakukan ekstrak rule berdasarkan klasifikasi dari data mentah dengan kriteria tertentu. Proses pencarian menggunakan database pelanggan dari suatu bank dengan teknik data mining dengan ant colony optimization. Dilakukan percobaan dengan min_case_per_rule variety dan phenomene updating pada periode waktu tertentu. Hasilnya adalah sekelompok class pelanggan yang didasarkan dari rules yang dibangun dengan ant dan dengan dimodifikasi dengan pheromone updating, area permasalahan menjadi lebih melebar. Prototype dari software ini menggunakan C++ versi 6. Database pelanggan dibangun dengan Microsoft Access. Paper ini memberikan informasi mengenai potensi pelanggan dari bank, sehingga dapat diklasifikasikan dengan prototype dari software. Kata kunci: ant colony optimization, classification, min_case_per_rule, term, pheromone updating

  18. Food-plant niche selection rather than the presence of ant nests explains oviposition patterns in the myrmecophilous butterfly genus Maculinea.

    Science.gov (United States)

    Thomas, J A; Elmes, G W

    2001-03-07

    It has been suggested that the socially parasitic butterfly Maculinea alcon detects ant odours before ovipositing on initial larval food plants near colonies of its obligate ant host Myrmica ruginodis. It has also been suggested that overcrowding on food plants near M. ruginodis is avoided by an ability to detect high egg loads, resulting in a switch to selecting plants near less suitable ant species. If confirmed, this hypothesis (H1) would have serious implications for the application of current population models aimed at the conservation of endangered Maculinea species, which are based on the null hypothesis (H0) that females randomly select food plants whose flower buds are at a precise phenological stage, making oviposition independent of ants. If H1 were wrong, practical management based upon its assumptions could lead to the extinction of protected populations. We present data for the five European species of Maculinea which show that (i) each oviposits on a phenologically restricted flower-bud stage, which accounts for the apparent host-ant-mediated niche separation in sympatric populations of Maculinea nausithous and Maculinea teleius, (ii) there is no temporal shift in oviposition by Maculinea arion in relation to host ant distribution or egg density, and (iii) oviposition patterns in 13 populations of M. alcon's closest relative, Macaulinea rebeli, conform to H0 not H1 predictions. It is concluded that conservation measures should continue to be based on H0.

  19. Channeler Ant Model: 3 D segmentation of medical images through ant colonies

    International Nuclear Information System (INIS)

    Fiorina, E.; Valzano, S.; Arteche Diaz, R.; Bosco, P.; Gargano, G.; Megna, R.; Oppedisano, C.; Massafra, A.

    2011-01-01

    In this paper the Channeler Ant Model (CAM) and some results of its application to the analysis of medical images are described. The CAM is an algorithm able to segment 3 D structures with different shapes, intensity and background. It makes use of virtual and colonies and exploits their natural capabilities to modify the environment and communicate with each other by pheromone deposition. Its performance has been validated with the segmentation of 3 D artificial objects and it has been already used successfully in lung nodules detection on Computer Tomography images. This work tries to evaluate the CAM as a candidate to solve the quantitative segmentation problem in Magnetic Resonance brain images: to evaluate the percentage of white matter, gray matter and cerebrospinal fluid in each voxel.

  20. Imported fire ants near the edge of their range: disturbance and moisture determine prevalence and impact of an invasive social insect.

    Science.gov (United States)

    LeBrun, Edward G; Plowes, Robert M; Gilbert, Lawrence E

    2012-07-01

    1. Habitat disturbance and species invasions interact in natural systems, making it difficult to isolate the primary cause of ecosystem degradation. A general understanding requires case studies of how disturbance and invasion interact across a variety of ecosystem - invasive species combinations. 2. Dramatic losses in ant diversity followed the invasion of central Texas by red imported fire ants (Solenopsis invicta). However, recent manipulative studies in Florida revealed no effect on ant diversity following the removal of S. invicta from a disturbed pasture habitat, but moderate loss of diversity associated with their introduction into undisturbed habitat and no invasion occurred without disturbance. Thus, the importance of S. invicta in driving diversity loss and its ability to invade undisturbed systems is unresolved. 3. We examine the distribution and abundance of a large monogyne S. invicta population and its association with the co-occurring ant assemblage at a site in south Texas close to the aridity tolerance limit of S. invicta. 4. We document that moisture modulates S. invicta densities. Further, soil disturbing habitat manipulations greatly increase S. invicta population densities. However, S. invicta penetrates all habitats regardless of soil disturbance history. In contrast, controlled burns depress S. invicta densities. 5. In habitats where S. invicta is prevalent, it completely replaces native fire ants. However, S. invicta impacts native ants as a whole less strongly. Intriguingly, native ants responded distinctly to S. invicta in different environments. In wet, undisturbed environments, high S. invicta abundance disrupts the spatial structure of the ant assemblage by increasing clumping and is associated with reduced species density, while in dry-disturbed habitats, sites with high S. invicta abundance possess high numbers of native species. Analyses of co-occurrence indicate that reduced species density in wet

  1. Regulation and specificity of antifungal metapleural gland secretion in leaf-cutting ants

    DEFF Research Database (Denmark)

    Yek, Sze Huei; Nash, David Richard; Jensen, Annette Bruun

    2012-01-01

    significantly larger for ants challenged with virulent and mild pathogens/weeds than for controls and Escovopsis-challenged ants. We conclude that the MG defence system of leaf-cutting ants has characteristics reminiscent of an additional cuticular immune system, with specific and non-specific components......Ants have paired metapleural glands (MGs) to produce secretions for prophylactic hygiene. These exocrine glands are particularly well developed in leaf-cutting ants, but whether the ants can actively regulate MG secretion is unknown. In a set of controlled experiments using conidia of five fungi...

  2. Effects of an African weaver ant, Oecophylla longinoda, in controlling mango fruit flies (Diptera: Tephritidae) in Benin.

    Science.gov (United States)

    Van Mele, Paul; Vayssières, Jean-François; Van Tellingen, Esther; Vrolijks, Jan

    2007-06-01

    Six mango, Mangifera indica L., plantations around Parakou, northern Benin, were sampled at 2-wk intervals for fruit fly damage from early April to late May in 2005. Mean damage ranged from 1 to 24% with a weaver ant, Oecophylla longinoda (Latreille), being either abundant or absent. The fruit fly complex is made up of Ceratitis spp. and Bactrocera invadens Drew et al., a new invasive species in West Africa. In 2006, Ceratitis spp. peaked twice in the late dry season in early April and early May, whereas B. invadens populations quickly increased at the onset of the rains, from mid-May onward. Exclusion experiments conducted in 2006 with 'Eldon', 'Kent', and 'Gouverneur' confirmed that at high ant abundance levels, Oecophylla significantly reduced fruit fly infestation. Although fruit fly control methods are still at an experimental stage in this part of the world, farmers who tolerated weaver ants in their orchard were rewarded by significantly better fruit quality. Conservation biological control with predatory ants such as Oecophylla in high-value tree crops has great potential for African and Asian farmers. Implications for international research for development at the Consultative Group on International Agricultural Research level are discussed.

  3. Serum macro minerals in adults Thoroughbred horses, before and after the high intensity exercise. Macrominerais séricos em equinos atletas da raça Puro Sangue Inglês, antes e após exercício físico de alta intensidade

    Directory of Open Access Journals (Sweden)

    Regina Kiomi Takahira

    2009-12-01

    Full Text Available With the aim of analyzing the effect of high intensity physical activity on the serum values of macro minerals, 19 clinically health adults Thoroughbred horses, males and females from 3 to 5 years of age, were submitted to a galloping in a 2,000 meters sand track. Two blood samples were collected from each animal, one before and another after the high intensity exercise. The results had shown some significative changes (p<0.05 with an increase in the serum values of calcium and magnesium and a decrease in serum and potassium. Meanwhile, there were no alterations (p>0.05 in the concentration of phosphorus and potassium. It is concluded, therefore, that the high intensity exercise leads to transitory and physiologic changes in the serum concentration of macro minerals.Com o objetivo de analisar o efeito da atividade física de alta intensidade sobre os valores séricos dos macrominerais, 19 equinos adultos, com idade entre três e cinco anos, machos e fêmeas, clinicamente saudáveis da raça Puro Sangue Inglês, foram submetidos ao galope de corrida em pistas de areia, na distância de 2000 metros. De cada animal foram colhidas duas amostras de sangue, uma antes e outra após a realização do exercício físico de alta intensidade. A análise dos resultados obtidos demonstrou que houve alterações significativas nos valores séricos do cálcio e magnésio, que apresentaram elevação, e do sódio e cloreto, que apresentaram redução, enquanto não foram verificadas variações significativas nos teores séricos do fósforo e potássio. Conclui-se, portanto, que a atividade física de alta intensidade (galope de corrida altera, transitória e fisiologicamente, a concentração sérica dos macrominerais.

  4. Application of chaotic ant swarm optimization in electric load forecasting

    International Nuclear Information System (INIS)

    Hong, W.-C.

    2010-01-01

    Support vector regression (SVR) had revealed strong potential in accurate electric load forecasting, particularly by employing effective evolutionary algorithms to determine suitable values of its three parameters. Based on previous research results, however, these employed evolutionary algorithms themselves have several drawbacks, such as converging prematurely, reaching slowly the global optimal solution, and trapping into a local optimum. This investigation presents an SVR-based electric load forecasting model that applied a novel algorithm, namely chaotic ant swarm optimization (CAS), to improve the forecasting performance by searching its suitable parameters combination. The proposed CAS combines with the chaotic behavior of single ant and self-organization behavior of ant colony in the foraging process to overcome premature local optimum. The empirical results indicate that the SVR model with CAS (SVRCAS) results in better forecasting performance than the other alternative methods, namely SVRCPSO (SVR with chaotic PSO), SVRCGA (SVR with chaotic GA), regression model, and ANN model.

  5. Social isolation and brain development in the ant Camponotus floridanus.

    Science.gov (United States)

    Seid, Marc A; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  6. Antígonas. Una visión intertextual

    Directory of Open Access Journals (Sweden)

    Elena Cano Turrión

    2011-04-01

    Full Text Available In this article and from an intertextual point of view, we will try to examine how theSophoclean hypotext has generated three very different hypertexts. The first one is the short story“Antígona o la elección” by M. Yourcenar, which goes further the religious motivation in the originaltext; then, there is an essay written as a dialogue by Maria Zambrano, entitled La tumba de Antígonawhich main topics are confrontation against power, lack of freedom and destiny and faith in humanconscience. Finally, Luis Riaza’s Antígona…¡Cerda! Appears closer to its hypotext but at the same timesemantic deviation becomes more relevant.

  7. Effective ANT based Routing Algorithm for Data Replication in MANETs

    Directory of Open Access Journals (Sweden)

    N.J. Nithya Nandhini

    2013-12-01

    Full Text Available In mobile ad hoc network, the nodes often move and keep on change its topology. Data packets can be forwarded from one node to another on demand. To increase the data accessibility data are replicated at nodes and made as sharable to other nodes. Assuming that all mobile host cooperative to share their memory and allow forwarding the data packets. But in reality, all nodes do not share the resources for the benefits of others. These nodes may act selfishly to share memory and to forward the data packets. This paper focuses on selfishness of mobile nodes in replica allocation and routing protocol based on Ant colony algorithm to improve the efficiency. The Ant colony algorithm is used to reduce the overhead in the mobile network, so that it is more efficient to access the data than with other routing protocols. This result shows the efficiency of ant based routing algorithm in the replication allocation.

  8. Mating, hybridisation and introgression in Lasius ants (Hymenoptera: Formicidae)

    DEFF Research Database (Denmark)

    Van der Have, Tom; Pedersen, Jes Søe; Boomsma, Jacobus Jan

    2011-01-01

    Recent reviews have shown that hybridisation among ant species is likely to be more common than previously appreci-ated, but that documented cases of introgression remain rare. After molecular phylogenetic work had shown that Euro-pean Lasius niger (LINNAEUS, 1758) and L. psammophilus SEIFERT, 1992...... (formerly L. alienus (FOERSTER, 1850)) are unlikely to be very closely related, we decided to analyse an old data set confirming the conclusion by PEARSON (1983) that these two ants can indeed form viable hybrids. We show that signatures of introgression can be detected in a Danish site...... sympatrically. This would imply that multiple accessible field sites are available to study the molecular details of hybridisation and in-trogression between two ant species that have variable degrees of sympatry throughout their distributional ranges...

  9. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan

    2011-01-01

    hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...... classes. Remarkably, the single symbiont that is shared by species of the crown group of Atta and Acromyrmex leaf-cutting ants mostly showed metalloproteinase activity, suggesting that recurrent changes in enzyme production may have occurred throughout the domestication history of fungus-garden symbionts......Background: Attine ants live in symbiosis with a basidiomycetous fungus that they rear on a substrate of plant material. This indirect herbivory implies that the symbiosis is likely to be nitrogen deprived, so that specific mechanisms may have evolved to enhance protein availability. We therefore...

  10. Comparative Immature Morphology of Brazilian Fire Ants (Hymenoptera: Formicidae: Solenopsis

    Directory of Open Access Journals (Sweden)

    Eduardo Gonçalves Paterson Fox

    2012-01-01

    Full Text Available Although common in Brazil, the biology of the fire ant Solenopsis saevissima (Smith is still poorly studied. Larval descriptions are useful to genus-level ant systematics and sometimes to species-level taxonomy. This study presents a detailed description of juveniles of S. saevissima from Brazil, which were compared with Brazilian specimens of Solenopsis invicta Buren, Solenopsis geminata (Fabricius, and Solenopsis altipunctata Pitts. Different larval instars were separated by diagnostic morphological traits which were confirmed by observing moults. Reproductive larvae could be easily sorted by their distinctive body dimensions and shape. Contrary to previous reports on this species, the larvae of S. saevissima proved to be generally identical to those of S. invicta, while a few specimens resembled those of other close species, such as Solenopsis megergates Trager. Mature larvae thus presented considerable intraspecific variation in some characters recently proposed to aid fire ant species separation (morphology of head hairs.

  11. Social context predicts recognition systems in ant queens

    DEFF Research Database (Denmark)

    Dreier, Stéphanie Agnès Jeanine; d'Ettorre, Patrizia

    2009-01-01

    Recognition of group-members is a key feature of sociality. Ants use chemical communication to discriminate nestmates from intruders, enhancing kin cooperation and preventing parasitism. The recognition code is embedded in their cuticular chemical profile, which typically varies between colonies....... We predicted that ants might be capable of accurate recognition in unusual situations when few individuals interact repeatedly, as new colonies started by two to three queens. Individual recognition would be favoured by selection when queens establish dominance hierarchies, because repeated fights...... for dominance are costly; but it would not evolve in absence of hierarchies. We previously showed that Pachycondyla co-founding queens, which form dominance hierarchies, have accurate individual recognition based on chemical cues. Here, we used the ant Lasius niger to test the null hypothesis that individual...

  12. Natural selection drives the evolution of ant life cycles.

    Science.gov (United States)

    Wilson, Edward O; Nowak, Martin A

    2014-09-02

    The genetic origin of advanced social organization has long been one of the outstanding problems of evolutionary biology. Here we present an analysis of the major steps in ant evolution, based for the first time, to our knowledge, on combined recent advances in paleontology, phylogeny, and the study of contemporary life histories. We provide evidence of the causal forces of natural selection shaping several key phenomena: (i) the relative lateness and rarity in geological time of the emergence of eusociality in ants and other animal phylads; (ii) the prevalence of monogamy at the time of evolutionary origin; and (iii) the female-biased sex allocation observed in many ant species. We argue that a clear understanding of the evolution of social insects can emerge if, in addition to relatedness-based arguments, we take into account key factors of natural history and study how natural selection acts on alleles that modify social behavior.

  13. Native supercolonies of unrelated individuals in the invasive Argentine ant

    DEFF Research Database (Denmark)

    Pedersen, Jes Søe; Krieger, Michael J. B.; Vogel, Valérie

    2006-01-01

    organization is not only a key attribute responsible for the ecological dominance of these ants, but also an evolutionary paradox because relatedness between nestmates is effectively zero. Recently, it has been proposed that, in the Argentine ant, unicoloniality is a derived trait that evolved after its......Kinship among group members has long been recognized as a main factor promoting the evolution of sociality and reproductive altruism, yet some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social...... with related individuals who are aggressive toward members of other colonies, we found that native populations also form supercolonies, and are effectively unicolonial. Moreover, just as in introduced populations, the relatedness between nestmates is not distinguishable from zero in these native range...

  14. Ants at Ton Nga Chang Wildlife Sanctuary, Songkhla

    Directory of Open Access Journals (Sweden)

    Watanasit, S.

    2005-03-01

    Full Text Available The aim of this study was to investigate diversity of ant at Ton Nga Chang Wildlife Sanctuary, Hat Yai, Songkhla. Three line transects (100 m each were randomly set up in 2 types of forest area, disturbed and undisturbed. Hand collecting (HC and leaf litter sampling (LL were applied for ant collection within a time limit of 30 minutes for each method. This study was carried out every month during Febuary 2002- Febuary 2003. The results showed that 206 species were placed under 8 subfamilies: Aenictinae, Cerapachyinae, Dolichoderinae, Formicinae, Leptanillinae, Myrmicinae, Ponerinae and Pseudomyrmecinae. Study sites and collection methods could divide ant species into 2 groups, whereas seasonal change could not distinguish the groups by DCA of multivariate analysis.

  15. Social isolation and brain development in the ant Camponotus floridanus

    Science.gov (United States)

    Seid, Marc A.; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  16. EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS

    DEFF Research Database (Denmark)

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G

    2010-01-01

    an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across...... the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens...... are targeted primarily towards partial degradation of plant cell walls, reflecting a plesiomorphic state of non-domesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major...

  17. Pericarpial nectary-visiting ants do not provide fruit protection against pre-dispersal seed predators regardless of ant species composition and resource availability.

    Directory of Open Access Journals (Sweden)

    Priscila Andre Sanz-Veiga

    Full Text Available Extrafloral nectaries can occur in both vegetative and reproductive plant structures. In many Rubiaceae species in the Brazilian Cerrado, after corolla abscission, the floral nectary continues to secret nectar throughout fruit development originating post-floral pericarpial nectaries which commonly attract many ant species. The occurrence of such nectar secreting structures might be strategic for fruit protection against seed predators, as plants are expected to invest higher on more valuable and vulnerable parts. Here, we performed ant exclusion experiments to investigate whether the interaction with ants mediated by the pericarpial nectaries of Tocoyena formosa affects plant reproductive success by reducing the number of pre-dispersal seed predators. We also assessed whether ant protection was dependent on ant species composition and resource availability. Although most of the plants were visited by large and aggressive ant species, such as Ectatomma tuberculatum and species of the genus Camponotus, ants did not protect fruits against seed predators. Furthermore, the result of the interaction was neither related to ant species composition nor to the availability of resources. We suggest that these results may be related to the nature and behavior of the most important seed predators, like Hemicolpus abdominalis weevil which the exoskeleton toughness prevent it from being predated by most ant species. On the other hand, not explored factors, such as reward quality, local ant abundance, ant colony characteristics and/or the presence of alternative energetic sources could also account for variations in ant frequency, composition, and finally ant protective effects, highlighting the conditionality of facultative plant-ant mutualisms.

  18. Agricultural matrices affect ground ant assemblage composition inside forest fragments.

    Directory of Open Access Journals (Sweden)

    Diego Santana Assis

    Full Text Available The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates; sugarcane (3; and pasture (3. At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart. Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

  19. Agricultural matrices affect ground ant assemblage composition inside forest fragments.

    Science.gov (United States)

    Assis, Diego Santana; Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Barrios-Rojas, Katty Elena; Majer, Jonathan David; Vilela, Evaldo Ferreira

    2018-01-01

    The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

  20. Characterization of actinobacteria associated with three ant-plant mutualisms.

    Science.gov (United States)

    Hanshew, Alissa S; McDonald, Bradon R; Díaz Díaz, Carol; Djiéto-Lordon, Champlain; Blatrix, Rumsaïs; Currie, Cameron R

    2015-01-01

    Ant-plant mutualisms are conspicuous and ecologically important components of tropical ecosystems that remain largely unexplored in terms of insect-associated microbial communities. Recent work has revealed that ants in some ant-plant systems cultivate fungi (Chaetothyriales) within their domatia, which are fed to larvae. Using Pseudomyrmex penetrator/Tachigali sp. from French Guiana and Petalomyrmex phylax/Leonardoxa africana and Crematogaster margaritae/Keetia hispida, both from Cameroon, as models, we tested the hypothesis that ant-plant-fungus mutualisms co-occur with culturable Actinobacteria. Using selective media, we isolated 861 putative Actinobacteria from the three systems. All C. margaritae/K. hispida samples had culturable Actinobacteria with a mean of 10.0 colony forming units (CFUs) per sample, while 26 % of P. penetrator/Tachigali samples (mean CFUs 1.3) and 67 % of P. phylax/L. africana samples (mean CFUs 3.6) yielded Actinobacteria. The largest number of CFUs was obtained from P. penetrator workers, P. phylax alates, and C. margaritae pupae. 16S rRNA gene sequencing and phylogenetic analysis revealed the presence of four main clades of Streptomyces and one clade of Nocardioides within these three ant-plant mutualisms. Streptomyces with antifungal properties were isolated from all three systems, suggesting that they could serve as protective symbionts, as found in other insects. In addition, a number of isolates from a clade of Streptomyces associated with P. phylax/L. africana and C. margaritae/K. hispida were capable of degrading cellulose, suggesting that Streptomyces in these systems may serve a nutritional role. Repeated isolation of particular clades of Actinobacteria from two geographically distant locations supports these isolates as residents in ant-plant-fungi niches.

  1. Plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense.

    Science.gov (United States)

    Mooney, Kailen A; Agrawal, Anurag A

    2008-06-01

    Little is known about the mechanisms by which plant genotype shapes arthropod community structure. In a field experiment, we measured the effects of milkweed (Asclepias syriaca) genotype and ants on milkweed arthropods. Populations of the ant-tended aphid Aphis asclepiadis and the untended aphid Myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. There was no milkweed effect on predatory arthropods. Ants increased Aphis abundance 59%, decreased Myzocallis abundance 52%, and decreased predator abundance 56%. Milkweed genotype indirectly influenced ants via direct effects on Aphis and Myzocallis abundance. Milkweed genotype also modified ant-aphid interactions, influencing the number of ants attracted per Aphis and Myzocallis. While ant effects on Myzocallis were consistently negative, effects on Aphis ranged from antagonistic to mutualistic among milkweed genotypes. As a consequence of milkweed effects on ant-aphid interactions, ant abundance varied 13-fold among milkweed genotypes, and monarch caterpillar survival was negatively correlated with genetic variation in ant abundance. We speculate that heritable variation in milkweed phloem sap drives these effects on aphids, ants, and caterpillars. In summary, milkweed exerts genetic control over the interactions between aphids and an ant that provides defense against foliage-feeding caterpillars.

  2. Intrapopulation differences in ant eating in the mountain gorillas of Bwindi Impenetrable National Park, Uganda.

    Science.gov (United States)

    Ganas, Jessica; Robbins, Martha M

    2004-10-01

    Variability in ant eating has been observed in several populations of eastern and western gorillas. We investigated the occurrence of ant (Dorylus sp.) eating in two groups of mountain gorillas (Gorilla beringei beringei) with overlapping home ranges within Bwindi Impenetrable National Park, Uganda from September 2001 to August 2002. We calculated the frequency of ant eating by an indirect method of analyzing fecal samples from silverbacks, adult females, and juveniles. One group consumed ants significantly more often than the other (3.3 vs 17.6% of days sampled). Furthermore, the group that consumed ants more often also consumed them on a seasonal basis (September-February monthly range: 0-8%; March-August monthly range: 30-42.9%). Finally, females and juveniles of this group consumed ants significantly more often than did the silverback (total samples containing ants: silverback, 2.1%; adult female, 13.2%; juvenile, 11.2%). Differences in ant eating between groups are likely due to variability in use of habitats where ants occur (particularly secondary forests). Surveys of ant densities in differing habitats, nutritional analysis of ants, and quantification of the amount of ants in their diets are necessary to understand if ant consumption is due to availability, nutritional value, group traditions, or taste preference.

  3. Five new records of ants (Hymenoptera: Formicidae) from Morocco.

    Science.gov (United States)

    Taheri, Ahmed; Reyes-López, Joaquin L

    2015-01-01

    A recent catalogue of the rich ant fauna of Morocco included 214 species, with later studies adding an additional 12 species. Following recent fieldwork in the north of Morocco, we report five new records for the country (Plagiolepis pygmaea Latreille, 1798, Ponera testacea Emery, 1895, Strumigenys tenuipilis Emery, 1915, Temnothorax pardoi Tinaut, 1987, and Tetramorium parvioculum Guillem & Bensusan, 2009) and we present new data on the distribution and natural history of six additional species. This work brings the total number of ants known from Morocco to 233, taking into account two species which were omitted in the list of Cagniant. © Crown copyright 2015.

  4. Core Business Selection Based on Ant Colony Clustering Algorithm

    Directory of Open Access Journals (Sweden)

    Yu Lan

    2014-01-01

    Full Text Available Core business is the most important business to the enterprise in diversified business. In this paper, we first introduce the definition and characteristics of the core business and then descript the ant colony clustering algorithm. In order to test the effectiveness of the proposed method, Tianjin Port Logistics Development Co., Ltd. is selected as the research object. Based on the current situation of the development of the company, the core business of the company can be acquired by ant colony clustering algorithm. Thus, the results indicate that the proposed method is an effective way to determine the core business for company.

  5. Significance of chemical recognition cues is context dependent in ants

    DEFF Research Database (Denmark)

    Bos, N.; Guerrieri, F.J.; d'Ettorre, P.

    2010-01-01

    signatures, composed primarily of long-chain cuticular hydrocarbons. These signatures are colony specific and allow discrimination between nestmates and non-nestmates. Nevertheless, the mechanisms underlying detection, perception and information processing of chemical signatures are poorly understood. It has...... context, affects aggression against non-nestmates carrying the hydrocarbon profile associated with food. Individual ant workers were able to associate the non-nestmate chemical profile with food. However, conditioned ants were still aggressive when encountering a non-nestmate carrying the odour profile...

  6. Mutualistic fungi control crop diversity in fungus-growing ants

    DEFF Research Database (Denmark)

    Poulsen, Michael; Boomsma, Jacobus J

    2005-01-01

    Leaf-cutting ants rear clonal fungi for food and transmit the fungi from mother to daughter colonies so that symbiont mixing and conflict, which result from competition between genetically different clones, are avoided. Here we show that despite millions of years of predominantly vertical...... transmission, the domesticated fungi actively reject mycelial fragments from neighboring colonies, and that the strength of these reactions are in proportion to the overall genetic difference between these symbionts. Fungal incompatibility compounds remain intact during ant digestion, so that fecal droplets...

  7. Are queen ants inhibited by their own pheromone?

    DEFF Research Database (Denmark)

    Holman, L.; Leroy, C.; Jørgensen, Charlotte

    2013-01-01

    . Communication in social insects is predominantly chemical, and the mechanisms regulating processes such as reproductive division of labor are becoming increasingly well understood. Recently, a queen cuticular hydrocarbon (3-MeC31) that inhibits worker reproduction and aggression was isolated in the ant Lasius...... niger. Here, we find that this pheromone also has a weak negative effect on queen productivity and oogenesis. Because 3-MeC31 is present on both queens and their brood, we suggest that it is used by ants of both castes to adjust their fecundity to the amount of developing brood and the presence of other...

  8. Sperm storage induces an immunity cost in ants

    DEFF Research Database (Denmark)

    Baer, Boris; Armitage, Sophie A O; Boomsma, Jacobus J

    2006-01-01

    Ant queens are among the most long-lived insects known. They mate early in adult life and maintain millions of viable sperm in their sperm storage organ until they die many years later. Because they never re-mate, the reproductive success of queens is ultimately sperm-limited, but it is not known...... what selective forces determine the upper limit to sperm storage. Here we show that sperm storage carries a significant cost of reduced immunity during colony founding. Newly mated queens of the leaf-cutting ant Atta colombica upregulate their immune response shortly after completing their nest burrow...

  9. The search rate of the African weaver ant in cashew

    DEFF Research Database (Denmark)

    Henriksen, Signe; Axelsen, Jørgen Aagaard; Lemming, Katrine Hansen

    2015-01-01

    Oecophylla longinoda is a species of eusocial colony living ants that prey upon other insects to feed their larva. Many of these insects are considered pests. An ecosystem model of the interactions between an O. longinoda colony and its potential prey is under construction by the team behind...... this article, and it is unknown which functional response equations are useful for eusocial insect colonies. We investigated the search rate of O. longinoda using artificial feeding experiments in a Tanzanian cashew (Anacardium occidentale L.) orchard to determine the search efficiency of the ants...

  10. Sex-specific kleptoparasitic foraging in ant-eating spiders

    DEFF Research Database (Denmark)

    Martisová, Martina; Bilde, T.; Pekar, Stano

    2009-01-01

    . To investigate this hypothesis, we studied the effect of sex and life history stage on the frequency of kleptoparasitism in ant-eating spiders of the genus Zodarion in the field. These spiders use a special capture technique involving a quick attack on an ant that is left unguarded by spiders for several minutes......, providing ample opportunities for kleptoparasitism. We found that adult females consistently hunted actively, while adult males ceased active prey capture and instead engaged in kleptoparasitism. Juvenile spiders were active hunters irrespective of sex. Consistent with an ontogenetic shift in foraging...

  11. Industrious leaf cutter ants and their carbon footprints

    Science.gov (United States)

    Swanson, A. C.; Dierick, D.; Trahan, N. A.; Allen, M. F.; Schwendenmann, L.; Harmon, T. C.; Oberbauer, S. F.; Fernandez Bou, A. S.; Zelikova, T. J.

    2017-12-01

    Leaf cutter ants (LCA) are considered ecosystem engineers in Neotropical forest ecosystems because they alter physical and environmental conditions for other organisms. LCA excavate large underground nests, maintaining intricate tunnels and fungal and waste chambers, and they continuously bring in vast amounts of fresh leaf material. In order to understand their ecosystem-wide impacts, we set out to determine whether their engineering activities fundamentally alter soil structure, soil nutrient pools, and gas fluxes in a wet tropical rainforest in Costa Rica. To directly compare LCA nest to non-nest sites, we utilized embedded sensor arrays with series of soil moisture, CO2, O2, and temperature sensors placed at four soil depths and automated minirhizotrons (AMR) to measure root and hyphal production and turnover. We also collected soils for biogeochemical analyses and measured soil CO2 fluxes and carbon isotope ratios of below-ground CO2 for two years. Our measurements confirmed that LCA alter their soil environment to regulate internal soil CO2 concentrations, moisture, and temperature, increasing O2 concentrations in the process. There were marked differences in soil structure inside nests relative to non-nests and these were associated with increased root and hyphal production and turnover in nests. Soil C, N, P, and their respective degrading enzymes were highly variable among sites and between nests and controls but N and P increased with soil depth and were generally higher in nests than controls. Contrary to our expectations, C mineralization rates were lower in nests but CO2 fluxes were high from nest vents and similar to non-nests elsewhere. At the system scale, LCA appear to fundamentally change the soil environment inside their nests and create spatial heterogeneity in biogeochemical processes and root and hyphal growth, influencing the overall C balance of Neotropical forests.

  12. Conflict over reproduction in an ant-plant symbiosis: why Allomerus octoarticulatus ants sterilize Cordia nodosa trees.

    Science.gov (United States)

    Frederickson, Megan E

    2009-05-01

    The evolutionary stability of mutualism is thought to depend on how well the fitness interests of partners are aligned. Because most ant-myrmecophyte mutualisms are persistent and horizontally transmitted, partners share an interest in growth but not in reproduction. Resources invested in reproduction are unavailable for growth, giving rise to a conflict of interest between partners. I investigated whether this explains why Allomerus octoarticulatus ants sterilize Cordia nodosa trees. Allomerus octoarticulatus nests in the hollow stem domatia of C. nodosa. Workers protect C. nodosa leaves against herbivores but destroy inflorescences. Using C. nodosa trees with Azteca ants, which do not sterilize their hosts, I cut inflorescences off trees to simulate sterilization by A. octoarticulatus. Sterilized C. nodosa grew faster than control trees, providing evidence for a trade-off between growth and reproduction. Allomerus octoarticulatus manipulates this trade-off to its advantage; sterilized trees produce more domatia and can house larger, more fecund colonies.

  13. Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii

    Science.gov (United States)

    Gutrich, J.J.; VanGelder, E.; Loope, L.

    2007-01-01

    Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA. ?? 2007 Elsevier Ltd. All rights reserved.

  14. Comparison of Ant Community Diversity and Functional Group Composition Associated to Land Use Change in a Seasonally Dry Oak Forest.

    Science.gov (United States)

    Cuautle, M; Vergara, C H; Badano, E I

    2016-04-01

    Ants have been used to assess land use conversion, because they reflect environmental change, and their response to these changes have been useful in the identification of bioindicators. We evaluated ant diversity and composition associated to different land use change in a temperate forest (above 2000 m asl) in Mexico. The study was carried out in "Flor del Bosque" Park a vegetation mosaic of native Oak Forests and introduced Eucalyptus and grasslands. Species richness, dominance and diversity rarefaction curves, based on ant morphospecies and functional groups, were constructed and compared among the three vegetation types, for the rainy and the dry seasons of 2008-2009. Jaccard and Sorensen incidence-based indices were calculated to obtain similarity values among all the habitats. The Oak Forest was a rich dominant community, both in species and functional groups; the Eucalyptus plantation was diverse with low dominance. The most seasonality habitat was the grassland, with low species and high functional group diversity during the dry seasons, but the reverse pattern during the wet season. The Oak Forest was more similar to the Eucalyptus plantation than to the grassland, particularly during the dry season. Oak Forests are dominated by Cold Climate Specialists, specifically Prenolepis imparis (Say). The Eucalyptus and the grassland are characterized by generalized Myrmicinae, as Pheidole spp. and Monomorium ebenium (Forel). The conservation of the native Oak Forest is primordial for the maintenance of Cold Climate Specialist ant communities. The microclimatic conditions in this forest, probably, prevented the invasion by opportunistic species.

  15. First evidence for slave rebellion: enslaved ant workers systematically kill the brood of their social parasite protomognathus americanus.

    Science.gov (United States)

    Achenbach, Alexandra; Foitzik, Susanne

    2009-04-01

    During the process of coevolution, social parasites have evolved sophisticated strategies to exploit the brood care behavior of their social hosts. Slave-making ant queens invade host colonies and kill or eject all adult host ants. Host workers, which eclose from the remaining brood, are tricked into caring for the parasite brood. Due to their high prevalence and frequent raids, following which stolen host broods are similarly enslaved, slave-making ants exert substantial selection upon their hosts, leading to the evolution of antiparasite adaptations. However, all host defenses shown to date are active before host workers are parasitized, whereas selection was thought to be unable to act on traits of already enslaved hosts. Yet, here we demonstrate the rebellion of enslaved Temnothorax workers, which kill two-thirds of the female pupae of the slave-making ant Protomognathus americanus. Thereby, slaves decrease the long-term parasite impact on surrounding related host colonies. This novel antiparasite strategy of enslaved workers constitutes a new level in the coevolutionary battle after host colony defense has failed. Our discovery is analogous to recent findings in hosts of avian brood parasites where perfect mimicry of parasite eggs leads to the evolution of chick recognition as a second line of defense.

  16. How much variation can one ant species hold? Species delimitation in the Crematogaster kelleri-group in Madagascar.

    Directory of Open Access Journals (Sweden)

    Bonnie B Blaimer

    Full Text Available We investigated the species-level taxonomy of the Malagasy Crematogaster (Crematogaster kelleri-group and an additional more distantly related species of the same subgenus. Morphological data from worker, queen and male ants, as well as genetic data from three nuclear genes (long wavelength rhodopsin, arginine kinase and carbomoylphosphate synthase and one mitochondrial marker (cytochrome oxidase I led to the recognition of six species. Within the C. kelleri-group, three new species are described: C. hazolava Blaimer sp. n., C. hafahafa Blaimer sp. n. and C. tavaratra Blaimer sp. n. The previously described taxa C. kelleri Forel and C. madagascariensis André are validated by our analysis. Conversely, our data suggests synonymy of C. adrepens Forel (with C. kelleri and C. gibba Emery (with C. madagascariensis. A more distantly related and phylogenetically isolated species, C. tsisitsilo Blaimer sp. n., is further described. We report high levels of morphological and molecular variation in C. kelleri and illustrate that this variation can be explained partly by geography. Species descriptions, images, distribution maps and identification keys based on worker ants, as well as on queen and male ants where available, are presented for all six species. Our work highlights the elevated species richness of Crematogaster ants throughout Madagascar's humid forests, especially in the far northern tip of the island, and the need to use multiple data sources to ensure clear demarcation of this diversity.

  17. The genomic impact of 100 million years of social evolution in seven ant species

    DEFF Research Database (Denmark)

    Gadau, Jürgen; Helmkampf, Martin; Nygaard, Sanne

    2012-01-01

    Ants (Hymenoptera, Formicidae) represent one of the most successful eusocial taxa in terms of both their geographic distribution and species number. The publication of seven ant genomes within the past year was a quantum leap for socio- and ant genomics. The diversity of social organization in ants...... between social and solitary insects, as well as among ant species. Altogether, these seven ant genomes open exciting new research avenues and opportunities for understanding the genetic basis and regulation of social species, and adaptive complex systems in general....... makes them excellent model organisms to study the evolution of social systems. Comparing the ant genomes with those of the honeybee, a lineage that evolved eusociality independently from ants, and solitary insects suggests that there are significant differences in key aspects of genome organization...

  18. Impact of imidacloprid on new queens of imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae)

    Science.gov (United States)

    Neonicotinoid insecticides are commonly used in managing pest ants, including the imported fire ant, Solenopsis invicta Buren. There is increasing evidence that neonicotinoid insecticides at sublethal concentrations have profound effects on social insects. However, the sublethal effect of neonicot...

  19. Founding weaver ant queens (Oecophylla longinoda) increase production and nanitic worker size when adopting non-nestmate pupae.

    Science.gov (United States)

    Ouagoussounon, Issa; Offenberg, Joachim; Sinzogan, Antonio; Adandonon, Appolinaire; Kossou, Dansou; Vayssières, Jean-François

    2015-01-01

    Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10-fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants.

  20. Live and let die: why fighter males of the ant Cardiocondyla kill each other but tolerate their winged rivals

    DEFF Research Database (Denmark)

    Anderson, Carl; Cremer, Sylvia Maria; Heinze, Jürgen

    2003-01-01

    alternative dispersal tactics, ants, Cardiocondyla, ergatoid males, fighting, male dimorphism, toleration......alternative dispersal tactics, ants, Cardiocondyla, ergatoid males, fighting, male dimorphism, toleration...

  1. Olfactory memory established during trophallaxis affects food search behaviour in ants

    OpenAIRE

    Provecho, Y.; Josens, R.

    2009-01-01

    Camponotus mus ants can associate sucrose and odour at the source during successive foraging cycles and use this memory to locate the nectar in the absence of other cues. These ants perform conspicuous trophallactic behaviour during recruitment while foraging for nectar. In this work, we studied whether Camponotus mus ants are able to establish this odour-sucrose association in the social context of trophallaxis and we evaluated this memory in another context previously experienced by the ant...

  2. Individual Rules for Trail Pattern Formation in Argentine Ants (Linepithema humile)

    OpenAIRE

    Perna, Andrea; Granovskiy, Boris; Garnier, Simon; Nicolis, Stamatios C.; Labédan, Marjorie; Theraulaz, Guy; Fourcassié, Vincent; Sumpter, David J. T.

    2012-01-01

    We studied the formation of trail patterns by Argentine ants exploring an empty arena. Using a novel imaging and analysis technique we estimated pheromone concentrations at all spatial positions in the experimental arena and at different times. Then we derived the response function of individual ants to pheromone concentrations by looking at correlations between concentrations and changes in speed or direction of the ants. Ants were found to turn in response to local pheromone concentrations,...

  3. [Comparison of eight screening tests for ant-HCV antibody].

    Science.gov (United States)

    Deguchi, Matsuo; Kagita, Masanori; Yamashita, Naoko; Nakano, Takasi; Tahara, Kazuko; Asari, Seishi; Iwatani, Yoshinori

    2002-09-01

    We compared eight HCV screening tests for detection of anti-HCV antibody; Ortho Quick Chaser HCV Ab (QC), Ortho HCV Ab ELISA III (ELISA), Ortho HVC Ab PA test III (PA), Lumipulse II Ortho HCV (LUMI), IMx HCV.DAINAPACKII (IMx), ARCHITECT HCV (ARCH), Immucheck.F-HCV C50 Ab (Immu), RANREAM HCV Ab Ex II (RAN). Sera from six hundred patients were examined by these eight screening tests. The positive rates of the eight screening tests were from 9.0% to 13.2%. Forty-five sera showed discrepant results between the eight screening tests, and about half of them showed weak positive reaction and/or false positive. Twenty-five of the forty-five sera were negative for ant-HCV antibody in the CHIRON RIBA III confirmatory test, and forty-four of them were negative for HCV-RNA in the PCR method. The agreement rates between the two reagents were from 95.5% to 99.2%, but were not always high between the two reagents that used similar antigen. The specificities and sensitivities evaluated by using the RIBA III confirmatory test were excellent in ELISA, LUMI, IMx, ARCH and Immu. Three BBI seroconversion panels were used to compare the positive readings in the initial stage of HCV infection by eight screening tests. ELISA and ARCH showed the earliest positive readings, and then IMx, LUMI = RAN, PA, QC and Immu in this order. These findings indicate that ELISA and ARCH were the most excellent in the sensitivity, specificity and early diagnosis of HCV infection. However, we must pay attention to the weak positive reaction in the screening tests, because there is a possibility of "false positive".

  4. 9 CFR 381.71 - Condemnation on ante mortem inspection.

    Science.gov (United States)

    2010-01-01

    ... dressed, nor shall they be conveyed into any department of the official establishment where poultry... AGRICULTURE AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS Ante Mortem Inspection § 381.71...

  5. Application of ant colony optimisation in distribution transformer sizing

    African Journals Online (AJOL)

    This study proposes an optimisation method for transformer sizing in power system using ant colony optimisation and a verification of the process by MATLAB software. The aim is to address the issue of transformer sizing which is a major challenge affecting its effective performance, longevity, huge capital cost and power ...

  6. Formulation des betons autopla~ants : Optimisation du squelette ...

    African Journals Online (AJOL)

    Formulation des betons autopla~ants : Optimisation du squelette granulaire par la methode graphique de Dreux - Gorisse. Fatiha Boumaza - Zeraoulia* & Mourad Behim. Laboratoire Materiaux, Geo - Materiaux et Environnement - Departement de Genie Civil. Universite Badji Mokhtar Annaba - BP 12, 23000 Annaba - ...

  7. Ant and rattan associations in forest of tropical Africa | Sunderland ...

    African Journals Online (AJOL)

    Recent fieldwork aimed at increasing our knowledge of the taxonomy and ecology of African rattans has indicated that there is a significant relationship between these climbing palms and a number of ant species. A closer investigation into this relationship has found that the morphology of rattan palms is particularly ...

  8. Are workers of Atta leafcutter ants capable of reproduction?

    DEFF Research Database (Denmark)

    Dijkstra, Michiel Bendert; Boomsma, Jacobus Jan

    2006-01-01

    ovaries. Workers of Atta leafcutter ants only lay trophic eggs in queenright colonies. Although Atta colonies are commonly kept at universities, museums, and zoos, no reports of worker sons in orphaned colonies exist, suggesting that Atta workers are infertile. To explicitly test this, we created eleven...

  9. Does the afrotropical army ant Dorylus (Anomma) molestus go ...

    African Journals Online (AJOL)

    Swarm-raiding army ants are extremely polyphagous nomadic predators inhabiting tropical forests. They are considered keystone species because their raids can regulate the population dynamics of their prey and because a plethora of both invertebrate and vertebrate species are obligatorily or facultatively associated with ...

  10. Biogeography of Puerto Rican ants: a non-equilibrium case?

    Science.gov (United States)

    J.A. Torres; R.R. Snelling

    1997-01-01

    Ants were studied on Puerto Rico and 44 islands surrounding Puerto Rico. Habitat diversity was the best predictor of the number of species per island and the distributions of species followed a nested subset pattern. The number of extinctions per island was low, approximately 1 to 2 extinctions per island in a period of 18 years, and the rates of colonization seem to...

  11. Recurrent bridgehead effects accelerate global alien ant spread

    Science.gov (United States)

    Cleo Bertelsmeier; Sébastien Ollier; Andrew M. Liebhold; Eckehard G. Brockerhoff; Darren Ward; Laurent Keller

    2018-01-01

    Biological invasions are a major threat to biological diversity, agriculture, and human health. To predict and prevent new invasions, it is crucial to develop a better understanding of the drivers of the invasion process. The analysis of 4,533 border interception events revealed that at least 51 different alien ant species were intercepted at US ports over a period of...

  12. Ultrastructure of antennal sensillae of the samsum ant ...

    African Journals Online (AJOL)

    Jane

    2010-10-11

    Oct 11, 2010 ... subsequently may form the basis in producing its effective control measure in future. ... persons that may deteriorate into serious health condi- tions. ... with the behavioral ecology of ants (Faucheux et al.,. 2006) ... Basiconic type acts as food and CO2 receptor, trichoids ..... Sex pheromone perception in male.

  13. Energy Efficient Routing in Wireless Sensor Networks based on Ant ...

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... improved Ant System and their application in WSN routing process. The simulation results show ... and Mobile ad-hoc networks (MANETs) are inappropriate for ... Dorigo in 1992 in his PhD thesis, the first algorithm was aiming ...

  14. Irving Babbitti humanismi põhijooned / Ants Oras

    Index Scriptorium Estoniae

    Oras, Ants

    2003-01-01

    Varem ilmunud: rmt.: "Kultuuri ja teaduse teilt: mõtteid ja uurimusi Tartu Ülikooli 300-nda mälestusaasta puhuks". Tartu : Loodus, 1932, lk. 144-153 ; Ants Oras, "Irving Babbitt' i humanismi põhijooned: äratrükk koguteosest "Kultuuri ja teaduse teilt"". Tartu, 1932

  15. Ant-egg cataract. An electron microscopic study

    DEFF Research Database (Denmark)

    Schrøder, H D; Nissen, S H

    1979-01-01

    an intermittent growth of the structure. In the ant-eggs, as well as in some areas separate from these, membrane limited cytoplasmic bodies could be seen in many cases, the membranes of which were partly joint and partly separated by an electron dense material. It is suggested that the calcifications seen...

  16. Variability in individual activity bursts improves ant foraging success.

    Science.gov (United States)

    Campos, Daniel; Bartumeus, Frederic; Méndez, Vicenç; Andrade, José S; Espadaler, Xavier

    2016-12-01

    Using experimental and computational methods, we study the role of behavioural variability in activity bursts (or temporal activity patterns) for individual and collective regulation of foraging in A. senilis ants. First, foraging experiments were carried out under special conditions (low densities of ants and food and absence of external cues or stimuli) where individual-based strategies are most prevalent. By using marked individuals and recording all foraging trajectories, we were then able to precisely quantify behavioural variability among individuals. Our main conclusions are that (i) variability of ant trajectories (turning angles, speed, etc.) is low compared with variability of temporal activity profiles, and (ii) this variability seems to be driven by plasticity of individual behaviour through time, rather than the presence of fixed behavioural stereotypes or specialists within the group. The statistical measures obtained from these experimental foraging patterns are then used to build a general agent-based model (ABM) which includes the most relevant properties of ant foraging under natural conditions, including recruitment through pheromone communication. Using the ABM, we are able to provide computational evidence that the characteristics of individual variability observed in our experiments can provide a functional advantage (in terms of foraging success) to the group; thus, we propose the biological basis underpinning our observations. Altogether, our study reveals the potential utility of experiments under simplified (laboratory) conditions for understanding information-gathering in biological systems. © 2016 The Author(s).

  17. Ant Colony Optimization and the Minimum Cut Problem

    DEFF Research Database (Denmark)

    Kötzing, Timo; Lehre, Per Kristian; Neumann, Frank

    2010-01-01

    Ant Colony Optimization (ACO) is a powerful metaheuristic for solving combinatorial optimization problems. With this paper we contribute to the theoretical understanding of this kind of algorithm by investigating the classical minimum cut problem. An ACO algorithm similar to the one that was prov...

  18. Evolutionary transitions in enzyme activity of ant fungus gardens.

    Science.gov (United States)

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G; Boomsma, Jacobus J

    2010-07-01

    Fungus-growing (attine) ants and their fungal symbionts passed through several evolutionary transitions during their 50 million year old evolutionary history. The basal attine lineages often shifted between two main cultivar clades, whereas the derived higher-attine lineages maintained an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens are targeted primarily toward partial degradation of plant cell walls, reflecting a plesiomorphic state of nondomesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major breakdown of cell walls. The adaptive significance of the lower-attine symbiont shifts remains unclear. One of these shifts was obligate, but digestive advantages remained ambiguous, whereas the other remained facultative despite providing greater digestive efficiency.

  19. An object-oriented model for ex ante accounting information

    NARCIS (Netherlands)

    Verdaasdonk, P.J.A.

    2003-01-01

    Present accounting data models such as the Research-Event-Agent (REA) model merely focus on the modeling of static accounting phenomena. In this paper, it is argued that these models are not able to provide relevant ex ante accounting data for operations management decisions. These decisions require

  20. A model of ant route navigation driven by scene familiarity.

    Directory of Open Access Journals (Sweden)

    Bart Baddeley

    2012-01-01

    Full Text Available In this paper we propose a model of visually guided route navigation in ants that captures the known properties of real behaviour whilst retaining mechanistic simplicity and thus biological plausibility. For an ant, the coupling of movement and viewing direction means that a familiar view specifies a familiar direction of movement. Since the views experienced along a habitual route will be more familiar, route navigation can be re-cast as a search for familiar views. This search can be performed with a simple scanning routine, a behaviour that ants have been observed to perform. We test this proposed route navigation strategy in simulation, by learning a series of routes through visually cluttered environments consisting of objects that are only distinguishable as silhouettes against the sky. In the first instance we determine view familiarity by exhaustive comparison with the set of views experienced during training. In further experiments we train an artificial neural network to perform familiarity discrimination using the training views. Our results indicate that, not only is the approach successful, but also that the routes that are learnt show many of the characteristics of the routes of desert ants. As such, we believe the model represents the only detailed and complete model of insect route guidance to date. What is more, the model provides a general demonstration that visually guided routes can be produced with parsimonious mechanisms that do not specify when or what to learn, nor separate routes into sequences of waypoints.