Termites amplify effects of wood traits on decomposition rates among multiple bamboo and dicot woody species

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Liu, Guofang; Cornwell, W.K.; Cao, Kunfang; Hu, Yukun; van Logtestijn, R.S.P; Yang, Shijian; Xie, Xiufang; Zhang, Yalin; Ye, Duo; Pan, Xu; Ye, Xuehua; Huang, Zhenying; Dong, Ming; Cornelissen, J.H.C.

2015-01-01

Wood decomposition is a key process in the terrestrial carbon cycle, controlling carbon storage with feedback to climate. In (sub) tropical forest, termites are major players in wood decomposition, but their role relative to that of microbial decomposers and wood traits of different tree species is

Subterranean Termite Resistance of Polystyrene-Treated Wood from Three Tropical Wood Species

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Yusuf Sudo Hadi

2016-07-01

Full Text Available The objective of this work was to investigate the resistance of three Indonesian wood species to termite attack. Samples from sengon (Falcataria moluccana, mangium (Acacia mangium, and pine (Pinus merkusii were treated with polystyrene at loading levels of 26.0%, 8.6%, and 7.7%, respectively. Treated and untreated samples were exposed to environmental conditions in the field for 3 months. Untreated specimens of sengon, mangium, and pine had resistance ratings of 3.0, 4.6, and 2.4, respectively, based on a 10-point scale from 0 (no resistance to 10 (complete or near-complete resistance. Corresponding resistance values of 7.8, 7.2, and 8.2 were determined for specimens treated with polystyrene. Overall weight loss values of 50.3%, 23.3%, and 66.4% were found for untreated sengon, mangium, and pine samples, respectively; for treated samples, the values were 7.6%, 14.4%, and 5.1%, respectively. Based on the findings in this study, overall resistance to termite attack was higher for treated samples compared to untreated samples.

Production of wood vinegars from coconut shells and additional materials for control of termite workers, Odontotermes sp. and striped mealy bugs, Ferrisia virgata

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Sunan Wititsiri

2011-06-01

Full Text Available Coconut shells and coir are considered as wastes of coconut based products that have not been utilized efficiently.By using these abundant bioresources, which are widely available in Thailand, as raw materials, we were able to producewood vinegars that may be alternatives to termiticides and pesticides. The wood vinegars were obtained from carbonizationprocess using a 200-liter fuel tank as charcoal brazier under temperatures of 300-400°C. In this study, termiticidal and pesticidalactivities of wood vinegars were evaluated against termite workers, Odontotermes sp., and striped mealy bugs, Ferrisiavirgata, using direct contact application. Percent mortalities in the experiments were recorded after 24 hours and correctedfor control mortality with Abbott’s formula. Wood vinegars of 850, 696, and 898 milliliters were produced from coconut shell(wood vinegar A and the mixture of coconut shell and coir (wood vinegar B and the mixture of coconut shell, coir and holybasil (wood vinegar C, respectively. Wood vinegar A exhibited high termiticidal activity against termite workers at a dilutionof 1:50, wood vinegar: sterile water (v/v. By this way, 85% (81.71% corrected mortality of termite workers were killed afterthe 24 hours of test. At a dilution of 1:10, both wood vinegar A and B had exhibited high pesticidal activities against mealybugs, 96% (95.12% corrected mortality of striped mealy bugs were killed by those wood vinegars. In the weakest termiticidaland pesticidal activities, wood vinegar C was able to kill 60% (51.22% corrected mortality of termite workers at a dilution of1:50 within 24 hours. Also it killed 93% (91.89% corrected mortality of striped mealy bugs with a dilution of 1:10 (v/v withinthe same amount of time. Post-hoc comparisons (Tukey test revealed that wood vinegar A possessed the most effectivetermiticidal activity against termite workers. However, a similarity in high pesticidal activity was found among three woodvinegars

Pillotinas and hollandinas: distribution and behaviour of large spirochaetes symbiotic in termites.

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To, L; Margulis, L; Cheung, A T

1978-01-01

Pillotina spirochaetes have been observed in the hindguts of wood-eating cockroaches (Cryptocercus punctulatus), and in 25 out of 28 species of termites examined. They were especially abundant in 21 species of dry wood termites of the family Kalotermitidae, from Europe, North America and Australia. These included many species of Kalotermes and one or a few of the following: Glyptotermes, Bifidotermes, Neotermes, Ceratokalotermes, Paraneotermes, Cryptotermes, Porotermes, Marginitermes, Pterotermes, Zootermopsis, Reticulitermes, Coptotermes, Heterotermes, and nasutitermitids. Identifications of pillotinas were made on the basis of large size (0.5--2 micromtere in diameter, 50 to greater than 100 micrometers in length) and wave pattern; these were verified by electron microscopy in K. schwarzi, Pterotermes occidentis and others. Pillotinas were also present in all species of subterranean termites (Family Rhinotermitidae) examined, and in the most primitive Australian termite, Mastotermes darwiniensis (Family Mastotermitidae). They were not observed in damp wood termites (Family Hodotermidiae). Pillotinas are invariably associated with a rich, complex xylophagous microbial community composed primarily of motile prokaryotes, and hypermastigote and polymastigote flagellates. Some have been previously described by those primarily concerned with termite hindgut protozoa. Observations were made on their modes of behaviour, division, and microbial associates. A new genus of spirochaetes, Hollandina, is also described. It is distinguished from Pillotina by a smaller size and several ultrastructural features, but is otherwise closely related taxonomically. Evidence is provided to support Hollande and Gharagozlou's (1967) concept that the pillotinas and hollandinas deserve the taxonomic status of 'family' and that they should be classified with the cristispire siprochaetes a-cording to the scheme developed by Hovind-Hougen (1976). Spirochaetes are treated as a Phylum of the

Metagenomic and functional analysis of hindgut microbiota of a wood-feeding higher termite

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Warnecke, Falk; Warnecke, Falk; Luginbuhl, Peter; Ivanova, Natalia; Ghassemian, Majid; Richardson, Toby H.; Stege, Justin T.; Cayouette, Michelle; McHardy, Alice C.; Djordjevic, Gordana; Aboushadi, Nahla; Sorek, Rotem; Tringe, Susannah G.; Podar, Mircea; Martin, Hector Garcia; Kunin, Victor; Dalevi, Daniel; Madejska, Julita; Kirton, Edward; Platt, Darren; Szeto, Ernest; Salamov, Asaf; Barry, Kerrie; Mikhailova, Natalia; Kyrpides, Nikos C.; Matson, Eric G.; Ottesen, Elizabeth A.; Zhang, Xinning; Hernandez, Myriam; Murillo, Catalina; Acosta, Luis G.; Rigoutsos, Isidore; Tamayo, Giselle; Green, Brian D.; Chang, Cathy; Rubin, Edward M.; Mathur, Eric J.; Robertson, Dan E.; Hugenholtz, Philip; Leadbetter, Jared R.

2007-10-01

From the standpoints of both basic research and biotechnology, there is considerable interest in reaching a clearer understanding of the diversity of biological mechanisms employed during lignocellulose degradation. Globally, termites are an extremely successful group of wood-degrading organisms and are therefore important both for their roles in carbon turnover in the environment and as potential sources of biochemical catalysts for efforts aimed at converting wood into biofuels. Only recently have data supported any direct role for the symbiotic bacteria in the gut of the termite in cellulose and xylan hydrolysis. Here we use a metagenomic analysis of the bacterial community resident in the hindgut paunch of a wood-feeding Nasutitermes species to show the presence of a large, diverse set of bacterial genes for cellulose and xylan hydrolysis. Many of these genes were expressed in vivo or had cellulase activity in vitro, and further analyses implicate spirochete and fibrobacter species in gut lignocellulose degradation. New insights into other important symbiotic functions including H{sub 2} metabolism, CO{sub 2}-reductive acetogenesis and N{sub 2} fixation are also provided by this first system-wide gene analysis of a microbial community specialized towards plant lignocellulose degradation. Our results underscore how complex even a 1-{micro}l environment can be.

Termite and fungal resistance of in situ polymerized tributyltin acrylate and acetylated Indonesian and USA wood

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Rebecca E. Ibach; Yusuf Sudo Hadi; Dodi Nandika; Sulaeman Yusuf; Yuliati Indrayani

2000-01-01

Wood [Indonesian pine (IP), Indonesian Jabon (IJ) and USA southern yellow pine (USP)] was either in situ polymerized with tributyltin acrylate (TBTA) or acetylated and then exposed to termite and fungal degradation both in laboratory tests and field exposure. The TBTA woods had an average weight percent gain (WPG) of 11% for IP, 12% for IJ, and 10% for USP. The...

Termites utilise clay to build structural supports and so increase foraging resources.

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Oberst, Sebastian; Lai, Joseph C S; Evans, Theodore A

2016-02-08

Many termite species use clay to build foraging galleries and mound-nests. In some cases clay is placed within excavations of their wooden food, such as living trees or timber in buildings; however the purpose for this clay is unclear. We tested the hypotheses that termites can identify load bearing wood, and that they use clay to provide mechanical support of the load and thus allow them to eat the wood. In field and laboratory experiments, we show that the lower termite Coptotermes acinaciformis, the most basal species to build a mound-nest, can distinguish unloaded from loaded wood, and use clay differently when eating each type. The termites target unloaded wood preferentially, and use thin clay sheeting to camouflage themselves while eating the unloaded wood. The termites attack loaded wood secondarily, and build thick, load-bearing clay walls when they do. The termites add clay and build thicker walls as the load-bearing wood is consumed. The use of clay to support wood under load unlocks otherwise unavailable food resources. This behaviour may represent an evolutionary step from foraging behaviour to nest building in lower termites.

Screening and characterizing of xylanolytic and xylose-fermenting yeasts isolated from the wood-feeding termite, Reticulitermes chinensis.

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Sameh Samir Ali

Full Text Available The effective fermentation of xylose remains an intractable challenge in bioethanol industry. The relevant xylanase enzyme is also in a high demand from industry for several biotechnological applications that inevitably in recent times led to many efforts for screening some novel microorganisms for better xylanase production and fermentation performance. Recently, it seems that wood-feeding termites can truly be considered as highly efficient natural bioreactors. The highly specialized gut systems of such insects are not yet fully realized, particularly, in xylose fermentation and xylanase production to advance industrial bioethanol technology as well as industrial applications of xylanases. A total of 92 strains from 18 yeast species were successfully isolated and identified from the gut of wood-feeding termite, Reticulitermes chinensis. Of these yeasts and strains, seven were identified for new species: Candida gotoi, Candida pseudorhagii, Hamamotoa lignophila, Meyerozyma guilliermondii, Sugiyamaella sp.1, Sugiyamaella sp. 2, and Sugiyamaella sp.3. Based on the phylogenetic and phenotypic characterization, the type strain of C. pseudorhagii sp. nov., which was originally designated strain SSA-1542T, was the most frequently occurred yeast from termite gut samples, showed the highly xylanolytic activity as well as D-xylose fermentation. The highest xylanase activity was recorded as 1.73 and 0.98 U/mL with xylan or D-xylose substrate, respectively, from SSA-1542T. Among xylanase-producing yeasts, four novel species were identified as D-xylose-fermenting yeasts, where the yeast, C. pseudorhagii SSA-1542T, showed the highest ethanol yield (0.31 g/g, ethanol productivity (0.31 g/L·h, and its fermentation efficiency (60.7% in 48 h. Clearly, the symbiotic yeasts isolated from termite guts have demonstrated a competitive capability to produce xylanase and ferment xylose, suggesting that the wood-feeding termite gut is a promising reservoir for novel

Evaluating the role of Actinobacteria in the gut of wood-feeding termites (Reticulitermes spp.)

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Rachel A. Arango; Frederick Green III; Vina W. Yang; Joliene R. Lindholm; Nathaniel P. Chotlos; Kenneth F. Raffa

2017-01-01

Nitrogen has been shown to be a limiting nutrient across a range of xylophagous insects. These insects often rely on symbiotic microorganisms in the gut for nitrogen acquisition, via fixation of atmospheric nitrogen or break down of other available nitrogenous substances. In phylogenetically lower, wood-feeding termites, the role of nitrogen fixing bacteria has been...

Nutritional ecology of the formosan subterranean termite (Isoptera: Rhinotermitidae): feeding response to commercial wood species.

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Morales-Ramos, J A; Rojas, M G

2001-04-01

The feeding preferences of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were tested in three separate experiments on 28 different wood species. Experiment 1 was a multiple-choice test designed to test relative preferences among 24 wood species commercially available in New Orleans, LA. Experiment 2 was a similar study designed to test relative preferences among 21 wood species shown or reported to be unpalatable to the Formosan subterranean termite. Experiment 3 was a no-choice test to examine the feeding deterrence of the 10 least preferred wood species. Preference was determined by consumption rates. Birch (Betula alleghaniensis Britton), red gum (Liquidambar styraciflua L.), Parana pine [Araucaria angustifolia (Bert.) 1, sugar maple (Acer saccharum Marsh.), pecan (Carya illinoensis Wangenh.), and northern red oak (Quercus rubra L.) were the most preferred species by C. formosanus in order of consumption rate. All of these species were significantly more preferred than southern yellow pine (Pinus taeda L.), widely used for monitoring. Sinker cypress [ = old growth bald cypress, Taxodium distichum (L.)], western red cedar (Thuja plicata Donn), Alaskan yellow cedar (Chamaecyparis nootkatensis D. Don), eastern red cedar (Juniperus virginiana L.), sassafras [Sassafras albidum (Nutt.)], Spanish cedar (Cedrella odorata L.), Honduras mahogany (Swietenia macrophyla King), Indian rosewood (Dalbergia latifolia Roxb.), Honduras rosewood (D. stevensonii Standl.), and morado (Machaerium sp.) induced significant feeding deterrence and mortality to C. formosanus. The last eight species produced 100% mortality after 3 mo.

Resistance of Particleboards Made from Fast-Growing Wood Species to Subterranean Termite Attack.

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Hermawan, Dede; Hadi, Yusuf S; Fajriani, Esi; Massijaya, Muhamad Y; Hadjib, Nurwati

2012-05-29

Laboratory-made particleboards were tested for their resistance to subterranean termite, Coptotermes curvignathus Holmgren (Order Isoptera, Family Termitidae) by Indonesian standard SNI 01.7207-2006, during four weeks and at the end of the test their mass loss percentage and feeding rate were determined. Particleboards consisted of: jabon (Anthocephalus cadamba, Family Rubiacea) with a density of 0.41 g/cm³; sungkai (Peronema canescens, Family Verbenaceae) with a density of 0.46 g/cm³; mangium (Acacia mangium, Family Rhamnaceae) with a density of 0.60 g/cm³ separately and the three species mixture at a rate of 1:1:1. Densities of the boards were targetted at 0.60 g/cm³ and 0.80 g/cm³ by using 12% urea formaldehyde as binder with 2% paraffin as additive based on oven dry wood particle weight. The hand-formed mats and hot-pressing at 130 °C and 2.45 MPa for 10 min were applied. The results showed that particleboards density did not affect mass loss and feeding rate, but the particleboards made from higher density wood resulted in higher resistance to subterranean termite attack. The most resistant particleboards were made of magium, followed by sungkai, mixed species, and jabon.

Resistance of Particleboards Made from Fast-Growing Wood Species to Subterranean Termite Attack

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Nurwati Hadjib

2012-05-01

Full Text Available Laboratory-made particleboards were tested for their resistance to subterranean termite, Coptotermes curvignathus Holmgren (Order Isoptera, Family Termitidae by Indonesian standard SNI 01.7207–2006, during four weeks and at the end of the test their mass loss percentage and feeding rate were determined. Particleboards consisted of: jabon (Anthocephalus cadamba, Family Rubiacea with a density of 0.41 g/cm³; sungkai (Peronema canescens, Family Verbenaceae with a density of 0.46 g/cm³; mangium (Acacia mangium, Family Rhamnaceae with a density of 0.60 g/cm³ separately and the three species mixture at a rate of 1:1:1. Densities of the boards were targetted at 0.60 g/cm³ and 0.80 g/cm³ by using 12% urea formaldehyde as binder with 2% paraffin as additive based on oven dry wood particle weight. The hand-formed mats and hot-pressing at 130 °C and 2.45 MPa for 10 min were applied. The results showed that particleboards density did not affect mass loss and feeding rate, but the particleboards made from higher density wood resulted in higher resistance to subterranean termite attack. The most resistant particleboards were made of magium, followed by sungkai, mixed species, and jabon.

Quantifying arthropod contributions to wood decay

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Michael Ulyshen; Terry Wagner

2013-01-01

Termites carry large amounts of soil into dead wood, and this behaviour complicates efforts to measure their contributions to wood decay. A novel method for isolating termite soil by burning the wood is described, and some preliminary results are presented.

IDENTIFICATION, PRODUCTION AND CHARACTERIZATION OF NOVEL LIGNASE PROTEINS FROM TERMITES FOR DEPOLYMERIZATION OF LIGNOCELLULOSE

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SLACK, JEFFREY, M.

2012-12-06

Wood is a potential source for biofuels such as ethanol if it can be digested into sugars and fermented by yeast. Biomass derived from wood is a challenging substrate for ethanol production since it is made of lignin and cellulose which cannot be broken down easily into fermentable sugars. Some insects, and termites in particular, are specialized at using enzymes in their guts to digest wood into sugars. If termite gut enzymes could be made abundantly by a recombinant protein expression vector system, they could be applied to an industrial process to make biofuels from wood. In this study, a large cDNA library of relevant termite genes was made using termites fed a normal diet, or a diet with added lignin. A subtracted library yielded genes that were overexpressed in the presence of lignin. Termite gut enzyme genes were identified and cloned into recombinant insect viruses called baculoviruses. Using our PERLXpress system for protein expression, these termite gene recombinant baculoviruses were prepared and used to infect insect larvae, which then expressed abundant recombinant termite enzymes. Many of these expressed enzymes were prepared to very high purity, and the activities were studied in conjunction with collaborators at Purdue University. Recombinant termite enzymes expressed in caterpillars were shown to be able to release sugars from wood. Mixing different combinations of these enzymes increased the amount of sugars released from a model woody biomass substrate. The most economical, fastest and energy conserving way to prepare termite enzymes expressed by recombinant baculoviruses in caterpillars was by making crude liquid homogenates. Making enzymes stable in homogenates therefore was a priority. During the course of these studies, improvements were made to the recombinant baculovirus expression platform so that caterpillar-derived homogenates containing expressed termite enzymes would be more stable. These improvements in the baculoviruses included

Nutritional ecology of the Formosan subterranean termite (Isoptera: Rhinotermitidae): growth and survival of incipient colonies feeding on preferred wood species.

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Morales-Ramos, Juan A; Rojas, M Guadalupe

2003-02-01

The wood of 11 plant species was evaluated as a food source significantly impacting the growth and survival of incipient colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Colonies of C. formosanus feeding on pecan, Carya illinoensis (Wangenh.), and red gum, Liquidambar styraciflua L., produced significantly more progeny than colonies feeding on other wood species tested. Progeny of colonies feeding on pecan and American ash, Fraxinus americana L., had significantly greater survival than progeny of colonies feeding on other wood species. Colonies feeding on a nutritionally supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. These results indicate that differences observed in colony fitness can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species have different nutritional values to the Formosan subterranean termites. Colonies feeding on loblolly pine, Pinus taeda L., and ponderosa pine, Pinus ponderosa Laws., had significantly lower survival and produced significantly fewer workers and soldiers than colonies feeding on other wood species. Colony survival from 90 to 180 d of age and from 90 to 360 d of age was significantly correlated with the number of workers present at 90 d of colony age, indicating that colony survival depends on the presence of workers. Wood consumption in a multiple-choice study was significantly correlated with colony fitness value. This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source.

Effect of chemical cues on the foraging and tunneling behavior of Formosan subterranean termites (Isoptera: Rhinotermitidae)

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Wood rot fungi can cause directional tunneling, aggregation behavior and increased wood consumption by subterranean termites. Because vanillin and guaiacol are byproducts of lignin degradation, these chemicals were tested as potential attractants to Formosan subterranean termites, Coptotermes formo...

Differential Ecological Specificity of Protist and Bacterial Microbiomes across a Set of Termite Species

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Waidele, Lena

2017-12-19

The gut microbiome of lower termites comprises protists and bacteria that help these insects to digest cellulose and to thrive on wood. The composition of the termite gut microbiome correlates with phylogenetic distance of the animal host and host ecology (diet) in termites collected from their natural environment. However, carryover of transient microbes from host collection sites are an experimental concern and might contribute to the ecological imprints on the termite gut microbiome. Here, we set out to test whether an ecological imprint on the termite gut microbiome remains, when focusing on the persistent microbiome. Therefore, we kept five termite species under strictly controlled dietary conditions and subsequently profiled their protist and bacterial gut microbial communities using 18S and 16S rRNA gene amplicon sequencing. The species differed in their ecology; while three of the investigated species were wood-dwellers that feed on the piece of wood they live in and never leave except for the mating flight, the other two species were foragers that regularly leave their nests to forage for food. Despite these prominent ecological differences, protist microbiome structure aligned with phylogenetic relatedness of termite host species. Conversely, bacterial communities seemed more flexible, suggesting that microbiome structure aligned more strongly with the foraging and wood-dwelling ecologies. Interestingly, protist and bacterial community alpha-diversity correlated, suggesting either putative interactions between protists and bacteria, or that both types of microbes in the termite gut follow shared structuring principles. Taken together, our results add to the notion that bacterial communities are more variable over evolutionary time than protist communities and might react more flexibly to changes in host ecology.

Differential Ecological Specificity of Protist and Bacterial Microbiomes across a Set of Termite Species

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Lena Waidele

2017-12-01

Full Text Available The gut microbiome of lower termites comprises protists and bacteria that help these insects to digest cellulose and to thrive on wood. The composition of the termite gut microbiome correlates with phylogenetic distance of the animal host and host ecology (diet in termites collected from their natural environment. However, carryover of transient microbes from host collection sites are an experimental concern and might contribute to the ecological imprints on the termite gut microbiome. Here, we set out to test whether an ecological imprint on the termite gut microbiome remains, when focusing on the persistent microbiome. Therefore, we kept five termite species under strictly controlled dietary conditions and subsequently profiled their protist and bacterial gut microbial communities using 18S and 16S rRNA gene amplicon sequencing. The species differed in their ecology; while three of the investigated species were wood-dwellers that feed on the piece of wood they live in and never leave except for the mating flight, the other two species were foragers that regularly leave their nests to forage for food. Despite these prominent ecological differences, protist microbiome structure aligned with phylogenetic relatedness of termite host species. Conversely, bacterial communities seemed more flexible, suggesting that microbiome structure aligned more strongly with the foraging and wood-dwelling ecologies. Interestingly, protist and bacterial community alpha-diversity correlated, suggesting either putative interactions between protists and bacteria, or that both types of microbes in the termite gut follow shared structuring principles. Taken together, our results add to the notion that bacterial communities are more variable over evolutionary time than protist communities and might react more flexibly to changes in host ecology.

Anti-termite efficacy of Capparis decidua and its combinatorial ...

African Journals Online (AJOL)

Michael Horsfall

ABSTRACT: Capparis deciduas and its combinatorial mixtures were evaluated to observe the anti-termite efficacy against Indian white termite Odontotermes obesus. These have shown very high termiticidal activity and wood protection in the soil. It is proved by very low LD50 values i.e. 0.0218mg/g and 0.021mg/g obtained ...

Preferences of Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann (Blattodea: Rhinotermitidae among Three Commercial Wood Species

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Nirmala K. Hapukotuwa

2011-11-01

Full Text Available The Formosan subterranean termite, Coptotermes formosanus Shiraki, and the Asian subterranean termite, Coptotermes gestroi (Wasmann, are both pests of wood in service in Hawaii and Florida. We conducted a laboratory study using method modified from those described in standard E1-09 of the American Wood Protection Association (AWPA 2009 to assess the termite resistance of three commercially available wood species used in regions of the USA where both termite species occur: Douglas fir, Pseudotsuga menziessii, southern yellow pine, Pinus spp. and redwood, Sequoia sempervirens. A multiple-choice (three-choice assay was used for four weeks (28 days in order to simulate field conditions of food choice and assess termite feeding preferences under 28 °C and 72–80% RH. 400 termites (360 workers: 40 soldiers were released into each test jar. Five replicates and two controls of each wood species were used with each termite species. Termite mortality was recorded at the end of the test; and wood wafers were oven-dried and weighed before and after termite exposure to determine the mass loss due to termite feeding, and rated visually on a 0 (failure to 10 (sound scale. There were significant differences in mean mass loss values among the three wood species and between two termite species. The mean mass loss value for redwood was significantly lower than Douglas fir and southern yellow pine with both termite species. However, C. formosanus showed increased feeding on Douglas fir and southern yellow pine compared to C. gestroi.

Trace elements in termites by PIXE analysis

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Yoshimura, T. E-mail: tsuyoshi@termite.kuwri.kyoto-u.ac.jp; Kagemori, N.; Kawai, S.; Sera, K.; Futatsugawa, S

2002-04-01

Trace elements in a Japanese subterranean xylophagous termite, Coptotermes formosanus Shiraki, were analyzed by the PIXE method. The total amount of the 14 predominant elements out of 27 detected in an intact termite was higher in a soldier termite (23 000 {mu}g/g) than in a worker termite (10 000 {mu}g/g). A block of wood (Pinus densiflora Sieb. et Zucc.) for termite feed had a much lower concentration (3600 {mu}g/g) compared with that in an intact termite. This probably relates the functional bio-condensation and/or bio-recycling of trace elements in C. formosanus. When a termite was separated into three anatomical parts, head, degutted body and gut, the worker gut contained the highest total amount of the 14 predominant measured elements (31 000 {mu}g/g). This might be correlated with the higher activity of food digestion and energy production in the worker gut. Moreover, the mandible of the soldier head, with an exoskeleton that is intensely hardened, showed a preferential distribution of Mn and Fe. These results suggest that the characteristic localization of elements will be closely related to the functional role of the individual anatomical part of C. formosanus.

Effects of heartwood extractives on symbiotic protozoan communities and mortality in two termite species

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Babar Hassan; Mark E. Mankowski; Grant Kirker; Sohail Ahmed

2017-01-01

Lower termites (Isoptera: Rhinotermitidae) are considered severe pests of wood in service, crops and plantation forests. Termites mechanically remove and digest lignocellulosic material as a food source. The ability to digest lignocellulose not only depends on their digestive physiology, but also on the symbiotic relationship between termites and their intestinal...

Response of Microtermes mycophagus (Isoptera: Termitidae to twenty one wood species

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Naeem Iqbal

2015-08-01

Full Text Available The responses of termite species to bait depend upon the quality of the food used in the stations. Woods are the most common food sources for termites but different termite species behave differently to different wood species and types. The knowledge of the preference status of different wood species to a termite species helps in effective monitoring and baiting program. The current study was carried out to evaluate the preference of 21 wood species to the termite, Microtermes mycophagus in the field by no-choice and choice feeding tests. The results indicated silk cotton tree and sacred fig woods as the most preferred wood species with mean mass losses of 71.21 ± 5.09% and 68.38 ± 7.27% in no-choice test and 95.02 ± 1.65% and 91.69 ± 2.07% in choice tests, respectively. White cedar was the least preferred wood species with mean mass losses of 7.49 ± 1.64% and 13.92 ± 1.89% in no choice and choice feeding tests, respectively. Based on present studies, sapwood of silk cotton tree and sacred fig may be used in effective monitoring and baiting program against M. mycophagus.

Mildew fungi found in termites (Reticulitermes lucifugus and their nests

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A. Wójcik

2015-04-01

Full Text Available This paper presents the results of observation of mould growth in laboratory colonies of termites. It also attempts to determine the species of mould fungi present in the research laboratory and the main colonies and their entomopathogenic for the termites. The following four species were found in test termite colonies: Trichoderme viride, Mucor himeralis, Rhizopus nigricans, Aspergillus sp., Aspergillus flavus, Alternaria sp., Penicylium verucosum and Fusarium sp. were recognisable in test colonies with domestic and exotic wood. Morphological observations of the fungi were carried out using a microscope with a 40x magnification. The growth of mould fungi in test containers caused death of whole termite colonies.

Transcriptome analysis of the digestive system of a wood-feeding termite (Coptotermes formosanus) revealed a unique mechanism for effective biomass degradation.

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Geng, Alei; Cheng, Yanbing; Wang, Yongli; Zhu, Daochen; Le, Yilin; Wu, Jian; Xie, Rongrong; Yuan, Joshua S; Sun, Jianzhong

2018-01-01

Wood-feeding termite, Coptotermes formosanus Shiraki, represents a highly efficient system for biomass deconstruction and utilization. However, the detailed mechanisms of lignin modification and carbohydrate degradation in this system are still largely elusive. In order to reveal the inherent mechanisms for efficient biomass degradation, four different organs (salivary glands, foregut, midgut, and hindgut) within a complete digestive system of a lower termite, C. formosanus , were dissected and collected. Comparative transcriptomics was carried out to analyze these organs using high-throughput RNA sequencing. A total of 71,117 unigenes were successfully assembled, and the comparative transcriptome analyses revealed significant differential distributions of GH (glycosyl hydrolase) genes and auxiliary redox enzyme genes in different digestive organs. Among the GH genes in the salivary glands, the most abundant were GH9, GH22, and GH1 genes. The corresponding enzymes may have secreted into the foregut and midgut to initiate the hydrolysis of biomass and to achieve a lignin-carbohydrate co-deconstruction system. As the most diverse GH families, GH7 and GH5 were primarily identified from the symbiotic protists in the hindgut. These enzymes could play a synergistic role with the endogenous enzymes from the host termite for biomass degradation. Moreover, twelve out of fourteen genes coding auxiliary redox enzymes from the host termite origin were induced by the feeding of lignin-rich diets. This indicated that these genes may be involved in lignin component deconstruction with its redox network during biomass pretreatment. These findings demonstrate that the termite digestive system synergized the hydrolysis and redox reactions in a programmatic process, through different parts of its gut system, to achieve a maximized utilization of carbohydrates. The detailed unique mechanisms identified from the termite digestive system may provide new insights for advanced design of

Differential Ecological Specificity of Protist and Bacterial Microbiomes across a Set of Termite Species

KAUST Repository

Waidele, Lena; Korb, Judith; Voolstra, Christian R.; Kü nzel, Sven; Dedeine, Franck; Staubach, Fabian

2017-01-01

The gut microbiome of lower termites comprises protists and bacteria that help these insects to digest cellulose and to thrive on wood. The composition of the termite gut microbiome correlates with phylogenetic distance of the animal host and host

Occurrence of termites (Isoptera on living and standing dead trees in a tropical dry forest in Mexico

Directory of Open Access Journals (Sweden)

Nancy Calderón-Cortés

2018-05-01

Full Text Available Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60–98% of standing dead trees and 23–59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057–0.066 trees/m2 than in riparian forests (0.022 and 0.027 trees/m2, even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01–0.09 trees/m2 than in larger class sizes (0–0.02 trees/m2. Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil.

Occurrence of termites (Isoptera) on living and standing dead trees in a tropical dry forest in Mexico.

Science.gov (United States)

Calderón-Cortés, Nancy; Escalera-Vázquez, Luis H; Oyama, Ken

2018-01-01

Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60-98% of standing dead trees and 23-59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057-0.066 trees/m 2 ) than in riparian forests (0.022 and 0.027 trees/m 2 ), even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01-0.09 trees/m 2 ) than in larger class sizes (0-0.02 trees/m 2 ). Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil.

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan

Science.gov (United States)

Mark Mankowski; Blossie Boyd; Barbar Hassan; Grant T. Kirker

2016-01-01

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, ...

Termites Are Resistant to the Effects of Fire at Multiple Spatial Scales.

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Sarah C Avitabile

Full Text Available Termites play an important ecological role in many ecosystems, particularly in nutrient-poor arid and semi-arid environments. We examined the distribution and occurrence of termites in the fire-prone, semi-arid mallee region of south-eastern Australia. In addition to periodic large wildfires, land managers use fire as a tool to achieve both asset protection and ecological outcomes in this region. Twelve taxa of termites were detected by using systematic searches and grids of cellulose baits at 560 sites, clustered in 28 landscapes selected to represent different fire mosaic patterns. There was no evidence of a significant relationship between the occurrence of termite species and time-since-fire at the site scale. Rather, the occurrence of species was related to habitat features such as the density of mallee trees and large logs (>10 cm diameter. Species richness was greater in chenopod mallee vegetation on heavier soils in swales, rather than Triodia mallee vegetation of the sandy dune slopes. At the landscape scale, there was little evidence that the frequency of occurrence of termite species was related to fire, and no evidence that habitat heterogeneity generated by fire influenced termite species richness. The most influential factor at the landscape scale was the environmental gradient represented by average annual rainfall. Although termites may be associated with flammable habitat components (e.g. dead wood, they appear to be buffered from the effects of fire by behavioural traits, including nesting underground, and the continued availability of dead wood after fire. There is no evidence to support the hypothesis that a fine-scale, diverse mosaic of post-fire age-classes will enhance the diversity of termites. Rather, termites appear to be resistant to the effects of fire at multiple spatial scales.

Immobilisation of bifenthrin for termite control.

Science.gov (United States)

Guan, Yan-Qing; Chen, Jia Mei; Li, Zhi Bin; Feng, Qi Li; Liu, Jun-Ming

2011-02-01

Termites are worldwide pests causing considerable damage to agriculture, forestry and buildings. While various approaches have been tried to eliminate termite populations, the relevant toxicants are associated with certain risks to the environment and human health. In this study, to combine the merits of effective chemical control by bifenthrin and a drug photoimmobilisation technique, silk fibroin was used as a carrier to embed bifenthrin, which was then photoactively immobilised by ultraviolet treatment on the surface of wood (cellulose). The immobilised bifenthrin embedded in the photoactive silk fibroin was characterised by Fourier transform infrared spectroscopy (FTIR), ultraviolet absorption spectroscopy (UV), fluorescence measurement and CHN analysis. The surface structures and biological activity were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), electron spectroscopy for chemical analysis (ESCA) and bioassays respectively. The results indicate that the embedded and immobilised bifenthrin has been very well protected from free release and has a long-term stability allowing slow release with a high efficiency against termites at a low dose of 1.25 µg cm(-2). This study provides a novel and environmentally benign technique for termite control by photoimmobilising silk-fibroin-embedded bifenthrin on the surface of materials that are otherwise easily attacked by termites. Copyright © 2010 Society of Chemical Industry.

Influence of Soil Properties on Soldierless Termite Distribution.

Science.gov (United States)

Bourguignon, Thomas; Drouet, Thomas; Šobotník, Jan; Hanus, Robert; Roisin, Yves

2015-01-01

In tropical rainforests, termites constitute an important part of the soil fauna biomass, and as for other soil arthropods, variations in soil composition create opportunities for niche partitioning. The aim of this study was twofold: first, we tested whether soil-feeding termite species differ in the foraging substrate; second, we investigated whether soil-feeding termites select their foraging sites to enhance nutrients intake. To do so, we collected termites and analysed the composition and structure of their feeding substrates. Although Anoplotermes-group members are all considered soil-feeders, our results show that some species specifically feed on abandoned termite nests and very rotten wood, and that this substrate selection is correlated with previous stable isotope analyses, suggesting that one component of niche differentiation among species is substrate selection. Our results show that the composition and structure of bare soils on which different termite species foraged do not differ, suggesting that there is no species specialization for a particular type of bare soil. Finally, the bare soil on which termites forage does not differ from random soil samples. Overall, our results suggest that few species of the Anoplotermes-group are specialized toward substrates rich in organic matter, but that the vast majority forage on soil independently of its structural and chemical composition, being ecologically equivalent for this factor.

Parallel evolution of mound-building and grass-feeding in Australian nasute termites.

Science.gov (United States)

Arab, Daej A; Namyatova, Anna; Evans, Theodore A; Cameron, Stephen L; Yeates, David K; Ho, Simon Y W; Lo, Nathan

2017-02-01

Termite mounds built by representatives of the family Termitidae are among the most spectacular constructions in the animal kingdom, reaching 6-8 m in height and housing millions of individuals. Although functional aspects of these structures are well studied, their evolutionary origins remain poorly understood. Australian representatives of the termitid subfamily Nasutitermitinae display a wide variety of nesting habits, making them an ideal group for investigating the evolution of mound building. Because they feed on a variety of substrates, they also provide an opportunity to illuminate the evolution of termite diets. Here, we investigate the evolution of termitid mound building and diet, through a comprehensive molecular phylogenetic analysis of Australian Nasutitermitinae. Molecular dating analysis indicates that the subfamily has colonized Australia on three occasions over the past approximately 20 Myr. Ancestral-state reconstruction showed that mound building arose on multiple occasions and from diverse ancestral nesting habits, including arboreal and wood or soil nesting. Grass feeding appears to have evolved from wood feeding via ancestors that fed on both wood and leaf litter. Our results underscore the adaptability of termites to ancient environmental change, and provide novel examples of parallel evolution of extended phenotypes. © 2017 The Author(s).

Identification, Geographical Distribution and Hosts of Subterranean Termites in the United Arab Emirates Arid Ecosystem

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W. Kaakeh

2005-01-01

Full Text Available Six termite species, belonging to five genera and three families (Hodotermitidae, Rhinotermitidae and Termitidae were identified in the United Arab Emirates (UAE. Termite species recorded were the harvester termites Anacanthotermes ochraceus (Burmeister and Anacanthotermes ubachi (Navas, the sand termite Psammotermes hypostoma (Desneux and the small waxy termites Microcerotermes diversus (Silvestri, Heterotermes aethiopicus (Sjostedt, and Microtermes najdensis (Harris. Except for a previous record of H. aethiopicus, the other five species were recorded for the first time in the UAE. All species were subterranean in habitat and reach wood sources through earthen gallery systems. Termites were available in areas with varied conditions of climate, vegetation and soil types. Termites showed host preference for dead, living, or decaying plant materials and non-cellulose materials. The dominant termite species recorded was A. ochraceus, followed by P. hypostoma and M. diversus. The distributions of the six termite species varied in each of the seven Emirates. All species were present in the two largest Emirates of Abu Dhabi and Dubai.

Effects of termites on infiltration in crusted soil.

NARCIS (Netherlands)

Mando, A.; Stroosnijder, L.; Brussaard, L.

1996-01-01

In northern Burkina Faso (West Africa), a study was undertaken to explore the possibilities of restoring the infiltration capacity of crusted soils through the stimulation of termite activity. Treatments consisted of the application of a mulch of a mixture of wood and straw without insecticides

Efficacy of vetiver oil and nootkatone as soil barriers against Formosan subterranean termite (Isoptera: Rhinotermitidae).

Science.gov (United States)

Maistrello, L; Henderson, G; Laine, R A

2001-12-01

Vetiver oil and its components nootkatone and cedrene were assessed as sand treatments for their efficacy to disrupt food recruitment by Coptotermes formosanus Shiraki. Termites were required to tunnel through sand treated with vetiver oil, nootkatone, cedrene, or untreated sand to reach a food source. Results showed that sand treated with vetiver oil or nootkatone disrupted termite tunneling behavior. As a consequence, after 21 d, wood consumption and termite survival were significantly lower compared with cedrene-treated or untreated sand treatments. Sand treated with vetiver oil or nootkatone at 100 microg/g substrate were effective barriers to termites.

The complexities of hydrolytic enzymes from the termite digestive system.

Science.gov (United States)

Saadeddin, Anas

2014-06-01

The main challenge in second generation bioethanol production is the efficient breakdown of cellulose to sugar monomers (hydrolysis). Due to the recalcitrant character of cellulose, feedstock pretreatment and adapted hydrolysis steps are needed to obtain fermentable sugar monomers. The conventional industrial production process of second-generation bioethanol from biomass comprises several steps: thermochemical pretreatment, enzymatic hydrolysis and sugar fermentation. This process is undergoing continuous optimization in order to increase the bioethanol yield and reduce the economic cost. Therefore, the discovery of new enzymes with high lignocellulytic activity or new strategies is extremely important. In nature, wood-feeding termites have developed a sophisticated and efficient cellulose degrading system in terms of the rate and extent of cellulose hydrolysis and exploitation. This system, which represents a model for digestive symbiosis has attracted the attention of biofuel researchers. This review describes the termite digestive system, gut symbionts, termite enzyme resources, in vitro studies of isolated enzymes and lignin degradation in termites.

Nitrous Oxide (N2O) Emissions by Termites: Does the Feeding Guild Matter?

Science.gov (United States)

Brauman, Alain; Majeed, Muhammad Zeeshan; Buatois, Bruno; Robert, Alain; Pablo, Anne-Laure; Miambi, Edouard

2015-01-01

In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O). Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1) (g dry wt.)(-1) for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1) (g dry wt.)(-1) for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1) (g dry wt.)(-1). Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA) and denitrifying (nirK, nirS, nosZ) gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

Nitrous Oxide (N2O Emissions by Termites: Does the Feeding Guild Matter?

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Alain Brauman

Full Text Available In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O. Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1 (g dry wt.(-1 for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1 (g dry wt.(-1 for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1 (g dry wt.(-1. Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA and denitrifying (nirK, nirS, nosZ gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

Potential of kaolin-based particle film barriers for Formosan subterranean termite (Isoptera: Rhinotermitidae) control

Science.gov (United States)

Wiltz, B.A.; Woodson, W.D.; Puterka, G.J.

2010-01-01

Effects of three particle film products on Formosan subterranean termites, Coptotermes formosanus Shiraki, were evaluated in feeding, tunneling, and contact assays. The particle films, hydrophobic M96-018 and hydrophilic Surround and Surround WP are based on the inert clay mineral kaolin. In 2-week long no-choice feeding tests, significant mortality occurred only with M96-018-coated wood. When a choice was provided, M96-018 and Surround were consumed at higher rates than untreated wood. Surround WP did not differ from controls in either test. In the tunneling assay termites were given the option of crossing a kaolin-sand mixture to reach an alternate food source. After 3-weeks, rates of 1% and 5% M96-018 provided an effective barrier to Formosan termite tunneling, while termites were not stopped by rates as high as 20% Surround and Surround WP. Dust treatments of all three formulations caused significant increases in mortality within 24 h, with mortality rates ranging from 72.0 - 97.3% within 72 h of treatment. The particle films were most effective when moisture levels were low, suggesting that desiccation was the mechanism for mortality. All particle films showed potential for use in above ground applications while hydrophobic M06-018 has the most potential as a soil barrier to subterranean termites.

Preliminary evaluation of storax and its constituents: Fungal decay mold and termite resistance

Science.gov (United States)

S. Nami Kartal; Evren Terzi; Tsuyoshi Yoshimura; Rachel Arango; Carol A. Clausen; Frederick Green III

2012-01-01

Essential oils and their derivatives might be one of the promising preserving agents to prevent funga ldecay and termite/insect attack in wood since such compounds have a long history of safe usage as antimicrobial agents in various industries. Considerable research has focused on utilizing bioactive essential oils and wood extractives based on green technologies to...

Holistic approach to wood protection

Science.gov (United States)

Roger M. Rowell

2006-01-01

When untreated wood is exposed to adverse outdoor conditions, nature has a series of chemistries to degrade it to its original building blocks of carbon dioxide and water. Fungi, termites, heat, moisture, ultraviolet (UV) energy, and chemicals take their toll on the performance properties of wood. We tend to study each of these degradation chemistries as individual...

Origin and alteration of organic matter in termite mounds from different feeding guilds of the Amazon rainforests.

Science.gov (United States)

Siebers, Nina; Martius, Christopher; Eckhardt, Kai-Uwe; Garcia, Marcos V B; Leinweber, Peter; Amelung, Wulf

2015-01-01

The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feeding habits in the Terra Firme rainforests to the properties of potential food sources soil, wood, and microepiphytes. Chemical analyses comprised isotopic composition of C and N, cellulosic (CPS), non-cellulosic (NCPS), and N-containing saccharides, and molecular composition screening using pyrolysis-field ionization mass spectrometry (Py-FIMS). The isotopic analysis revealed higher soil δ13C (-27.4‰) and δ15N (6.6‰) values in nests of wood feeding Nasutitermes and Cornitermes than in wood samples (δ13C = -29.1‰, δ15N = 3.4‰), reflecting stable-isotope enrichment with organic matter alterations during or after nest construction. This result was confirmed by elevated NCPS:CPS ratios, indicating a preferential cellulose decomposition in the nests. High portions of muramic acid (MurAc) pointed to the participation of bacteria in the transformation processes. Non-metric multidimensional scaling (MDS) revealed increasing geophagy in the sequence Termes rainforest termites shows variations and evidence of modification by microbial processes, but nevertheless it primarily reflects the trophic niches of the constructors.

Caste-, sex-, and age-dependent expression of immune-related genes in a Japanese subterranean termite, Reticulitermes speratus

OpenAIRE

Mitaka, Yuki; Kobayashi, Kazuya; Matsuura, Kenji

2017-01-01

Insects protect themselves from microbial infections through innate immune responses, including pathogen recognition, phagocytosis, the activation of proteolytic cascades, and the synthesis of antimicrobial peptides. Termites, eusocial insects inhabiting microbe-rich wood, live in closely-related family groups that are susceptible to shared pathogen infections. To resist pathogenic infection, termite families have evolved diverse immune adaptations at both individual and societal levels, and ...

Testing protozoacidal activity of ligand-lytic peptides against termite gut protozoa in vitro (protozoa culture) and in vivo (microinjection into termite hindgut).

Science.gov (United States)

Husseneder, Claudia; Sethi, Amit; Foil, Lane; Delatte, Jennifer

2010-12-29

We are developing a novel approach to subterranean termite control that would lead to reduced reliance on the use of chemical pesticides. Subterranean termites are dependent on protozoa in the hindguts of workers to efficiently digest wood. Lytic peptides have been shown to kill a variety of protozoan parasites (Mutwiri et al. 2000) and also protozoa in the gut of the Formosan subterranean termite, Coptotermes formosanus (Husseneder and Collier 2009). Lytic peptides are part of the nonspecific immune system of eukaryotes, and destroy the membranes of microorganisms (Leuschner and Hansel 2004). Most lytic peptides are not likely to harm higher eukaryotes, because they do not affect the electrically neutral cholesterol-containing cell membranes of higher eukaryotes (Javadpour et al. 1996). Lytic peptide action can be targeted to specific cell types by the addition of a ligand. For example, Hansel et al. (2007) reported that lytic peptides conjugated with cancer cell membrane receptor ligands could be used to destroy breast cancer cells, while lytic peptides alone or conjugated with non-specific peptides were not effective. Lytic peptides also have been conjugated to human hormones that bind to receptors on tumor cells for targeted destruction of prostate and testicular cancer cells (Leuschner and Hansel 2004). In this article we present techniques used to demonstrate the protozoacidal activity of a lytic peptide (Hecate) coupled to a heptapeptide ligand that binds to the surface membrane of protozoa from the gut of the Formosan subterranean termite. These techniques include extirpation of the gut from termite workers, anaerobic culture of gut protozoa (Pseudotrichonympha grassii, Holomastigotoides hartmanni,Spirotrichonympha leidyi), microscopic confirmation that the ligand marked with a fluorescent dye binds to the termite gut protozoa and other free-living protozoa but not to bacteria or gut tissue. We also demonstrate that the same ligand coupled to a lytic

Origin and Alteration of Organic Matter in Termite Mounds from Different Feeding Guilds of the Amazon Rainforests

Science.gov (United States)

Siebers, Nina; Martius, Christopher; Eckhardt, Kai-Uwe; Garcia, Marcos V. B.; Leinweber, Peter; Amelung, Wulf

2015-01-01

The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feeding habits in the Terra Firme rainforests to the properties of potential food sources soil, wood, and microepiphytes. Chemical analyses comprised isotopic composition of C and N, cellulosic (CPS), non-cellulosic (NCPS), and N-containing saccharides, and molecular composition screening using pyrolysis-field ionization mass spectrometry (Py-FIMS). The isotopic analysis revealed higher soil δ13C (-27.4‰) and δ15N (6.6‰) values in nests of wood feeding Nasutitermes and Cornitermes than in wood samples (δ13C = -29.1‰, δ15N = 3.4‰), reflecting stable-isotope enrichment with organic matter alterations during or after nest construction. This result was confirmed by elevated NCPS:CPS ratios, indicating a preferential cellulose decomposition in the nests. High portions of muramic acid (MurAc) pointed to the participation of bacteria in the transformation processes. Non-metric multidimensional scaling (NMDS) revealed increasing geophagy in the sequence Termes termites shows variations and evidence of modification by microbial processes, but nevertheless it primarily reflects the trophic niches of the constructors. PMID:25909987

Variation in the Gut Microbiota of Termites (Tsaitermes ampliceps) Against Different Diets.

Science.gov (United States)

Su, Lijuan; Yang, Lele; Huang, Shi; Li, Yan; Su, Xiaoquan; Wang, Fengqin; Bo, Cunpei; Wang, En Tao; Song, Andong

2017-01-01

Termites are well recognized for their thriving on recalcitrant lignocellulosic diets through nutritional symbioses with gut-dwelling microbiota; however, the effects of diet changes on termite gut microbiota are poorly understood, especially for the lower termites. In this study, we employed high-throughput 454 pyrosequencing of 16S V1-V3 amplicons to compare gut microbiotas of Tsaitermes ampliceps fed with lignin-rich and lignin-poor cellulose diets after a 2-week-feeding period. As a result, the majority of bacterial taxa were shared across the treatments with different diets, but their relative abundances were modified. In particular, the relative abundance was reduced for Spirochaetes and it was increased for Proteobacteria and Bacteroides by feeding the lignin-poor diet. The evenness of gut microbiota exhibited a significant difference in response to the diet type (filter paper diets corn stover diets < wood diets), while their richness was constant, which may be related to the lower recalcitrance of this biomass to degradation. These results have important implications for sampling and analysis strategies to probe the lignocellulose degradation features of termite gut microbiota and suggest that the dietary lignocellulose composition could cause shifting rapidly in the termite gut microbiota.

Density-body mass relationships: Inconsistent intercontinental patterns among termite feeding-groups

Science.gov (United States)

Dahlsjö, Cecilia A. L.; Parr, Catherine L.; Malhi, Yadvinder; Meir, Patrick; Rahman, Homathevi; Eggleton, Paul

2015-02-01

Allometric relationships are useful for estimating and understanding resource distribution in assemblages with species of different masses. Damuth's law states that body mass scales with population density as M-0.75, where M is body mass and -0.75 is the slope. In this study we used Damuth's law (M-0.75) as a null hypothesis to examine the relationship between body mass and population density for termite feeding-groups in three different countries and regions (Cameroon, West Africa; Peru South America; and Malaysia SE Asia). We found that none of the feeding-groups had a relationship where M-0.75 while the data suggested that population density-body mass relationships for true soil-feeding termites in Cameroon (M2.7) and wood-feeding termites in Peru (M1.5) were significantly different from the expected values given by Damuth's law. The dominance of large-bodied true soil-feeding termites in Cameroon and the absence of fungus-growing termites from Peru suggest that these allometric patterns are due to heterogeneities in termite biogeographical evolution. Additionally, as these feeding-groups have higher population density than expected by their body masses it may be suggested that they also have a higher energy throughput than expected. The results presented here may be used to gain further understanding of resource distribution among termite feeding-groups across regions and an insight into the importance of evolutionary history and biogeography on allometric patterns. Further understanding of population density-body mass relationships in termite feeding-groups may also improve understanding of the role these feeding-groups play in ecosystem processes in different regions.

Response of Termite (Blattodea: Termitoidae) Assemblages to Lower Subtropical Forest Succession: A Case Study in Dinghushan Biosphere Reserve, China.

Science.gov (United States)

Li, Zhi-Qiang; Ke, Yun-Ling; Zeng, Wen-Hui; Zhang, Shi-Jun; Wu, Wen-Jing

2016-02-01

Termite (Blattodea: Termitoidae) assemblages have important ecological functions and vary in structure between habitats, but have not been studied in lower subtropical forests. To examine whether differences in the richness and relative abundance of termite species and functional groups occur in lower subtropical regions, termite assemblages were sampled in Dinghushan Biosphere Reserve, China, among pine forest, pine and broad-leaved mixed forest (mixed forest), and monsoon evergreen broad-leaved forest (monsoon forest). The dominant functional group was wood-feeding termites (family Termitidae), and the mixed forest hosted the greatest richness and relative abundance. Soil-feeding termites were absent from the lower subtropical system, while humus-feeding termites were sporadically distributed in mixed forest and monsoon forest. The species richness and functional group abundance of termites in our site may be linked to the forest succession. Altitude, soil temperature, air temperature, surface air relative humidity, and litter depth were significant influences on species and functional group diversity.

Protecting wood fences for yard and garden

Science.gov (United States)

R. C. De Groot; W. C. Feist; W. E. Eslyn; L. R. Gjovik

For maximum protection against wood decay and termites, use posts that have an in-depth preservative treatment, preferably a pressure treatment for below ground use. When selecting posts of naturally decay-resistant woods, choose posts with mostly heartwood. Horizontal rails require more protection from decay than do vertical boards. In regions of high and moderate...

Construction and characterization of normalized cDNA libraries by 454 pyrosequencing and estimation of DNA methylation levels in three distantly related termite species.

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Yoshinobu Hayashi

Full Text Available In termites, division of labor among castes, categories of individuals that perform specialized tasks, increases colony-level productivity and is the key to their ecological success. Although molecular studies on caste polymorphism have been performed in termites, we are far from a comprehensive understanding of the molecular basis of this phenomenon. To facilitate future molecular studies, we aimed to construct expressed sequence tag (EST libraries covering wide ranges of gene repertoires in three representative termite species, Hodotermopsis sjostedti, Reticulitermes speratus and Nasutitermes takasagoensis. We generated normalized cDNA libraries from whole bodies, except for guts containing microbes, of almost all castes, sexes and developmental stages and sequenced them with the 454 GS FLX titanium system. We obtained >1.2 million quality-filtered reads yielding >400 million bases for each of the three species. Isotigs, which are analogous to individual transcripts, and singletons were produced by assembling the reads and annotated using public databases. Genes related to juvenile hormone, which plays crucial roles in caste differentiation of termites, were identified from the EST libraries by BLAST search. To explore the potential for DNA methylation, which plays an important role in caste differentiation of honeybees, tBLASTn searches for DNA methyltransferases (dnmt1, dnmt2 and dnmt3 and methyl-CpG binding domain (mbd were performed against the EST libraries. All four of these genes were found in the H. sjostedti library, while all except dnmt3 were found in R. speratus and N. takasagoensis. The ratio of the observed to the expected CpG content (CpG O/E, which is a proxy for DNA methylation level, was calculated for the coding sequences predicted from the isotigs and singletons. In all of the three species, the majority of coding sequences showed depletion of CpG O/E (less than 1, and the distributions of CpG O/E were bimodal, suggesting

Construction and characterization of normalized cDNA libraries by 454 pyrosequencing and estimation of DNA methylation levels in three distantly related termite species.

Science.gov (United States)

Hayashi, Yoshinobu; Shigenobu, Shuji; Watanabe, Dai; Toga, Kouhei; Saiki, Ryota; Shimada, Keisuke; Bourguignon, Thomas; Lo, Nathan; Hojo, Masaru; Maekawa, Kiyoto; Miura, Toru

2013-01-01

In termites, division of labor among castes, categories of individuals that perform specialized tasks, increases colony-level productivity and is the key to their ecological success. Although molecular studies on caste polymorphism have been performed in termites, we are far from a comprehensive understanding of the molecular basis of this phenomenon. To facilitate future molecular studies, we aimed to construct expressed sequence tag (EST) libraries covering wide ranges of gene repertoires in three representative termite species, Hodotermopsis sjostedti, Reticulitermes speratus and Nasutitermes takasagoensis. We generated normalized cDNA libraries from whole bodies, except for guts containing microbes, of almost all castes, sexes and developmental stages and sequenced them with the 454 GS FLX titanium system. We obtained >1.2 million quality-filtered reads yielding >400 million bases for each of the three species. Isotigs, which are analogous to individual transcripts, and singletons were produced by assembling the reads and annotated using public databases. Genes related to juvenile hormone, which plays crucial roles in caste differentiation of termites, were identified from the EST libraries by BLAST search. To explore the potential for DNA methylation, which plays an important role in caste differentiation of honeybees, tBLASTn searches for DNA methyltransferases (dnmt1, dnmt2 and dnmt3) and methyl-CpG binding domain (mbd) were performed against the EST libraries. All four of these genes were found in the H. sjostedti library, while all except dnmt3 were found in R. speratus and N. takasagoensis. The ratio of the observed to the expected CpG content (CpG O/E), which is a proxy for DNA methylation level, was calculated for the coding sequences predicted from the isotigs and singletons. In all of the three species, the majority of coding sequences showed depletion of CpG O/E (less than 1), and the distributions of CpG O/E were bimodal, suggesting the presence of

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes.

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Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A

2016-03-30

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermesat 59.5 Ma (49.9-69.5 Ma 95% CI), yet the oldest split within Reticulitermes(Eurasia and North America) is 16.1 Ma (13.4-19.5 Ma) and the oldest split within Heterotermes + Coptotermesis 36.0 Ma (33.9-40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. © 2016 The Author(s).

Resistência natural da madeira de Corymbia maculata (Hook. K.D.Hill & L.A.S. Johnson a fungos e cupins xilófagos, em condições de laboratório Wood natural resistance of Corymbia maculata (Hook. K.D.Hill & L.A.S Johnson to wood destroying fungi and termites, under laboratory tests

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Juarez Benigno Paes

2002-11-01

Full Text Available A pesquisa teve o objetivo de avaliar a resistência natural da madeira de Corymbia maculata a fungos e a cupins xilófagos, em condições de laboratório. De peças radiais (tábuas que continham o cerne e o alburno intactos foram retirados corpos-de-prova de 2,00 x 2,00 x 1,00 cm, com a menor dimensão na direção tangencial (ensaio com fungos, e de 2,54 x 2,00 x 0,64 cm, com a maior dimensão na direção das fibras (ensaio com cupins, em quatro posições na direção medula-casca. As amostras foram submetidas à ação dos fungos Postia placenta, Neolentinus lepideus e Polyporus fumosus por 12 semanas, ou à ação de cupins do gênero Nasutitermes por 30 dias. Constatou-se que a resistência da madeira ao apodrecimento foi dependente da posição na direção medula-casca e dos fungos utilizados. As amostras retiradas nas posições mais externas do tronco foram mais deterioradas que as internas. Dentro de cada posição, os fungos causaram deterioração semelhante à madeira, exceto para a posição mais externa (alburno, em que o fungo P. fumosus causou menos deterioração que os demais. De modo geral, a madeira de C. maculata foi altamente resistente (posições internas ou resistente (posições externas aos fungos ensaiados. Somente para o fungo N. lepideus a posição mais externa foi moderadamente resistente. Quanto aos cupins, a resistência da madeira não foi afetada pela posição na direção medula-casca e apresentou uma baixa perda de massa para as posições analisadas. Além disto, os cupins causaram somente desgaste superficial à madeira, e morreram durante o ensaio, o que permitiu classificar a madeira de C.maculata como resistente aos cupins ensaiados.This research evaluated the natural resistance of Corymbia maculata wood to wood-destroying fungi and termites, under laboratory tests. Radial pieces (boards, containing intact heartwood and sapwood were transformed into test samples measuring 2.00 x 2.00 x 1.00 cm

Origin and alteration of organic matter in termite mounds from different feeding guilds of the Amazon rainforests.

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Nina Siebers

Full Text Available The impact of termites on nutrient cycling and tropical soil formation depends on their feeding habits and related material transformation. The identification of food sources, however, is difficult, because they are variable and changed by termite activity and nest construction. Here, we related the sources and alteration of organic matter in nests from seven different termite genera and feeding habits in the Terra Firme rainforests to the properties of potential food sources soil, wood, and microepiphytes. Chemical analyses comprised isotopic composition of C and N, cellulosic (CPS, non-cellulosic (NCPS, and N-containing saccharides, and molecular composition screening using pyrolysis-field ionization mass spectrometry (Py-FIMS. The isotopic analysis revealed higher soil δ13C (-27.4‰ and δ15N (6.6‰ values in nests of wood feeding Nasutitermes and Cornitermes than in wood samples (δ13C = -29.1‰, δ15N = 3.4‰, reflecting stable-isotope enrichment with organic matter alterations during or after nest construction. This result was confirmed by elevated NCPS:CPS ratios, indicating a preferential cellulose decomposition in the nests. High portions of muramic acid (MurAc pointed to the participation of bacteria in the transformation processes. Non-metric multidimensional scaling (MDS revealed increasing geophagy in the sequence Termes < Embiratermes < Anoplotermes and increasing xylophagy for Cornitermes < Nasutitermes., and that the nest material of Constrictotermes was similar to the microepiphytes sample, confirming the report that Constrictotermes belongs to the microepiphyte-feeders. We therewith document that nest chemistry of rainforest termites shows variations and evidence of modification by microbial processes, but nevertheless it primarily reflects the trophic niches of the constructors.

Escaping and repairing behaviors of the termite Odontotermes formosanus (Blattodea: Termitidae in response to disturbance

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Hongpeng Xiong

2018-03-01

Full Text Available The escaping behavior of termites has been documented under laboratory conditions; however, no study has been conducted in a field setting due to the difficulty of observing natural behaviors inside wood or structures (e.g., nests, tunnels, etc.. The black-winged termite, Odontotermes formosanus (Shiraki, is a subterranean macrotermitine species which builds extensive mud tubes on tree trunks. In the present study, 41 videos (totaling ∼2,700 min were taken on 22 colonies/subcolonies of O. formosanus after their mud tubes were partially damaged by hand. In general, termites consistently demonstrated three phases of escape, including initiation (wandering near the mud-tube breach, individual escaping (single termites moving downward, and massive, unidirectional escaping flows (groups of termites moving downward. Downward moving and repairing were the dominant behavioral activities of individuals and were significantly more frequent than upward moving, turning/backward moving, or wandering. Interestingly, termites in escaping flows moved significantly faster than escaping individuals. Repairing behavior was observed shortly after the disturbance, and new mud tubes were preferentially constructed from the bottom up. When predators (i.e., ants were present, however, termites stopped moving and quickly sealed the mud-tube openings by capping the broken ends. Our study provides an interesting example that documents an animal (besides humans simultaneously carrying out pathway repairs and emergency evacuation without congestion.

Escaping and repairing behaviors of the termite Odontotermes formosanus (Blattodea: Termitidae) in response to disturbance.

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Xiong, Hongpeng; Chen, Xuan; Wen, Yuzhen; Layne, Michael; Sun, Zhaohui; Ma, Tao; Wen, Xiujun; Wang, Cai

2018-01-01

The escaping behavior of termites has been documented under laboratory conditions; however, no study has been conducted in a field setting due to the difficulty of observing natural behaviors inside wood or structures (e.g., nests, tunnels, etc.). The black-winged termite, Odontotermes formosanus (Shiraki), is a subterranean macrotermitine species which builds extensive mud tubes on tree trunks. In the present study, 41 videos (totaling ∼2,700 min) were taken on 22 colonies/subcolonies of O. formosanus after their mud tubes were partially damaged by hand. In general, termites consistently demonstrated three phases of escape, including initiation (wandering near the mud-tube breach), individual escaping (single termites moving downward), and massive, unidirectional escaping flows (groups of termites moving downward). Downward moving and repairing were the dominant behavioral activities of individuals and were significantly more frequent than upward moving, turning/backward moving, or wandering. Interestingly, termites in escaping flows moved significantly faster than escaping individuals. Repairing behavior was observed shortly after the disturbance, and new mud tubes were preferentially constructed from the bottom up. When predators (i.e., ants) were present, however, termites stopped moving and quickly sealed the mud-tube openings by capping the broken ends. Our study provides an interesting example that documents an animal (besides humans) simultaneously carrying out pathway repairs and emergency evacuation without congestion.

Antitermite Activities of C. decidua Extracts and Pure Compounds against Indian White Termite Odontotermes obesus (Isoptera: Odontotermitidae

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Ravi Kant Upadhyay

2012-01-01

Full Text Available In the present investigation, we have tested antitermite responses of Capparis decidua stem, root, flower, and fruit extracts and pure compounds to Odontotermes obesus in various bioassays. Crude stem extract has shown very high susceptibility and very low LD50 values, that is, 14.171 μg/mg in worker termites. From stem extract, three pure compounds were isolated in pure form namely, heneicosylhexadecanoate (CDS2, triacontanol (CDS3, and 2-carboxy-1, 1-dimethylpyrrolidine (CDS8 which have shown very low LD50 value in a range of 5.537–10.083 μg/mg. Similarly, one novel compound 6-(1-hydroxy-non-3-enyl-tetrahydropyran-2-one (CDF1 was isolated from flower extract that has shown an LD50 8.08 μg/gm. Repellent action of compounds was tested in a Y-shaped glass olfactometer in which CDF1 compounds have significantly repelled termites to the opposite arm. Besides this, C. decidua extracts have shown significant reduction (P<0.05 and 0.01 in termite infestation in garden saplings when it was coated on cotton tags and employed over tree trunks. Further, C. deciduas stem extract was used for wood seasoning, which gave very good results as test wood sticks have shown significantly (P<0.05 and 0.01 very low termite infestation.

Metagenomic insights into metabolic capacities of the gut microbiota in a fungus-cultivating termite (Odontotermes yunnanensis.

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Ning Liu

Full Text Available Macrotermitinae (fungus-cultivating termites are major decomposers in tropical and subtropical areas of Asia and Africa. They have specifically evolved mutualistic associations with both a Termitomyces fungi on the nest and a gut microbiota, providing a model system for probing host-microbe interactions. Yet the symbiotic roles of gut microbes residing in its major feeding caste remain largely undefined. Here, by pyrosequencing the whole gut metagenome of adult workers of a fungus-cultivating termite (Odontotermes yunnanensis, we showed that it did harbor a broad set of genes or gene modules encoding carbohydrate-active enzymes (CAZymes relevant to plant fiber degradation, particularly debranching enzymes and oligosaccharide-processing enzymes. Besides, it also contained a considerable number of genes encoding chitinases and glycoprotein oligosaccharide-processing enzymes for fungal cell wall degradation. To investigate the metabolic divergence of higher termites of different feeding guilds, a SEED subsystem-based gene-centric comparative analysis of the data with that of a previously sequenced wood-feeding Nasutitermes hindgut microbiome was also attempted, revealing that SEED classifications of nitrogen metabolism, and motility and chemotaxis were significantly overrepresented in the wood-feeder hindgut metagenome, while Bacteroidales conjugative transposons and subsystems related to central aromatic compounds metabolism were apparently overrepresented here. This work fills up our gaps in understanding the functional capacities of fungus-cultivating termite gut microbiota, especially their roles in the symbiotic digestion of lignocelluloses and utilization of fungal biomass, both of which greatly add to existing understandings of this peculiar symbiosis.

Preliminary investigation of biological resistance, water absorption and swelling of thermally compressed pine wood panels

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Oner Unsal; S. Nami Kartal; Zeki Candan; Rachel Arango; Carol A. Clausen; Frederick Green

2008-01-01

Wood can be modified by compressive, thermal and chemical treatments. Compression of wood under thermal conditions is resulted in densification of wood. This study evaluated decay and termite resistance of thermally compressed pine wood panels at either 5 or 7 MPa and at either 120 or 150°C for one hour. The process caused increases in density and decreases in...

Laboratory evaluations of woods from Pakistan and their extractives against Postia placenta and Trametes versicolor

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Mark Mankowski; Barbar Hassan; Amy Blodgett; Grant T. Kirker

2016-01-01

Natural durable wood species are those which exhibit innate tolerance to wood decay organisms such as fungi and termites. The goal of this study was to evaluate 4 wood species (Dalbergia sissoo, Cedrus deodara, Morus alba and Pinus roxburghii) from Pakistan in order to determine their resistance to both a model brown (

Diversity and resilience of the wood?feeding higher termite Mironasutitermes shangchengensis gut microbiota in response to temporal and diet variations

OpenAIRE

Wang, Ying; Su, Lijuan; Huang, Shi; Bo, Cunpei; Yang, Sen; Li, Yan; Wang, Fengqin; Xie, Hui; Xu, Jian; Song, Andong

2016-01-01

Abstract Termites are considered among the most efficient bioreactors, with high capacities for lignocellulose degradation and utilization. Recently, several studies have characterized the gut microbiota of diverse termites. However, the temporal dynamics of the gut microbiota within a given termite with dietary diversity are poorly understood. Here, we employed 16S rDNA barcoded pyrosequencing analysis to investigate temporal changes in bacterial diversity and richness of the gut microbiota ...

Integrating Ethno-Ecological and Scientific Knowledge of Termites for Sustainable Termite Management and Human Welfare in Africa

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Gudeta W. Sileshi

2009-06-01

Full Text Available Despite their well-known role as pests, termites also provide essential ecosystem services. In this paper, we undertook a comprehensive review of studies on human-termite interactions and farmers' indigenous knowledge across Sub-Saharan Africa in an effort to build coherent principles for termite management. The review revealed that local communities have comprehensive indigenous knowledge of termite ecology and taxonomy, and apply various indigenous control practices. Many communities also have elaborate knowledge of the nutritional and medicinal value of termites and mushrooms associated with termite nests. Children and women also widely consume termite mound soil for nutritional or other benefits encouraged by indigenous belief systems. In addition, subsistence farmers use termites as indicators of soil fertility, and use termite mound soil in low-risk farming strategies for crop production. In the past, chemical control of termites has been initiated without empirical data on the termite species, their damage threshold, and the social, ecological, or economic risks and trade-offs of the control. This review has provided new insights into the intimate nature of human-termite interactions in Africa and the risks of chemical control of termites to human welfare and the environment. We recommend that management of termites in future should be built on farmers' indigenous knowledge and adequate understanding of the ecology of the local termite species.

Saccharification of Agricultural Lignocellulose Feedstocks and Protein-Level Responses by a Termite Gut-Microbe Bioreactor

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Rajarapu, Swapna Priya; Scharf, Michael E.

2017-01-01

This study investigated saccharification and protein-level responses to the candidate biofuel feedstocks corn stover (CS) and soybean residue (SR) by the gut of a lower termite. The focus termite was Reticulitermes flavipes, which is a highly efficient digester of wood lignocellulose that houses a mixture of prokaryotic and eukaryotic microbes in its gut. Our specific objectives were to (i) measure saccharification potential of the CS and SR feedstocks by termite gut protein extracts, (ii) identify specific proteins in the termite gut responding to feeding on CS and SR diets, and (iii) evaluate gut lignocellulase and accessory enzyme activity responses to CS and SR feeding. Cellulose paper was the control diet. Although CS was saccharified at higher levels, termite gut protein extracts saccharified both CS and SR irrespective of feedstock loading. Consumption of the CS and SR feedstocks by termites resulted in surprisingly few differences in gut protein profiles, with the main exception being elevated myosin abundance with SR feeding. Activity of potential lignocellulases and accessory enzymes was generally similar between CS and SR fed guts as well; however, cellobiohydrolase/exoglucanase activity was higher with CS feeding and glutathione peroxidase activity with SR feeding. These findings have significance from two perspectives. First, SR feeding/digestion appears to cause physiological stress in the termite gut that likely would extend to other types of microbial environments including those within industrial bioreactors. Second, because termites can survive on exclusive CS and SR diets and their guts exhibit clear CS and SR saccharification activity, this validates the R. flavipes system as a potential source for CS and SR degrading enzymes; in particular, cellobiohydrolases/exoglucanases and glutathione peroxidases from this system may play roles in CS and SR breakdown.

Saccharification of Agricultural Lignocellulose Feedstocks and Protein-Level Responses by a Termite Gut-Microbe Bioreactor

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Rajarapu, Swapna Priya; Scharf, Michael E., E-mail: mscharf@purdue.edu [Department of Entomology, Purdue University, West Lafayette, IN (United States)

2017-04-07

This study investigated saccharification and protein-level responses to the candidate biofuel feedstocks corn stover (CS) and soybean residue (SR) by the gut of a lower termite. The focus termite was Reticulitermes flavipes, which is a highly efficient digester of wood lignocellulose that houses a mixture of prokaryotic and eukaryotic microbes in its gut. Our specific objectives were to (i) measure saccharification potential of the CS and SR feedstocks by termite gut protein extracts, (ii) identify specific proteins in the termite gut responding to feeding on CS and SR diets, and (iii) evaluate gut lignocellulase and accessory enzyme activity responses to CS and SR feeding. Cellulose paper was the control diet. Although CS was saccharified at higher levels, termite gut protein extracts saccharified both CS and SR irrespective of feedstock loading. Consumption of the CS and SR feedstocks by termites resulted in surprisingly few differences in gut protein profiles, with the main exception being elevated myosin abundance with SR feeding. Activity of potential lignocellulases and accessory enzymes was generally similar between CS and SR fed guts as well; however, cellobiohydrolase/exoglucanase activity was higher with CS feeding and glutathione peroxidase activity with SR feeding. These findings have significance from two perspectives. First, SR feeding/digestion appears to cause physiological stress in the termite gut that likely would extend to other types of microbial environments including those within industrial bioreactors. Second, because termites can survive on exclusive CS and SR diets and their guts exhibit clear CS and SR saccharification activity, this validates the R. flavipes system as a potential source for CS and SR degrading enzymes; in particular, cellobiohydrolases/exoglucanases and glutathione peroxidases from this system may play roles in CS and SR breakdown.

Termite assemblages in five semideciduous Atlantic Forest fragments in the northern coastland limit of the biome

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Heitor Bruno de Araújo Souza

2012-03-01

Full Text Available Termites are abundant organisms in tropical ecosystems and strongly influence the litter decomposition and soil formation. Despite their importance, few studies about their assemblage structures have been made in Brazilian Atlantic Forest fragments, especially in the area located north of the São Francisco River. This study aims to analyze the assemblage composition of five Atlantic Forest fragments located in the northern biome limit along the Brazilian coast. A standardized sampling protocol of termites was applied in each fragment. Thirty-three termite species belonging to twenty genera and three families were found in the forest fragments. The wood-feeder group was dominant both concerning to species richness and number of encounters in all areas. In sites northern to 7°S, there is an evident simplification of the termite assemblage composition regarding species richness and number of encounters by feeding group. This fact is apparently due to a higher sandy level in soils and to semideciduous character of the vegetation in the northern fragments. Thus, even on the north of São Francisco River, termite biodiversity is heterogeneously spread with highest density of species in the portion between 07°S and São Francisco River mouth (10°29'S.

How Termite Mounds Breath?

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Saxena, Saurabh; Yaghoobian, Neda

2017-11-01

Fungus-cultivating termites of the subfamily Macrotermitinae that are extensively found throughout sub-Saharan Africa and south East Asia are one species of termites that collectively build massive, uninhabited, complex structures. These structures, which are much larger than the size of an individual termite, effectively use natural wind and solar energies and the energy embodied in colony's metabolic activity to maintain the necessary condition for termite survival. These mounds enclose a subterranean nest, where the termite live and cultivate fungus, as well as a complex network of tunnels consisting of a large, vertically oriented central chimney, surface conduits, and lateral connectives that connect the chimney and the surface conduits. In this study, we use computational modeling to explore the combined interaction of geometry, heterogeneous thermal mass, and porosity with the external turbulent wind and solar radiation to investigate the physical principles and fundamental aero-thermodynamics underlying the controlled and stable climate of termite mounds. Exploitation of natural resources of wind and solar energies in these natural systems for the purpose of ventilation will lead to new lessons for improving human habitats conditions.

Disappearance and Compressibility of Buried Pine Wood in a Warm Temperate Soil Environment.

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Gholz, H L; Krazynski, L M; Volk, B G

1991-02-01

The rate of disappearance of buried pine wood in Florida was found to be 15%/yr.As consumption by microorganisms and termites proceeded, the wood also became more compressible. After only 5 yr, consumption and compression could account for 60-70% loss of original volume of wood under pavement near the surface of an embankment. This large volume loss occurring in a relatively short time period may be responsible for many surface deformations in pavements and weaknesses in other embankments where wood may occur as a contaminant. © 1991 by the Ecological Society of America.

Termite-egg mimicry by a sclerotium-forming fungus.

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Matsuura, Kenji

2006-05-22

Mimicry has evolved in a wide range of organisms and encompasses diverse tactics for defence, foraging, pollination and social parasitism. Here, I report an extraordinary case of egg mimicry by a fungus, whereby the fungus gains competitor-free habitat in termite nests. Brown fungal balls, called 'termite balls', are frequently found in egg piles of Reticulitermes termites. Phylogenetic analysis illustrated that termite-ball fungi isolated from different hosts (Reticulitermes speratus, Reticulitermes flavipes and Reticulitermes virginicus) were all very similar, with no significant molecular differences among host species or geographical locations. I found no significant effect of termite balls on egg survivorship. The termite-ball fungus rarely kills termite eggs in natural colonies. Even a termite species (Reticulitermes okinawanus) with no natural association with the fungus tended termite balls along with its eggs when it was experimentally provided with termite balls. Dummy-egg bioassays using glass beads showed that both morphological and chemical camouflage were necessary to induce tending by termites. Termites almost exclusively tended termite balls with diameters that exactly matched their egg size. Moreover, scanning electron microscopic observations revealed sophisticated mimicry of the smooth surface texture of eggs. These results provide clear evidence that this interaction is beneficial only for the fungus, i.e. termite balls parasitically mimic termite eggs.

TERMITES ENDANGERED TRADITIONAL MEDICAL PLANTS

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Syaukani Syaukani

2014-04-01

Full Text Available Surveys on traditional medical plants affected by termites have been conducted since June to August 2010 at Ketambe, northern Aceh. Traditional medical plants and their natural habitats were obtained through interviewing local people. Termites were collected by adopted a Standardized Sampling Protocol and final. taxonomic confirmation was done with the help of Termite Research Group (the Natural History Museum, London. About 20 species of medical plants were attacked by termites with various levels. Nine genera and 20 species were collected from various habitats throughout Ketambe, Simpur as well as Gunung Setan villages. Coffe (Coffea arabica, hazelnut (Aleurites moluccana , and areca (Area catechu were among the worse of traditional medical  plant that had been attached by the termites.

Digestive beta-glucosidases from the wood-feeding higher termite, Nasutitermes takasagoensis: intestinal distribution, molecular characterization, and alteration in sites of expression.

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Tokuda, Gaku; Miyagi, Mio; Makiya, Hiromi; Watanabe, Hirofumi; Arakawa, Gaku

2009-12-01

beta-Glucosidase [EC 3.2.1.21] hydrolyzes cellobiose or cello-oligosaccharides into glucose during cellulose digestion in termites. SDS-PAGE and zymogram analyses of the digestive system in the higher termite Nasutitermes takasagoensis revealed that beta-glucosidase activity is localized in the salivary glands and midgut as dimeric glycoproteins. Degenerate PCR using primers based on the N-terminal amino acid sequences of the salivary beta-glucosidase resulted in cDNA fragments of 1.7 kb, encoding 489 amino acids with a sequence similar to glycosyl hydrolase family 1. Moreover, these primers amplified cDNA fragments from the midgut, and the deduced amino acid sequences are 87-91% identical to those of the salivary beta-glucosidases. Successful expression of the cDNAs in Escherichia coli implies that these sequences also encode functional beta-glucosidases. These results indicate that beta-glucosidases that primarily contribute to the digestive process of N. takasagoensis are produced in the midgut. Reverse transcription-PCR analysis indicated the site-specific expression of beta-glucosidase mRNAs in the salivary glands and midgut. These results suggest that termites have developed the ability to produce beta-glucosidases in the midgut, as is the case for endo-beta-1,4-glucanase, in which the site of expression has shifted from the salivary glands of lower termites to the midgut of higher termites. Copyright 2009 Elsevier Ltd. All rights reserved.

Termites as targets and models for biotechnology.

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Scharf, Michael E

2015-01-07

Termites have many unique evolutionary adaptations associated with their eusocial lifestyles. Recent omics research has created a wealth of new information in numerous areas of termite biology (e.g., caste polyphenism, lignocellulose digestion, and microbial symbiosis) with wide-ranging applications in diverse biotechnological niches. Termite biotechnology falls into two categories: (a) termite-targeted biotechnology for pest management purposes, and (b) termite-modeled biotechnology for use in various industrial applications. The first category includes several candidate termiticidal modes of action such as RNA interference, digestive inhibition, pathogen enhancement, antimicrobials, endocrine disruption, and primer pheromone mimicry. In the second category, termite digestomes are deep resources for host and symbiont lignocellulases and other enzymes with applications in a variety of biomass, industrial, and processing applications. Moving forward, one of the most important approaches for accelerating advances in both termite-targeted and termite-modeled biotechnology will be to consider host and symbiont together as a single functional unit.

Inside the guts of wood-eating catfishes: can they digest wood?

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German, Donovan P

2009-11-01

To better understand the structure and function of the gastrointestinal (GI) tracts of wood-eating catfishes, the gross morphology, length, and microvilli surface area (MVSA) of the intestines of wild-caught Panaque nocturnus, P. cf. nigrolineatus "Marañon", and Hypostomus pyrineusi were measured, and contrasted against these same metrics of a closely related detritivore, Pterygoplichthys disjunctivus. All four species had anatomically unspecialized intestines with no kinks, valves, or ceca of any kind. The wood-eating catfishes had body size-corrected intestinal lengths that were 35% shorter than the detritivore. The MVSA of all four species decreased distally in the intestine, indicating that nutrient absorption preferentially takes place in the proximal and mid-intestine, consistent with digestive enzyme activity and luminal carbohydrate profiles for these same species. Wild-caught Pt. disjunctivus, and P. nigrolineatus obtained via the aquarium trade, poorly digested wood cellulose (<33% digestibility) in laboratory feeding trials, lost weight when consuming wood, and passed stained wood through their digestive tracts in less than 4 h. Furthermore, no selective retention of small particles was observed in either species in any region of the gut. Collectively, these results corroborate digestive enzyme activity profiles and gastrointestinal fermentation levels in the fishes' GI tracts, suggesting that the wood-eating catfishes are not true xylivores such as beavers and termites, but rather, are detritivores like so many other fishes from the family Loricariidae.

Dominant ectosymbiotic bacteria of cellulolytic protists in the termite gut also have the potential to digest lignocellulose.

Science.gov (United States)

Yuki, Masahiro; Kuwahara, Hirokazu; Shintani, Masaki; Izawa, Kazuki; Sato, Tomoyuki; Starns, David; Hongoh, Yuichi; Ohkuma, Moriya

2015-12-01

Wood-feeding lower termites harbour symbiotic gut protists that support the termite nutritionally by degrading recalcitrant lignocellulose. These protists themselves host specific endo- and ectosymbiotic bacteria, functions of which remain largely unknown. Here, we present draft genomes of a dominant, uncultured ectosymbiont belonging to the order Bacteroidales, 'Candidatus Symbiothrix dinenymphae', which colonizes the cell surface of the cellulolytic gut protists Dinenympha spp. We analysed four single-cell genomes of Ca. S. dinenymphae, the highest genome completeness was estimated to be 81.6-82.3% with a predicted genome size of 4.28-4.31 Mb. The genome retains genes encoding large parts of the amino acid, cofactor and nucleotide biosynthetic pathways. In addition, the genome contains genes encoding various glycoside hydrolases such as endoglucanases and hemicellulases. The genome indicates that Ca. S. dinenymphae ferments lignocellulose-derived monosaccharides to acetate, a major carbon and energy source of the host termite. We suggest that the ectosymbiont digests lignocellulose and provides nutrients to the host termites, and hypothesize that the hydrolytic activity might also function as a pretreatment for the host protist to effectively decompose the crystalline cellulose components. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Starch inclusion complex to emulsify cedarwood oil and pressure treat wood

Science.gov (United States)

Previously, we have demonstrated that CO2-derived cedarwood oil has a range of bioactivities, including insect repellency and toxicity as well as conferring resistance to both termites and wood-rot fungi. In the earlier pressure treatment work, ethanol was used as the diluent/carrier. However, it is...

Cultural significance of termites in sub-Saharan Africa.

Science.gov (United States)

van Huis, Arnold

2017-01-26

The number of termite species in the world is more than 2500, and Africa with more than 1000 species has the richest intercontinental diversity. The family Termitidae contains builders of great mounds up to 5 m high. Colonies are composed of casts: a queen, a king, soldiers and workers. Some species of termite cultivate specialised fungi to digest cellulose. Termites constitute 10% of all animal biomass in the tropics. The purpose of the study was to make an overview of how termites are utilized, perceived and experienced in daily life across sub-Saharan Africa. Ethno-entomological information on termites (Isoptera) in sub-Saharan Africa was collected by: (1) interviews with more than 300 people from about 120 ethnic groups from 27 countries in the region; (2) library studies in Africa, London, Paris and Leiden. Vernacular names relate to mounds, insects as food, the swarming, and the behaviour of termites. Swarming reproductive, soldiers and queens are collected as food. There are many different ways to harvest them. Termites can also be used as feed for poultry or as bait to catch birds and fish. The mushrooms that grow each year from the fungus gardens on the termite mounds are eaten. The soldiers, the fungus gardens and the soil of termite mounds are used for multiple medicinal purposes. Mounds and soil of termites have numerous functions: for geochemical prospecting, making bricks, plastering houses, making pots, and for storage. Termite soil is often used as fertilizer. The act of eating soil (geophagy) among women, especially those that are pregnant, is practised all over Africa. The mounds can serve as burying places and are often associated with the spiritual world, especially containing the spirits of ancestors. Termites also play a role as oracle, in superstitious beliefs, in art and literature. The following characteristics make termites so appealing: the dominance in the landscape, the social organization, the destructive power, and the provision of

Profiling the Succession of Bacterial Communities throughout the Life Stages of a Higher Termite Nasutitermes arborum (Termitidae, Nasutitermitinae) Using 16S rRNA Gene Pyrosequencing

Science.gov (United States)

Diouf, Michel; Roy, Virginie; Mora, Philippe; Frechault, Sophie; Lefebvre, Thomas; Hervé, Vincent; Rouland-Lefèvre, Corinne; Miambi, Edouard

2015-01-01

Previous surveys of the gut microbiota of termites have been limited to the worker caste. Termite gut microbiota has been well documented over the last decades and consists mainly of lineages specific to the gut microbiome which are maintained across generations. Despite this intimate relationship, little is known of how symbionts are transmitted to each generation of the host, especially in higher termites where proctodeal feeding has never been reported. The bacterial succession across life stages of the wood-feeding higher termite Nasutitermes arborum was characterized by 16S rRNA gene deep sequencing. The microbial community in the eggs, mainly affiliated to Proteobacteria and Actinobacteria, was markedly different from the communities in the following developmental stages. In the first instar and last instar larvae and worker caste termites, Proteobacteria and Actinobacteria were less abundant than Firmicutes, Bacteroidetes, Spirochaetes, Fibrobacteres and the candidate phylum TG3 from the last instar larvae. Most of the representatives of these phyla (except Firmicutes) were identified as termite-gut specific lineages, although their relative abundances differed. The most salient difference between last instar larvae and worker caste termites was the very high proportion of Spirochaetes, most of which were affiliated to the Treponema Ic, Ia and If subclusters, in workers. The results suggest that termite symbionts are not transmitted from mother to offspring but become established by a gradual process allowing the offspring to have access to the bulk of the microbiota prior to the emergence of workers, and, therefore, presumably through social exchanges with nursing workers. PMID:26444989

Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

Science.gov (United States)

Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

2015-04-01

Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

Wood Decomposition of Cyrilla racemiflora (Cyrillaceae) in Puerto Rican Dry and Wet Forests: A 13-year Case Study.

Science.gov (United States)

Juan A. Torres; Grizelle Gonzalez

2005-01-01

We studied the decomposition of Cyrilla racemiflora logs over a 13-yr period in tropical dry and wet forests in Puerto Rico. The mean mass loss, ratio of soft to hard wood, nutrient concentrations, and the diversity of wood-inhabiting organisms were greater in logs decomposing in the dry forest than in the wet forest. Termites were also more abundant in the logs...

The first report of gynandromorphy in termites (Isoptera; Kalotermitidae; Neotermes koshunensis)

Science.gov (United States)

Miyaguni, Yasushi; Nozaki, Tomonari; Yashiro, Toshihisa

2017-08-01

This is the first report of gynandromorphy in Isoptera. An Asian dry-wood termite, Neotermes koshunensis (Shiraki) [Kalotermitidae], possessing both male and female phenotypic characteristics, was found on Okinawa Island, Japan. This deformed individual showed morphological and anatomical hermaphroditism in the abdomen. The right side of the seventh sternite was the female form and contained an ovary, while the left side was the male form and contained a testis. Genotypic analysis revealed that this individual was a genotypic bilateral chimera. These results suggested that the termite was a bilateral gynandromorph with a male left side and a female right side. As reported previously in other insects, double fertilization (by two sperms, one with an X and one with a Y chromosome) of a binucleate egg is the most likely mechanism that generated this genotypic bilateral chimera. N. koshunensis has the ability to reproduce through parthenogenesis, in which the secondary polar body is likely to be used for nuclear phase recovery. If the second polar body in this mechanism has high fertility and healthy embryogenic potential, like an egg nucleus, some of gynandromorphs might be produced by a side effect of parthenogenetic ability.

Putting the bite on termites

International Nuclear Information System (INIS)

Anon.

1984-01-01

An Australian program for studying and controlling termites traces the insects by feeding them a bait containing a short-lived isotope such as lanthanum-140 or scandium-46. It has been discovered that termites can live entirely above the ground. Another discovery is that colonies often occupy several shared mounds

Applicability of Vegetable Oils as a Wood Preservative

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Eylem Dizman Tomak

2012-04-01

Full Text Available Conventional heavy duty wood preservatives have been banned or restricted for some applications due to their mammalian toxicity and their adverse effect on the environment. New, eco-friendly, but nevertheless still effective protection systems, is needed to protect wood in outdoors. Non-toxic vegetable oils can form of a protective layer on the surface of the wood cells which decrease water uptake of wood. For that reason, oils have a good potential as being a wood preservative. However, impregnation with vegetable oils is insufficient to impart adequate biological decay and termite resistance, and indeed the treatment may increase wood’s propensity to burn. In addition, a high level of oil absorption required for good protection make the process impractical and uneconomic to use. The efficiency of the treatment can be improved with using the biocides and oils together. Beside this, usage of modified oils can decrease the retention levels in wood. In this study, applicability of vegetable oils being one of the environment-friendly, biodegradable water repellents on wood treatments was reported. Furthermore, problems related to the use of oils for wood protection, and possible solutions for the problems were discussed.In this study, applicability of vegetable oils as one of the environment-friendly, biodegradable water repellents was reported. Furthermore, problems related to the use of oils for wood protection and possible solutions for the problems were discussed

Nest sanitation through defecation: antifungal properties of wood cockroach feces

Science.gov (United States)

Rosengaus, Rebeca B.; Mead, Kerry; Du Comb, William S.; Benson, Ryan W.; Godoy, Veronica G.

2013-11-01

The wood cockroach Cryptocercus punctulatus nests as family units inside decayed wood, a substrate known for its high microbial load. We tested the hypothesis that defecation within their nests, a common occurrence in this species, reduces the probability of fungal development. Conidia of the entomopathogenic fungus, Metarhizium anisopliae, were incubated with crushed feces and subsequently plated on potato dextrose agar. Relative to controls, the viability of fungal conidia was significantly reduced following incubation with feces and was negatively correlated with incubation time. Although the cockroach's hindgut contained abundant β-1,3-glucanase activity, its feces had no detectable enzymatic function. Hence, these enzymes are unlikely the source of the fungistasis. Instead, the antifungal compound(s) of the feces involved heat-sensitive factor(s) of potential microbial origin. When feces were boiled or when they were subjected to ultraviolet radiation and subsequently incubated with conidia, viability was "rescued" and germination rates were similar to those of controls. Filtration experiments indicate that the fungistatic activity of feces results from chemical interference. Because Cryptocercidae cockroaches have been considered appropriate models to make inferences about the factors fostering the evolution of termite sociality, we suggest that nesting in microbe-rich environments likely selected for the coupling of intranest defecation and feces fungistasis in the common ancestor of wood cockroaches and termites. This might in turn have served as a preadaptation that prevented mycosis as these phylogenetically related taxa diverged and evolved respectively into subsocial and eusocial organizations.

Caste-, sex-, and age-dependent expression of immune-related genes in a Japanese subterranean termite, Reticulitermes speratus.

Directory of Open Access Journals (Sweden)

Yuki Mitaka

Full Text Available Insects protect themselves from microbial infections through innate immune responses, including pathogen recognition, phagocytosis, the activation of proteolytic cascades, and the synthesis of antimicrobial peptides. Termites, eusocial insects inhabiting microbe-rich wood, live in closely-related family groups that are susceptible to shared pathogen infections. To resist pathogenic infection, termite families have evolved diverse immune adaptations at both individual and societal levels, and a strategy of trade-offs between reproduction and immunity has been suggested. Although termite immune-inducible genes have been identified, few studies have investigated the differential expression of these genes between reproductive and neuter castes, and between sexes in each caste. In this study, we compared the expression levels of immune-related genes among castes, sexes, and ages in a Japanese subterranean termite, Reticulitermes speratus. Using RNA-seq, we found 197 immune-related genes, including 40 pattern recognition proteins, 97 signalling proteins, 60 effectors. Among these genes, 174 showed differential expression among castes. Comparing expression levels between males and females in each caste, we found sexually dimorphic expression of immune-related genes not only in reproductive castes, but also in neuter castes. Moreover, we identified age-related differential expression of 162 genes in male and/or female reproductives. In addition, although R. speratus is known to use the antibacterial peptide C-type lysozyme as an egg recognition pheromone, we determined that R. speratus has not only C-type, but also P-type and I-type lysozymes, as well as other termite species. Our transcriptomic analyses revealed immune response plasticity among all castes, and sex-biased expression of immune genes even in neuter castes, suggesting a sexual division of labor in the immune system of R. speratus. This study heightens the understanding of the evolution of

Expanding the knowledge on lignocellulolytic and redox enzymes of worker and soldier castes from the lower termite Coptotermes gestroi

Directory of Open Access Journals (Sweden)

João Paulo Lourenço Franco Cairo

2016-10-01

Full Text Available Termites are considered one of the most efficient decomposers of lignocelluloses on Earth due to their ability to produce, along with its microbial symbionts, a repertoire of carbohydrate-active enzymes (CAZymes. Recently, a set of Pro-oxidant, Antioxidant, and Detoxification enzymes (PAD were also correlated with the metabolism of carbohydrates and lignin in termites. The lower termite Coptotermes gestroi is considered the main urban pest in Brazil, causing damage to wood constructions. Recently, analysis of the enzymatic repertoire of C. gestroi unveiled the presence of different CAZymes. Because the gene profile of CAZy/PAD enzymes endogenously synthesized by C. gestroi and also by their symbiotic protists remains unclear, the aim of this study was to explore the eukaryotic repertoire of these enzymes in worker and soldier castes of C. gestroi. Our findings showed that worker and soldier castes present similar repertoires of CAZy/PAD enzymes, and also confirmed that endo-glucanases (GH9 and beta-glucosidases (GH1 were the most important glycoside hydrolase families related to lignocellulose degradation in both castes. Classical cellulases such as exo-glucanases (GH7 and endo-glucanases (GH5 and GH45, as well as classical xylanases (GH10 and GH11, were found in both castes only taxonomically related to protists, highlighting the importance of symbiosis in C. gestroi. Moreover, our analysis revealed the presence of Auxiliary Activity enzyme families (AAs, which could be related to lignin modifications in termite digestomes. In conclusion, this report expanded the knowledge on genes and proteins related to CAZy/PAD enzymes from worker and soldier castes of lower termites, revealing new potential enzyme candidates for second-generation biofuel processes.

Expanding the Knowledge on Lignocellulolytic and Redox Enzymes of Worker and Soldier Castes from the Lower Termite Coptotermes gestroi.

Science.gov (United States)

Franco Cairo, João P L; Carazzolle, Marcelo F; Leonardo, Flávia C; Mofatto, Luciana S; Brenelli, Lívia B; Gonçalves, Thiago A; Uchima, Cristiane A; Domingues, Romênia R; Alvarez, Thabata M; Tramontina, Robson; Vidal, Ramon O; Costa, Fernando F; Costa-Leonardo, Ana M; Paes Leme, Adriana F; Pereira, Gonçalo A G; Squina, Fabio M

2016-01-01

Termites are considered one of the most efficient decomposers of lignocelluloses on Earth due to their ability to produce, along with its microbial symbionts, a repertoire of carbohydrate-active enzymes (CAZymes). Recently, a set of Pro-oxidant, Antioxidant, and Detoxification enzymes (PAD) were also correlated with the metabolism of carbohydrates and lignin in termites. The lower termite Coptotermes gestroi is considered the main urban pest in Brazil, causing damage to wood constructions. Recently, analysis of the enzymatic repertoire of C. gestroi unveiled the presence of different CAZymes. Because the gene profile of CAZy/PAD enzymes endogenously synthesized by C. gestroi and also by their symbiotic protists remains unclear, the aim of this study was to explore the eukaryotic repertoire of these enzymes in worker and soldier castes of C. gestroi . Our findings showed that worker and soldier castes present similar repertoires of CAZy/PAD enzymes, and also confirmed that endo-glucanases (GH9) and beta-glucosidases (GH1) were the most important glycoside hydrolase families related to lignocellulose degradation in both castes. Classical cellulases such as exo-glucanases (GH7) and endo-glucanases (GH5 and GH45), as well as classical xylanases (GH10 and GH11), were found in both castes only taxonomically related to protists, highlighting the importance of symbiosis in C. gestroi . Moreover, our analysis revealed the presence of Auxiliary Activity enzyme families (AAs), which could be related to lignin modifications in termite digestomes. In conclusion, this report expanded the knowledge on genes and proteins related to CAZy/PAD enzymes from worker and soldier castes of lower termites, revealing new potential enzyme candidates for second-generation biofuel processes.

Attraction of subterranean termites (Isoptera) to carbon dioxide.

Science.gov (United States)

Bernklau, Elisa Jo; Fromm, Erich A; Judd, Timothy M; Bjostad, Louis B

2005-04-01

Subterranean termites, Reticulitermes spp., were attracted to carbon dioxide (CO2) in laboratory and field tests. In behavioral bioassays, Reticulitermes flavipes (Kollar), Reticulitermes tibialis Banks, and Reticulitermes virginicus Banks were attracted to CO2 concentrations between 5 and 50 mmol/mol. In further bioassays, R. tibialis and R. virginicus were attracted to the headspace from polyisocyanurate construction foam that contained 10-12 mmol/mol CO2. In soil bioassays in the laboratory, more termites foraged in chambers containing CO2-generating formulations than in unbaited control chambers. In field tests, stations containing CO2-generating baits attracted R. tibialis away from wooden fence posts at rangeland sites in Colorado. For all of the CO2 formulations tested, termites foraged in significantly more bait stations at treatment fenceposts than in bait stations at the control fenceposts. By the end of the 8-wk study, the number of bait stations located by termites at treatment fenceposts ranged from 40 to 90%. At control fenceposts, termites foraged in only a single station and the one positive station was not located by termites until week 5 of the study. At treatment fenceposts, termites foraged equally in active stations (containing a CO2-generating bait) and passive stations (with no CO2-generating bait), indicating that bait stations may benefit passively from a proximal CO2 source in the soil. CO2 used as an attractant in current baiting systems could improve their effectiveness by allowing earlier exposure of termites to an insecticide.

Termite Resistance of MDF Panels Treated with Various Boron Compounds

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Sedat Ondaral

2009-06-01

Full Text Available In this study, the effects of various boron compounds on the termite resistance of MDF panels were evaluated. Either borax (BX, boric acid (BA, zinc borate (ZB, or sodium perborate tetrahydrate (SPT were added to urea-formaldehyde (UF resin at target contents of 1%, 1.5%, 2% and 2.5% based on dry fiber weight. The panels were then manufactured using 12% urea-formaldehyde resin and 1% NH4Cl. MDF samples from the panels were tested against the subterranean termites, Coptotermes formosanus Shiraki. Laboratory termite resistance tests showed that all samples containing boron compounds had greater resistance against termite attack compared to untreated MDF samples. At the second and third weeks of exposure, nearly 100% termite mortalities were recorded in all boron compound treated samples. The highest termite mortalities were determined in the samples with either BA or BX. Also, it was found that SPT showed notable performance on the termite mortality. As chemical loadings increased, termite mortalities increased, and at the same time the weight losses of the samples decreased.

Colony social organization and population genetic structure of an introduced population of formosan subterranean termite from New Orleans, Louisiana.

Science.gov (United States)

Husseneder, Claudia; Messenger, Matthew T; Su, Nan-Yao; Grace, J Kenneth; Vargo, Edward L

2005-10-01

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is an invasive species in many parts of the world, including the U.S. mainland. The reasons for its invasive success may have to do with the flexible social and spatial organization of colonies. We investigated the population and breeding structure of 14 C. formosanus colonies in Louis Armstrong Park, New Orleans, LA. This population has been the focus of extensive study for many years, providing the opportunity to relate aspects of colony breeding structure to previous findings on colony characteristics such as body weight and number of workers, wood consumption, and intercolony aggression. Eight colonies were headed by a single pair of outbred reproductives (simple families), whereas six colonies were headed by low numbers of multiple kings and/or queens that were likely the neotenic descendants of the original colony (extended families). Within the foraging area of one large extended family colony, we found genetic differentiation among different collection sites, suggesting the presence of separate reproductive centers. No significant difference between simple family colonies and extended family colonies was found in worker body weight, soldier body weight, foraging area, population size, or wood consumption. However, level of inbreeding within colonies was negatively correlated with worker body weight and positively correlated with wood consumption. Also, genetic distance between colonies was positively correlated with aggression levels, suggesting a genetic basis to nestmate discrimination cues in this termite population. No obvious trait associated with colony reproductive structure was found that could account for the invasion success of this species.

Termite activity in relation to natural grassland soil attributes

NARCIS (Netherlands)

Kaschuk, G.; Pires Santos, J.C.; Almeida, J.A.; Sinhorati, D.S.; Berton-Junior, J.F.

2006-01-01

Soil-feeding termites transport soil for mound building, and this process can affect soil characteristics. To verify the influence of soil termite activity on soil characteristics, samples were collected from top, bottom and center of termite mounds, and of the adjacent area, to assess chemical and

Identifying the core microbial community in the gut of fungus-growing termites

DEFF Research Database (Denmark)

Otani, Saria; Mikaelyan, Aram; Nobre, Tânia

2014-01-01

Gut microbes play a crucial role in decomposing lignocellulose to fuel termite societies, with protists in the lower termites and prokaryotes in the higher termites providing these services. However, a single basal subfamily of the higher termites, the Macrotermitinae, also domesticated a plant......, and Synergistetes. A set of 42 genus-level taxa was present in all termite species and accounted for 56-68% of the species-specific reads. Gut communities of termites from the same genus were more similar than distantly related species, suggesting that phylogenetic ancestry matters, possibly in connection...... with specific termite genus-level ecological niches. Finally, we show that gut communities of fungus-growing termites are similar to cockroaches, both at the bacterial phylum level and in a comparison of the core Macrotermitinae taxa abundances with representative cockroach, lower termite, and higher non...

[Status of termite-mushroom artificial domestication cultivation--a review].

Science.gov (United States)

Zhang, Yujin; Guo, Huachun; Li, Rongchun

2010-10-01

Two models of domestication and cultivation of termite-mushroom were discussed: the cultivation of termitomyces model, which method of woodrotting fungi cultivation was emphasized and the original ecological model, which multiplication of symbiotic termites was focused. The problems and possible solutions during termite-mushroom cultivation were also discussed.

Farmers' perception of termites in agriculture production and their indigenous utilization in Northwest Benin.

Science.gov (United States)

Yêyinou Loko, Laura Estelle; Orobiyi, Azize; Agre, Paterne; Dansi, Alexandre; Tamò, Manuele; Roisin, Yves

2017-11-21

Although termites are considered as agricultural pests, they play an important role in maintaining the ecosystem. Therefore, it matters to investigate the farmers' perception of the impacts of the termites on the agriculture and their indigenous utilization. A semi-structured questionnaire was used to interview 94 farmers through 10 villages of Atacora department, in the northwestern region of Benin, to obtain information for the development of successful strategies of termite management and conservation. Their perceptions on the importance and management of termites along with the indigenous nomenclature and utilization of termite mounds were assessed. Termite species identified by farmers were collected and preserved in 80% alcohol for identification. Eight crops were identified by farmers as susceptible to termites with maize, sorghum, and yam as being the most susceptible. According to farmers, the susceptibility to termites of these crops is due to their high-water content and sweet taste. A total of 27 vernacular names of termites were recorded corresponding to 10 species, Amitermes evuncifer, Macrotermes subhyalinus, and Trinervitermes oeconomus being the most damaging termite species. All the names given to termite species had a meaning. The drought was identified by farmers as the main factor favouring termite attacks. Demolition of termite mounds in the fields was the most commonly reported control method. Salt and other pesticides were commonly used by farmers to protect stored farm products. The lack of effective control methods is the main constraint for termite management. In northwestern Benin, farmers reported different purpose utilizations of termite mounds and termites. The study has shown that farmers perceived termites as pests of several agricultural crops and apply various indigenous control practices whose efficiency need to be verified. Utilization of termites and termite mound soil as food and medicinal resources underlines the need for a

A new shock wave assisted wood preservative injection system

Science.gov (United States)

Rao, K. S.; Ravikumar, G.; Lai, Ram; Jagadeesh, G.

Preservative treatment of many tropical hard woods and bamboo pose severe problem. A number of wood preservatives (chemical formulations toxic to wood decay/ destroying organisms like fungi, wood destroying termites, marine borers etc.) and wood impregnating techniques are currently in use for improving bio resistance of timber and bamboo and thereby enhancing service life for different end uses. How ever, some species of tropical hardwoods and many species of bamboo are difficult to treat, posing technical problems. In this paper we report preliminary results of treatment of bamboo with a novel Shockwave assisted injection treatment. Samples (30×2.5×1.00 cm) of an Indian species of bamboo Dendrocalamus strictus prepared from defect free culms of dry bamboo are placed in the driven section of a vertical shock tube filled with the 4Coppepr-Chrome-Arsenic(CCA) preservative solution.The bamboo samples are subjected to repeated shock wave loading (3 shots) with typical over pressures of 30 bar. The results from the study indicate excellent penetration and retention of CCA preservative in bamboo samples. The method itself is much faster compared to the conventional methods like pressure treatment or hot and cold process.

A genomic comparison of two termites with different social complexity.

Science.gov (United States)

Korb, Judith; Poulsen, Michael; Hu, Haofu; Li, Cai; Boomsma, Jacobus J; Zhang, Guojie; Liebig, Jürgen

2015-01-01

The termites evolved eusociality and complex societies before the ants, but have been studied much less. The recent publication of the first two termite genomes provides a unique comparative opportunity, particularly because the sequenced termites represent opposite ends of the social complexity spectrum. Zootermopsis nevadensis has simple colonies with totipotent workers that can develop into all castes (dispersing reproductives, nest-inheriting replacement reproductives, and soldiers). In contrast, the fungus-growing termite Macrotermes natalensis belongs to the higher termites and has very large and complex societies with morphologically distinct castes that are life-time sterile. Here we compare key characteristics of genomic architecture, focusing on genes involved in communication, immune defenses, mating biology and symbiosis that were likely important in termite social evolution. We discuss these in relation to what is known about these genes in the ants and outline hypothesis for further testing.

Wood decomposition as influenced by invertebrates.

Science.gov (United States)

Ulyshen, Michael D

2016-02-01

The diversity and habitat requirements of invertebrates associated with dead wood have been the subjects of hundreds of studies in recent years but we still know very little about the ecological or economic importance of these organisms. The purpose of this review is to examine whether, how and to what extent invertebrates affect wood decomposition in terrestrial ecosystems. Three broad conclusions can be reached from the available literature. First, wood decomposition is largely driven by microbial activity but invertebrates also play a significant role in both temperate and tropical environments. Primary mechanisms include enzymatic digestion (involving both endogenous enzymes and those produced by endo- and ectosymbionts), substrate alteration (tunnelling and fragmentation), biotic interactions and nitrogen fertilization (i.e. promoting nitrogen fixation by endosymbiotic and free-living bacteria). Second, the effects of individual invertebrate taxa or functional groups can be accelerative or inhibitory but the cumulative effect of the entire community is generally to accelerate wood decomposition, at least during the early stages of the process (most studies are limited to the first 2-3 years). Although methodological differences and design limitations preclude meta-analysis, studies aimed at quantifying the contributions of invertebrates to wood decomposition commonly attribute 10-20% of wood loss to these organisms. Finally, some taxa appear to be particularly influential with respect to promoting wood decomposition. These include large wood-boring beetles (Coleoptera) and termites (Termitoidae), especially fungus-farming macrotermitines. The presence or absence of these species may be more consequential than species richness and the influence of invertebrates is likely to vary biogeographically. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

A genomic comparison of two termites with different social complexity

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Judith eKorb

2015-03-01

Full Text Available The termites evolved eusociality and complex societies before the ants, but have been studied much less. The recent publication of the first two termite genomes provides a unique comparative opportunity, particularly because the sequenced termites represent opposite ends of the social complexity spectrum. Zootermopsis nevadensis has simple colonies with totipotent workers that can develop into all castes (dispersing reproductives, nest-inheriting replacement reproductives, and soldiers. In contrast, the fungus-growing termite Macrotermes natalensis belongs to the higher termites and has very large and complex societies with morphologically distinct castes that are life-time sterile. Here we compare key characteristics of genomic architecture, focusing on genes involved in communication, immune defenses, mating biology and symbiosis that were likely important in termite social evolution. We discuss these in relation to what is known about these genes in the ants and outline hypotheses for further testing.

Termites in the hominin diet: a meta-analysis of termite genera, species and castes as a dietary supplement for South African robust australopithecines.

Science.gov (United States)

Lesnik, Julie J

2014-06-01

Termite foraging by chimpanzees and present-day modern humans is a well-documented phenomenon, making it a plausible hypothesis that early hominins were also utilizing this resource. Hominin termite foraging has been credited by some to be the explanation for the unexpected carbon isotope signatures present in South African hominin teeth, which suggest the diet was different from that of extant non-human great apes, consisting of a significant amount of resources that are not from woody-plants. Grass-eating termites are one potential resource that could contribute to the carbon signature. However, not all termites eat grasses, and in fact, the termites that are most widely consumed by chimpanzees and by many present-day human populations at best have a mixed diet that includes small amounts of grasses. Here I review the ecology of termites and how it affects their desirability as a food resource for hominins, and conduct a meta-analysis of nutritional values for various genera, species and castes from the literature. Termites are very diverse, even within species, and this variability affects both their carbon signatures and nutritional value, hindering generalizations regarding the contribution of termites to the hominin diet. It is concluded here that a combination of soldiers and alates of the genus Macrotermes be used to model the insectivory component of the Plio-Pleistocene hominin diet due to their significant amounts of energy-yielding nutrients and potential role as a critical resource for supporting larger-brained hominins. Copyright © 2014. Published by Elsevier Ltd.

Behaviour and Ecological Impacts of Termites: Fecundity Investigations in Mounds

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Wako Sutuma Edessa

2015-03-01

Full Text Available A radical study was conducted on the behaviour and ecological impacts of termites in Haru District of Western Oromia, Ethiopia. It was aimed at investigating the natural behaviour, fecundity in mounds, ecological impacts and recommending possible solutions to termite problems. Four mounds in different sites were vertically dug down to display the profile of the queen, soldiers, workers, number of laid eggs, nymphs and colonies of termites. On an average, termite queens of the study site may lay about 25 eggs per minute, 36, 000 eggs per day and 13, 140, 000 eggs annually. The fourth queen was unearthed to study the structure, size, number of ovaries and fecundity. It was examined that the death of a queen does not affect the colony, because four small queens are formed and one of them becomes the queen of queens and replaced the dead queen promptly. Accordingly, termites are found to be one of the most destructive agents of our ecosystems and their management requests careful and biological control methods. As a result, the negative effect of termites outweighs the positive effect of termites so that minimising the population size is important for human beings.

Comparative effects of vetiver oil, nootkatone and disodium octaborate tetrahydrate on Coptotermes formosanus and its symbiotic fauna.

Science.gov (United States)

Maistrello, Lara; Henderson, Gregg; Laine, Roger A

2003-01-01

The potential of vetiver oil and nootkatone as wood treatments against Coptotermes formosanus Shiraki was examined by assessing the effects on termite tunneling, feeding activity and survival, and the consequences on the symbiont protozoa responsible for wood digestion. Comparisons were made with non-treated wood (control), wood treated with the borate compound Tim-Bor (a commonly used lumber preservative) and absence of a food source (starved termites), using choice and no-choice tests. All wood slices were prepared at the same time using a 10 g liter(-1) solution of each substance and were tested in four different sessions over one year to investigate longevity of the effects. Termites had to tunnel through sand to exploit the food sources, consisting of two wood slices, placed on opposite sides of the experimental enclosure. No-choice tests showed that in the presence of vetiver oil or nootkatone, tunneling activity was always the lowest; wood consumption, termite survival and flagellate numbers and species distribution were significantly different from the control and similar to the results obtained for starved termites and with Tim-Bor-treated wood. Nootkatone negatively affected termites for 12 months and was longer lasting than vetiver oil. In choice tests, when vetiver oil or nootkatone were present, termites exhibited a significant preference for non-treated wood. Our results confirmed both the toxicity and absence of repellency of Tim-Bor. Vetiver oil and especially nootkatone affected Formosan subterranean termites and their protozoa, acting as arrestants, repellents and feeding deterrents, and represent a promising natural alternative for the control of this invasive pest.

Termite Mounds Effects on Soil Properties in the Atlantic Forest Biome

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Sandra Santana de Lima

2018-03-01

Full Text Available ABSTRACT Termites have peculiar activities in the soil, inducing significant changes in the soil properties. The objective of this study was to assess physical and chemical properties and soil organic matter to evaluate the effect of termite activity and termite mounds on the soil. Two toposequences were selected and divided in slope thirds (shoulder, backslope, and footslope. In each of these, four termite mounds were selected. Samples were taken from the soils and termite mounds (top, center, and base along with a variety of termites for identification. Analyses were carried out for physical, soil texture, and chemical properties, as well as for particle size and chemical fractioning of organic matter. The species Cornitermes cumulans was found in all mounds. Soil with termite mound presented higher clay content, acidity, and Al3+ content. Phosphorus contents differed considerably between mound material and soil. Sum of bases and cation exchange capacity of the soil were higher in mounds, and differed within the mounds, according to the sampling height. Total organic carbon and particulate carbon content were highest at the mound base. A marked disparity was observed between the contents of humic substances in the mounds and surrounding soil, with humin fraction differences in distinct topographic position. The high nutrient contents detected in the termite mounds confirm the importance of termites in concentrating nutrients.

Building mud castles: a perspective from brick-laying termites.

Science.gov (United States)

Zachariah, Nikita; Das, Aritra; Murthy, Tejas G; Borges, Renee M

2017-07-05

Animal constructions such as termite mounds have received scrutiny by architects, structural engineers, soil scientists and behavioural ecologists but their basic building blocks remain uncharacterized and the criteria used for material selection unexplored. By conducting controlled experiments on Odontotermes obesus termites, we characterize the building blocks of termite mounds and determine the key elements defining material choice and usage by these accomplished engineers. Using biocement and a self-organized process, termites fabricate, transport and assemble spherical unitary structures called boluses that have a bimodal size distribution, achieving an optimal packing solution for mound construction. Granular, hydrophilic, osmotically inactive, non-hygroscopic materials with surface roughness, rigidity and containing organic matter are the easiest to handle and are crucial determinants of mass transfer during mound construction. We suggest that these properties, along with optimal moisture availability, are important predictors of the global geographic distribution of termites.

The evolutionary history of termites as inferred from 66 mitochondrial genomes.

Science.gov (United States)

Bourguignon, Thomas; Lo, Nathan; Cameron, Stephen L; Šobotník, Jan; Hayashi, Yoshinobu; Shigenobu, Shuji; Watanabe, Dai; Roisin, Yves; Miura, Toru; Evans, Theodore A

2015-02-01

Termites have colonized many habitats and are among the most abundant animals in tropical ecosystems, which they modify considerably through their actions. The timing of their rise in abundance and of the dispersal events that gave rise to modern termite lineages is not well understood. To shed light on termite origins and diversification, we sequenced the mitochondrial genome of 48 termite species and combined them with 18 previously sequenced termite mitochondrial genomes for phylogenetic and molecular clock analyses using multiple fossil calibrations. The 66 genomes represent most major clades of termites. Unlike previous phylogenetic studies based on fewer molecular data, our phylogenetic tree is fully resolved for the lower termites. The phylogenetic positions of Macrotermitinae and Apicotermitinae are also resolved as the basal groups in the higher termites, but in the crown termitid groups, including Termitinae + Syntermitinae + Nasutitermitinae + Cubitermitinae, the position of some nodes remains uncertain. Our molecular clock tree indicates that the lineages leading to termites and Cryptocercus roaches diverged 170 Ma (153-196 Ma 95% confidence interval [CI]), that modern Termitidae arose 54 Ma (46-66 Ma 95% CI), and that the crown termitid group arose 40 Ma (35-49 Ma 95% CI). This indicates that the distribution of basal termite clades was influenced by the final stages of the breakup of Pangaea. Our inference of ancestral geographic ranges shows that the Termitidae, which includes more than 75% of extant termite species, most likely originated in Africa or Asia, and acquired their pantropical distribution after a series of dispersal and subsequent diversification events. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Methane emissions from termites - landscape level estimates and methods of measurement

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Jamali, Hizbullah; Livesley, Stephen J.; Hutley, Lindsay B.; Arndt, Stefan K.

2013-04-01

Termites contribute between mound-building termite species diurnally and seasonally in tropical savannas in the Northern Territory, Australia. Our results showed that there were significant diel and seasonal variations of methane emissions from termite mounds and we observed large species-specific differences. On a diurnal basis, methane fluxes were least at the coolest time of the day and greatest at the warmest for all species for both wet and dry seasons. We observed a strong and significant positive correlation between methane flux and mound temperature for all species. Fluxes in the wet season were 5-26-fold greater than those in the dry season and this was related to population dynamics of the termites. We observed significant relationships between mound methane flux and mound carbon dioxide flux, enabling the prediction of methane flux from measured carbon dioxide flux. However, these relationships were clearly termite species specific. We also determined significant relationships between mound flux and gas concentration inside mound, for both gases, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Consequently, there was no generic relationship that would enable an easier prediction of methane flux from termite mounds. On a landscape scale we estimated that termites were a methane source of +0.24 kg methane-C ha-1 year-1 whilst savanna soils were a methane sink of 1.14 kg methane-C ha-1 year-1. Termites therefore only offset 21% of methane consumed by savanna soil resulting in net sink strength of -0.90 kg methane-C ha-1 year-1 for these savannas. Assuming a similar contribution of termites in the savannas and tropical rain forests worldwide, termites would globally produce around 27 Tg CO2-e year-1, which is 0.2% of the global methane source budget or an order of magnitude smaller than many of the previous estimates.

A genomic comparison of two termites with different social complexity

DEFF Research Database (Denmark)

Korb, Judith; Thomas-Poulsen, Michael; Hu, Haofu

2015-01-01

large and complex societies with morphologically distinct castes that are life-time sterile. Here we compare key characteristics of genomic architecture, focusing on genes involved in communication, immune defenses, mating biology and symbiosis that were likely important in termite social evolution. We......The termites evolved eusociality and complex societies before the ants, but have been studied much less. The recent publication of the first two termite genomes provides a unique comparative opportunity, particularly because the sequenced termites represent opposite ends of the social complexity...

Perceptions of termites in urban areas of semiarid Brazil

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Maria Avany Bezerra Gusmão

2014-07-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2014v27n4p117 Perception of termites in urban areas of semiarid Brazil. Termites are present in the daily life of most people, although they usually evoke a sense of strong dislike, especially in populations of urban areas. This study sought to analyze the perception of these insects in human populations in urban areas in the towns of Fagundes (A1 and Pocinhos (A2, in Paraíba state, Brazil. Semi-structured questionnaires were answered by 100 residents in these two areas, following both synchronic and diachronic situations. In spite of the fact that most of the interviewees (64% in A1 and 72% in A2 were able to identify termites by morphology and had knowledge of use for treating eight types of human diseases, very few understood their ecological roles in nature. Attempts to eliminate termites from human environments were linked to the popular belief that these animals are sources of bad luck. Twenty-two percent of the interviewees in A1 and 8% in A2 believe that termites are capable of doing damage or harm, of having a foul smell, and/or of containing pus.In this sense, academic studies are important because they can inform people of the ecological roles of termites in natural and urban environments, while demystifying the termite as an agent of fear and destruction.

Molecular characterization and phylogeny of four new species of the genus Trichonympha (Parabasalia, Trichonymphea) from lower termite hindguts.

Science.gov (United States)

Boscaro, Vittorio; James, Erick R; Fiorito, Rebecca; Hehenberger, Elisabeth; Karnkowska, Anna; Del Campo, Javier; Kolisko, Martin; Irwin, Nicholas A T; Mathur, Varsha; Scheffrahn, Rudolf H; Keeling, Patrick J

2017-09-01

Members of the genus Trichonympha are among the most well-known, recognizable and widely distributed parabasalian symbionts of lower termites and the wood-eating cockroach species of the genus Cryptocercus. Nevertheless, the species diversity of this genus is largely unknown. Molecular data have shown that the superficial morphological similarities traditionally used to identify species are inadequate, and have challenged the view that the same species of the genus Trichonympha can occur in many different host species. Ambiguities in the literature, uncertainty in identification of both symbiont and host, and incomplete samplings are limiting our understanding of the systematics, ecology and evolution of this taxon. Here we describe four closely related novel species of the genus Trichonympha collected from South American and Australian lower termites: Trichonympha hueyi sp. nov. from Rugitermes laticollis, Trichonympha deweyi sp. nov. from Glyptotermes brevicornis, Trichonympha louiei sp. nov. from Calcaritermes temnocephalus and Trichonympha webbyae sp. nov. from Rugitermes bicolor. We provide molecular barcodes to identify both the symbionts and their hosts, and infer the phylogeny of the genus Trichonympha based on small subunit rRNA gene sequences. The analysis confirms the considerable divergence of symbionts of members of the genus Cryptocercus, and shows that the two clades of the genus Trichonympha harboured by termites reflect only in part the phylogeny of their hosts.

Fungus-Growing Termites Originated in African Rain Forest

DEFF Research Database (Denmark)

Aanen, Duur Kornelis; Eggleton, Paul

2005-01-01

are consumed (cf. [ [1] and [2] ]). Fungus-growing termites are found throughout the Old World tropics, in rain forests and savannas, but are ecologically dominant in savannas [ 3 ]. Here, we reconstruct the ancestral habitat and geographical origin of fungus-growing termites. We used a statistical model...... of habitat switching [ 4 ] repeated over all phylogenetic trees sampled in a Bayesian analysis of molecular data [ 5 ]. Our reconstructions provide strong evidence that termite agriculture originated in African rain forest and that the main radiation leading to the extant genera occurred there. Because...

Vibration characteristics of teak wood filled steel tubes

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Danawade, Bharatesh Adappa; Malagi, Ravindra Rachappa

2018-05-01

The objective of this paper is to determine fundamental frequency and damping ratio of teak wood filled steel tubes. Mechanically bonded teak wood filled steel tubes have been evaluated by experimental impact hammer test using modal analysis. The results of impact hammer test were verified and validated by finite element tool ANSYS using harmonic analysis. The error between the two methods was observed to be within acceptable limit.

Diversity, Roles, and Biotechnological Applications of Symbiotic Microorganisms in the Gut of Termite.

Science.gov (United States)

Zhou, Jing; Duan, Jiwei; Gao, Mingkun; Wang, Ying; Wang, Xiaohua; Zhao, Kai

2018-05-12

Termites are global pests and can cause serious damage to buildings, crops, and plantation forests. The symbiotic intestinal flora plays an important role in the digestion of cellulose and nitrogen in the life of termites. Termites and their symbiotic microbes in the gut form a synergistic system. These organism work together to digest lignocellulose to make the termites grow on nitrogen deficient food. In this paper, the diversity of symbiotic microorganisms in the gut of termites, including protozoan, spirochetes, actinomycetes, fungus and bacteria, and their role in the digestion of lignocellulose and also the biotechnological applications of these symbiotic microorganisms are discussed. The high efficiency lignocellulose degradation systems of symbiotic microbes in termite gut not only provided a new way of biological energy development, but also has immense prospect in the application of cellulase enzymes. In addition, the study on the symbiotic microorganisms in the gut of termites will also provide a new method for the biological control of termites by the endophytic bacteria in the gut of termites.

The antibacterial protein lysozyme identified as the termite egg recognition pheromone.

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Kenji Matsuura

Full Text Available Social insects rely heavily on pheromone communication to maintain their sociality. Egg protection is one of the most fundamental social behaviours in social insects. The recent discovery of the termite-egg mimicking fungus 'termite-ball' and subsequent studies on termite egg protection behaviour have shown that termites can be manipulated by using the termite egg recognition pheromone (TERP, which strongly evokes the egg-carrying and -grooming behaviours of workers. Despite the great scientific and economic importance, TERP has not been identified because of practical difficulties. Herein we identified the antibacterial protein lysozyme as the TERP. We isolated the target protein using ion-exchange and hydrophobic interaction chromatography, and the MALDI-TOF MS analysis showed a molecular size of 14.5 kDa. We found that the TERP provided antibacterial activity against a gram-positive bacterium. Among the currently known antimicrobial proteins, the molecular size of 14.5 kDa limits the target to lysozyme. Termite lysozymes obtained from eggs and salivary glands, and even hen egg lysozyme, showed a strong termite egg recognition activity. Besides eggs themselves, workers also supply lysozyme to eggs through frequent egg-grooming, by which egg surfaces are coated with saliva containing lysozyme. Reverse transcript PCR analysis showed that mRNA of termite lysozyme was expressed in both salivary glands and eggs. Western blot analysis confirmed that lysozyme production begins in immature eggs in queen ovaries. This is the first identification of proteinaceous pheromone in social insects. Researchers have focused almost exclusively on hydrocarbons when searching for recognition pheromones in social insects. The present finding of a proteinaceous pheromone represents a major step forward in, and result in the broadening of, the search for recognition pheromones. This novel function of lysozyme as a termite pheromone illuminates the profound influence

Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites

DEFF Research Database (Denmark)

Visser, Anna A.; Nobre, Tânia; Currie, Cameron R.

2012-01-01

In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play...... a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets...... for morphological (288 isolates, grouped in 44 morphotypes) and for 16S rRNA (35 isolates, spanning the majority of morphotypes) characterisation. Actinobacteria were found throughout all sampled nests and colony parts and, phylogenetically, they are interspersed with Actinobacteria from origins other than fungus...

Methane oxidation by termite mounds estimated by the carbon isotopic composition of methane

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Sugimoto, Atsuko; Inoue, Tetsushi; Kirtibutr, Nit; Abe, Takuya

1998-12-01

Emission rates and carbon isotope ratios of CH4, emitted by workers of termites, and of CH4, emitted from their mounds, were observed in a dry evergreen forest in Thailand to estimate the proportion of CH4 oxidized during emission through the mound. The δ13C of CH4 emitted from a termite mound (-70.9 to -82.4‰) was higher than that of CH4 emitted by workers in the mound (-85.4 to -97. l‰). Using a fractionation factor (a = 0.987) for oxidation of CH4 which was obtained in the incubation experiment, an emission factor defined as (CH4 emitted from a termite mound/CH4 produced by termites) was calculated. The emission factor obtained in each termite mound was nearly zero for Macrotermes (fungus-growing termites), of which the nest has a thick soil wall and subterrannean termites, and 0.17 to 0.47 for Termitinae (small-mound-making termites). Global CH4 emission by termites was estimated on the basis of the CH4 emission rates by workers and termite biomass with the emission factors. The calculated result was 1.5 to 7.4 Tg/y (0.3 to 1.3% of total source), which is considerably smaller than the estimate by the IPCC [1994].

Antimicrobial activity of actinobacteria isolated from the guts of subterranean termites

Science.gov (United States)

Rachel Arango; C. M. Carlson; C. R. Currie; B. R. McDonald; A. J. Book; Frederick Green; K. F. Raffa; N.K. Lebow

2016-01-01

Subterranean termites need to minimize potentially pathogenic and competitive fungi in their environment in order to maintain colony health. We examined the ability of Actinobacteria isolated from termite guts in suppressing microorganisms commonly encountered in a subterranean environment. Guts from two subterranean termite species, Reticulitermes flavipes...

A Preliminary Study on Elimination of Colonies of the Mound Building Termite Macrotermes gilvus (Hagen) Using a Chlorfluazuron Termite Bait in the Philippines

OpenAIRE

Partho Dhang

2011-01-01

The effectiveness of a chlorfluazuron termite bait in eliminating colonies of the termite species Macrotermes gilvus (Hagen) was evaluated under field conditions. Three active termite mounds were chosen for this study, two acted as test mounds and the other as the control. Four In-Ground Stations (IGS) were installed around each mound. Interception occurred almost immediately in all the stations, which were subsequently baited. The control mound was fed a bait matrix lacking the active ingred...

Chemical communication in termites: syn-4,6-dimethylundecan-1-ol as trail-following pheromone, syn-4,6-dimethylundecanal and (5E)-2,6,10-trimethylundeca-5,9-dienal as the respective male and female sex pheromones in Hodotermopsis sjoestedti (Isoptera, Archotermopsidae)

Czech Academy of Sciences Publication Activity Database

Lacey, M. J.; Sémon, E.; Krasulová, Jana; Sillam-Dusses, David; Robert, A.; Cornette, R.; Hoskovec, Michal; Žáček, Petr; Valterová, Irena; Bordereau, Ch.

2011-01-01

Roč. 57, č. 12 (2011), s. 1585-1591 ISSN 0022-1910 Institutional research plan: CEZ:AV0Z40550506 Keywords : sex-specific pheromone s * basal termites * classification * phylogenetic relationships * zootermopsis Subject RIV: CC - Organic Chemistry Impact factor: 2.236, year: 2011

Levels of specificity of Xylaria species associated with fungus-growing termites: a phylogenetic approach

DEFF Research Database (Denmark)

Visser, Andre; Ros, V I D; De Beer, Z. W.

2009-01-01

of the ascomycete genus Xylaria appear and rapidly cover the fungus garden. This raises the question whether certain Xylaria species are specialised in occupying termite nests or whether they are just occasional visitors. We tested Xylaria specificity at four levels: (1) fungus-growing termites, (2) termite genera...... of the ITS region revealed 16 operational taxonomic units of Xylaria, indicating high levels of Xylaria species richness. Not much of this variation was explained by termite genus, species, or colony; thus, at level 2-4 the specificity is low. Analysis of the large subunit rDNA region, showed that all...... termite-associated Xylaria belong to a single clade, together with only three of the 26 non-termite-associated strains. Termite-associated Xylaria thus show specificity for fungus-growing termites (level 1). We did not find evidence for geographic or temporal structuring in these Xylaria phylogenies...

Vertical Distribution of Termites on Trees in Two Forest Landscapes in Taiwan.

Science.gov (United States)

Li, Hou-Feng; Yeh, Hsin-Ting; Chiu, Chun-I; Kuo, Chih-Yu; Tsai, Ming-Jer

2016-03-25

Termites are a key functional group in the forest ecosystem, but they damage trees. To investigate the termite infestation pattern on the whole tree, we cut 108 blackboard trees,Alstonia scholaris(L.) R. Br., and 50 Japanese cedars,Cryptomeria japonica (L. f.) D. Don, into sections. The bark surface and cross sections of the tree trunk were examined along the axes. A high percentage of blackboard trees (92.6%) was infested by fungus-growing termites,Odontotermes formosanus(Shiraki), but damage was limited to the bark surface at a 2-m height. The infestation rate of dampwood termites,Neotermes koshunensis(Shiraki), was only 4.6% (5/108), and all infestations were associated with trunk wounds.N. koshunensiswas found at significantly higher portion of a tree thanO. formosanus Among 50 Japanese cedars, 20 living trees were not infested by any termites, but 26 of the 30 dead trees were infested by subterranean termites,Reticulitermes flaviceps(Oshima), which excavated tunnels in the trunk. The infestation rate at basal sections was higher than that at distal sections. Only one Japanese cedar tree was infested by another dampwood termite,Glyptotermes satsumensis(Matsumura). The two dominant termite species,O. formosanusandR. flaviceps, had subterranean nests and infested trees from bottom up. The two primitive termitesN. koshunensis andG. satsumensishad low infestation rates and are most likely to infest trees by alates from top down. The niche segregation in trees of three termite families, Kalotermitidae, Rhinotermitidae, and Termitidae, was distinct. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Permanent groundwater storage in basaltic dyke fractures and termite mound viability

Science.gov (United States)

Mège, Daniel; Rango, Tewodros

2010-04-01

Many basaltic dykes of the Ethiopian flood basalt province are observed in the northwestern Ethiopian lowlands. In this area, the termites preferentially build their epigeous mounds on the top of dolerite dykes. The relationship between termite mounds and dykes is investigated from the analysis of their distribution along one of these dykes, of thickness 2-5 m, that we could follow over 2000 m. Termite mounds are periodically spaced (mean distance 63 m, R2 = 0.995), and located exclusively where the topographic relief of the dyke is not more than 2 m above the surrounding area. From these observations and from the geological context, a hydrological circuit model is proposed in which (1) dykes are preferential conduits for groundwater drainage during the rainy season due to pervasive jointing, (2) during the dry season, the portion of the dyke forming a local topographic relief area dries up more quickly than the surroundings, the elevation difference between the dyke summit and the surroundings being a factor restricting termite mound development. For dyke topographic relief >2 m, drying is an obstacle for maintaining the appropriate humidity for the termite colony life. Periodic termite mound spacing is unlikely to be related to dyke or other geological properties. It is more likely related to termite population behaviour, perhaps to clay shortage, which restricts termite population growth by limiting the quantity of building material available for mound extension, and triggers exploration for a new colonization site that will be located along the dyke at a distance from the former colony that may be controlled by the extent of the zone covered by its trail pheromones. This work brings out the importance of dykes in channelling and storing groundwater in semiarid regions, and shows that dykes can store groundwater permanently in such settings even though the dry season is half the year long. It contributes also to shedding light on water supply conditions

A comparison of wood preservatives in posts in southern Mississippi : results from a half-decade of testing

Science.gov (United States)

Mike H. Freeman; Douglas Crawford; Patricia Lebow; James A. Brient

2005-01-01

Wood preservatives extend the useful service life of all wooden commodities used above ground and in ground contact, Over SO years ago, the USDA-Forest Products Lab established tests in a high decay and high termite hazard zone in southern Mississippi. During the last five decades, periodic reports have been issued by researchers located at the USDA-FPL, in Madison, WI...

Exploring the Potential for Actinobacteria as Defensive Symbionts in Fungus-Growing Termites

NARCIS (Netherlands)

Visser, A.A.; Mesquita Nobre, T.; Currie, C.R.; Aanen, D.K.; Poulsen, M.

2012-01-01

In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a

Host-Symbiont Cospeciation of Termite-Gut Cellulolytic Protists of the Genera Teranympha and Eucomonympha and their Treponema Endosymbionts.

Science.gov (United States)

Noda, Satoko; Shimizu, Daichi; Yuki, Masahiro; Kitade, Osamu; Ohkuma, Moriya

2018-03-29

Cellulolytic flagellated protists inhabit the hindgut of termites. They are unique and essential to termites and related wood-feeding cockroaches, enabling host feeding on cellulosic matter. Protists of two genera in the family Teranymphidae (phylum Parabasalia), Eucomonympha and Teranympha, are phylogenetically closely related and harbor intracellular endosymbiotic bacteria from the genus Treponema. In order to obtain a clearer understanding of the evolutionary history of this triplex symbiotic relationship, the molecular phylogenies of the three symbiotic partners, the Teranymphidae protists, their Treponema endosymbionts, and their host termites, were inferred and compared. Strong congruence was observed in the tree topologies of all interacting partners, implying their cospeciating relationships. In contrast, the coevolutionary relationship between the Eucomonympha protists and their endosymbionts was more complex, and evidence of incongruence against cospeciating relationships suggested frequent host switches of the endosymbionts, possibly because multiple Eucomonympha species are present in the same gut community. Similarities in the 16S rRNA and gyrB gene sequences of the endosymbionts were higher among Teranympha spp. (>99.25% and >97.2%, respectively), whereas those between Teranympha and Eucomonympha were lower (<97.1% and <91.9%, respectively). In addition, the endosymbionts of Teranympha spp. formed a phylogenetic clade distinct from those of Eucomonympha spp. Therefore, the endosymbiont species of Teranympha spp., designated here as "Candidatus Treponema teratonymphae", needs to be classified as a species distinct from the endosymbiont species of Eucomonympha spp.

Aerodynamics of Ventilation in Termite Mounds

Science.gov (United States)

Bailoor, Shantanu; Yaghoobian, Neda; Turner, Scott; Mittal, Rajat

2017-11-01

Fungus-cultivating termites collectively build massive, complex mounds which are much larger than the size of an individual termite and effectively use natural wind and solar energy, as well as the energy generated by the colony's own metabolic activity to maintain the necessary environmental condition for the colony's survival. We seek to understand the aerodynamics of ventilation and thermoregulation of termite mounds through computational modeling. A simplified model accounting for key mound features, such as soil porosity and internal conduit network, is subjected to external draft conditions. The role of surface flow conditions in the generation of internal flow patterns and the ability of the mound to transport gases and heat from the nursery are examined. The understanding gained from our study could be used to guide sustainable bio-inspired passive HVAC system design, which could help optimize energy utilization in commercial and residential buildings. This research is supported by a seed Grant from the Environment, Energy Sustainability and Health Institute of the Johns Hopkins University.

Use of termite mounds in geochemical exploration in North Ethiopia [rapid communication

Science.gov (United States)

Kebede, Fassil

2004-09-01

The geochemistry of the termite mounds was studied in lower Giba River basin, Kolla Tambien district, northern Ethiopia to show that they are useful in searching for metals. Specimens from the termite mounds and parent materials were collected to quantify gold, silver, copper, zinc, cobalt, manganese, iron and nickel. The results of the geochemical analysis of the samples indicated that these metals exist both in the termite mound and the parent material in the surrounding area. Correlation analysis shows that termite mounds and the parent materials are positively correlated for gold ( r = 0.75∗), copper ( r = 0.77∗), silver ( r = 0.56∗) and manganese ( r = 0.72). This positive correlation leads to the conclusion that there is a direct relation between the concentration of metals in termite mound and the parent rocks. Termite mounds can therefore be used as tools in exploring for these metals.

Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites.

Science.gov (United States)

Visser, Anna A; Nobre, Tânia; Currie, Cameron R; Aanen, Duur K; Poulsen, Michael

2012-05-01

In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets for morphological (288 isolates, grouped in 44 morphotypes) and for 16S rRNA (35 isolates, spanning the majority of morphotypes) characterisation. Actinobacteria were found throughout all sampled nests and colony parts and, phylogenetically, they are interspersed with Actinobacteria from origins other than fungus-growing termites, indicating lack of specificity. Antibiotic-activity screening of 288 isolates against the fungal cultivar and competitor revealed that most of the Actinobacteria-produced molecules with antifungal activity. A more detailed bioassay on 53 isolates, to test the specificity of antibiotics, showed that many Actinobacteria inhibit both Pseudoxylaria and Termitomyces, and that the cultivar fungus generally is more susceptible to inhibition than the competitor. This suggests that either defensive symbionts are not present in the system or that they, if present, represent a subset of the community isolated. If so, the antibiotics must be used in a targeted fashion, being applied to specific areas by the termites. We describe the first discovery of an assembly of antibiotic-producing Actinobacteria occurring in fungus-growing termite nests. However, due to the diversity found, and the lack of both phylogenetic and bioactivity specificity, further work is necessary for a better understanding of the putative role of antibiotic-producing bacteria in the fungus

Impact of termite activity on soil environment: A perspective from their soluble chemical components

International Nuclear Information System (INIS)

Semhi, K.; Chaudhuri, S.; Clauer, N.; Boeglin, J. L.

2008-01-01

An investigation on varied types of termite mounds relative to the nearby soils that are not inhabited by the termites in different places of Cameroon show that the activity of the termites is increasing the contents of most major and some trace elements in the termite mounds, except for Si and sometimes Fe, Mn, Na and K. These released elements are relocated into newly formed mineral phases that are dissolved by either H 2 O dilute HCl leaching. The Ca and Mn released by the termite activity testify for crystallization of Ca-Mg carbonates and phosphates as well as of Fe oxy-hydroxides and/or Mn hydroxides. Termite activity also induces an increase in the lanthanide contents, the mound materials being especially enriched in light lanthanides relative to the corresponding soils without termite activity. The shapes of the patterns support precipitation of Mn-Fe oxy-hydroxides and Ca carbonates-phosphates. The increased amounts of Eu and Ce linked to termite activity seem to relate to the occurrence of reducing agents that are released by the termites, modifying Eu +3 into Eu +2 and Ce +4 into Ce +3 , favoring in turn selective incorporation of Eu +2 and Ce +3 in the new phases of the termite mounds. Another consequence of the termite activity is the precipitation of H 2 O and HCl extractable phases having low Sr/Ca ratios. Even if the K/Rb values of the termite mounds are typical for common soil-forming silicate minerals, their relocation by an inorganic process alone does not explain an abnormally high ratio in the H 2 O leachable mineral phases. It was also shown that the main source for K and Rb of the dissolved phases is not only the interlayer site of clay particles, but also nutrients immobilized in and by the termites

Influence of Soil Properties on Soldierless Termite Distribution

Czech Academy of Sciences Publication Activity Database

Bourguignon, T.; Drouet, T.; Šobotník, J.; Hanus, Robert; Roisin, Y.

2015-01-01

Roč. 10, č. 8 (2015), e0135341/1-e0135341/11 E-ISSN 1932-6203 Institutional support: RVO:61388963 Keywords : tropical termites * soil -feeding termites * soil properties * soil preference Subject RIV: EH - Ecology, Behaviour Impact factor: 3.057, year: 2015 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135341

Termites facilitate methane oxidation and shape the methanotrophic community

NARCIS (Netherlands)

Ho, A.; Erens, H.; Mujinya, B.B.; Boeckx, P.; Baert, G.; Schneider, B.; Frenzel, P.; Boon, N.; Van Ranst, E.

2013-01-01

Termite-derived methane contributes 3-4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of methane produced can be consumed by methanotrophs that inhabit the mound material. Yet, methanotroph

appraisal of the economic activities of termites: a review

African Journals Online (AJOL)

DR.AMIN

result of their feeding habits cannot be over emphasized. It includes ... Termites are a highly successful group of true social animals, as .... 90.6% Alate termites are eaten by people in West. Africa. ..... Biological Letters, June 7, cited in. Science ...

Tunneling behavior of the formosan subterranean termite (isoptera: rhinotermitadae) in dry soil

Science.gov (United States)

This study examines the effect of dry soil on tunnel construction by the Formosan subterranean termite, Cptotermes formosanus. Termites did not construct tunnels in dry soil in any of the treatments. Termites only constructed tunnels in moist areas in treatments where the soil was partially moistene...

Odor aversion and pathogen-removal efficiency in grooming behavior of the termite Coptotermes formosanus.

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Aya Yanagawa

Full Text Available The results of biocontrol with entomopathogens in termites have been discouraging because of the strong social hygiene behavior for removing pathogens from termite colonies. However, the mechanism of pathogen detection is still unclear. For the successful application of biopesticides to termites in nature, it would be beneficial to identify substances that could disrupt the termite's ability to perceive pathogens. We hypothesized that termites can perceive pathogens and this ability plays an important role in effective hygiene behavior. In this study, pathogen-detection in the subterranean termite Coptotermes formosanus was investigated. We performed quantitative assays on conidia removal by grooming behavior using epifluoresence microscopy and Y-maze tests to examine the perception of fungal odor by termites. Three species each of high- and low-virulence entomopathogenic fungi were used in each test. The results demonstrated that termites removed conidia more effectively from a nestmate's cuticle if its odor elicited stronger aversion. Highly virulent pathogens showed higher attachment rates to termite surfaces and their odors were more strongly avoided than those of low-virulence isolates in the same species. Moreover, termites appeared to groom each other more persistently when they had more conidia on their bodies. In brief, insect perception of pathogen-related odor seems to play a role in the mechanism of their hygiene behavior.

Potential for nitrogen fixation in fungus-growing termite symbiosis

DEFF Research Database (Denmark)

Sapountzis, Panagiotis; de Verges, Jane; Rousk, Kathrin

2016-01-01

Termites host a gut microbiota of diverse and essential symbionts that enable specialization on dead plant material; an abundant, but nutritionally imbalanced food source. To supplement the severe shortage of dietary nitrogen (N), some termite species make use of diazotrophic bacteria to fix atmo...

Watching termites

International Nuclear Information System (INIS)

Carrard, G.

1983-01-01

Radioactive tracking techniques are being used to aid the investigation and control of termites. Studies include work related to the restoration of historic buildings when the damage inflicted on the timbers needs to be determined with minimum disturbance to the building. Another investigation has been the radioactive monitoring of pest-control techniques. Scandium-46, lanthanum-140 and gold-198 have been used in different investigations

Termites facilitate methane oxidation and shape the methanotrophic community.

Science.gov (United States)

Ho, Adrian; Erens, Hans; Mujinya, Basile Bazirake; Boeckx, Pascal; Baert, Geert; Schneider, Bellinda; Frenzel, Peter; Boon, Nico; Van Ranst, Eric

2013-12-01

Termite-derived methane contributes 3 to 4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of the methane produced can be consumed by methanotrophs that inhabit the mound material, yet the methanotroph ecology in these environments is virtually unknown. The potential for methane oxidation was determined using slurry incubations under conditions with high (12%) and in situ (∼0.004%) methane concentrations through a vertical profile of a termite (Macrotermes falciger) mound and a reference soil. Interestingly, the mound material showed higher methanotrophic activity. The methanotroph community structure was determined by means of a pmoA-based diagnostic microarray. Although the methanotrophs in the mound were derived from populations in the reference soil, it appears that termite activity selected for a distinct community. Applying an indicator species analysis revealed that putative atmospheric methane oxidizers (high-indicator-value probes specific for the JR3 cluster) were indicative of the active nest area, whereas methanotrophs belonging to both type I and type II were indicative of the reference soil. We conclude that termites modify their environment, resulting in higher methane oxidation and selecting and/or enriching for a distinct methanotroph population.

Termite Population Dynamics in Arenic Kandiudults as Influenced by ...

African Journals Online (AJOL)

Result shows that carbofuran significantly (P=<0.0001) recorded least termite population per square meter after tuber harvest, whereas A. indica leaves and municipal waste increased termite population per square meter. Also, cassava tuber yield was significantly influenced with application of A. indica leaves and ...

No evidence for an elephant-termite feedback loop in Sand Forest, South Africa

NARCIS (Netherlands)

Lagendijk, D. D G; Davies, A. B.; Eggleton, P.; Slotow, R.

2016-01-01

Termites and mammalian herbivores might derive mutual benefit from each other through positive feedback loops, but empirical evidence is lacking. One suggested positive feedback loop is between termites and elephant, both ecosystem engineers. Termites, as decomposer organisms, contribute to nutrient

Stability of termite mound populations in a variable environment ...

African Journals Online (AJOL)

Of all the climatic variables in the environment of termites in southern Kenya, only rainfall shows marked seasonality and unpredictability. But despite the great variability in rainfall patterns, the populations of termite mounds of various species in three well-separated study areas remained remarkably constant over a period ...

Do termites avoid carcasses? Behavioral responses depend on the nature of the carcasses.

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Kok-Boon Neoh

Full Text Available BACKGROUND: Undertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe (lower termites and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites. We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1 the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2 the termites repeatedly crawled under the aging carcass piles; and (3 only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature. CONCLUSION: We conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species.

Geochemical prospecting for rare earth elements using termite mound materials

Science.gov (United States)

Horiuchi, Yu; Ohno, Tetsuji; Hoshino, Mihoko; Shin, Ki-Cheol; Murakami, Hiroyasu; Tsunematsu, Maiko; Watanabe, Yasushi

2014-12-01

The Blockspruit fluorite prospect, located in North West State of the Republic of South Africa, occurs within an actinolite rock zone that was emplaced into the Kenkelbos-type granite of Proterozoic age. There are a large number of termite mounds in the prospect. For geochemical prospecting for rare earth elements (REEs), in total, 200 samples of termite mound material were collected from actinolite rock and granite zones in the prospect. Geochemical analyses of these termite mound materials were conducted by two methods: portable X-ray fluorescence (XRF) spectrometry and inductively coupled plasma-mass spectrometry (ICP-MS). Comparison of the two methods broadly indicates positive correlations of REEs (La, Ce, Pr, Nd, and Y), in particular Y and La having a strong correlation. As the result of modal abundance analyses, the actinolite rock at surface mainly consists of ferro-actinolite (89.89 wt%) and includes xenotime (0.26 wt%) and monazite (0.21 wt%) grains as REE minerals. Termite mound materials from actinolite rock also contain xenotime (0.27 wt%) and monazite (0.41 wt%) grains. In addition, termite mound materials from the actinolite rock zone have high hematite and Fe silicate contents compared to those from granite zone. These relationships suggest that REE minerals in termite mound materials originate form actinolite rock. Geochemical anomaly maps of Y, La, and Fe concentrations drawn based on the result of the portable XRF analyses show that high concentrations of these elements trend from SW to NE which broadly correspond to occurrences of actinolite body. These results indicate that termite mounds are an effective tool for REE geochemical prospection in the study area for both light REEs and Y, but a more detailed survey is required to establish the distribution of the actinolite rock body.

Indigenous methods of controlling termites in agroforestry systems in ...

African Journals Online (AJOL)

Mo

Termites are one of the major agroforestry pests in the tropics causing substantial economic losses. Losses ranging from 50% to 100% have been reported. Control of termites has largely relied on insecticides. There are however serious limitations to these pesticides in terms of cost, pollution and destruction of non targets.

Biogeochemical study of termite mounds: a case study from Tummalapalle area of Andhra Pradesh, India.

Science.gov (United States)

Arveti, Nagaraju; Reginald, S; Kumar, K Sunil; Harinath, V; Sreedhar, Y

2012-04-01

Termite mounds are abundant components of Tummalapalle area of uranium mineralization of Cuddapah District of Andhra Pradesh, India. The systematic research has been carried out on the application of termite mound sampling to mineral exploration in this region. The distribution of chemical elements Cu, Pb, Zn, Ni, Co, Cr, Li, Rb, Sr, Ba, and U were studied both in termite soils and adjacent surface soils. Uranium accumulations were noticed in seven termite mounds ranging from 10 to 36 ppm. A biogeochemical parameter called "Biological Absorption Coefficient" of the termite mounds indicated the termite affected soils contained huge amounts of chemical elements than the adjacent soils.

Termites as ecological indicators of mine-land rehabilitation in tropical Australia

International Nuclear Information System (INIS)

Hinz, D.A.

2001-01-01

This paper presents examples from field research of termites as indicators of rehabilitation success in the wet-dry tropics at Nabalco's bauxite mine, Gove, Australia and in Sierra Leone, West Africa. Field studies indicate that soil-plant-animal interactions are crucial in determining the recovery of disturbed land and that termites play an over-riding role in the process. Termites are seen as ecological indicators for successful soil and vegetation development in humid tropical environments. In land rehabilitation, termites help to create healthy, self-regulated vegetation systems that integrate with the surrounding landscapes and build structures and functions equal to those of the pre-disturbed system. They are reliable in signaling the health and stress factors of a system and provide a predictable response

Temperature fluctuations inside savanna termite mounds: Do size and plant shade matter?

Science.gov (United States)

Ndlovu, M; Pérez-Rodríguez, A

2018-05-01

Mound building termites are key ecosystem engineers of subtropical savanna regions. Mounds allow termites to maintain suitable conditions for termite reproduction and food cultivation ('fungus gardens'). We studied how the internal mound temperature of Macrotermes natalensis, a dominant mound-building termite of the subtropical savanna of southern Africa, responds to a number of environmental variables. We used general additive mixed models (GAMM) to determine how external temperature, mound size (volume) and the amount of vegetation shade affects mound internal temperature over a 24-h period. Internal mound temperature varied daily following changes of the external temperature, although the range of variation was much smaller. Active termite mounds maintained a higher internal temperature than inactive ones, and mound activity reinforced the positive effect of mound size and moderated the negative effect of vegetation shade on internal temperatures. In turn, external temperature fluctuations equally affected active and inactive mounds. Large mounds maintained near optimal internal temperatures compared to smaller sized mounds. We therefore conclude that termite mound size is a stronger determinant of internal mound temperature stability compared to plant shade cover. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ketahanan Papan Unting (Oriented Strand Board) terhadap Serangan Rayap Tanah dan Rayap Kayu Kering

OpenAIRE

Gea, Bud diman

2011-01-01

Oriented strand board is panel of wood raw material from which strand composed of cross and upright structure. In order to oriented strand board can be used for interior and exterior needs, than necessary to be applied various thenology of quality improvement like durabelities and endurance of oriented strand board. For it does found endurance oriented strand board from attack of ground termite and wood dry termite, necessary doing grave yard trial and wood dry termite trial. This research ta...

Karakteristik Emisi Akustik untuk Mendeteksi Rayap Tanah pada Kayu

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Muhammad Achirul Nanda

2017-12-01

Full Text Available Various methods for detecting termites in the wood have been developed, one of those was based on acoustic emission. Eventhough, that method was difficult to distinguish the signal generated by termites or interference noise from the environment. It could be solved through a combination of acoustic emission and behavior of termites. Therefore, the purposes of this study were to analyze the acoustic signal and the moisture content to classify infested and uninfested wood by termites. The wood used in this study were made from Pinus logs, in air dried condition, which measure of 20(l x 9.5(w x 2.5(h cm. Five wood were infested by 220 of C. curvignathus (‘infested wood’, the others were in sound condition (‘uninfested wood’. The acoustic signal was analyzed by FFT (Fast Fourier Transform to transform from the time domain into the frequency domain. The results showed that moisture content of infested wood (11.94±0.792% was higher than uninfested board (10.82±0.525%. Whereas the results of the acoustic signal indicated that the value of zero moment power of infested wood as well as uninfested wood, i.e., 13.405±3.019 and 9.573±2.188 respectively. Finally, the parameters which able to classify infested and uninfested wood by termites significantly were moisture content and the zero moment power.

The draft genome of a termite illuminates alternative social organization

Science.gov (United States)

Termites have substantial economic and ecological impact worldwide. They are also the oldest organisms living in complex societies, having evolved a caste system independent of that of eusocial Hymenoptera (ants, bees and wasps). Here we provide the first genome sequence for a termite, Zootermopsis ...

A Preliminary Study on Elimination of Colonies of the Mound Building Termite Macrotermes gilvus (Hagen Using a Chlorfluazuron Termite Bait in the Philippines

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Partho Dhang

2011-11-01

Full Text Available The effectiveness of a chlorfluazuron termite bait in eliminating colonies of the termite species Macrotermes gilvus (Hagen was evaluated under field conditions. Three active termite mounds were chosen for this study, two acted as test mounds and the other as the control. Four In-Ground Stations (IGS were installed around each mound. Interception occurred almost immediately in all the stations, which were subsequently baited. The control mound was fed a bait matrix lacking the active ingredient. Stations were re-baited every 2 weeks for 10–12 weeks until bait consumption ceased in the test mounds. The mounds were left undisturbed for four more weeks before being destructively sampled. The desiccated remains of workers, soldiers, late instars and queen were found upon sampling the treated mounds. A few live termites were located in one treated mound but were darkly pigmented indicating bait consumption. The control mound remained healthy and did not show any visible sign of negative impact. The bait successfully suppressed or eliminated both M. gilvus colonies within 16 weeks from commencement of feeding.

Solar-powered ventilation of African termite mounds.

Science.gov (United States)

Ocko, Samuel A; King, Hunter; Andreen, David; Bardunias, Paul; Turner, J Scott; Soar, Rupert; Mahadevan, L

2017-09-15

How termite mounds function to facilitate climate control is still only partially understood. Recent experimental evidence in the mounds of a single species, the south Asian termite Odontotermes obesus , suggests that the daily oscillations of radiant heating associated with diurnal insolation patterns drive convective flow within them. How general this mechanism is remains unknown. To probe this, we consider the mounds of the African termite Macrotermes michaelseni , which thrives in a very different environment. By directly measuring air velocities and temperatures within the mound, we see that the overall mechanisms and patterns involved are similar to that in the south Asian species. However, there are also some notable differences between the physiology of these mounds associated with the temporal variations in radiant heating patterns and CO 2 dynamics. Because of the difference between direct radiant heating driven by the position of the sun in African conditions, and the more shaded south Asian environments, we see changes in the convective flows in the two types of mounds. Furthermore, we also see that the south Asian mounds show a significant overturning of stratified gases, once a day, while the African mounds have a relatively uniform concentration of CO 2 Overall, our observations show that despite these differences, termite architectures can harness periodic solar heating to drive ventilation inside them in very different environments, functioning as an external lung, with clear implications for human engineering. © 2017. Published by The Company of Biologists Ltd.

Termites, vertebrate herbivores, and the fruiting success of Acacia drepanolobium.

Science.gov (United States)

Brody, Alison K; Palmer, Todd M; Fox-Dobbs, Kena; Doak, Dan F

2010-02-01

In African savannas, vertebrate herbivores are often identified as key determinants of plant growth, survivorship, and reproduction. However, plant reproduction is likely to be the product of responses to a suite of abiotic and biotic factors, including nutrient availability and interactions with antagonists and mutualists. In a relatively simple system, we examined the role of termites (which act as ecosystem engineers--modifying physical habitat and creating islands of high soil fertility), vertebrate herbivores, and symbiotic ants, on the fruiting success of a dominant plant, Acacia drepanolobium, in East African savannas. Using observational data, large-scale experimental manipulations, and analysis of foliar N, we found that Acacia drepanolobium trees growing at the edge of termite mounds were more likely to reproduce than those growing farther away, in off-mound soils. Although vertebrate herbivores preferentially used termite mounds as demonstrated by dung deposits, long-term exclusion of mammalian grazers did not significantly reduce A. drepanolobium fruit production. Leaf N was significantly greater in trees growing next to mounds than in those growing farther away, and this pattern was unaffected by exclusion of vertebrates. Thus, soil enrichment by termites, rather than through dung and urine deposition by large herbivores, is of primary importance to fruit production near mounds. Across all mound-herbivore treatment combinations, trees that harbored Crematogaster sjostedti were more likely to fruit than those that harbored one of the other three ant species. Although C. sjostedti is less aggressive than the other ants, it tends to inhabit large, old trees near termite mounds which are more likely to fruit than smaller ones. Termites play a key role in generating patches of nutrient-rich habitat important to the reproductive success of A. drepanolobium in East African savannas. Enhanced nutrient acquisition from termite mounds appears to allow plants to

Large herbivores maintain termite-caused differences in herbaceous species diversity patterns.

Science.gov (United States)

Okullo, Paul; Moe, Stein R

2012-09-01

Termites and large herbivores affect African savanna plant communities. Both functional groups are also important for nutrient redistribution across the landscape. We conducted an experiment to study how termites and large herbivores, alone and in combination, affect herbaceous species diversity patterns in an African savanna. Herbaceous vegetation on large vegetated Macrotermes mounds (with and without large herbivores) and on adjacent savanna areas (with and without large herbivores) was monitored over three years in Lake Mburo National Park, Uganda. We found substantial differences in species richness, alpha diversity, evenness, and stability between termite mound herbaceous vegetation and adjacent savanna vegetation. Within months of fencing, levels of species richness, evenness, and stability were no longer significantly different between savanna and mounds. However, fencing reduced the cumulative number of species, particularly for forbs, of which 48% of the species were lost. Fencing increased the beta diversity (dissimilarity among plots) on the resource-poor (in terms of both nutrients and soil moisture) savanna areas, while it did not significantly affect beta diversity on the resource-rich termite mounds. While termites cause substantial heterogeneity in savanna vegetation, large herbivores further amplify these differences by reducing beta diversity on the savanna areas. Large herbivores are, however, responsible for the maintenance of a large number of forbs at the landscape level. These findings suggest that the mechanisms underlying the effects of termites and large herbivores on savanna plant communities scale up to shape community structure and dynamics at a landscape level.

Evaluation of the physical, mechanical and biological properties of the combined wood-plastic in Nothofagus Pumilio wood

International Nuclear Information System (INIS)

Benedetto Acuna, Andres

2010-01-01

In this project he studied the physical, mechanical and biological properties of wood-plastic combinations (WPC) in timber Nothofagus pumilio (Lenga) impregnated with the monomer methyl methacrylate (MMA), trying to get a hold and maximum penetration into the wood . It was used for impregnation method fills the cell (Bethell). To achieve the polymerization, the MMA once absorbed by the specimens under study are irradiated with gamma rays at a dose of 25 kGy, ensuring a high percentage of final polymerization, which fluctuated between 55.09% and 84.48%. The tests applied to the specimens were moisture content, dimensional stability, density, compression perpendicular to grain, compression parallel to grain to grain compression 'new' Janka hardness, shear parallel to grain, static bending and termites. In general, except for the static bending test, the WPC had an increase in their property, being the tests of hardness, density and water absorption which achieved higher profits, increasing their properties at 104%, 79% and 75% respectively compared to untreated specimens. From the economic viewpoint, the production of an inch Lenga timber has a cost of $ 19,805, so it may be feasible marketing both domestically and internationally (author)

Comparison of termite assemblages along a landuse gradient on peat areas in Sarawak, Malaysia.

NARCIS (Netherlands)

Vaessen, T.; Verwer, C.; Demies, M.; Kaliang, H.; Meer, van der P.J.

2011-01-01

VAESSEN T, VERWER C, DEMIES M, KALIANG H & VAN DER MEER PJ. 2011. Comparison of termite assemblages along a landuse gradient on peat areas in Sarawak, Malaysia. In this study we assessed the species density and relative abundance of termites in peat land in Sarawak, Malaysia. Termites were

Molecular signatures of nicotinoid-pathogen synergy in the termite gut.

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Ruchira Sen

Full Text Available Previous studies in lower termites revealed unexpected synergies between nicotinoid insecticides and fungal entomopathogens. The present study investigated molecular mechanisms of nicotinoid-pathogen synergy in the lower termite Reticulitermes flavipes, using the nicotinoid, imidacloprid, in combination with fungal and bacterial entomopathogens. Particular focus was placed on metatranscriptome composition and microbial dynamics in the symbiont-rich termite gut, which houses diverse mixes of protists and bacteria. cDNA microarrays containing a mix of host and protist symbiont oligonucleotides were used to simultaneously assess termite and protist gene expression. Five treatments were compared that included single challenges with sublethal doses of fungi (Metharizium anisopliae, bacteria (Serratia marcescens or imidacloprid, and dual challenges with fungi + imidacloprid or bacteria + imidacloprid. Our findings point towards protist dysbiosis and compromised social behavior, rather than suppression of stereotypical immune defense mechanisms, as the dominant factors underlying nicotinoid-pathogen synergy in termites. Also, greater impacts observed for the fungal pathogen than for the bacterial pathogen suggest that the rich bacterial symbiont community in the R. flavipes gut (>5000 species-level phylotypes exists in an ecological balance that effectively excludes exogenous bacterial pathogens. These findings significantly advance our understanding of antimicrobial defenses in this important eusocial insect group, as well as provide novel insights into how nicotinoids can exert deleterious effects on social insect colonies.

Farming termites determine the genetic population structure of Termitomyces fungal symbionts

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Nobre, Tânia; Fernandes, Cecília; Boomsma, Jacobus J

2011-01-01

Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fu...

Diet Segregation between Cohabiting Builder and Inquiline Termite Species.

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Daniela Faria Florencio

Full Text Available How do termite inquilines manage to cohabit termitaria along with the termite builder species? With this in mind, we analysed one of the several strategies that inquilines could use to circumvent conflicts with their hosts, namely, the use of distinct diets. We inspected overlapping patterns for the diets of several cohabiting Neotropical termite species, as inferred from carbon and nitrogen isotopic signatures for termite individuals. Cohabitant communities from distinct termitaria presented overlapping diet spaces, indicating that they exploited similar diets at the regional scale. When such communities were split into their components, full diet segregation could be observed between builders and inquilines, at regional (environment-wide and local (termitarium scales. Additionally, diet segregation among inquilines themselves was also observed in the vast majority of inspected termitaria. Inquiline species distribution among termitaria was not random. Environmental-wide diet similarity, coupled with local diet segregation and deterministic inquiline distribution, could denounce interactions for feeding resources. However, inquilines and builders not sharing the same termitarium, and thus not subject to potential conflicts, still exhibited distinct diets. Moreover, the areas of the builder's diet space and that of its inquilines did not correlate negatively. Accordingly, the diet areas of builders which hosted inquilines were in average as large as the areas of builders hosting no inquilines. Such results indicate the possibility that dietary partitioning by these cohabiting termites was not majorly driven by current interactive constraints. Rather, it seems to be a result of traits previously fixed in the evolutionary past of cohabitants.

Termite: Emulation Testbed for Encounter Networks

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Rodrigo Bruno

2015-08-01

Full Text Available Cutting-edge mobile devices like smartphones and tablets are equipped with various infrastructureless wireless interfaces, such as WiFi Direct and Bluetooth. Such technologies allow for novel mobile applications that take advantage of casual encounters between co-located users. However, the need to mimic the behavior of real-world encounter networks makes testing and debugging of such applications hard tasks. We present Termite, an emulation testbed for encounter networks. Our system allows developers to run their applications on a virtual encounter network emulated by software. Developers can model arbitrary encounter networks and specify user interactions on the emulated virtual devices. To facilitate testing and debugging, developers can place breakpoints, inspect the runtime state of virtual nodes, and run experiments in a stepwise fashion. Termite defines its own Petri Net variant to model the dynamically changing topology and synthesize user interactions with virtual devices. The system is designed to efficiently multiplex an underlying emulation hosting infrastructure across multiple developers, and to support heterogeneous mobile platforms. Our current system implementation supports virtual Android devices communicating over WiFi Direct networks and runs on top of a local cloud infrastructure. We evaluated our system using emulator network traces, and found that Termite is expressive and performs well.

Adaptations in bacterial and fungal communities to termite fungiculture

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Otani, Saria

in the bacterial and fungal communities. To do this, we used pyrosequencing, fluorescent in situ hybridisation, light and confocal microscopy, enzymatic assays, chemical extractions, in vitro assays, and feeding experiments in this thesis work to elucidate these predicted changes in fungus-growing termite...... in the proportion of fungal material provided to the cockroaches. However, gut microbiotas remained distinct from those of termites after Termitomyces-feeding, indicating that a fungal diet can play a role in structuring gut community composition, but at the same time exemplifies how original community compositions......, and possibly gut microenvironment constrain the magnitude of change. This thesis also characterises the fungus comb fungal communities (mycobiotas) in fungusgrowing termites, and shows that non-Termitomyces fungi were essentially absent in combs, and that Termitomyces fungal crops are maintained...

Towards an integrated understanding of the consequences of fungus domestication on the fungus-growing termite gut microbiota

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Thomas-Poulsen, Michael

2015-01-01

Approximately 30 million years ago (MYA), the subfamily of higher termites Macrotermitinae domesticated a fungus, Termitomyces, as the main plant decomposer and food source for the termite host. The origin of fungiculture shifted the composition of the termite gut microbiota, and some of the func......Approximately 30 million years ago (MYA), the subfamily of higher termites Macrotermitinae domesticated a fungus, Termitomyces, as the main plant decomposer and food source for the termite host. The origin of fungiculture shifted the composition of the termite gut microbiota, and some...... will be powerful, particularly if executed in comparative analyses across the well-established congruent termite-fungus phylogenies. This will allow for testing if gut communities have evolved in parallel with their hosts, with implications for our general understanding of the evolution of gut symbiont communities...

Effect of soil type and moisture availability on the foraging behavior of the Formosan subterranean termite (Isoptera: Rhinotermitidae).

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Cornelius, Mary L; Osbrink, Weste L A

2010-06-01

This study examined the influence of soil type and moisture availability on termite foraging behavior. Physical properties of the soil affected both tunneling behavior and shelter tube construction. Termites tunneled through sand faster than top soil and clay. In containers with top soil and clay, termites built shelter tubes on the sides of the containers. In containers with sand, termites built shelter tubes directly into the air and covered the sides of the container with a layer of sand. The interaction of soil type and moisture availability affected termite movement, feeding, and survival. In assays with moist soils, termites were more likely to aggregate in top soil over potting soil and peat moss. However, termites were more likely to move into containers with dry peat moss and potting soil than containers with dry sand and clay. Termites were also significantly more likely to move into containers with dry potting soil than dry top soil. In the assay with dry soils, termite mortality was high even though termites were able to travel freely between moist sand and dry soil, possibly due to desiccation caused by contact with dry soil. Evaporation from potting soil and peat moss resulted in significant mortality, whereas termites were able to retain enough moisture in top soil, sand, and clay to survive for 25 d. The interaction of soil type and moisture availability influences the distribution of foraging termites in microhabitats.

Asymmetric interaction specificity between two sympatric termites and their fungal symbionts.

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Fine Licht, De H.H.; Boomsma, J.J.

2007-01-01

1. Fungus-growing termites live in an obligate mutualistic symbiosis with Termitomyces fungi. The functions of the fungal symbiont have been hypothesised to differ between species and to range from highly specific roles of providing plant-degrading enzymes complementary to termite gut enzymes, to

The Physiology of Microbial Symbionts in Fungus-Farming Termites

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Rodrigues da Costa, Rafael

. The termites provide the fungus with optimal growth conditions (e.g., stable temperature and humidity), as well as with constant inoculation of growth substrate and protection against alien fungi. In reward, the fungus provides the termites with a protein-rich fungal biomass based diet. In addition...... with their symbionts are main decomposer of organic matter in Africa, and this is reflect of a metabolic complementarity to decompose plant biomass in the genome of the three organisms involved in this symbiosis. Many of the physiological aspects of this symbiosis remain obscure, and here I focus on physiology...... of microbial symbionts associated with fungus-growing termites. Firstly, by using a set of enzyme assays, plant biomass compositional analyses, and RNA sequencing we gained deeper understanding on what enzymes are produced and active at different times of the decomposition process. Our results show that enzyme...

Harvesting and consumption of fuel and timber wood in rural area of district tank, pakistan

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Badshah, L.; Hussain, F.; Burni, T.

2014-01-01

The study revealed that 90% of the rural people with different age group of District Tank, Pakistan depended upon firewood for catering. The total annual wood consumption for fueling by brick brewers, food sellers and domestic utilization was 18371 metric tons in this remote region. The saw machines also convert 13650 metric tons of timber wood yearly into logs and boards of various grades. The total wood consumption exceeds the quantity of wood harvested by tree fellers, farmers and wood sellers. Therefore the balance of over 13000 metric tons is sourced from neighboring forest of Tehsil Kulachi and Dera Ismail Khan. The quantity of wood removed and consumed for various purposes did not show a significant difference at (0.05) among the six locations. However student t-test showed significant difference existed in the mean annual removal and consumption of wood in the area. The study also enumerated Acacia nilotica, Tamarix aphylla, and Sueda fruticosa as the best and preferred fuel species. While Acacia nilotica, Prosopis farcta and Dalbergia sisso as the frequently used timber species in the region. The criterion of firewood and lumber consumption was very conventional like durability in blaze and opposed to termite. Consequently, it is recommended scientific vegetation conservation strategies meant at improved burning of fuel wood and maximized used of timber products as a complimentary efforts to enforced tree planting for conservation of plant resources. (author)

Monitoring Termite-Mediated Ecosystem Processes Using Moderate and High Resolution Satellite Imagery

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Lind, B. M.; Hanan, N. P.

2016-12-01

Termites are considered dominant decomposers and prominent ecosystem engineers in the global tropics and they build some of the largest and architecturally most complex non-human-made structures in the world. Termite mounds significantly alter soil texture, structure, and nutrients, and have major implications for local hydrological dynamics, vegetation characteristics, and biological diversity. An understanding of how these processes change across large scales has been limited by our ability to detect termite mounds at high spatial resolutions. Our research develops methods to detect large termite mounds in savannas across extensive geographic areas using moderate and high resolution satellite imagery. We also investigate the effect of termite mounds on vegetation productivity using Landsat-8 maximum composite NDVI data as a proxy for production. Large termite mounds in arid and semi-arid Senegal generate highly reflective `mound scars' with diameters ranging from 10 m at minimum to greater than 30 m. As Sentinel-2 has several bands with 10 m resolution and Landsat-8 has improved calibration, higher radiometric resolution, 15 m spatial resolution (pansharpened), and improved contrast between vegetated and bare surfaces compared to previous Landsat missions, we found that the largest and most influential mounds in the landscape can be detected. Because mounds as small as 4 m in diameter are easily detected in high resolution imagery we used these data to validate detection results and quantify omission errors for smaller mounds.

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

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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.

Termites community as environmental bioindicators in highlands: a case study in eastern slopes of Mount Slamet, Central Java

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IDHAM SAKTI HARAHAP

2011-10-01

Full Text Available Pribadi T,Raffiudin R,HarahapIS (2011Termites community as environmental bioindicators in highlands: a case study in eastern slopes of Mount Slamet, Central Java. Biodiversitas 12: 235-240. Termites ecological behaviour is much affected by land use change and disturbance level. Their variation in diversity can be used as bioindicator of environmental quality. However, termite community response to land use changes and habitat disturbance in highland ecosystems remains poorly understood. This study was conducted to investigate the response of termite community to land use intensification and to explore their role as environmental bioindicator in Mount Slamet. A standard survey protocol was used to collect termites in five land use typesof various disturbance levels,i.e. protected forest, recreation forest, production forest,agroforestry, and urban area. It was found two termite families i.e. Rhinotermitidae and Termitidae with seven species, i.e Schedorhinotermes javanicus, Procapritermes sp, Pericapritermes semarangi, Macrotermes gilvus, Microtermes insperatus, Nasutitermes javanicus, and N. matanganensis. Termite species’ richness and evenness, Shannon-Wiener index, relative abundance, and biomass of termite were declined along with the land use types and disturbance level from protected forest to urban area. Habitat disturbance was the main declining factor of termite diversity. Termite composition changed along with the land use disturbance level. Soil feeding termites were sensitive to the disturbance – they were not found in urban area. Hence, their presence or absence can be used as environmental bioindicator to detect habitat disturbance.

First forensic records of termite activity on non-fossilized human bones in Brazil

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R. A. Queiroz

Full Text Available Abstract The aim of this study was to describe the first records of termite activity on non-fossilized human bones in Brazil. The cases reported in this study resulted from forensic analysis of six human skeletons found in northeastern Brazil between 2012 and 2014. Traces of tunnels and nests commonly produced by termites were found on several human bone surfaces as well as the specimens and characteristic signs of osteophagic activity. In four cases, the species were identified: Amitermes amifer Silvestri, 1901, Nasutitermes corniger (Motschulsky, 1855 (on two skeletons, and Microcerotermes indistinctus Mathews, 1977. In two other cases, the activity of termites on bone surfaces was evidenced by remains of nests and tunnels produced by these insects. At least in the samples of human remains available for this report, the number of termites collected was greater on bones found during autumn, the rainy season in the Northeast of Brazil. The human bones examined showed termites like insects with lots of strength at bone degradation, capable of continuing the process of decomposition of human remains even in completely skeletonized bodies.

A Preliminary Survey of Species Composition of Termites (Insecta: Isoptera) in Samunsam Wildlife Sanctuary, Sarawak.

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Jamil, Norsyarizan; Ismail, Wan Nurainie Wan; Abidin, Siti Shamimi; Amaran, Mazdan Ali; Hazali, Ratnawati

2017-07-01

A survey on termite species composition was conducted in Samunsam Wildlife Sanctuary, Sarawak in February 2015. Overall 19 species of termite belonging to 13 genera and 8 subfamilies was found in the sanctuary. It was recorded the subfamily of Termitinae had the highest number of species (6 species, equal to 31.58% of total species), followed by Nasutermitinae (3 species, 15.79%), Macrotermitinae, Amitermitinae, Rhinotermitinae, Coptotermitinae, (2 species, 10.53% respectively), and Heterotermitinae, Termitogetoninae (1 species, 5.26% respectively). Since this rapid survey is the first termite assemblage representation in Samunsam Wildlife Sanctuary, the preliminary result may serve as the baseline data for termite composition in the area. Therefore, a whole coverage for the area within this sanctuary would definitely increase the number of termite species found in the sanctuary.

Differences between bacterial communities in the gut of a soil-feeding termite (Cubitermes niokoloensis) and its mounds.

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Fall, Saliou; Hamelin, Jérôme; Ndiaye, Farma; Assigbetse, Komi; Aragno, Michel; Chotte, Jean Luc; Brauman, Alain

2007-08-01

In tropical ecosystems, termite mound soils constitute an important soil compartment covering around 10% of African soils. Previous studies have shown (S. Fall, S. Nazaret, J. L. Chotte, and A. Brauman, Microb. Ecol. 28:191-199, 2004) that the bacterial genetic structure of the mounds of soil-feeding termites (Cubitermes niokoloensis) is different from that of their surrounding soil. The aim of this study was to characterize the specificity of bacterial communities within mounds with respect to the digestive and soil origins of the mound. We have compared the bacterial community structures of a termite mound, termite gut sections, and surrounding soil using PCR-denaturing gradient gel electrophoresis (DGGE) analysis and cloning and sequencing of PCR-amplified 16S rRNA gene fragments. DGGE analysis revealed a drastic difference between the genetic structures of the bacterial communities of the termite gut and the mound. Analysis of 266 clones, including 54 from excised bands, revealed a high level of diversity in each biota investigated. The soil-feeding termite mound was dominated by the Actinobacteria phylum, whereas the Firmicutes and Proteobacteria phyla dominate the gut sections of termites and the surrounding soil, respectively. Phylogenetic analyses revealed a distinct clustering of Actinobacteria phylotypes between the mound and the surrounding soil. The Actinobacteria clones of the termite mound were diverse, distributed among 10 distinct families, and like those in the termite gut environment lightly dominated by the Nocardioidaceae family. Our findings confirmed that the soil-feeding termite mound (C. niokoloensis) represents a specific bacterial habitat in the tropics.

Incomplete Co-cladogenesis Between Zootermopsis Termites and Their Associated Protists.

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Taerum, Stephen J; De Martini, Francesca; Liebig, Jürgen; Gile, Gillian H

2018-02-08

Coevolution is a major driver of speciation in many host-associated symbionts. In the termite-protist digestive symbiosis, the protists are vertically inherited by anal feeding among nest mates. Lower termites (all termite families except Termitidae) and their symbionts have broadly co-diversified over ~170 million yr. However, this inference is based mainly on the restricted distribution of certain protist genera to certain termite families. With the exception of one study, which demonstrated congruent phylogenies for the protist Pseudotrichonympha and its Rhinotermitidae hosts, coevolution in this symbiosis has not been investigated with molecular methods. Here we have characterized the hindgut symbiotic protists (Phylum Parabasalia) across the genus Zootermopsis (Archotermopsidae) using single cell isolation, molecular phylogenetics, and high-throughput amplicon sequencing. We report that the deepest divergence in the Zootermopsis phylogeny (Zootermopsis laticeps [Banks; Isoptera: Termopsidae]) corresponds with a divergence in three of the hindgut protist species. However, the crown Zootermopsis taxa (Zootermopsis angusticollis [Hagen; Isoptera: Termopsidae], Z. nevadensis nevadensis [Hagen; Isoptera: Termopsidae], and Z. nevadensis nuttingi [Haverty & Thorne; Isoptera: Termopsidae]) share the same protist species, with no evidence of co-speciation under our methods. We interpret this pattern as incomplete co-cladogenesis, though the possibility of symbiont exchange cannot be entirely ruled out. This is the first molecular evidence that identical communities of termite-associated protist species can inhabit multiple distinct host species. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Nootkatone is a repellent for Formosan subterranean termite (Coptotermes formosanus).

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Zhu, B C; Henderson, G; Chen, F; Maistrello, L; Laine, R A

2001-03-01

We examined the behavior of Formosan subterranean termites toward one of the components of vetiver grass oil, the roots of which manufacture insect repellents. We found nootkatone, a sesquiterpene ketone, isolated from vetiver oil is a strong repellent and toxicant to Formosan subterranean termites. The lowest effective concentration tested was 10 micrograms/g substrate. This is the first report of nootkatone being a repellent to insects.

Interacting effects of insects and flooding on wood decomposition.

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Michael D Ulyshen

Full Text Available Saproxylic arthropods are thought to play an important role in wood decomposition but very few efforts have been made to quantify their contributions to the process and the factors controlling their activities are not well understood. In the current study, mesh exclusion bags were used to quantify how arthropods affect loblolly pine (Pinus taeda L. decomposition rates in both seasonally flooded and unflooded forests over a 31-month period in the southeastern United States. Wood specific gravity (based on initial wood volume was significantly lower in bolts placed in unflooded forests and for those unprotected from insects. Approximately 20.5% and 13.7% of specific gravity loss after 31 months was attributable to insect activity in flooded and unflooded forests, respectively. Importantly, minimal between-treatment differences in water content and the results from a novel test carried out separately suggest the mesh bags had no significant impact on wood mass loss beyond the exclusion of insects. Subterranean termites (Isoptera: Rhinotermitidae: Reticulitermes spp. were 5-6 times more active below-ground in unflooded forests compared to flooded forests based on wooden monitoring stakes. They were also slightly more active above-ground in unflooded forests but these differences were not statistically significant. Similarly, seasonal flooding had no detectable effect on above-ground beetle (Coleoptera richness or abundance. Although seasonal flooding strongly reduced Reticulitermes activity below-ground, it can be concluded from an insignificant interaction between forest type and exclusion treatment that reduced above-ground decomposition rates in seasonally flooded forests were due largely to suppressed microbial activity at those locations. The findings from this study indicate that southeastern U.S. arthropod communities accelerate above-ground wood decomposition significantly and to a similar extent in both flooded and unflooded forests

Termite mounds as hot spots of nitrous oxide emissions in South-Sudanian savanna of Burkina Faso (West Africa)

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Brümmer, Christian; Papen, Hans; Wassmann, Reiner; Brüggemann, Nicolas

2009-05-01

Despite a considerable knowledge of the significant role of termites in the global methane budget, very little is known about their contribution to the global nitrous oxide (N2O) budget. Release of N2O from termite (Cubitermes fungifaber) mounds was measured at a natural savanna site in the southwest of Burkina Faso from May to September 2006. Termite N2O emissions were around 20 μg N2O-N m-2 h-1 at the end of the dry season, and up to two orders of magnitude higher than N2O emissions from the surrounding termite-free soil after the onset of the rainy season. The average N2O emission rate from termite mounds during the observation period was 204 μg N2O-N m-2 h-1, and termite mounds contributed 3.0% to total N2O emissions from this savanna ecosystem. However, in other tropical terrestrial ecosystems with other termite species and/or higher termite density this share might be significantly higher.

Unrelated secondary reproductives in the neotropical termite Silvestritermes euamignathus (Isoptera: Termitidae)

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Haifig, Ives; Vargo, Edward L.; Labadie, Paul; Costa-Leonardo, Ana Maria

2016-02-01

A termite colony is usually founded by a pair of alates, the primary reproductives, which produce all the nestmates. In some species, secondary reproductives appear to either replace the primaries or supplement colony reproduction. In termites, secondary reproductives are generally ergatoids derived from workers or nymphoids derived from nymphs. Silvestritermes euamignathus is a termite species that forms multiple nymphoid reproductives, and to date it was hypothesized that these secondary reproductives were the progeny of the primary founding reproductives. We developed markers for 12 microsatellite loci and used COI mitochondrial DNA (mtDNA) to genotype 59 nymphoid neotenics found in a colony of S. euamignathus to test this hypothesis. Our results showed that nymphoids of S. euamignathus are not all siblings. The microsatellite analysis suggests that the secondary reproductives derived from a minimum of four different pairs of reproductives belonging to at least two different matrilines. This is the first record of non-sibling secondary reproductives occupying the same nest in a higher termite. These unrelated reproductives might be the result of either pleometrotic colony foundation or colony fusion.

Effects of permethrin treated wood on the subterranean termite Reticulitermes flavipes (Kollar) and comparison of solvent extraction for HPLC analysis of permethrin in wood

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Mark Mankowski; Blossie Boyd; Geoffrey Webb

2016-01-01

Permethrin is a common insecticide used in wood preservation. It is an effective synthetic pyrethroid that is considered to be less toxic to higher organisms than organochlorine insecticides. In wood preservation, it can be used in combination with fungicides such as 3-iodo-2-propynyl butyl carbamate (IPBC). Permethrin has a dual mode of action as it is a repellent and...

A Laboratory Maintenance Regime for a Fungus-Growing Termite Macrotermes gilvus (Blattodea: Termitidae).

Science.gov (United States)

Lee, Ching-Chen; Lee, Chow-Yang

2015-06-01

The optimum maintenance conditions of the fungus-growing termite, Macrotermes gilvus (Hagen) (Blattodea: Termitidae), in the laboratory were studied. Termites were kept on a matrix of moist sand and with fungus comb as food. The survival of groups of termites was measured when maintained at different population densities by changing group size and container volume. Larger groups (≥0.6 g) were more vigorous and had significant higher survival rates than smaller groups (≤0.3 g). The population density for optimal survival of M. gilvus is 0.0025 g per container volume (ml) or 0.0169 g per matrix volume (cm(3)), i.e., 1.2 g of termites kept in a 480-ml container filled with 71 cm3 of sand. In termite groups of smaller size (i.e., 0.3 g) or groups maintained in smaller container (i.e., 100 ml) the fungus comb was overgrown with Xylaria spp., and subsequently all termites died within the study period. The insufficient number of workers for regulating the growth of unwanted fungi other than Termitomyces spp. in the fungus comb is the most likely reason. Unlike some other mound-building termite species, M. gilvus showed satisfactory survival when maintained in non-nutritious matrix (i.e., sand). There was no significant difference in the survival rate between different colonies of M. gilvus (n=5), with survival in the range of 78.5-84.4% after 4 wk. Advances in the maintenance of Macrotermes will enable researchers to study with more biological relevance many aspects of the biology, behavior, and management of this species. © 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.

Genes underlying reproductive division of labor in termites, with comparisons to social Hymenoptera

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Judith eKorb

2016-04-01

Full Text Available All social insects are characterized by a reproductive division of labor. Within a colony only a few individuals reproduce (queens and in termites, also a king while the large majority (workers and soldiers forgo reproduction, at least temporarily. The evolution of such reproductive altruism can ultimately be explained by inclusive fitness theory. Here, I will review the proximate genetic mechanisms underlying this altruism in termites. As social cockroaches they evolved eusociality independently from the social Hymenoptera, which makes them interesting test cases to look for common underlying mechanisms of eusociality and lineage specific idiosyncrasies. First, I will provide a summary of the genes and their function that have been identified to underlie reproductive division of labor - so called 'queen genes,' - in the drywood termite Cryptotermes secundus, an emerging model to study termite social evolution. Second, I outline how widespread these queen genes are across the termite phylogeny, using also evidence from recent genome analyses. I will provide hypotheses about the evolutionary origin of these queen genes, aiming to link proximate mechanisms with ultimate functions. Finally, I will draw comparisons to social Hymenoptera to indicate potential common underpinnings that warrant further testing.

Sound quality assessment of wood for xylophone bars.

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Aramaki, Mitsuko; Baillères, Henri; Brancheriau, Loïc; Kronland-Martinet, Richard; Ystad, Sølvi

2007-04-01

Xylophone sounds produced by striking wooden bars with a mallet are strongly influenced by the mechanical properties of the wood species chosen by the xylophone maker. In this paper, we address the relationship between the sound quality based on the timbre attribute of impacted wooden bars and the physical parameters characterizing wood species. For this, a methodology is proposed that associates an analysis-synthesis process and a perceptual classification test. Sounds generated by impacting 59 wooden bars of different species but with the same geometry were recorded and classified by a renowned instrument maker. The sounds were further digitally processed and adjusted to the same pitch before being once again classified. The processing is based on a physical model ensuring the main characteristics of the wood are preserved during the sound transformation. Statistical analysis of both classifications showed the influence of the pitch in the xylophone maker judgement and pointed out the importance of two timbre descriptors: the frequency-dependent damping and the spectral bandwidth. These descriptors are linked with physical and anatomical characteristics of wood species, providing new clues in the choice of attractive wood species from a musical point of view.

Genetically Engineered Yeast Expressing a Lytic Peptide from Bee Venom (Melittin) Kills Symbiotic Protozoa in the Gut of Formosan Subterranean Termites.

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Husseneder, Claudia; Donaldson, Jennifer R; Foil, Lane D

2016-01-01

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a costly invasive urban pest in warm and humid regions around the world. Feeding workers of the Formosan subterranean termite genetically engineered yeast strains that express synthetic protozoacidal lytic peptides has been shown to kill the cellulose digesting termite gut protozoa, which results in death of the termite colony. In this study, we tested if Melittin, a natural lytic peptide from bee venom, could be delivered into the termite gut via genetically engineered yeast and if the expressed Melittin killed termites via lysis of symbiotic protozoa in the gut of termite workers and/or destruction of the gut tissue itself. Melittin expressing yeast did kill protozoa in the termite gut within 56 days of exposure. The expressed Melittin weakened the gut but did not add a synergistic effect to the protozoacidal action by gut necrosis. While Melittin could be applied for termite control via killing the cellulose-digesting protozoa in the termite gut, it is unlikely to be useful as a standalone product to control insects that do not rely on symbiotic protozoa for survival.

Control Of Book Termites Using Solid Attractants At The Central Library Of Universitas Sumatera Utara USU

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Ameilia Zuliyanti Siregar

2017-10-01

Full Text Available It has been identified the extent of damage due to the activity of Captotermes sp Microtermis sp Formica sp Araneus sp and Stegonium sp on books in the USU Library. Furthermore prevention of dominant pest attack on the book containing cellulose as the main food of termites termites control action term control by Action Research method action research Kurt Lewin adoption is done intensively from July to September 2017. used are of neem leaf Azadirachta indica tobacco leaf Nicotiana tabacum rubber cassava leaf Manihot glaziovii and betel nut Areca catechu which can be used as Termite Baiting System TBS. This method includes three stages in the form of planning planning activity and reflection actuating and reflexion and evaluation evaluation. The results show the higher number of termites in F1799.3 0.328 with zero days after application. Based on the research recorded in sampling for 3 months with 4 treatments had a significant effect on the percentage of the number of termites that died and collected with the value of F is 86.27 p amp706 0000 and the percentage of death is F 59.13 p amp706 0000. Pearson correlation value recorded percentage of termite mortality r 0.349 and percentage of book affected r -0597 showed a very significant relationship. Pinet pellet is the best attractant in controlling termite pests followed by tobacco plants poisonous yams and neem. Optimal FFB techniques in its use can control termite colonies in an environmentally friendly manner.

Pipe damping

International Nuclear Information System (INIS)

Ware, A.G.

1985-01-01

Studies are being conducted at the Idaho National Engineering Laboratory to determine whether an increase in the damping values used in seismic structural analyses of nuclear piping systems is justified. Increasing the allowable damping would allow fewer piping supports which could lead to safer, more reliable, and less costly piping systems. Test data from availble literature were examined to determine the important parameters contributing to piping system damping, and each was investigated in separate-effects tests. From the combined results a world pipe damping data bank was established and multiple regression analyses performed to assess the relative contributions of the various parameters. The program is being extended to determine damping applicable to higher frequency (33 to 100 Hz) fluid-induced loadings. The goals of the program are to establish a methodology for predicting piping system damping and to recommend revised guidelines for the damping values to be included in analyses

The relationships between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

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H. Jamali

2013-04-01

Full Text Available We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the

The relationships between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

Science.gov (United States)

Jamali, H.; Livesley, S. J.; Hutley, L. B.; Fest, B.; Arndt, S. K.

2013-04-01

We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e) basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past) would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but

A Preliminary Study on Termite Mound Soil as Agricultural Soil for Crop Production in South West, Nigeria

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O. E. Omofunmi

2017-08-01

Full Text Available It is a popular belief of the people in the Southern region of Nigeria that a land infested with termite usually brings prosperity to the land owner regardless of the type of its usage. Therefore, the present study assessed termite mounds soil properties which are important to crop production. Two soil samples were collected and their physical and chemical properties determined in accordance with American Public Health Association (APHA, 2005. Data were analyzed using descriptive statistics. The textural classes showed that the termite mound soil was sand clay loam while the surrounding soil was clay loam. This results revealed that: Termites’ activity induced significant chemical changes in the soil possible due to the materials used in building their nests. There was increase the concentrations of nitrogen, phosphorus, Potassium, calcium and magnesium higher in the termite’s mounds, while the micro-nutrients (zinc, iron and copper except sulphur and manganese lower in the soil infested by termites. There were significant differences (p ≥ 0.05 between termite mound soil and surrounding soil. It showed highly positive correlation between termite mound and surrounding soil (r= 0.92. The concentration of the soil properties around the termite mound are within the range of soil nutrients suitable for arable crop production. Termite mound soil is recommended to be used as an alternative to local farmers who cannot afford to buy expensive inorganic fertilizers.

Thermoregulation and ventilation of termite mounds

Science.gov (United States)

Korb, Judith

2003-05-01

Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO2 concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.

A phylogenetic community approach for studying termite communities in a West African savannah.

Science.gov (United States)

Hausberger, Barbara; Korb, Judith

2015-10-01

Termites play fundamental roles in tropical ecosystems, and mound-building species in particular are crucial in enhancing species diversity, from plants to mammals. However, it is still unclear which factors govern the occurrence and assembly of termite communities. A phylogenetic community approach and null models of species assembly were used to examine structuring processes associated with termite community assembly in a pristine savannah. Overall, we did not find evidence for a strong influence of interspecific competition or environmental filtering in structuring these communities. However, the presence of a single species, the mound-building termite Macrotermes bellicosus, left a strong signal on structuring and led to clustered communities of more closely related species. Hence, this species changes the assembly rules for a whole community. Our results show the fundamental importance of a single insect species for community processes, suggesting that more attention to insect species is warranted when developing conservation strategies. © 2015 The Author(s).

Natalamycin A, an ansamycin from a termite-associated Streptomyces sp

DEFF Research Database (Denmark)

Kim, Ki Hyun; Ramadhar, Timothy R.; Beemelmanns, Christine

2014-01-01

We report a preliminary functional and complete structural characterization of a highly unusual geldanamycin analog, natalamycin A, that was isolated from Streptomyces strain M56 recovered from a South African nest of Macrotermes natalensis termites. Bioassay-guided fractionation based on antifun......We report a preliminary functional and complete structural characterization of a highly unusual geldanamycin analog, natalamycin A, that was isolated from Streptomyces strain M56 recovered from a South African nest of Macrotermes natalensis termites. Bioassay-guided fractionation based...

Protozoacidal Trojan-Horse: use of a ligand-lytic peptide for selective destruction of symbiotic protozoa within termite guts.

Science.gov (United States)

Sethi, Amit; Delatte, Jennifer; Foil, Lane; Husseneder, Claudia

2014-01-01

For novel biotechnology-based termite control, we developed a cellulose bait containing freeze-dried genetically engineered yeast which expresses a protozoacidal lytic peptide attached to a protozoa-recognizing ligand. The yeast acts as a 'Trojan-Horse' that kills the cellulose-digesting protozoa in the termite gut, which leads to the death of termites, presumably due to inefficient cellulose digestion. The ligand targets the lytic peptide specifically to protozoa, thereby increasing its protozoacidal efficiency while protecting non-target organisms. After ingestion of the bait, the yeast propagates in the termite's gut and is spread throughout the termite colony via social interactions. This novel paratransgenesis-based strategy could be a good supplement for current termite control using fortified biological control agents in addition to chemical insecticides. Moreover, this ligand-lytic peptide system could be used for drug development to selectively target disease-causing protozoa in humans or other vertebrates.

The impact of edge effect on termite community (Blattodea: Isoptera) in fragments of Brazilian Atlantic Rainforest.

Science.gov (United States)

Almeida, C S; Cristaldo, P F; Florencio, D F; Ribeiro, E J M; Cruz, N G; Silva, E A; Costa, D A; Araújo, A P A

2017-01-01

Habitat fragmentation is considered to be one of the biggest threats to tropical ecosystem functioning. In this region, termites perform an important ecological role as decomposers and ecosystem engineers. In the present study, we tested whether termite community is negatively affected by edge effects on three fragments of Brazilian Atlantic Rainforest. Termite abundance and vegetation structure were sampled in 10 transects (15 × 2 m), while termite richness, activity, and soil litter biomass were measured in 16 quadrants (5 × 2 m) at forest edge and interior of each fragment. Habitat structure (i.e. number of tree, diameter at breast height and soil litter biomass) did not differ between forest edge and interior of fragments. Termite richness, abundance and activity were not affected by edge effect. However, differences were observed in the β diversity between forest edge and interior as well as in the fragments sampled. The β diversity partitioning indicates that species turnover is the determinant process of termite community composition under edge effect. Our results suggest that conservation strategies should be based on the selection of several distinct sites instead of few rich sites (e.g. nesting).

Mitochondrial Phylogenomics Resolves the Global Spread of Higher Termites, Ecosystem Engineers of the Tropics.

Science.gov (United States)

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Ho, Simon Y W; Iqbal, Naeem; Coissac, Eric; Lee, Maria; Jendryka, Martin M; Sillam-Dussès, David; Krížková, Barbora; Roisin, Yves; Evans, Theodore A

2017-03-01

The higher termites (Termitidae) are keystone species and ecosystem engineers. They have exceptional biomass and play important roles in decomposition of dead plant matter, in soil manipulation, and as the primary food for many animals, especially in the tropics. Higher termites are most diverse in rainforests, with estimated origins in the late Eocene (∼54 Ma), postdating the breakup of Pangaea and Gondwana when most continents became separated. Since termites are poor fliers, their origin and spread across the globe requires alternative explanation. Here, we show that higher termites originated 42-54 Ma in Africa and subsequently underwent at least 24 dispersal events between the continents in two main periods. Using phylogenetic analyses of mitochondrial genomes from 415 species, including all higher termite taxonomic and feeding groups, we inferred 10 dispersal events to South America and Asia 35-23 Ma, coinciding with the sharp decrease in global temperature, sea level, and rainforest cover in the Oligocene. After global temperatures increased, 23-5 Ma, there was only one more dispersal to South America but 11 to Asia and Australia, and one dispersal back to Africa. Most of these dispersal events were transoceanic and might have occurred via floating logs. The spread of higher termites across oceans was helped by the novel ecological opportunities brought about by environmental and ecosystem change, and led termites to become one of the few insect groups with specialized mammal predators. This has parallels with modern invasive species that have been able to thrive in human-impacted ecosystems. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Termite hindguts and the ecology of microbial communities in the sequencing age.

Science.gov (United States)

Tai, Vera; Keeling, Patrick J

2013-01-01

Advances in high-throughput nucleic acid sequencing have improved our understanding of microbial communities in a number of ways. Deeper sequence coverage provides the means to assess diversity at the resolution necessary to recover ecological and biogeographic patterns, and at the same time single-cell genomics provides detailed information about the interactions between members of a microbial community. Given the vastness and complexity of microbial ecosystems, such analyses remain challenging for most environments, so greater insight can also be drawn from analysing less dynamic ecosystems. Here, we outline the advantages of one such environment, the wood-digesting hindgut communities of termites and cockroaches, and how it is a model to examine and compare both protist and bacterial communities. Beyond the analysis of diversity, our understanding of protist community ecology will depend on using statistically sound sampling regimes at biologically relevant scales, transitioning from discovery-based to experimental ecology, incorporating single-cell microbiology and other data sources, and continued development of analytical tools. © 2013 The Author(s) Journal of Eukaryotic Microbiology © 2013 International Society of Protistologists.

Comparison of performance of wood extractives as preservatives in field tests against termites and decay in the USA and Pakistan

Science.gov (United States)

Babar Hassan; Sohail Ahmed; Mark Mankowski; Grant Kirker

2017-01-01

Increasing environmental regulations have limited the use of certain broad spectrum synthetic pesticides as wood preservatives creating a need for more environmentally benign wood preservative systems. Biocidal compounds from natural products have been proposed as alternatives to commercial wood preservatives, but field data from long term performance testing is...

Patterns of interaction specificity of fungus-growing termites and Termitomyces symbionts in South Africa

NARCIS (Netherlands)

Aanen, D.K.; Ros, V.I.D.; Fine Licht, de H.H.; Mitchell, J.; Beer, de Z.W.; Slippers, B.; Rouland-Lefevre, C.; Boomsma, J.J.

2007-01-01

Background Termites of the subfamily Macrotermitinae live in a mutualistic symbiosis with basidiomycete fungi of the genus Termitomyces. Here, we explored interaction specificity in fungus-growing termites using samples from 101 colonies in South-Africa and Senegal, belonging to eight species

Clay preference and particle transport behavior of Formosan subterranean termites (Isoptera: Rhinotermitidae): a laboratory study.

Science.gov (United States)

Wang, Cai; Henderson, Gregg

2014-12-01

Although preference and utilization of clay have been studied in many higher termites, little attention has been paid to lower termites, especially subterranean termites. The Formosan subterranean termite, Coptotermes formosanus Shiraki, can modify its habitat by using clay to fill tree cavities. Here, the biological significance of clay on C. formosanus was investigated. Choice tests showed that significantly more termites aggregated in chambers where clay blocks were provided, regardless of colony group, observation period, or nutritional condition (fed or starved). No-choice tests showed that clay had no observable effect on survivorship, live or dry biomass, water content, and tunneling activity after 33-35 d. However, clay appeared to significantly decrease filter paper consumption (dry weight loss). Active particle (sand, paper, and clay) transport behavior was observed in both choice and no-choice tests. When present, clay was preferentially spread on the substrate, attached to the smooth surfaces of the containers, and used to line sand tunnels. Mechanisms and potential application of clay attraction are discussed. © 2013 Institute of Zoology, Chinese Academy of Sciences.

EFFECTS OF SOME BORON COMPOUNDS ON THE LEACHABILITY OF EUCALYPTUS (Eucalyptus camaldulensis Dehn. WOOD

Directory of Open Access Journals (Sweden)

Hüseyin Tan

2003-04-01

Full Text Available Wood preservation effectiveness of boron compounds against biological damagers and fire is well known. But these compounds are not widely used in preservation of wood because of their leachability from wood by rain water and making wood more hyroscopic than untreated wood in damp environments. Main aim of this study is; therefore, to improve the undesired leachability properties of some boron compounds by various water repellents (WRs. Aqueous solutions with polyethyleneglycole (PEG-400 of boric acid and sodium perborate were chosen as boron compounds. WRs were used as secondary treatment chemicals which were considered as dimensional stabilizer of wood and phsical bariers of boron retained at innerparts of treated wood. Results indicated that WRs were reduced leachability of boron from wood significantly (P<0.05. Boron salts applied with. PEG were more leachable than were of equeous solutions. WRs were not found effective on reducing the leachability of boron solved in PEG. Longer leaching time caused more leachant and reduction the phsical alleviation of WRs on boron leaching.

The evolutionary transition from subsocial to eusocial behaviour in Dictyoptera: phylogenetic evidence for modification of the "shift-in-dependent-care" hypothesis with a new subsocial cockroach.

Science.gov (United States)

Pellens, Roseli; D'Haese, Cyrille A; Bellés, Xavier; Piulachs, Maria-Dolors; Legendre, Frédéric; Wheeler, Ward C; Grandcolas, Philippe

2007-05-01

Cockroaches have always been used to understand the first steps of social evolution in termites because they are close relatives with less complex and integrated social behaviour. Termites are all eusocial and ingroup comparative analysis would be useless to infer the origin of their social behaviour. The cockroach genus Cryptocercus was used as a so-called "prototermite" model because it shows key-attributes similar to the termites (except Termitidae): wood-feeding, intestinal flagellates and subsocial behaviour. In spite of these comparisons between this subsocial cockroach and eusocial termites, the early and remote origin of eusocial behaviour in termites is not well understood yet and the study of other relevant "prototermite" models is however needed. A molecular phylogenetic analysis was carried out to validate a new "prototermite" model, Parasphaeria boleiriana which shows a peculiar combination of these key-attributes. It shows that these attributes of Parasphaeria boleiriana have an independent origin from those of other wood-eating cockroaches and termites. The case of P. boleiriana suggests that a short brood care was selected for with life on an ephemeral wood resource, even with the need for transmission of flagellates. These new phylogenetic insights modify evolutionary hypotheses, contradicting the assumption made with Cryptocercus model that a long brood care is necessary for cooperation between broods in the "shift-in-dependent-care" hypothesis. An ephemeral wood resource is suggested to prompt generation overlap and the evolution of cooperation, even if brood care is shortened.

Patterns of interaction specificity of fungus-growing termites and Termitomyces symbionts in South Africa

DEFF Research Database (Denmark)

Aanen, Duur K; Ros, Vera I D; de Fine Licht, Henrik H

2007-01-01

BACKGROUND: Termites of the subfamily Macrotermitinae live in a mutualistic symbiosis with basidiomycete fungi of the genus Termitomyces. Here, we explored interaction specificity in fungus-growing termites using samples from 101 colonies in South-Africa and Senegal, belonging to eight species di...

Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

Energy Technology Data Exchange (ETDEWEB)

Esa, Mohammad Faris Mohammad; Hassan, Ibrahim Haji [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia); Rahim, Faszly; Hanifah, Sharina Abu [School of Environmental Scieces and Natural Resources Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia)

2015-09-25

Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration.

Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

International Nuclear Information System (INIS)

Esa, Mohammad Faris Mohammad; Hassan, Ibrahim Haji; Rahim, Faszly; Hanifah, Sharina Abu

2015-01-01

Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration

Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

Science.gov (United States)

Esa, Mohammad Faris Mohammad; Rahim, Faszly; Hassan, Ibrahim Haji; Hanifah, Sharina Abu

2015-09-01

Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration.

Cospeciation in the triplex symbiosis of termite gut protists (Pseudotrichonympha spp.), their hosts, and their bacterial endosymbionts.

Science.gov (United States)

Noda, S; Kitade, O; Inoue, T; Kawai, M; Kanuka, M; Hiroshima, K; Hongoh, Y; Constantino, R; Uys, V; Zhong, J; Kudo, T; Ohkuma, M

2007-03-01

A number of cophylogenetic relationships between two organisms namely a host and a symbiont or parasite have been studied to date; however, organismal interactions in nature usually involve multiple members. Here, we investigated the cospeciation of a triplex symbiotic system comprising a hierarchy of three organisms -- termites of the family Rhinotermitidae, cellulolytic protists of the genus Pseudotrichonympha in the guts of these termites, and intracellular bacterial symbionts of the protists. The molecular phylogeny was inferred based on two mitochondrial genes for the termites and nuclear small-subunit rRNA genes for the protists and their endosymbionts, and these were compared. Although intestinal microorganisms are generally considered to have looser associations with the host than intracellular symbionts, the Pseudotrichonympha protists showed almost complete codivergence with the host termites, probably due to strict transmissions by proctodeal trophallaxis or coprophagy based on the social behaviour of the termites. Except for one case, the endosymbiotic bacteria of the protists formed a monophyletic lineage in the order Bacteroidales, and the branching pattern was almost identical to those of the protists and the termites. However, some non-codivergent evolutionary events were evident. The members of this triplex symbiotic system appear to have cospeciated during their evolution with minor exceptions; the evolutionary relationships were probably established by termite sociality and the complex microbial community in the gut.

Green house gas emissions from termite ecosystem

African Journals Online (AJOL)

USER

sink for chlorine (Cl) molecules and a source of water vapor, which is a dominant greenhouse gas. Analysis has .... termite gut harbors different kinds of bacteria, fungi and protozoa. ..... responses to the presence of oxygen and their sensitivity.

Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite

OpenAIRE

Mitaka, Yuki; Kobayashi, Kazuya; Mikheyev, Alexander; Tin, Mandy M. Y.; Watanabe, Yutaka; Matsuura, Kenji

2016-01-01

The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship ...

A Novel Approach to Managing Invasive Termite Species Using Genetically Engineered Bacteria

Science.gov (United States)

2008-08-01

Coptotcnnes fonnosanus; lytic peptide; defaunation; tennite gut bacteria ; yeast 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF...genetically modified bacteria in a termite colony ; no detrimental gene products were expressed for termite control. Preliminary data suggested that lytic...defaunated within 4 weeks. The yeast -based prototype paratransgenesis system provided proof of concept that a symbiotic microorganism can act as a “Trojan

Natural durability of tropical and native woods against termite damage by Reticulitermes flavipes (Kollar)

Science.gov (United States)

Rachel A. Arango; Frederick Green; Kristina Hintz; Patricia K. Lebow; Regis B. Miller

2006-01-01

Environmental pressure has resulted in voluntary removal of chromated copper arsenate (CCA) from wood preservatives in residential applications in the United States. A new generation of copper organic preservatives was formulated as replacements, but these preservatives may not provide a permanent solution to all related problems. Some of these issues include concern...

The relationship between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

Science.gov (United States)

Jamali, H.; Livesley, S. J.; Hutley, L. B.; Fest, B.; Arndt, S. K.

2012-12-01

1. We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of Northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. 2. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a CO2-e basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. 3. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux, however, these relationships were clearly termite species specific. 4. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in past) would result in errors of more than 5-fold for CH4 and 3-fold for CO2. 5. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a~mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but these relationships vary greatly among termite species. Consequently, there is no generic relationship that will allow for the prediction of CH4 fluxes from termite mounds of all species.

Inducible immune proteins in the dampwood termite Zootermopsis angusticollis

Science.gov (United States)

Rosengaus, Rebeca B.; Cornelisse, Tara; Guschanski, Katerina; Traniello, James F. A.

2007-01-01

Dampwood termites, Zootermopsis angusticollis (Isoptera: Termopsidae), mount an immune response to resist microbial infection. Here we report on results of a novel analysis that allowed us to electrophoretically assess changes in hemolymph proteins in the same individual before and after exposure to a pathogen. We demonstrate that contact with a sublethal concentration of the entomopathogenic fungus Metarhizium anisopliae (Deuteromycotina:Hypomycetes) induces the production of protective proteins in nymphs, pseudergates (false workers), and soldiers. Termites exposed to an immunizing dosage of fungal conidia consistently showed an enhancement of constitutive proteins (62-85 kDa) in the hemolymph as well as an induction of novel proteins (28-48 kDa) relative to preimmunization levels. No significant differences in protein banding patterns relative to baseline levels in control and naïve termites were observed. Incubating excised and eluted induced proteins produced by immunized pseudergates or immunized soldiers with conidia significantly reduced the germination of the fungus. The fungistatic effect of eluted proteins differed significantly among five colonies examined. Our results show that the upregulation of protective proteins in the hemolymph underscores the in vivo immune response we previously recorded in Z. angusticollis.

Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos.

Science.gov (United States)

Miyagawa, Shuichi; Koyama, Yusaku; Kokubo, Mika; Matsushita, Yuichi; Adachi, Yoshinao; Sivilay, Sengdeaune; Kawakubo, Nobumitsu; Oba, Shinya

2011-08-18

The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009. Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m3 mound(-1) year(-1) on average due to several mounds being completely cut out. It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied.

Soil Physical and Chemical Properties in Epigeal Termite Mounds in Pastures

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Sandra Santana de Lima

2018-03-01

Full Text Available ABSTRACT We characterized soil physical and chemical properties and soil organic matter in epigeal termite mounds in pastures to evaluate the changes promoted by termites in comparison to an adjacent area. We selected seven active epigeal termite mounds in the municipality of Seropédica, state of Rio de Janeiro, Brazil. Soil samples were collected from top, center and base positions of each mound, at 0.50 and 1.50 m distance from the base of the mound. We identified individuals of the genus Embiratermes, Velocitermes, and Orthognathotermes. The humin fraction predominated over the humic and fulvic acid fractions both in mounds and adjacent soil. The amount of organic matter and the mineral fractions (mineral-associated organic carbon - MOC varied among builder species. The studied chemical attributes point to a higher concentration of nutrients in the mounds than in the adjacent soil.

ALIMENTARY CANAL ANATOMY AND HISTOLOGY OF THE WORKER TERMITE NEOTERMES BOSEI

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LEKSONO EKOPURANTO HARIPRABOWO

2006-01-01

Full Text Available As social insects, termites live in a colony that consist of reproductive (drone and queen, and non-reproductive (soldiers and workers castes. Workers obtain their food directly from wood, humus, and other substances that contain cellulose. The objective of this study was to examine the alimentary canal of the Neotermes bosei workers. Observations of gut transverse section were carried out through the length, perimeter, and area of each alimentary canal region. The results showed that total length of N. bosei alimentary canal was 13.71+1.28 mm. The canal was divided into fore-, mid-, and hindgut which were 24, 28, and 48%, respectively of the gut total length. Two types of alimentary canal epithelial cells were found, i.e. the squamous and transitional cells. Areas covered with thick muscular tissues were crop, proventriculus, and rectum. Proventriculus was characterized with six large dentitions. There was no gastric caeca in N. bosei midgut, which commonly occurred in chewing insect. Secretory cells .wer e observed at proventriculus and ventriculus regions. Cardiac valve was found at the anterior end of ventriculus. Area with the largest outer perimeter was the rectum pouch. Enteric valve had three internal folds.

Effects of rice husk ash and termite hill types on the physical and ...

African Journals Online (AJOL)

This waste can be recycled through inclusion as stabilizer in brick making, thereby eliminating the hazard posed to the environment. This paper examined the effects of rice husk ash (RHA) on the two termite clay soils in brick making. The two termite clay soils obtained from red and gray anthills were stabilized with rice husk ...

Parametric City Scale Energy Modeling Perspectives on using Termite in city scaled models

DEFF Research Database (Denmark)

Negendahl, Kristoffer; Nielsen, Toke Rammer

Termite is a parametric tool using the Danish building performance simulation engine Be10 written for the Grasshopper3D/Rhino3D environment. The tool Be10 is originally intended for building energy frame calculations and is required by Danish law when constructing new buildings. Termite opens up...... requirements, placing solar energy production facilities etc....

The fungus-growing termite Macrotermes natalensis harbors bacillaene-producing Bacillus sp. that inhibit potentially antagonistic fungi

DEFF Research Database (Denmark)

Um, Soohyun; Fraimout, Antoine; Sapountzis, Panagiotis

2013-01-01

colonies produce a single major antibiotic, bacillaene A (1), which selectively inhibits known and putatively antagonistic fungi of Termitomyces. Comparative analyses of the genomes of symbiotic Bacillus strains revealed that they are phylogenetically closely related to Bacillus subtilis, their genomes...... have high homology with more than 90% of ORFs being 100% identical, and the sequence identities across the biosynthetic gene cluster for bacillaene are higher between termite-associated strains than to the cluster previously reported in B. subtilis. Our findings suggest that this lineage of antibiotic......The ancient fungus-growing termite (Mactrotermitinae) symbiosis involves the obligate association between a lineage of higher termites and basidiomycete Termitomyces cultivar fungi. Our investigation of the fungus-growing termite Macrotermes natalensis shows that Bacillus strains from M. natalensis...

Long-Lived Termite Queens Exhibit High Cu/Zn-Superoxide Dismutase Activity

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Eisuke Tasaki

2018-01-01

Full Text Available In most organisms, superoxide dismutases (SODs are among the most effective antioxidant enzymes that regulate the reactive oxygen species (ROS generated by oxidative energy metabolism. ROS are considered main proximate causes of aging. However, it remains unclear if SOD activities are associated with organismal longevity. The queens of eusocial insects, such as termites, ants, and honeybees, exhibit extraordinary longevity in comparison with the nonreproductive castes, such as workers. Therefore, the queens are promising candidates to study the underlying mechanisms of aging. Here, we found that queens have higher Cu/Zn-SOD activity than nonreproductive individuals of the termite Reticulitermes speratus. We identified three Cu/Zn-SOD sequences and one Mn-SOD sequence by RNA sequencing in R. speratus. Although the queens showed higher Cu/Zn-SOD activity than the nonreproductive individuals, there were no differences in their expression levels of the Cu/Zn-SOD genes RsSOD1 and RsSOD3A. Copper (Cu2+ and Cu+ is an essential cofactor for Cu/Zn-SOD enzyme activity, and the queens had higher concentrations of copper than the workers. These results suggest that the high Cu/Zn-SOD activity of termite queens is related to their high levels of the cofactor rather than gene expression. This study highlights that Cu/Zn-SOD activity contributes to extraordinary longevity in termites.

Pycnoscelus surinamensis cockroach gut microbiota respond consistently to a fungal diet without mirroring those of fungus-farming termites.

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Callum Richards

Full Text Available The gut microbiotas of cockroaches and termites play important roles in the symbiotic digestion of dietary components, such as lignocellulose. Diet has been proposed as a primary determinant of community structure within the gut, acting as a selection force to shape the diversity observed within this "bioreactor", and as a key factor for the divergence of the termite gut microbiota from the omnivorous cockroach ancestor. The gut microbiota in most termites supports primarily the breakdown of lignocellulose, but the fungus-farming sub-family of higher termites has become similar in gut microbiota to the ancestral omnivorous cockroaches. To assess the importance of a fungus diet as a driver of community structure, we compare community compositions in the guts of experimentally manipulated Pycnoscelus surinamensis cockroaches fed on fungus cultivated by fungus-farming termites. MiSeq amplicon analysis of gut microbiotas from 49 gut samples showed a step-wise gradient pattern in community similarity that correlated with an increase in the proportion of fungal material provided to the cockroaches. Comparison of the taxonomic composition of manipulated communities to that of gut communities of a fungus-feeding termite species showed that although some bacteria OTUs shared by P. surinamensis and the farming termites increased in the guts of cockroaches on a fungal diet, cockroach communities remained distinct from those of termites. These results demonstrate that a fungal diet can play a role in structuring gut community composition, but at the same time exemplifies how original community compositions constrain the magnitude of such change.

Associations of Two Ecologically Significant Social Insect Taxa in the Litter of an Amazonian Rainforest: Is There a Relationship between Ant and Termite Species Richness?

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Amy L. Mertl

2012-01-01

Full Text Available In spite of the ecological dominance of Neotropical ants and termites, little is understood about how their interactions influence their species richness and distribution. We surveyed ground-dwelling termite and ant species in a primary rainforest in Ecuador and analyzed ecological correlates of diversity. Termite richness was positively correlated with ant richness and abundance of twig-nesting ants. We found no evidence of competition for twigs between termites and ants. No ecological factors were correlated with termite diversity although elevation and twig and log abundance influenced ant diversity. When ant richness was compared to the richness of termites employing different predator defenses, a positive correlation was found with soldierless termites, but not genera employing chemical or mechanical defense. Our results suggest that multiple ecological factors influence ant and termite diversity, and that ant predation on termites may have a greater effect than competition between ant and termites for nest sites and food sources.

Quadratic Damping

Science.gov (United States)

Fay, Temple H.

2012-01-01

Quadratic friction involves a discontinuous damping term in equations of motion in order that the frictional force always opposes the direction of the motion. Perhaps for this reason this topic is usually omitted from beginning texts in differential equations and physics. However, quadratic damping is more realistic than viscous damping in many…

Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

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Sivilay Sengdeaune

2011-08-01

Full Text Available Abstract Background The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. Methods The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009. Results Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m3 mound-1 year-1 on average due to several mounds being completely cut out. Conclusion It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied.

Ant and termite mound coinhabitants in the wetlands of Santo Antonio da Patrulha, Rio Grande do Sul, Brazil

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E. Diehl

Full Text Available This paper reports on ant and termite species inhabiting the mounds (murundus found in three wetland sites in Santo Antonio da Patrulha. Ants and termites were found in 100% of the mounds of two sites and in 20% of those in the third site. Colonies of Camponotus fastigatus were found inhabiting all the mounds, while colonies of Brachymyrmex sp., Linepithema sp., Pheidole sp., and/or Solenopsis sp. were collected in less than 30% of the mounds. In the mounds of the three sites, colonies of Anoplotermes sp. and/or Aparatermes sp. termites were found together with the ant colonies. Another cohabiting termite species, Cortaritermes sp., was found only in the mounds of one site. The results suggest that C. fastigatus is the species building the mounds, with the other species, whether ants or termites, being the inquilines.

Ant and termite mound coinhabitants in the wetlands of Santo Antonio da Patrulha, Rio Grande do Sul, Brazil.

Science.gov (United States)

Diehl, E; Junqueira, L K; Berti-Filho, E

2005-08-01

This paper reports on ant and termite species inhabiting the mounds (murundus) found in three wetland sites in Santo Antonio da Patrulha. Ants and termites were found in 100% of the mounds of two sites and in 20% of those in the third site. Colonies of Camponotus fastigatus were found inhabiting all the mounds, while colonies of Brachymyrmex sp., Linepithema sp., Pheidole sp., and/or Solenopsis sp. were collected in less than 30% of the mounds. In the mounds of the three sites, colonies of Anoplotermes sp. and/or Aparatermes sp. termites were found together with the ant colonies. Another cohabiting termite species, Cortaritermes sp., was found only in the mounds of one site. The results suggest that C. fastigatus is the species building the mounds, with the other species, whether ants or termites, being the inquilines.

Efficiency of fipronil in the control of the mound-building termite, Nasutitermes sp. (Isoptera: Termitidae) in sugarcane

OpenAIRE

Melo Fo, Reinaldo M.; Veiga, Antônio F.S.L.

1998-01-01

The efficiency of fipronil was evaluated in field conditions at different dosages and two formulations, against Nasutitermes sp. (isopteran: Termitidae) in sugarcane (Sccharum sp.). Termite mounds were indentified, measured and drilled until cellulosic chamber to allow insecticide application. Nine treatments were tested with ten replications in a completely randomized design and each termite mound considered as an experimental unit. after 50 days the termite mounds were opened and the mortal...

Diurnal respiration of a termite mound

Science.gov (United States)

King, Hunter; Ocko, Samuel; Mahadevan, L.

2014-11-01

Many species of fungus-harvesting termites build largely empty, massive mound structures which protrude from the ground above their subterranean nests. It has been long proposed that the function of these mounds is to facilitate exchange of heat, humidity, and respiratory gases; this would give the colony a controlled climate in which to raise fungus and brood. However, the specific mechanism by which the mound achieves ventilation has remained a topic of debate, as direct measurement of internal air flows has remained difficult. By directly measuring these elusive, tiny flows with a custom sensor, we find that the mound architecture of the species Odontotermes obesus takes advantage of daily oscillations in ambient temperature to drive convection and gas transport. This contradicts previous theories, which point to internal metabolic heating and external wind as driving forces. Our result, a novel example of deriving useful work from a fluctuating scalar parameter, should contribute to better understanding insect swarm construction and possible development in passive human architecture, both of which have been spurred by previous research on termites. We acknowledge support from HFSP.

Termites as a factor of spatial differentiation of CO2 fluxes from the soils of monsoon tropical forests in Southern Vietnam

Science.gov (United States)

Lopes de Gerenyu, Valentin; Anichkin, Alexander

2016-04-01

Termites play the key role in biogeochemical transformation of organic matter acting as "moderators" of fluxes of carbon and other nutrients. They destroy not only leave litter but also coarse woody debris. Termites translocate considerable masses of dead organic materials into their houses, which leads to significant accumulations of organic matter in termite mounds. We studied the impact of termite mounds on redistribution of CO2 fluxes from soils in semi-deciduous monsoon tropical forests of southern Vietnam. Field study was performed in the Cat Tien National Park (11°21'-11°48'N, 107°10'-107°34'E). The spatial and temporary dynamics of CO2 fluxes from soils (Andosols) populated by termites were studied in plain lagerstroemia (Lagerstroemia calyculata Kurz) monsoon tropical forests. The rate of CO2 emission from the soil surface was measured by closed chamber method two-three times per month from November 2010 to December 2011. Permanent cylindrical PVC chambers (9 cm in diameter and 15 cm in height) were installed beyond the areas occupied by termite mounds (5 replications). Litter was not removed from the soil surface before the measurements. To estimate the spatial heterogeneity of the CO2 emission fluxes from soils populated by termites, a special 'termite' plot (TerPl) was equipped. It was 10×10 m in size and included three termite mounds: one mound built up by Globitermes sulphureus and two mounds populated by termites of the Odontotermes genus. Overall, 52 PVC chambers were installed permanently on the 'termite' plot (ca. 1 m apart from one another). The CO2 emission rate from TerPl was also measured by chamber closed method once in the dry season (April) and twice through the wet season (July and August). The average rate of CO2 emission from termite mounds was two times higher than that from the surrounding area (SurAr). In the dry season, it comprised 91±7 mg C/m2/h from the surrounding soils and 196±16 mg C/m2/h from the termite mounds. In the

Relative repellency and lethality of the neonicotinoids thiamethoxam and acetamiprid and an acetamiprid/bifenthrin combination to Reticulitermes flavipes termites.

Science.gov (United States)

Smith, Joseph A; Pereira, Roberto M; Koehler, Philip G

2008-12-01

Field-collected Reticulitermes flavipes (Kollar) termites were placed in bioassay tubes containing soil treated with one of three termiticides: thiamethoxam, acetamiprid, or a combination of acetamiprid + bifenthrin. In the bioassay tubes, treated soil was placed in a layer centered within untreated sand between two 1.5-cm agar plugs. All termiticides were tested at concentrations of 0.1, 1, 10, and 100 ppm with narrow (1 mm), medium (5 mm), and broad (50 mm) thicknesses of treated soil. Soil penetration and termite mortality were measured after 7 d, and repellency was assessed. Thiamethoxam treatments allowed the greatest soil penetration, whereas acetamiprid + bifenthrin treatments were the most inhibitory to soil penetration. Thiamethoxam treatments also caused consistently greater termite mortality than acetamiprid treatments. These data indicated that acetamiprid prevented soil penetration by termites more than thiamethoxam, although both were less repellent compared with bifenthrin alone, which causes little termite mortality at the tested doses. When there was direct contact of treated soil with the agar plugs in broad treatments, the combination of acetamiprid + bifenthrin was more toxic to R. flavipes termites than either acetamiprid or thiamethoxam alone. The combination acetamiprid + bifenthrin termiticide may be effective in keeping termites away from the treated soil, because of the combined effects of acetamiprid and bifenthrin.

As you reap, so shall you sow: coupling of harvesting and inoculating stabilizes the mutualism between termites and fungi

DEFF Research Database (Denmark)

Aanen, Duur Kornelis

2006-01-01

is likely to be in monoculture and (ii) the termites ‘artificially' select for high nodule production, because their fungal food source also provides the inoculum for the next harvest. I also provide a brief comparison of the termite-fungus mutualism with the analogous agricultural mutualism between attine......At present there is no consensus theory explaining the evolutionary stability of mutualistic interactions. However, the question is whether there are general ‘rules', or whether each particular mutualism needs a unique explanation. Here, I address the ultimate evolutionary stability...... of the ‘agricultural' mutualism between fungus-growing termites and Termitomyces fungi, and provide a proximate mechanism for how stability is achieved. The key to the proposed mechanism is the within-nest propagation mode of fungal symbionts by termites. The termites suppress horizontal fungal transmission...

Decoherence and Landau-Damping

Energy Technology Data Exchange (ETDEWEB)

Ng, K.Y.; /Fermilab

2005-12-01

The terminologies, decoherence and Landau damping, are often used concerning the damping of a collective instability. This article revisits the difference and relation between decoherence and Landau damping. A model is given to demonstrate how Landau damping affects the rate of damping coming from decoherence.

Microbial community diversity in the gut of the South American termite Cornitermes cumulans (Isoptera: Termitidae).

Science.gov (United States)

Grieco, Maria Angela B; Cavalcante, Janaina J V; Cardoso, Alexander M; Vieira, Ricardo P; Machado, Ednildo A; Clementino, Maysa M; Medeiros, Marcelo N; Albano, Rodolpho M; Garcia, Eloi S; de Souza, Wanderley; Constantino, Reginaldo; Martins, Orlando B

2013-01-01

Termites inhabit tropical and subtropical areas where they contribute to structure and composition of soils by efficiently degrading biomass with aid of resident gut microbiota. In this study, culture-independent molecular analysis was performed based on bacterial and archaeal 16S rRNA clone libraries to describe the gut microbial communities within Cornitermes cumulans, a South American litter-feeding termite. Our data reveal extensive bacterial diversity, mainly composed of organisms from the phyla Spirochaetes, Bacteroidetes, Firmicutes, Actinobacteria, and Fibrobacteres. In contrast, a low diversity of archaeal 16S rRNA sequences was found, comprising mainly members of the Crenarchaeota phylum. The diversity of archaeal methanogens was further analyzed by sequencing clones from a library for the mcrA gene, which encodes the enzyme methyl coenzyme reductase, responsible for catalyzing the last step in methane production, methane being an important greenhouse gas. The mcrA sequences were diverse and divided phylogenetically into three clades related to uncultured environmental archaea and methanogens found in different termite species. C. cumulans is a litter-feeding, mound-building termite considered a keystone species in natural ecosystems and also a pest in agriculture. Here, we describe the archaeal and bacterial communities within this termite, revealing for the first time its intriguing microbiota.

Overview on methods for formulating explicit damping matrices for non-classically damped structures

International Nuclear Information System (INIS)

Xu, J.

1998-04-01

In computing the dynamic response of a connected system with multiple components having dissimilar damping characteristics, which is often referred to as nonclassically damped system such as nuclear power plant piping systems supported by stiff structures, one needs to define the system-level damping based upon the damping information of components. This is frequently done in practice using approximate methods expressed as composite modal damping with weighting functions. However, when the difference in damping among components is substantial, the composite modal damping may become inappropriate in the characterization of the damping behavior of such systems. In recent years, several new methods have emerged with the expectation that they could produce more exact system-level damping for a group of nonclassically damped structures which are comprised of components that possess classical modal damping. In this paper, an overview is presented to examine these methods in the light of their theoretical basis, the technical merits, and practical applications. To this end, a synthesis method is described, which was shown to reduce to the other methods in the literature

Do Epigeal Termite Mounds Increase the Diversity of Plant Habitats in a Tropical Rain Forest in Peninsular Malaysia?

Science.gov (United States)

Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D.

2011-01-01

The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation. PMID:21625558

Uric acid, an important antioxidant contributing to survival in termites

Science.gov (United States)

Tasaki, Eisuke; Sakurai, Hiroki; Nitao, Masaru; Matsuura, Kenji; Iuchi, Yoshihito

2017-01-01

Reactive oxygen species (ROS) are generated spontaneously in all organisms and cause oxidative damage to biomolecules when present in excess. Accumulated oxidative damage accelerates aging; enhanced antioxidant capacity may be a positive factor for longevity. Recently, numerous studies of aging and longevity have been performed using short-lived animals, however, longevity mechanisms remain unknown. Here we show that a termite Reticulitermes speratus that is thought to be long-lived eusocial insect than other solitary insects uses large quantities of uric acid as an antioxidant against ROS. We demonstrated that the accumulation of uric acid considerably increases the free radical-scavenging activity and resistance against ultraviolet-induced oxidative stress in laboratory-maintained termites. In addition, we found that externally administered uric acid aided termite survival under highly oxidative conditions. The present data demonstrates that in addition to nutritional and metabolic roles, uric acid is an essential antioxidant for survival and contributes significantly to longevity. Uric acid also plays important roles in primates but causes gout when present in excess in humans. Further longevity studies of long-lived organisms may provide important breakthroughs with human health applications. PMID:28609463

Bacterial density and community structure associated with aggregate size fractions of soil-feeding termite mounds.

Science.gov (United States)

Fall, S; Nazaret, S; Chotte, J L; Brauman, A

2004-08-01

The building and foraging activities of termites are known to modify soil characteristics such as the heterogeneity. In tropical savannas the impact of the activity of soil-feeding termites ( Cubitermes niokoloensis) has been shown to affect the properties of the soil at the aggregate level by creating new soil microenvironments (aggregate size fractions) [13]. These changes were investigated in greater depth by looking at the microbial density (AODC) and the genetic structure (automated rRNA intergenic spacer analysis: ARISA) of the communities in the different aggregate size fractions (i.e., coarse sand, fine sand, coarse silt, fine silt, and dispersible clays) separated from compartments (internal and external wall) of three Cubitermes niokoloensis mounds. The bacterial density of the mounds was significantly higher (1.5 to 3 times) than that of the surrounding soil. Within the aggregate size fractions, the termite building activity resulted in a significant increase in bacterial density within the coarser fractions (>20 mum). Multivariate analysis of the ARISA profiles revealed that the bacterial genetic structures of unfractionated soil and soil aggregate size fractions of the three mounds was noticeably different from the savanna soil used as a reference. Moreover, the microbial community associated with the different microenvironments in the three termite mounds revealed three distinct clusters formed by the aggregate size fractions of each mound. Except for the 2-20 mum fraction, these results suggest that the mound microbial genetic structure is more dependent upon microbial pool affiliation (the termite mound) than on the soil location (aggregate size fraction). The causes of the specificity of the microbial community structure of termite mound aggregate size fractions are discussed.

Pycnoscelus surinamensis cockroach gut microbiota respond consistently to a fungal diet without mirroring those of fungus-farming termites

DEFF Research Database (Denmark)

Richards, Callum; Otani, Saria; Mikaelyan, Aram

2017-01-01

The gut microbiotas of cockroaches and termites play important roles in the symbiotic digestion of dietary components, such as lignocellulose. Diet has been proposed as a primary determinant of community structure within the gut, acting as a selection force to shape the diversity observed within......-feeding termite species showed that although some bacteria OTUs shared by P. surinamensis and the farming termites increased in the guts of cockroaches on a fungal diet, cockroach communities remained distinct from those of termites. These results demonstrate that a fungal diet can play a role in structuring gut...

Dynamic environments of fungus-farming termite mounds exert growth-modulating effects on fungal crop parasites.

Science.gov (United States)

Katariya, Lakshya; Ramesh, Priya B; Borges, Renee M

2018-03-01

This study investigated for the first time the impact of the internal mound environment of fungus-growing termites on the growth of fungal crop parasites. Mounds of the termite Odontotermes obesus acted as (i) temperature and relative humidity (RH) 'stabilisers' showing dampened daily variation and (ii) 'extreme environments' exhibiting elevated RH and CO 2 levels, compared to the outside. Yet, internal temperatures exhibited seasonal dynamics as did daily and seasonal CO 2 levels. During in situ experiments under termite-excluded conditions within the mound, the growth of the crop parasite Pseudoxylaria was greater inside than outside the mound, i.e., Pseudoxylaria is 'termitariophilic'. Also, ex situ experiments on parasite isolates differing in growth rates and examined under controlled conditions in the absence of termites revealed a variable effect with fungal growth decreasing only under high CO 2 and low temperature conditions, reflecting the in situ parasite growth fluctuations. In essence, the parasite appears to be adapted to survive in the termite mound. Thus the mound microclimate does not inhibit the parasite but the dynamic environmental conditions of the mound affect its growth to varying extents. These results shed light on the impact of animal-engineered structures on parasite ecology, independent of any direct role of animal engineers. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Determination of the major compounds in the extract of the subterranean termite Macrotermes gilvus Hagen digestive tract by GC-MS method

Directory of Open Access Journals (Sweden)

N. Subekti

2017-08-01

Full Text Available Degradation of woody components by termites is associated with symbionts inside their digestive tract. In this study, the major compounds were determined in the extract of the termite guts by GC-MS method. Macrotermes gilvus Hagen (worker caste termites were collected and their dissected guts underwent methanol extraction. It was found that the gut of the termites has an alkaline environment (pH 8.83 ± 0.31 that supports the digestion of lignocellulose biomass and also helps to solubilize phenolic and recalcitrant compounds resul­ting from the depolymerization of woody components. The GC-MS analysis showed that termite guts contained hydrophobic organosilicon components including dodecamethylcyclohexasiloxane, tetradecamethylcyclohexa­siloxane, hexadecamethylcyclooctasiloxane, and octasiloxane, 1,1,3,3,5,5,7,7,9,9,11,11,13,13,15,15-hexa­decamethyl. The guts also contained a phytosterol, which was identified as β-sitosterol. Further analysis of these water-insoluble compounds is needed to reveal their importance in termite digestion.

Metagenomic mining of feruloyl esterases from termite enteric flora

CSIR Research Space (South Africa)

Rashamuse, K

2014-01-01

Full Text Available A metagenome expression library was created from Trinervitermes trinervoides termite hindgut symbionts and subsequently screened for feruloyl esterase (FAE) activities, resulting in seven recombinant fosmids conferring feruloyl esterase phenotypes...

Termite Communities in Sugarcane Plantations in Southeastern Brazil: an Ecological Approach

Directory of Open Access Journals (Sweden)

2015-08-01

Full Text Available Termites are key components of soil fauna, playing an essential role in organic matter decomposition and nutrient cycling. However, they can cause significant economic losses in commercial plantations, such as sugar cane. Therefore, the correct identification of termite species is critical for pest control. Here, we evaluated the species richness, abundance and functional groups of termites in sugarcane plantations in 53 cities throughout the state of São Paulo, southeastern Brazil. We also analyzed the influence of macroclimatic variables on termite species distribution and functional groups. We found 22 taxa of two families, of which the most frequent species were Termitidae (96.51%. Within this family, Apicotermitinae had the highest frequency of occurrence (37.12%, followed by Termitinae (30.57%, Syntermitinae (27.95%, and Nasutitermitinae (0.8 %. The other family, Rhinotermitidae, had the lowest frequency (3.5%, being represented only by Heterotermes sulcatus Mathews. We classified Neocapritermes opacus Hagen (29.26%, Apicotermitinae sp.2 (24.89%, Cornitermes cumulans Kollar (13.10%, and Apicotermitinae sp.1 (6.99% as common taxa. The remaining 18 species were classified as rare. The most common functional group was humus-feeders (37%, followed by wood-feeders (34%, grass-litter feeders (25%, and intermediate feeders (4%. Climate influenced the distribution of common species, humus-feeders and grass-litter feeders. Regarding the pest status of termites in sugar cane plantations, we suggest that the exasperated use of pesticide in the last decades has reduced the abundance of species considered pests (e.g. Heterotermes and reinforce the importance of ecological approaches for determining the best pest control methods. Comunidades de Cupins em Cultivos de Cana-de-Açúcar no Estado de São Paulo: Uma Abordagem Ecológica Resumo. Os cupins são importantes componentes da fauna de solo, atuando na decomposição da mat

Damped nonlinear Schrodinger equation

International Nuclear Information System (INIS)

Nicholson, D.R.; Goldman, M.V.

1976-01-01

High frequency electrostatic plasma oscillations described by the nonlinear Schrodinger equation in the presence of damping, collisional or Landau, are considered. At early times, Landau damping of an initial soliton profile results in a broader, but smaller amplitude soliton, while collisional damping reduces the soliton size everywhere; soliton speeds at early times are unchanged by either kind of damping. For collisional damping, soliton speeds are unchanged for all time

The damped wave equation with unbounded damping

Science.gov (United States)

Freitas, Pedro; Siegl, Petr; Tretter, Christiane

2018-06-01

We analyze new phenomena arising in linear damped wave equations on unbounded domains when the damping is allowed to become unbounded at infinity. We prove the generation of a contraction semigroup, study the relation between the spectra of the semigroup generator and the associated quadratic operator function, the convergence of non-real eigenvalues in the asymptotic regime of diverging damping on a subdomain, and we investigate the appearance of essential spectrum on the negative real axis. We further show that the presence of the latter prevents exponential estimates for the semigroup and turns out to be a robust effect that cannot be easily canceled by adding a positive potential. These analytic results are illustrated by examples.

Testing the assumptions of the pyrodiversity begets biodiversity hypothesis for termites in semi-arid Australia.

Science.gov (United States)

Davis, Hayley; Ritchie, Euan G; Avitabile, Sarah; Doherty, Tim; Nimmo, Dale G

2018-04-01

Fire shapes the composition and functioning of ecosystems globally. In many regions, fire is actively managed to create diverse patch mosaics of fire-ages under the assumption that a diversity of post-fire-age classes will provide a greater variety of habitats, thereby enabling species with differing habitat requirements to coexist, and enhancing species diversity (the pyrodiversity begets biodiversity hypothesis). However, studies provide mixed support for this hypothesis. Here, using termite communities in a semi-arid region of southeast Australia, we test four key assumptions of the pyrodiversity begets biodiversity hypothesis (i) that fire shapes vegetation structure over sufficient time frames to influence species' occurrence, (ii) that animal species are linked to resources that are themselves shaped by fire and that peak at different times since fire, (iii) that species' probability of occurrence or abundance peaks at varying times since fire and (iv) that providing a diversity of fire-ages increases species diversity at the landscape scale. Termite species and habitat elements were sampled in 100 sites across a range of fire-ages, nested within 20 landscapes chosen to represent a gradient of low to high pyrodiversity. We used regression modelling to explore relationships between termites, habitat and fire. Fire affected two habitat elements (coarse woody debris and the cover of woody vegetation) that were associated with the probability of occurrence of three termite species and overall species richness, thus supporting the first two assumptions of the pyrodiversity hypothesis. However, this did not result in those species or species richness being affected by fire history per se. Consequently, landscapes with a low diversity of fire histories had similar numbers of termite species as landscapes with high pyrodiversity. Our work suggests that encouraging a diversity of fire-ages for enhancing termite species richness in this study region is not necessary.

Resistência a compressão de tijolos de solo-cimento fabricados com o montículo do cupim Cornitermes cumulans (Kollar, 1832 Resistance the compression of manufactured cement bricks ground with the wooded hill of termite Cornitermes cumulans (Kollar, 1832

Directory of Open Access Journals (Sweden)

Leandro Queiroz Corrêa de Albuquerque

2008-04-01

Full Text Available Objetivou-se neste trabalho, comparar a resistência à compressão de tijolos de solo-cimento fabricados com o montículo do cupim Cornitermes cumulans (Kollar, 1832, com tijolos que utilizaram como matéria prima um NEOSSOLO QUARTZARÊNICO (EMBRAPA, 1999, ambos submetidos a duas idades de cura (07 ou 28 dias. O experimento foi montado em delineamento inteiramente casualizado, em esquema fatorial 2x2, sendo analisados dois cofatores: a matéria prima base e a idade de cura. Os ensaios físicos e mecânicos obedeceram às prescrições das normas da Associação Brasileira de Normas Técnicas NBR-8492 (ABNT, 1982 e NBR-8491 (ABNT, 1984. Concluiu-se que a resistência à compressão dos tijolos foi maior com o aumento das idades de cura. O tratamento T4 apresentou maior valor de resistência à compressão, não diferindo estatisticamente dos tratamentos T2 e T1. Os tijolos fabricados com o montículo do cupim C. cumulans (Kollar, 1832 apresentaram diminuição da absorção de água com o aumento das idades de cura, o que normalmente corresponde a um maior aumento da resistência à compressão, ao contrário dos que utilizaram o NEOSSOLO QUARTZARÊNICO (EMBRAPA, 1999.The aim of this research was to compare the compressive strength of ground-cement bricks manufactured with the wooded hill of termite Cornitermes cumulans (Kollar, 1832, to bricks that they were used as quartzaremico raw material one NEOSSOLO QUARTZARÊNICO (EMBRAPA, 1999, both submitted to two ages of cure (07 or 28 days. The experiment was performed in entirely randomized delineation, in factorial project 2x2, being analyzed two cofactors: the raw material base and age of cure. The physical and mechanical assays obeyed the lapsing of the norm of the Brazilian Association of Technical Rules NBR-8492 (ABNT, 1982 and NBR-8491 (ABNT, 1984. One concluded that the compressive strength of the bricks was bigger with the increase of the ages of cure. The T4 treatment presented bigger

Amount of leachant and water absorption levels of wood treated with borates and water repellents.

Science.gov (United States)

Baysal, Ergun; Sonmez, Abdullah; Colak, Mehmet; Toker, Hilmi

2006-12-01

Wood protection efficacy of borates against biological agents, flame retardancy, and suitability to the environment is well known. Since borates can be applied to timber as water based solutions, they are preferred economically as well. Even though they are highly mobile in wood, boron compounds are widely used in timber preservation. Borates migrate in liquid and increase the hygroscopicity of wood in damp conditions. This study deals with the physical restriction of water access in wood by impregnating water repellent agents into wood to limit amount of leachant and water absorption levels of wood after boron treatment. Borates were incorporated with polyethylene glycol-400 (PEG-400) their bulking effect in wood was considered. Results indicated that the amount of leachates from wood treated with borates in PEG-400 was remarkably higher compared to those of wood treated with the aqueous solutions of borates. Water absorption (WA) levels of wood treated with aqueous solutions of borates were higher than those of their treated samples with the solutions in PEG-400. Secondary treatments of wood with the water repellent (WR) chemicals following borate impregnation reduced the leaching of chemicals from wood in water and also WA of the specimens were less than those of the wood treated with only borates from aqueous and PEG solutions. Styrene (St) was the most effective monomer among the other agents used in terms of immobility effect on borates and WA.

Laboratory and field evaluation of Metarhizium anisopliae var. anisopliae for controlling subterranean termites

OpenAIRE

Hussain, A; Ahmed, S; Shahid, M

2011-01-01

The efficacy of the Metarhizium anisopliae strain ARSEF 6911 was determined in the laboratory and field against two sugarcane pests, Microtermes obesi Holmgren and Odontotermes obesus Rambur (Termitidae: Isoptera). The susceptibility of both termite species to different conidial suspensions (1 × 10(10), 1 × 10(8), 1 × 10(6) and 1 × 10(4) conidia/ml) was determined in laboratory. All conidial suspensions were able to induce mortality. Termite mortality caused by the fungal suspensions was dose...

Utilization of the termite Hodotermes mossambicus (Hagen) by ...

African Journals Online (AJOL)

Five species of primarily nocturnal geckos (Ptenopus garrulus maculatus, Chondrodactylus angulifer angulifer, Pachydactylus bibronii, P. mariquensis latirosths and P. punctatus) collected near Keetmanshoop, South West Africa on the night of 3 October 1987 were found to contain large numbers of the harvester termite ...

Laboratory and field evaluation of Metarhizium anisopliae var. anisopliae for controlling subterranean termites

Energy Technology Data Exchange (ETDEWEB)

Hussain, A. [South China Agricultural University, Guangzhou (China). College of Natural Resources and Environment; Ahmed, S. [South China Agricultural University, Guangzhou (China). Dept. of Agricultural Entomology; Shahid, M., E-mail: solvia_aah@yahoo.co [University of Agriculture, Faisalabad (Pakistan). Dept. of Chemistry and Biochemistry

2011-03-15

The efficacy of the Metarhizium anisopliae strain ARSEF 6911 was determined in the laboratory and field against two sugarcane pests, Microtermes obesi Holmgren and Odontotermes obesus Rambur (Termitidae: Isoptera). The susceptibility of both termite species to different conidial suspensions (1 x 10{sup 10}, 1 x 10{sup 8}, 1 x 10{sup 6} and 1 x 10{sup 4} conidia/ml) was determined in laboratory. All conidial suspensions were able to induce mortality. Termite mortality caused by the fungal suspensions was dose dependent. There were no significant differences in the LT{sub 50} values between species. Field evaluation of M. anisopliae alone or in combination with diesel oil and thyamethoxam was carried out in two growing seasons (autumn 2005 and spring 2006) at two sites located in Punjab, Pakistan. Dipping the sugarcane setts in these suspensions was tried to determine their effects on germination and percentage of bud damage to sugarcane setts. All treatments significantly reduced termite infestation compared to the untreated control. The combined treatment of M. anisopliae and diesel oil significantly reduced insect damage by attaining higher germination > 55% and lower bud damage < 5.50% at both sites in both seasons. The results suggest that the application of M. anisopliae and diesel oil in combination might be a useful treatment option for the management of termites in sugarcane. (author)

Distribution of corazonin and pigment-dispersing factor in the cephalic ganglia of termites.

Science.gov (United States)

Závodská, Radka; Wen, Chih-Jen; Hrdý, Ivan; Sauman, Ivo; Lee, How-Jing; Sehnal, Frantisek

2008-07-01

Distribution of neurones detectable with antisera to the corazonin (Crz) and the pigment-dispersing factor (PDF) was mapped in the workers or pseudergates of 10 species representing six out of seven termite families. All species contained two triads of Crz-immunoreactive (Crz-ir) neurones in the protocerebrum. Their fibres were linked to the opposite hemisphere, formed a network in the fronto-lateral protocerebrum, and projected to the corpora cardiaca (CC); in most species the fibres also supplied the deuto- and tritocerebrum and the frontal ganglion. Some species possessed additional Crz-ir perikarya in the protocerebrum and the suboesophageal ganglion (SOG). The PDF-ir somata were primarily located in the optic lobe (OL) and SOG. OL harboured a group (3 groups in Coptotermes) of 2-6 PDF-ir cells with processes extending to the medulla, connecting to the contralateral OL, forming 1-2 networks in the protocerebrum, and in most species running also to CC. Such a PDF-ir system associated with the OL was missing in Reticulitermes. Except for Mastotermes, the termites contained 1-2 PDF-ir cell pairs in the SOG and two species had additional perikarya in the protocerebrum. The results are consistent with the view of a monophyletic termite origin and demonstrate how the Crz-ir and PDF-ir systems diversified in the course of termite phylogeny.

Laboratory and field evaluation of Metarhizium anisopliae var. anisopliae for controlling subterranean termites

International Nuclear Information System (INIS)

Hussain, A.; Ahmed, S.; Shahid, M.

2011-01-01

The efficacy of the Metarhizium anisopliae strain ARSEF 6911 was determined in the laboratory and field against two sugarcane pests, Microtermes obesi Holmgren and Odontotermes obesus Rambur (Termitidae: Isoptera). The susceptibility of both termite species to different conidial suspensions (1 x 10 10 , 1 x 10 8 , 1 x 10 6 and 1 x 10 4 conidia/ml) was determined in laboratory. All conidial suspensions were able to induce mortality. Termite mortality caused by the fungal suspensions was dose dependent. There were no significant differences in the LT 50 values between species. Field evaluation of M. anisopliae alone or in combination with diesel oil and thyamethoxam was carried out in two growing seasons (autumn 2005 and spring 2006) at two sites located in Punjab, Pakistan. Dipping the sugarcane setts in these suspensions was tried to determine their effects on germination and percentage of bud damage to sugarcane setts. All treatments significantly reduced termite infestation compared to the untreated control. The combined treatment of M. anisopliae and diesel oil significantly reduced insect damage by attaining higher germination > 55% and lower bud damage < 5.50% at both sites in both seasons. The results suggest that the application of M. anisopliae and diesel oil in combination might be a useful treatment option for the management of termites in sugarcane. (author)

Explosive Backpacks in Old Termite Workers

Czech Academy of Sciences Publication Activity Database

Šobotník, Jan; Bourguignon, T.; Hanus, Robert; Demianova, Zuzana; Pytelková, Jana; Mareš, Michael; Foltynová, P.; Preisler, J.; Cvačka, Josef; Krasulová, Jana; Roisin, Y.

2012-01-01

Roč. 337, č. 6093 (2012), s. 436-436 ISSN 0036-8075 R&D Projects: GA ČR GP525/09/P600 Grant - others:CEITEC(CZ) CZ.1.05/1.1.00/02.0068; GA ČR(CZ) GAP206/12/0538 Institutional support: RVO:61388963 Keywords : Neocapritermes taracua * chemical defense * termites * worker defense * suicidal defense Subject RIV: CC - Organic Chemistry Impact factor: 31.027, year: 2012

Chemical alarm in the termite Termitogeton planus (Rhinotermitidae)

Czech Academy of Sciences Publication Activity Database

Dolejšová, Klára; Krasulová, Jana; Kutalová, K.; Hanus, Robert

2014-01-01

Roč. 40, 11/12 (2014), s. 1269-1276 ISSN 0098-0331 R&D Projects: GA ČR GAP506/10/1570 Institutional support: RVO:61388963 Keywords : termites * soldiers * frontal gland * alarm pheromone * Rhinotermitidae * Termitogeton Subject RIV: CC - Organic Chemistry Impact factor: 2.747, year: 2014

Fuel Assembly Damping Summary

Energy Technology Data Exchange (ETDEWEB)

Lee, Kanghee; Kang, Heungseok; Oh, Dongseok; Yoon, Kyungho; Kim, Hyungkyu; Kim, Jaeyong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

This paper summary the fuel assembly damping data in air/in still water/under flow, released from foreign fuel vendors, compared our data with the published data. Some technical issues in fuel assembly damping measurement testing are also briefly discussed. Understanding of each fuel assembly damping mechanisms according to the surrounding medium and flow velocity can support the fuel design improvement in fuel assembly dynamics and structural integrity aspect. Because the upgraded requirements of the newly-developed advanced reactor system will demands to minimize fuel design margin in integrity evaluation, reduction in conservatism of fuel assembly damping can contribute to alleviate the fuel design margin for sure. Damping is an energy dissipation mechanism in a vibrating mechanical structure and prevents a resonant structure from having infinite vibration amplitudes. The sources of fuel assembly damping are various from support friction to flow contribution, and it can be increased by the viscosity or drag of surrounding fluid medium or the average velocity of water flowing. Fuel licensing requires fuel design evaluation in transient or accidental condition. Dynamic response analysis of fuel assembly is to show fuel integrity and requires information on assembly-wise damping in dry condition and under wet or water flowing condition. However, damping measurement test for the full-scale fuel assembly prototype is not easy to carry out because of the scale (fuel prototype, test facility), unsteadiness of test data (scattering, random sampling and processing), instrumentation under water flowing (water-proof response measurement), and noise. LWR fuel technology division in KAERI is preparing the infra structure for damping measurement test of full-scale fuel assembly, to support fuel industries and related research activities. Here is a preliminary summary of fuel assembly damping, published in the literature. Some technical issues in fuel assembly damping

Excavation and aggregation as organizing factors in de novo construction by mound-building termites.

Science.gov (United States)

Green, Ben; Bardunias, Paul; Turner, J Scott; Nagpal, Radhika; Werfel, Justin

2017-06-14

Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in which actions that change the environment provide cues that influence future work. Termite construction has long been thought to be organized via a putative 'cement pheromone': a chemical added to deposited soil that stimulates further deposition in the same area, thus creating a positive feedback loop whereby coherent structures are built up. To investigate the detailed mechanisms and behaviours through which termites self-organize the early stages of mound construction, we tracked the motion and behaviour of major workers from two Macrotermes species in experimental arenas. Rather than a construction process focused on accumulation of depositions, as models based on cement pheromone would suggest, our results indicated that the primary organizing mechanisms were based on excavation. Digging activity was focused on a small number of excavation sites, which in turn provided templates for soil deposition. This behaviour was mediated by a mechanism of aggregation, with termites being more likely to join in the work at an excavation site as the number of termites presently working at that site increased. Statistical analyses showed that this aggregation mechanism was a response to active digging, distinct from and unrelated to putative chemical cues that stimulate deposition. Agent-based simulations quantitatively supported the interpretation that the early stage of de novo construction is primarily organized by excavation and aggregation activity rather than by stigmergic deposition. © 2017 The Author(s).

Sex-specific inhibition and stimulation of worker-reproductive transition in a termite

Science.gov (United States)

Sun, Qian; Haynes, Kenneth F.; Hampton, Jordan D.; Zhou, Xuguo

2017-10-01

In social insects, the postembryonic development of individuals exhibits strong phenotypic plasticity in response to the environment, thus generating the caste system. Different from eusocial Hymenoptera, in which queens dominate reproduction and inhibit worker fertility, the primary reproductive caste in termites (kings and queens) can be replaced by neotenic reproductives derived from functionally sterile individuals. Feedback regulation of nestmate differentiation into reproductives has been suggested, but the sex specificity remains inconclusive. In the eastern subterranean termite, Reticulitermes flavipes, we tested the hypothesis that neotenic reproductives regulate worker-reproductive transition in a sex-specific manner. With this R. flavipes system, we demonstrate a sex-specific regulatory mechanism with both inhibitory and stimulatory functions. Neotenics inhibit workers of the same sex from differentiating into additional reproductives but stimulate workers of the opposite sex to undergo this transition. Furthermore, this process is not affected by the presence of soldiers. Our results highlight the reproductive plasticity of termites in response to social cues and provide insights into the regulation of reproductive division of labor in a hemimetabolous social insect.

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.

The damped wave equation with unbounded damping

Czech Academy of Sciences Publication Activity Database

Freitas, P.; Siegl, Petr; Tretter, C.

2018-01-01

Roč. 264, č. 12 (2018), s. 7023-7054 ISSN 0022-0396 Institutional support: RVO:61389005 Keywords : damped wave equation * unbounded damping * essential spectrum * quadratic operator funciton with unbounded coefficients * Schrodinger operators with complex potentials Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 1.988, year: 2016

Cellulolytic Protist Numbers Rise and Fall Dramatically in Termite Queens and Kings during Colony Foundation

Science.gov (United States)

Shimada, Keisuke; Lo, Nathan; Kitade, Osamu; Wakui, Akane

2013-01-01

Among the best-known examples of mutualistic symbioses is that between lower termites and the cellulolytic flagellate protists in their hindguts. Although the symbiosis in worker termites has attracted much attention, there have been only a few studies of protists in other castes. We have performed the first examination of protist population dynamics in queens and kings during termite colony foundation. Protist numbers, as well as measurements of hindgut and reproductive tissue sizes, were undertaken at five time points over 400 days in incipient colonies of Reticulitermes speratus, as well as in other castes of mature colonies of this species. We found that protist numbers increased dramatically in both queens and kings during the first 50 days of colony foundation but began to decrease by day 100, eventually disappearing by day 400. Hindgut width followed a pattern similar to that of protist numbers, while ovary and testis widths increased significantly only at day 400. Kings were found to contain higher numbers of protists than queens in incipient colonies, which may be linked to higher levels of nutrient transfer from kings to queens than vice versa, as is known in some other termite species. Protists were found to be abundant in soldiers from mature colonies but absent in neotenics. This probably reflects feeding of soldiers by workers via proctodeal trophallaxis and of reproductives via stomodeal trophallaxis. The results reveal the dynamic nature of protist numbers during colony foundation and highlight the trade-offs that exist between reproduction and parental care during this critical phase of the termite life cycle. PMID:23376945

Numerical studies of shear damped composite beams using a constrained damping layer

DEFF Research Database (Denmark)

Kristensen, R.F.; Nielsen, Kim Lau; Mikkelsen, Lars Pilgaard

2008-01-01

Composite beams containing one or more damping layers are studied numerically. The work is based on a semi-analytical model using a Timoshenko beam theory and a full 2D finite element model. The material system analysed, is inspired by a train wagon suspension system used in a EUREKA project Sigma......!1841. For the material system, the study shows that the effect of the damping layer is strongly influenced by the presence of a stiff constraining layer, that enforces large shear strain amplitudes. The thickness of the damping rubber layer itself has only a minor influence on the overall damping....... In addition, a large influence of ill positioned cuts in the damping layer is observed....

Cultural significance of termites in sub-Saharan Africa

NARCIS (Netherlands)

Huis, van Arnold

2017-01-01

Background: The number of termite species in the world is more than 2500, and Africa with more than 1000 species has the richest intercontinental diversity. The family Termitidae contains builders of great mounds up to 5 m high. Colonies are composed of casts: a queen, a king, soldiers and workers.

Gamma-ray backscatter applied to the on-line location of termite-damaged railway sleepers

International Nuclear Information System (INIS)

Fookes, R.A.; Watt, J.S.; Seatonberry, B.W.; Davison, A.; Greig, R.A.; Lowe, H.W.G.; Abbott, A.C.

1978-01-01

A radioisotope system has been developed to locate groups of termite-damaged sleepers during continuous scans of a railway track. It depends on measuring the intensities of collimated beams of 137 Cs γ-rays backscattered from within the sleeper. The detected intensity varies with the amount of termite damage (i.e. voidage). Variations in intensity caused by changes in the density of sound sleepers are minimised by the geometrical arrangement of source, shields and detector. The Atomic Voidage Detector (AVD) has been tested in field trials on the Newman to Port Hedland railway, Western Australia. Four separate groups of termite-damaged sleepers were located and examined. The lower limit of detectable voidage depends mainly on the scanning speed and distribution of voids within the sleeper, and is very approximately 8% voidage at 10.7 km/h and 5% at 2.7 km/h. (author)

Ecological feedbacks. Termite mounds can increase the robustness of dryland ecosystems to climatic change.

Science.gov (United States)

Bonachela, Juan A; Pringle, Robert M; Sheffer, Efrat; Coverdale, Tyler C; Guyton, Jennifer A; Caylor, Kelly K; Levin, Simon A; Tarnita, Corina E

2015-02-06

Self-organized spatial vegetation patterning is widespread and has been described using models of scale-dependent feedback between plants and water on homogeneous substrates. As rainfall decreases, these models yield a characteristic sequence of patterns with increasingly sparse vegetation, followed by sudden collapse to desert. Thus, the final, spot-like pattern may provide early warning for such catastrophic shifts. In many arid ecosystems, however, termite nests impart substrate heterogeneity by altering soil properties, thereby enhancing plant growth. We show that termite-induced heterogeneity interacts with scale-dependent feedbacks to produce vegetation patterns at different spatial grains. Although the coarse-grained patterning resembles that created by scale-dependent feedback alone, it does not indicate imminent desertification. Rather, mound-field landscapes are more robust to aridity, suggesting that termites may help stabilize ecosystems under global change. Copyright © 2015, American Association for the Advancement of Science.

Pipe damping studies

International Nuclear Information System (INIS)

Ware, A.G.

1986-01-01

The Idaho National Engineering Laboratory (INEL) is conducting a research program to assist the United States Nuclear Regulatory Commission (USNRC) in determining best-estimate damping values for use in the dynamic analysis of nuclear power plant piping systems. This paper describes four tasks in the program that were undertaken in FY-86. In the first task, tests were conducted on a 5-in. INEL laboratory piping system and data were analyzed from a 6-in. laboratory system at the ANCO Engineers facility to investigate the parameters influencing damping in the seismic frequency range. Further tests were conducted on 3- and 5-in. INEL laboratory piping systems as the second task to determine damping values representative of vibrations in the 33 to 100 Hz range, typical of hydrodynamic transients. In the third task a statistical evaluation of the available damping data was conduted to determine probability distributions suitable for use in probabilistic risk assessments (PRAs), and the final task evaluated damping data at high strain levels

Seasonal response of feeding, differentiation, and growth in the eastern subterranean termite Reticulitermes flavipes (Kollar) in Wisconsin

Science.gov (United States)

Rachel Ann Arango; Frederick Green; Glenn R. Esenther

2007-01-01

In termites, differentiation plasticity in undifferentiated Reticulitermes progresses with growth stages from larvae to workers, which may then differentiate into soldiers, winged nymphs, or neotenics. Although studies have been done on seasonality of the termite life cycle, data appears to vary from location to location. Reticulitermes populations in Wisconsin appear...

DGGE detection and screening of lignocellulolytic bacteria from the termite gut of Coptotermes formosanus

Directory of Open Access Journals (Sweden)

Mathew, G.M.

2011-01-01

Full Text Available Aims: Termites thrive in terrestrial ecosystems and play an important role in the bio-recycling of lignocellulose. The objective of this study is to isolate and detect bacteria from the termite gut of Coptotermes formosanus and to screen their various enzyme activities by qualitative methods. In addition, this study was aimed to isolate lignin and furfural tolerant strains for various industrial bioprocesses.Methodology and Results: In this study, 50 worker termites of Coptotermes formosanus were collected from dead trees, from a forest in Taichung, Taiwan in June 2008 and the composition of the microbial flora from the termite guts was analyzed by DGGE analysis. The results proved that anaerobic and facultatively anaerobic bacteria consisting of Acinetobacter, Bacteroides thetaiotaomicron, Escherichia coli, and Caulobacter readily existed in the guts of termites. Although the majority of these gut symbionts have not yet been cultivated or identified, some related bacteria were isolated. Two isolates 1-8 and 2-2 of Genus Bacillus, exhibited endocellulase, protease, lipase, amylase, peroxidase and lignin peroxidase activity. Under aerobic conditions, the growth density of isolate 1-8 cultured in 1000 ppm lignin containing MSM medium was two-folds higher than cultured in MSM medium without lignin. Furthermore, the isolate 1-8 was tolerant to 20 mM furfural supplemented in the MSM medium. HPLC analysis confirmed Bacillus isolate 1-8 could degrade up to 15 mM furfural.Conclusion, significance and impact of study: Hind gut bacteria from C. formosanus were detected by culture independent DGGE method. Also, Bacillus isolates 1-8 and 2-2 obtained by culture dependent methods could withstand higher concentration of furfural and as well as lignin. These isolates may be co-cultured with ethanologenic bacteria and be used as an industrial biocatalyst for biofuel production.

Patterns of interaction specificity of fungus-growing termites and Termitomyces symbionts in South Africa

Directory of Open Access Journals (Sweden)

de Beer Z Wilhelm

2007-07-01

Full Text Available Abstract Background Termites of the subfamily Macrotermitinae live in a mutualistic symbiosis with basidiomycete fungi of the genus Termitomyces. Here, we explored interaction specificity in fungus-growing termites using samples from 101 colonies in South-Africa and Senegal, belonging to eight species divided over three genera. Knowledge of interaction specificity is important to test the hypothesis that inhabitants (symbionts are taxonomically less diverse than 'exhabitants' (hosts and to test the hypothesis that transmission mode is an important determinant for interaction specificity. Results Analysis of Molecular Variance among symbiont ITS sequences across termite hosts at three hierarchical levels showed that 47 % of the variation occurred between genera, 18 % between species, and the remaining 35 % between colonies within species. Different patterns of specificity were evident. High mutual specificity was found for the single Macrotermes species studied, as M. natalensis was associated with a single unique fungal haplotype. The three species of the genus Odontotermes showed low symbiont specificity: they were all associated with a genetically diverse set of fungal symbionts, but their fungal symbionts showed some host specificity, as none of the fungal haplotypes were shared between the studied Odontotermes species. Finally, bilaterally low specificity was found for the four tentatively recognized species of the genus Microtermes, which shared and apparently freely exchanged a common pool of divergent fungal symbionts. Conclusion Interaction specificity was high at the genus level and generally much lower at the species level. A comparison of the observed diversity among fungal symbionts with the diversity among termite hosts, indicated that the fungal symbiont does not follow the general pattern of an endosymbiont, as we found either similar diversity at both sides or higher diversity in the symbiont. Our results further challenge the

Termites of the Savanna ecosystem project study area, Nylsvley

CSIR Research Space (South Africa)

Ferrar, P

1982-09-01

Full Text Available This report describes the termite fauna of the Savanna Ecosystem Project study area at the Nylsvley Nature Reserve, with an illustrated key for identification of species. Twenty-one species of fifteen genera and two families are recorded, and notes...

Piezoelectric shunt damping of a circular saw blade with autonomous power supply for noise and vibration reduction

Science.gov (United States)

Pohl, Martin; Rose, Michael

2016-01-01

Circular saws are widespread tools for machining metal, wood or even ceramics. Due to the thin blade and excitation by the workpiece contact of the cutting edges, circular saws are prone to vibration and intense noise emission. Damping the blade will lower the hearing protection requirements of the users and possibly increase precision. Therefore a new damping concept for circular saw blades is presented in this paper. It is based on negative capacitance shunted piezoelectric transducers which are applied to the saw blade core. The required energy for the electronics is harvested from the rotation by a generator, so that no change of the machine tool is required. All components are integrated into an autonomous saw tool. Finally, the system is experimentally investigated without rotation, in idling and in cutting condition in a circular saw test stand in the Institute for Machine Tools and Production Engineering (IWF) at TU Braunschweig. The experimental investigation shows a good reduction of the vibration amplitude over a wide frequency range in the non-rotating condition. When rotating, the damping effect is lower and limited to some narrow frequency bands. The proposed reason for the reduced damping effect in rotating condition consists in the saturation of the electronic circuits due to the limited supply voltage capabilities.

Seasonal Changes in the Caste Distribution of Foraging Populations of Formosan Subterranean Termite in New Orleans, Louisiana.

Science.gov (United States)

Cornelius, Mary L; Osbrink, Weste L A; Gallatin, Erin M

2015-01-01

This study examined the relationship between temperature, precipitation, soil composition, levels of feeding damage, and the caste distribution (workers, soldiers, nymphs) of the Formosan subterranean termite, Coptotermes formosanus Shiraki, collected in underground monitoring stations over a 12 mo period. Because nymphs are the caste that develops into alates, the seasonal abundance of nymphs was examined over a 5 yr period. Numbers of workers, soldiers, and soldier/worker ratio were significantly affected by month. Recruitment and retention of foraging termites in stations was significantly affected by the level of feeding damage. The number of nymphs collected in monitoring stations was highly variable. In the 12 mo test, there was a significant correlation between numbers of nymphs and level of feeding damage, temperature, precipitation, and soil composition. Over a 5 yr period, significantly more nymphs were collected in 2011 than in 2007 and 2008. Peak nymph collections varied from year to year. Overall, peak nymph collections were more likely to occur in Mar., Sept., and Oct. Increasing our knowledge of the environmental factors that influence recruitment and retention of foraging termites in monitoring stations could influence termite bait placement and improve baiting strategies for termite control. Identifying the key factors that cause aggregations of nymphs in underground stations could increase our ability to predict the intensity and location of alate swarms. © Crown copyright 2015.

Phylogenetic analyses of Podaxis specimens from Southern Africa reveal hidden diversity and new insights into associations with termites

NARCIS (Netherlands)

Conlon, Benjamin H.; Beer, de Z.W.; Fine Licht, De Henrik H.; Aanen, Duur K.; Poulsen, Michael

2016-01-01

Although frequently found on mounds of the grass-cutting termite genus . Trinervitermes, virtually nothing is known about the natural history of the fungal genus . Podaxis (Agaricaceae) nor why it associates with termite mounds. More than 40 species of this secotioid genus have been described

Effects of erosion from mounds of different termite genera on distinct functional grassland types in an African savannah

NARCIS (Netherlands)

Gosling, Cleo M.; Cromsigt, Joris P. G. M.; Mpanza, Nokukhanya; Olff, Han

A key aspect of savannah vegetation heterogeneity is mosaics formed by two functional grassland types, bunch grasslands, and grazing lawns. We investigated the role of termites, important ecosystem engineers, in creating high-nutrient patches in the form of grazing lawns. Some of the ways termites

Discovery of ectosymbiotic Endomicrobium lineages associated with protists in the gut of stolotermitid termites.

Science.gov (United States)

Izawa, Kazuki; Kuwahara, Hirokazu; Sugaya, Kaito; Lo, Nathan; Ohkuma, Moriya; Hongoh, Yuichi

2017-08-01

The genus Endomicrobium is a dominant bacterial group in the gut of lower termites, and most phylotypes are intracellular symbionts of gut protists. Here we report the discovery of Endomicrobium ectosymbionts of termite gut protists. We found that bristle-like Endomicrobium cells attached to the surface of spirotrichosomid protist cells inhabiting the termite Stolotermes victoriensis. Transmission electron microscopy revealed that a putative Endomicrobium cell likely attached to the protist surface via a protrusion from the tip of the bacterium. A phylotype, sharing 98.9% 16S rRNA sequence identity with the Endomicrobium ectosymbionts of the spirotrichosomid protists, was also found on the cell surface of the protist Trichonympha magna in the gut of the termite Porotermes adamsoni. We propose the novel species 'Candidatus Endomicrobium superficiale' for these bacteria. T. magna simultaneously harboured another Endomicrobium ectosymbiont that shared 93.5-94.2% 16S rRNA sequence identities with 'Ca. Endomicrobium superficiale'. Furthermore, Spirotrichonympha-like protists in P. adamsoni guts were associated with an Endomicrobium phylotype that possibly attached to the host flagella. A phylogenetic analysis suggested that these ectosymbiotic lineages have evolved multiple times from free-living Endomicrobium lineages and are relatively distant from the endosymbionts. Our results provide novel insights into the ecology and evolution of the Endomicrobium. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Symbiotic flagellate protists as cryptic drivers of adaptation and invasiveness of the subterranean termite Reticulitermes grassei Clément.

Science.gov (United States)

Duarte, Sónia; Nobre, Tânia; Borges, Paulo A V; Nunes, Lina

2018-06-01

Changes in flagellate protist communities of subterranean termite Reticulitermes grassei across different locations were evaluated following four predictions: (i) Rural endemic (Portugal mainland) termite populations will exhibit high diversity of symbionts; (ii) invasive urban populations (Horta city, Faial island, Azores), on the contrary, will exhibit lower diversity of symbionts, showing high similarity of symbiont assemblages through environmental filtering; (iii) recent historical colonization of isolated regions-as the case of islands-will imply a loss of symbiont diversity; and (iv) island isolation will trigger a change in colony breeding structure toward a less aggressive behavior. Symbiont flagellate protist communities were morphologically identified, and species richness and relative abundances, as well as biodiversity indices, were used to compare symbiotic communities in colonies from urban and rural environments and between island invasive and mainland endemic populations. To evaluate prediction on the impact of isolation (iv), aggression tests were performed among termites comprising island invasive and mainland endemic populations. A core group of flagellates and secondary facultative symbionts was identified. Termites from rural environments showed, in the majority of observed colonies, more diverse and abundant protist communities, probably confirming prediction (i). Corroborating prediction (ii), the two least diverse communities belong to termites captured inside urban areas. The Azorean invasive termite colonies had more diverse protist communities than expected and prediction (iii) which was not verified within this study. Termites from mainland populations showed a high level of aggressiveness between neighboring colonies, in contrast to the invasive colonies from Horta city, which were not aggressive to neighbors according to prediction (iv). The symbiotic flagellate community of R. grassei showed the ability to change in a way that might

Power oscillation damping controller

DEFF Research Database (Denmark)

2012-01-01

A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...

The role of the glucose-sensing transcription factor carbohydrate-responsive element-binding protein pathway in termite queen fertility

DEFF Research Database (Denmark)

Sillam-Dussès, David; Hanus, Robert; Thomas-Poulsen, Michael

2016-01-01

in eight different termite species. ChREBP is expressed in several tissues, including ovaries and fat bodies, and increases in expression in totipotent workers during their differentiation into neotenic mature queens. We further show that ChREBP is regulated by a carbohydrate diet in termite queens...

Coulomb Damping

Science.gov (United States)

Fay, Temple H.

2012-01-01

Viscous damping is commonly discussed in beginning differential equations and physics texts but dry friction or Coulomb friction is not despite dry friction being encountered in many physical applications. One reason for avoiding this topic is that the equations involve a jump discontinuity in the damping term. In this article, we adopt an energy…

Magnetic Damping For Maglev

Directory of Open Access Journals (Sweden)

S. Zhu

1998-01-01

Full Text Available Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.

Damping characteristics of reinforced concrete structures

International Nuclear Information System (INIS)

Hisano, M.; Nagashima, I.; Kawamura, S.

1987-01-01

Reinforced concrete structures in a nuclear power plant are not permitted to go far into the inelasticity generally, even when subjected to strong ground motion. Therefore it is important to evaluate the damping appropriately in linear and after cracking stage before yielding in the dynamic response analysis. Next three dampings are considered of reinforced concrete structures. 1) Internal damping in linear range material damping of concrete without cracks;2) Hysteretic damping in inelastic range material hysteretic damping of concrete due to cracking and yielding;3) Damping due to the energy dissipation into the ground. Among these damping material damping affects dynamic response of a nuclear power plant on hard rock site where damping due to energy dissipation into the ground is scarcely expected. However material damping in linear and slightly nonlinear range have only been assumed without enough experimental data. In this paper such damping is investigated experimentally by the shaking table tests of reinforced concrete box-walls which modeled roughly the outer wall structure of a P.W.R. type nuclear power plant

Processed products of termites and lake flies: improving ...

African Journals Online (AJOL)

The lake region is endowed with plenty of edible insects. Edible insects can provide partial solution to food insecurity. The aim of this project was to promote entomophagy for food security by adding value to termites and lake flies, enhancing taste and preference of edible insects, and improving shelf life of edible insect ...

Define Colony Number of Subterranean Termites Coptotermes gestroi (Isoptera: Rhinotermitidae) in Selected Infested Structures

International Nuclear Information System (INIS)

Abdul Hafiz Abdul Majid; Abu Hassan Ahmad

2015-01-01

Termites are one of the social insects living in large colonies that can cause economic loss. The objective of this study was to estimate foraging territory of infested subterranean termites on building structure. A mark-recapture study was conducted on eight Coptotermes gestroi colonies located at selected infested building structures in Penang, Malaysia. From the foraging study, the population of C. gestroi was estimated to be within the range of 106,592±6,968 to 4,185,000±2,127,328. Additionally, the foraging territory was from 13 to 300 m 2 of the infested building structures. Meanwhile the maximum foraging distance was from 4 to 30 m of the infested structures. The results indicated that each of the building structures was infested by a single colony. This study also showed that the triple mark recapture technique used to estimate the population size of the termite colony was capable of providing rough estimates of foraging population of C. gestroi. (author)

Digestive enzyme activities and gastrointestinal fermentation in wood-eating catfishes.

Science.gov (United States)

German, Donovan P; Bittong, Rosalie A

2009-11-01

To determine what capabilities wood-eating and detritivorous catfishes have for the digestion of refractory polysaccharides with the aid of an endosymbiotic microbial community, the pH, redox potentials, concentrations of short-chain fatty acids (SCFAs), and the activity levels of 14 digestive enzymes were measured along the gastrointestinal (GI) tracts of three wood-eating taxa (Panaque cf. nigrolineatus "Marañon", Panaque nocturnus, and Hypostomus pyrineusi) and one detritivorous species (Pterygoplichthys disjunctivus) from the family Loricariidae. Negative redox potentials (-600 mV) were observed in the intestinal fluids of the fish, suggesting that fermentative digestion was possible. However, SCFA concentrations were low (<3 mM in any intestinal region), indicating that little GI fermentation occurs in the fishes' GI tracts. Cellulase and xylanase activities were low (<0.03 U g(-1)), and generally decreased distally in the intestine, whereas amylolytic and laminarinase activities were five and two orders of magnitude greater, respectively, than cellulase and xylanase activities, suggesting that the fish more readily digest soluble polysaccharides. Furthermore, the Michaelis-Menten constants (K(m)) of the fishes' beta-glucosidase and N-acetyl-beta-D-glucosaminidase enzymes were significantly lower than the K(m) values of microbial enzymes ingested with their food, further suggesting that the fish efficiently digest soluble components of their detrital diet rather than refractory polysaccharides. Coupled with rapid gut transit and poor cellulose digestibility, the wood-eating catfishes appear to be detritivores reliant on endogenous digestive mechanisms, as are other loricariid catfishes. This stands in contrast to truly "xylivorous" taxa (e.g., beavers, termites), which are reliant on an endosymbiotic community of microorganisms to digest refractory polysaccharides.

Trail communication regulated by two trail pheromone components in the fungus-growing termite Odontotermes formosanus (Shiraki).

Science.gov (United States)

Wen, Ping; Ji, Bao-Zhong; Sillam-Dussès, David

2014-01-01

The eusocial termites are well accomplished in chemical communication, but how they achieve the communication using trace amount of no more than two pheromone components is mostly unknown. In this study, the foraging process and trail pheromones of the fungus-growing termite Odontotermes formosanus (Shiraki) were systematically studied and monitored in real-time using a combination of techniques, including video analysis, solid-phase microextraction, gas chromatography coupled with either mass spectrometry or an electroantennographic detector, and bioassays. The trail pheromone components in foraging workers were (3Z)-dodec-3-en-1-ol and (3Z,6Z)-dodeca-3,6-dien-1-ol secreted by their sternal glands. Interestingly, ratio of the two components changed according to the behaviors that the termites were displaying. This situation only occurs in termites whereas ratios of pheromone components are fixed and species-specific for other insect cuticular glands. Moreover, in bioassays, the active thresholds of the two components ranged from 1 fg/cm to 10 pg/cm according to the behavioral contexts or the pheromonal exposure of tested workers. The two components did not act in synergy. (3Z)-Dodec-3-en-1-ol induced orientation behavior of termites that explore their environment, whereas (3Z,6Z)-dodeca-3,6-dien-1-ol had both an orientation effect and a recruitment effect when food was discovered. The trail pheromone of O. formosanus was regulated both quantitatively by the increasing number of workers involved in the early phases of foraging process, and qualitatively by the change in ratio of the two pheromone components on sternal glandular cuticle in the food-collecting workers. In bioassays, the responses of workers to the pheromone were also affected by the variation in pheromone concentration and component ratio in the microenvironment. Thus, this termite could exchange more information with nestmates using the traces of the two trail pheromone components that can be easily

Green house gas emissions from termite ecosystem | Gomati ...

African Journals Online (AJOL)

Recent estimates of the total annual source strength of CH4 vary from 400 to 1200 Tg. Activities such as rice cultivation, cattle production, mining, use of fossil fuels and biomass burning is believed to be the cause of increasing methane levels in the atmosphere. To add to this list is the source from termites, which contributes ...

Degradation of mangrove tissues by arboreal termites (Nasutitermes acajutlae) and their role in the mangrove C cycle (Puerto Rico): Chemical characterization and organic matter provenance using bulk δ13C, C/N, alkaline CuO oxidation-GC/MS, and solid-state 13C NMR

Science.gov (United States)

Vane, Christopher H.; Kim, Alexander W.; Moss-Hayes, Vicky; Snape, Colin E.; Diaz, Miguel Castro; Khan, Nicole S.; Engelhart, Simon E.; Horton, Benjamin P.

2013-08-01

Arboreal termites are wood decaying organisms that play an important role in the first stages of C cycling in mangrove systems. The chemical composition of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa leaf, stem, and pneumatophore tissues as well as associated sediments was compared to that of nests of the termite Nasutitermes acajutlae. Nests gave δ13C values of -26.1 to -27.2‰ (±0.1) and C/N of 43.3 (±2.0) to 98.6 (±16.2) which were similar to all stem and pneumatophores but distinct from mangrove leaves or sediments. Organic matter processed by termites yielded lignin phenol concentrations (Λ, lambda) that were 2-4 times higher than stem or pneumatophores and 10-20 times higher than that of leaves or sediments, suggesting that the nests were more resistant to biodegradation than the mangrove vegetation source. 13C NMR revealed that polysaccharide content of mangrove tissues (50-69% C) was higher than that of the nests (46-51% C). Conversely, lignin accounted for 16.2-19.6% C of nest material, a threefold increase relative to living mangrove tissues; a similar increase in aromatic methoxyl content was also observed in the nests. Lipids (aliphatic and paraffinic moieties) were also important but rather variable chemical components of all three mangrove species, representing between 13.5 and 28.3% of the C content. Termite nests contained 3.14 Mg C ha-1 which represents approximately 2% of above ground C storage in mangroves, a value that is likely to increase upon burial due to their refractory chemical composition.

I. Structural studies of termite defense secretions. II. Structural studies of natural products of marine nudibranchs. [Kempene, tridachione

Energy Technology Data Exchange (ETDEWEB)

Solheim, B.A.

1977-12-01

Three families of termites have the ability to produce a sticky secretion that envelopes and immobilizes the enemy. In the family Termitidae the secretion contains the diterpenoid hydrocarbons, kempene I and kempene II. The molecular structure of kempene II from the termite, Nasutitermes kempae, is described in detail. Another species of termite, Cubitermes umbratus, contained the diterpenoid hydrocarbon biflora-4,10-19,15-triene in the secretion and this compound is described. Studies were also conducted on the mucous secretion of the pedal gland of the marine nudibranch, Tidachiella diomedea. Tridachione, a substituted ..gamma..-pyrone, was isolated in the pure state and its molecular structure is described in detail. (HLW)

The interdigital brace and other grips for termite nest perforation by chimpanzees of the Goualougo Triangle, Republic of Congo.

Science.gov (United States)

Lesnik, Julie J; Sanz, Crickette M; Morgan, David B

2015-06-01

Studies of chimpanzee termite foraging enlighten our understanding of early hominin tool use not only by modeling the cognitive ability of our ancestors but also by emphasizing the possible role of social insects in the hominin diet. The chimpanzees of the Goualougo Triangle are known to have one of the largest and most complex tool repertoires reported for wild chimpanzees. One tool set habitually used by this population includes a perforating tool to penetrate the hard outer crust of elevated termite nests before fishing for termite prey with an herbaceous stem. Here, we report the variation present in the grips used on the perforating tool. Our analysis of video recordings of chimpanzee visitation to termite nests over a 3-year period shows that these chimpanzees use a variety of grips to navigate the challenges encountered in opening a termite nest. For situations in which the soil is most hardened, perforating requires force and a power grip is often used. When the soil in the passageway is loose, precision grips are suitable for the task. One of the preferred grips reported here is an interdigital brace, which has previously been described in studies of how some people hold a pencil. In this study, for the first time, the interdigital brace has been thoroughly described for chimpanzees. The various strategies and grips used during perforation emphasize the importance of termites as a nutritional resource that should be considered more strongly as a food used by early hominins. © 2015 Wiley Periodicals, Inc.

Effects of Erosion from Mounds of Different Termite Genera on Distinct Functional Grassland Types in an African Savannah.

Science.gov (United States)

Gosling, Cleo M; Cromsigt, Joris P G M; Mpanza, Nokukhanya; Olff, Han

A key aspect of savannah vegetation heterogeneity is mosaics formed by two functional grassland types, bunch grasslands, and grazing lawns. We investigated the role of termites, important ecosystem engineers, in creating high-nutrient patches in the form of grazing lawns. Some of the ways termites can contribute to grazing lawn development is through erosion of soil from aboveground mounds to the surrounding soil surface. This may alter the nutrient status of the surrounding soils. We hypothesize that the importance of this erosion varies with termite genera, depending on feeding strategy and mound type. To test this, we simulated erosion by applying mound soil from three termite genera ( Macrotermes , Odontotermes , and Trinervitermes ) in both a field experiment and a greenhouse experiment. In the greenhouse experiment, we found soils with the highest macro nutrient levels (formed by Trinervitermes ) promoted the quality and biomass of both a lawn ( Digitaria longiflora ) and a bunch ( Sporobolus pyramidalis ) grass species. In the field we found that soils with the highest micro nutrient levels (formed by Macrotermes ) showed the largest increase in cover of grazing lawn species. By linking the different nutrient availability of the mounds to the development of different grassland states, we conclude that the presence of termite mounds influences grassland mosaics, but that the type of mound plays a crucial role in determining the nature of the effects.

Phylogeny of not-yet-cultured spirochetes from termite guts

DEFF Research Database (Denmark)

Paster, B.J.; Dewhirst, F.E.; Cooke, S.M.

1996-01-01

Comparisons of 16S rDNA sequences were used to determine the phylogeny of not-yet-cultured spirochetes from hindguts of the African higher termite, Nasutitermes lujae (Wasmann). The 16S rRNA genes were amplified directly from spirochete-rich hindguts by using universal primers, and the amplified...

Evaluation of bolted connections in wood-plastic composites

Science.gov (United States)

Arnandha, Yudhi; Satyarno, Iman; Awaludin, Ali; Irawati, Inggar Septia; Ihsan, Muhamad; Wijanarko, Felyx Biondy; William, Mahdinur, Fardhani, Arfiati

2017-03-01

Wood-plastic composite (WPC) is a relatively new material that consists of sawdust and plastic polymer using the extrusion process. Due to its attributes such as low water content, low maintenance, UV durability and being fungi and termite resistant. Nowadays, WPC has already been produced in Indonesia using sawdust from local wood such as Albizia (Paraserianthes falcataria) and Teak (Tectona grandis). Moreover preliminary studies about the physical and mechanical WPC board from Albizia sawdust and HDPE plastic have been carried out. Based on these studies, WPC has a high shear strength around 25-30 MPa higher than its original wood shear strength. This paper was a part of the research in evaluating WPC as potential sheathing in a shear wall system. Since still little is known about connection behavior in WPC using Indonesian local wood, this study evaluated the connection for both of these two types of wood-plastic composite. WPC board from Albizia sawdust will be projected as shear wall sheathing and WPC stud from Teak sawdust projected to be shear wall frame. For this study, the embedding strength for both WPC was determined according to ASTM D 5764 standard, using two types of bolts (stainless bolt and standard bolt) with several diameters as variation (6 mm, 8 mm, 10 and 12 mm). Hence, dowel-bearing test under fastened condition conducted accordance to ASTM D5652, hereby the yield strength then compared with the prediction yield strength from European Yield Model (EYM). According to both single and double shear connection, it can be concluded that yield strength from the EYM method tended to under-predict the 5% diameter offset yield than the actual yield strength from the test. The yield strength itself increase with the increase of bolt diameter. For single shear connection, the highest yield strength was 12 mm standard bolt around 9732 N, slightly higher than stainless bolt around 9393 N. Whereby for double shear connection, the highest yield strength was

Extended Rayleigh Damping Model

Directory of Open Access Journals (Sweden)

Naohiro Nakamura

2016-07-01

Full Text Available In dynamic analysis, frequency domain analysis can be used if the entire structure is linear. However, time history analysis is generally used if nonlinear elements are present. Rayleigh damping has been widely used in time history response analysis. Many articles have reported the problems associated with this damping and suggested remedies. A basic problem is that the frequency area across which the damping ratio is almost constant is too narrow. If the area could be expanded while incurring only a small increase in computational cost, this would provide an appropriate remedy for this problem. In this study, a novel damping model capable of expanding the constant frequency area by more than five times was proposed based on the study of a causal damping model. This model was constructed by adding two terms to the Rayleigh damping model and can be applied to the linear elements in the time history analysis of a nonlinear structure. The accuracy and efficiency of the model were confirmed using example analyses.

Toxicity of Turmeric Extracts to the Termite Reticulitermes flavipes (Blattodea: Rhinotermitidae).

Science.gov (United States)

Raje, Kapil R; Hughes, Gabriel P; Gondhalekar, Ameya D; Ginzel, Matthew D; Scharf, Michael E

2015-08-01

Turmeric is an important spice crop with documented human health benefits associated with chemicals called curcuminoids. In this study, the termite Reticulitermes flavipes (Kollar) was exposed to different solvent extracts of turmeric to investigate potential termiticidal properties. Treating termites with hexane extracts of purified lab-grade curcuminoids had no effect on termites. However, in continuous exposure assays, the LC(50) for hexane extracts of crude turmeric powder was 9.6 mg, or 1.0 mg starting material per square centimeter of filter paper substrate. These active components were soluble in a range of polar and apolar solvents, but only hexane could selectively fractionate active components away from the inactive curcuminoids. The active constituents of turmeric separated by thin layer chromatography (TLC) fluoresced in short-wave UV light but were not visible in long-wave UV light. By re-extracting TLC-separated bands in hexane and performing bioassays and gas chromatography-mass spectrometry, we demonstrated that termiticidal components of turmeric are extractable as a blend containing mainly ar-turmerone, turmerone, and curlone. This determination is consistent with findings of preceding work by other researchers that investigated insecticidal properties of turmeric in other pest insects. © 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.

Synthesis of AzPhchitosan-bifenthrin-PVC to protect cables against termites.

Science.gov (United States)

Zhang, Lingkun; Cai, Weiwei; Chen, Wu-Ya; Zhang, Li; Hu, Kaikai; Guan, Yan-Qing

2016-03-30

The destruction of PVC cables by termites is a continuing and long-standing problem, which can lead to power leakage and power cut. Given the environmental demerits of insecticide overuse, alternative methods of addressing this problem are a highly desirable goal. In this study, we used photo-immobilization to develop a chitosan carrier system to help bifenthrin immobilize on the surface of the PVC substrate. The immobilization was analyzed using nuclear magnetic resonance (NMR), UV absorption, reverse-phase high-performance liquid chromatography (RP-HPLC), Raman absorption spectroscopy, and thermal gravimetric analysis (TGA). The surface structure and biological activity of the embedded and immobilized bifenthrin were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photon-electron spectroscopy (XPS). Its efficacy was assessed in pest experiments. The results indicate a successful embedding and immobilization of bifenthrin. Furthermore, the chemical bonding network between AzPhchitosan, bifenthrin, and PVC is stable, guaranteeing no environmental release of bifenthrin, and also providing more efficacious protection against termites. The evidence suggests that this photo-immobilization of bifenthrin-embedded chitosan on the surface of PVC substrates is a novel and environmentally friendly technique for termite control. This paper also reports a modification of chitosan with respect to its novel application in environmental protection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Closed-form eigensolutions of nonviscously, nonproportionally damped systems based on continuous damping sensitivity

Science.gov (United States)

Lázaro, Mario

2018-01-01

In this paper, nonviscous, nonproportional, vibrating structures are considered. Nonviscously damped systems are characterized by dissipative mechanisms which depend on the history of the response velocities via hereditary kernel functions. Solutions of the free motion equation lead to a nonlinear eigenvalue problem involving mass, stiffness and damping matrices. Viscoelasticity leads to a frequency dependence of this latter. In this work, a novel closed-form expression to estimate complex eigenvalues is derived. The key point is to consider the damping model as perturbed by a continuous fictitious parameter. Assuming then the eigensolutions as function of this parameter, the computation of the eigenvalues sensitivity leads to an ordinary differential equation, from whose solution arises the proposed analytical formula. The resulting expression explicitly depends on the viscoelasticity (frequency derivatives of the damping function), the nonproportionality (influence of the modal damping matrix off-diagonal terms). Eigenvectors are obtained using existing methods requiring only the corresponding eigenvalue. The method is validated using a numerical example which compares proposed with exact ones and with those determined from the linear first order approximation in terms of the damping matrix. Frequency response functions are also plotted showing that the proposed approach is valid even for moderately or highly damped systems.

Rapid elimination of field colonies of subterranean termites (Isoptera: Rhinotermitidae) using bistrifluron solid bait pellets.

Science.gov (United States)

Evans, Theodore A

2010-04-01

The efficacy of bistrifluron, a chitin synthesis inhibitor, in cellulose bait pellets was evaluated on the mound-building subterranean termite, Coptotermes acinaciformis (Froggatt). Three concentrations of the bistrifluron were used: 0 (untreated control), 0.5, and 1.0% over an 8 wk period. Both doses of bistrifluron bait eliminated (viz. termites absent from nest or mound) termite colonies: 83% of colonies (10 of 12) were either eliminated or moribund (viz. colony had no reproductive capacity and decreased workforce) after 8 wk, compared with none of the control colonies. The remaining two treated colonies were deemed to be in decline. Early signs that bistrifluron was affecting the colonies included: 3 wk after baiting mound temperatures showed a loss of metabolic heat, 4 wk after baiting foraging activity in feeding stations was reduced or absent, and dissection of two mounds at 4 wk showed they were moribund. Colony elimination was achieved in around half or less the time, and with less bait toxicant, than other bait products tested under similar conditions in the field, because of either the active ingredient, the high surface area of the pellets, or a combination of both. This suggests the sometimes long times reported for control using baits may be reduced significantly. The use of a mound building species demonstrated clearly colony level effects before and after termites stopped foraging in bait stations.

Landau Damping Revisited

International Nuclear Information System (INIS)

Rees, John; Chao, Alexander

2008-01-01

Landau damping, as the term is used in accelerator science, is a physical process in which an ensemble of harmonic oscillators--an accelerator beam, for example--that would otherwise be unstable is stabilized by a spread in the natural frequencies of the oscillators. This is a study of the most basic aspects of that process. It has two main goals: to gain a deeper insight into the mechanism of Landau damping and to find the coherent motion of the ensemble and thus the dependence of the total damping rate on the frequency spread

Damping in LMFBR pipe systems

International Nuclear Information System (INIS)

Anderson, M.J.; Barta, D.A.; Lindquist, M.R.; Renkey, E.J.; Ryan, J.A.

1983-06-01

LMFBR pipe systems typically utilize a thicker insulation package than that used on water plant pipe systems. They are supported with special insulated pipe clamps. Mechanical snubbers are employed to resist seismic loads. Recent laboratory testing has indicated that these features provide significantly more damping than presently allowed by Regulatory Guide 1.61 for water plant pipe systems. This paper presents results of additional in-situ vibration tests conducted on FFTF pipe systems. Pipe damping values obtained at various excitation levels are presented. Effects of filtering data to provide damping values at discrete frequencies and the alternate use of a single equivalent modal damping value are discussed. These tests further confirm that damping in typical LMFBR pipe systems is larger than presently used in pipe design. Although some increase in damping occurred with increased excitation amplitude, the effect was not significant. Recommendations are made to use an increased damping value for both the OBE and DBE seismic events in design of LMFBR pipe systems

Termites create spatial structure and govern ecosystem function by affecting N2 fixation in an East African savanna.

Science.gov (United States)

Fox-Dobbs, Kena; Doak, Daniel F; Brody, Alison K; Palmer, Todd M

2010-05-01

The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the 15N natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence >50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure.

Asexual queen succession in the higher termite Embiratermes neotenicus

Czech Academy of Sciences Publication Activity Database

Fougeyrollas, R.; Dolejšová, Klára; Sillam-Dusses, D.; Roy, V.; Poteaux, C.; Hanus, Robert; Roisin, Y.

2015-01-01

Roč. 282, č. 1809 (2015), 20150260/1-20150260/7 ISSN 0962-8452 R&D Projects: GA ČR(CZ) GA14-12774S Institutional support: RVO:61388963 Keywords : thelytokous parthenogenesis * breeding system * termites * Isoptera * Termitidae * reproductive strategies Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.823, year: 2015

SPATIAL VARIABILITY AND VITALITY OF EPIGEOUS TERMITE MOUNDS IN PASTURES OF MATO GROSSO DO SUL, BRAZIL

Directory of Open Access Journals (Sweden)

Sandra Santana Lima

2015-02-01

Full Text Available Epigeous termite mounds are frequently observed in pasture areas, but the processes regulating their population dynamics are poorly known. This study evaluated epigeous termite mounds in cultivated grasslands used as pastures, assessing their spatial distribution by means of geostatistics and evaluating their vitality. The study was conducted in the Cerrado biome in the municipality of Rio Brilhante, Mato Grosso do Sul, Brazil. In two pasture areas (Pasture 1 and Pasture 2, epigeous mounds (nests were georeferenced and analyzed for height, circumference and vitality (inhabited or not. The area occupied by the mounds was calculated and termite specimens were collected for taxonomic identification. The spatial distribution pattern of the mounds was analyzed with geostatistical procedures. In both pasture areas, all epigeous mounds were built by the same species, Cornitermes cumulans. The mean number of mounds per hectare was 68 in Pasture 1 and 127 in Pasture 2, representing 0.4 and 1 % of the entire area, respectively. A large majority of the mounds were active (vitality, 91 % in Pasture 1 and 84 % in Pasture 2. A “pure nugget effect” was observed in the semivariograms of height and nest circumference in both pastures reflecting randomized spatial distribution and confirming that the distribution of termite mounds in pastures had a non-standard distribution.

Enzyme activities at different stages of plant biomass decomposition in three species of fungus-growing termites

DEFF Research Database (Denmark)

da Costa, Rafael R.; Hu, Haofu; Pilgaard, Bo

2018-01-01

contributing to the success of the termites as the main plant decomposers in the Old World. Here we evaluate which plant polymers are decomposed and which enzymes are active during the decomposition process in two major genera of fungus-growing termites. We find a diversity of active enzymes at different...... stages of decomposition and a consistent decrease in plant components during the decomposition process. Furthermore, our findings are consistent with the hypothesis that termites transport enzymes from the older mature parts of the fungus comb through young worker guts to freshly inoculated plant...... substrate. However, preliminary fungal RNAseq analyses suggest that this likely transport is supplemented with enzymes produced in situ Our findings support that the maintenance of an external fungus comb, inoculated with an optimal mix of plant material, fungal spores, and enzymes, is likely the key...

appraisal of the economic activities of termites: a review

African Journals Online (AJOL)

DR.AMIN

within the soil increases the rate of percolation of water into the soil, thereby ... into the soil, mineral nutrients of these trees. Man in ... soil barrier termiticides, treated zone termiticides, dust and fumigant, and, non ... a result of man's interference with natural food supply .... The destructive effects of termites to man, whenever.

EFFECTIVENESS OF A SUPERFICIAL TREATMENT USING BIFENTHRIN TO PROTECT RADIATA PINE FRAMING FROM DAMAGE BY SUBTERRANEAN AND DRYWOOD TERMITES IN INDONESIA

Directory of Open Access Journals (Sweden)

Paimin Sukartana

2010-06-01

Full Text Available Various experimental testing procedures were undertaken in Indonesia to determine the effectiveness of a patented superficial (envelope treatment using bifenthrin to protect radiata pine framing material from damage by two species of subterranean termites (Macrotermes gilvus and Coptotermes curvignathus and one species of drywood termite (Cryptotermes cynocephalus. Lengths of framing material (Pinus radiata sapwood were commercially treated to the targeted retention of 0.02% m/m of bifenthrin in the outer 2 mm depth penetration zone of the material. The treated and untreated materials were subsequently cut into test specimens and exposed to M. gilvus in the field and a semi-laboratory trial, to C. curvignathus in the laboratory and a semi-laboratory trial and to C. cynocephalus in a laboratory trial. No supplementary treatment was performed on the exposed cut ends of the treated test specimens. The results from the trials clearly demonstrated that the superficial treatment of bifenthrin seemed effective in protecting test specimens of radiata pine framing material from significant damage by Indonesia’s most notorious termite species that often causes serious economic loss to the timbers. Termites were unable to damage any of the bifenthrin-treated surfaces of test specimens. Any obser ved damage by termites, albeit minor, was in all cases confined to the exposed cut ends of test specimens. In contrast, attack by termites on the untreated control test specimens caused damage of the samples ranging from light to heavy.

Methane fluxes from the mound-building termite species of North Australian savannas

Science.gov (United States)

Jamali, H.; Livesely, S. J.; Arndt, S. K.; Dawes-Gromadzki, T.; Cook, G. D.; Hutley, L.

2009-04-01

Termites are estimated to contribute 3-19% to the global methane emissions. These estimates have large uncertainties because of the limited number of field-based studies and species studied, as well as issues of diel and seasonal variation. We measured methane fluxes from four common mound-building termite species (Microcerotermes nervosus, n=26; M. serratus, n=4; Tumulitermes pastinator, n=5; and Amitermes darwini, n=4) in tropical savannas near Darwin in the Northern Territory, Australia. Methane fluxes from replicated termite mounds were measured in the field using manual chambers with fluxes reported on a mound volume basis. Methane flux was measured in both wet and dry seasons and diel variation was investigated by measuring methane flux every 4 hours over a 24 hour period. Mound temperature was measured concurrently with flux to examine this relationship. In addition, five M. nervosus mounds removed from the field and incubated under controlled temperature conditions over a 24 hour period to remove the effect of varying temperature. During the observation campaigns, mean monthly minimum and maximum temperatures for February (wet season) were 24.7 and 30.8°C, respectively, and were 20.1 to 31.4 °C in June (dry season). Annual rainfall in 2008 for Darwin was 1970.1 mm, with a maximum of 670 mm falling in February and no rain in May and June. Methane fluxes were greatest in the wet season for all species, ranging from 265.1±101.1 (T. pastinator) to 2256.6±757.1 (M. serratus) µg CH4-C/m3/h. In the dry season, methane fluxes were at their lowest, ranging from 10.0±5.5 (T. pastinator) to 338.0±165.9 (M. serratus) µg CH4-C/m3/h. On a diel basis, methane fluxes were smallest at the coolest time of the day (~0700 hrs) and greatest at the warmest (~1400 hrs) for all species, and for both wet and dry seasons. Typical diel variation in flux from M. serratus dominated mounds ranged from 902.6±261.9 to 1392.1±408.1 µg CH4-C/m3/h in wet season and 99.6±57.4 to

Toxicity, tunneling and feeding behavior of the termite, Coptotermes vastator, in sand treated with oil of the physic nut, Jatropha curcas.

Science.gov (United States)

Acda, Menandro N

2009-01-01

Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite.

Nuclear piping system damping data studies

International Nuclear Information System (INIS)

Ware, A.G.; Arendts, J.G.

1985-01-01

A programm has been conducted at the Idaho National Engineering Laboratory to study structural damping data for nuclear piping systems and to evaluate if changes in allowable damping values for structural seismic analyses are justified. The existing pipe damping data base was examined, from which a conclusion was made that there were several sets of data to support higher allowable values. The parameters which most influence pipe damping were identified and an analytical investigation demonstrated that increased damping would reduce the required number of seismic supports. A series of tests on several laboratory piping systems was used to determine the effect of various parameters such as types of supports, amplitude of vibration, frequency, insulation, and pressure on damping. A multiple regression analysis was used to statistically assess the influence of the various parameters on damping, and an international pipe damping data bank has been formed. (orig.)

Combined effect of Azadirachta indica and the entomopathogenic nematode Steinernema glaseri against subterranean termite, Reticulitermes flavipes

Directory of Open Access Journals (Sweden)

Kadarkarai Murugan

2011-08-01

Full Text Available Laboratory study has been conducted on the bioactivities of entomopathogenic nematodes and neem seed kernel extract (NSKE against worker termites of Reticulitermes flavipes. Neem at various concentrations did not affect the survivability of nematodes, whereas neem had considerable impact on the survivability of worker termites and this may be due to the presence of active neem compounds (Azadirachtin, salanin etc.. Mortality was 40% on 4th day at lower concentration of 1.0% NSKE treatment; whereas mortality has been increased to 70% at higher concentration (4.0% on 4th day. There was 100% mortality after the combined treatment with 4.0% NSKE + 600 infective juvenile Steinernema glaseri, even at the first day of the experiment. In the present experiment, neem extract does not affected the survival of the nematodes. Hence, nematode and neem extract can be used for soil-insect control particularly for the subterranean termites.

Microtermolides A and B from termite-associated Streptomyces sp. and structural revision of vinylamycin

DEFF Research Database (Denmark)

Carr, Gavin; Poulsen, Michael; Klassen, Jonathan L.

2012-01-01

Microtermolides A (1) and B (2) were isolated from a Streptomyces sp. strain associated with fungus-growing termites. The structures of 1 and 2 were determined by 1D- and 2D-NMR spectroscopy and high-resolution mass spectrometry. Structural elucidation of 1 led to the re-examination of the struct......Microtermolides A (1) and B (2) were isolated from a Streptomyces sp. strain associated with fungus-growing termites. The structures of 1 and 2 were determined by 1D- and 2D-NMR spectroscopy and high-resolution mass spectrometry. Structural elucidation of 1 led to the re...

Damping measurements in flowing water

Science.gov (United States)

Coutu, A.; Seeley, C.; Monette, C.; Nennemann, B.; Marmont, H.

2012-11-01

Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

Damping measurements in flowing water

International Nuclear Information System (INIS)

Coutu, A; Monette, C; Nennemann, B; Marmont, H; Seeley, C

2012-01-01

Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

Transit-Time Damping, Landau Damping, and Perturbed Orbits

Science.gov (United States)

Simon, A.; Short, R. W.

1997-11-01

Transit-time damping(G.J. Morales and Y.C. Lee, Phys. Rev. Lett. 33), 1534 (1974).*^,*(P.A. Robinson, Phys. Fluids B 3), 545 (1991).** has traditionally been obtained by calculating the net energy gain of transiting electrons, of velocity v, to order E^2* in the amplitude of a localized electric field. This necessarily requires inclusion of the perturbed orbits in the equation of motion. A similar method has been used by others(D.R. Nicholson, Introduction to Plasma Theory) (Wiley, 1983).*^,*(E.M. Lifshitz and L.P. Pitaevskifi, Physical Kinetics) (Pergamon, 1981).** to obtain a ``physical'' picture of Landau damping in a nonlocalized field. The use of perturbed orbits seems odd since the original derivation of Landau (and that of Dawson) never went beyond a linear picture of the dynamics. We introduce a novel method that takes advantage of the time-reversal invariance of the Vlasov equation and requires only the unperturbed orbits to obtain the result. Obviously, there is much reduction in complexity. Application to finite slab geometry yields a simple expression for the damping rate. Equivalence to much more complicated results^2* is demonstrated. This method allows us to calculate damping in more complicated geometries and more complex electric fields, such as occur in SRS in filaments. See accompanying talk.(R.W. Short and A. Simon, this conference.) This work was supported by the U.S. DOE Office of Inertial Confinement Fusion under Co-op Agreement No. DE-FC03-92SF19460.

Damping in Timber Structures

OpenAIRE

Labonnote, Nathalie

2012-01-01

Key point to development of environmentally friendly timber structures, appropriate to urban ways of living, is the development of high-rise timber buildings. Comfort properties are nowadays one of the main limitations to tall timber buildings, and an enhanced knowledge on damping phenomena is therefore required, as well as improved prediction models for damping. The aim of this work has consequently been to estimate various damping quantities in timber structures. In particular, models h...

Sustainable Management of Subterranean Termite Populations (Isoptera: Rhinotermitidae) in Armstrong Park, New Orleans, With Durable Baits.

Science.gov (United States)

Su, Nan-Yao; Guidry, Eric; Cottone, Carrie

2016-03-27

Durable baits, Recruit HD, were installed in 45 Sentricon stations between September 2010 and July 2014 in the 32-acre Armstrong Park, New Orleans. After eliminating all detectable termite colonies in the Park, 6-12 mo elapsed before new activity was detected. Newly invading termite colonies were usually found near the Park border or were smaller colonies that originated from recently paired alates. After colony elimination, Recruit HD baits were left in the stations to intercept newly invading colonies of subterranean termites, leading to their elimination, and multiple cycles of such interception and elimination events were recorded. Because the presence of Recruit HD baits continues to eliminate incoming colonies with little effort in maintaining and resupplying baits in the target areas, the bait system offers an economically sustainable option for managing subterranean termite populations in a large area. The 32-acre Armstrong Park is a manageable size to carry out an area-wide (AW) project. If the number of such AW projects is gradually increased over time in selected metro areas of New Orleans, we predict that we may be able to turn the tide against the ever-increasing populations ofC. formosanusin the entire city. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Vibration and Damping Analysis of Composite Fiber Reinforced Wind Blade with Viscoelastic Damping Control

Directory of Open Access Journals (Sweden)

Tai-Hong Cheng

2015-01-01

Full Text Available Composite materials are increasingly used in wind blade because of their superior mechanical properties such as high strength-to-weight and stiffness-to-weight ratio. This paper presents vibration and damping analysis of fiberreinforced composite wind turbine blade with viscoelastic damping treatment. The finite element method based on full layerwise displacement theory was employed to analyze the damping, natural frequency, and modal loss factor of composite shell structure. The lamination angle was considered in mathematical modeling. The curved geometry, transverse shear, and normal strains were exactly considered in present layerwise shell model, which can depict the zig-zag in-plane and out-of-plane displacements. The frequency response functions of curved composite shell structure and wind blade were calculated. The results show that the damping ratio of viscoelastic layer is found to be very sensitive to determination of magnitude of composite structures. The frequency response functions with variety of thickness of damping layer were investigated. Moreover, the natural frequency, modal loss factor, and mode shapes of composite fiber reinforced wind blade with viscoelastic damping control were calculated.

Significance of wood extractives for wood bonding.

Science.gov (United States)

Roffael, Edmone

2016-02-01

Wood contains primary extractives, which are present in all woods, and secondary extractives, which are confined in certain wood species. Extractives in wood play a major role in wood-bonding processes, as they can contribute to or determine the bonding relevant properties of wood such as acidity and wettability. Therefore, extractives play an immanent role in bonding of wood chips and wood fibres with common synthetic adhesives such as urea-formaldehyde-resins (UF-resins) and phenol-formaldehyde-resins (PF-resins). Extractives of high acidity accelerate the curing of acid curing UF-resins and decelerate bonding with alkaline hardening PF-resins. Water-soluble extractives like free sugars are detrimental for bonding of wood with cement. Polyphenolic extractives (tannins) can be used as a binder in the wood-based industry. Additionally, extractives in wood can react with formaldehyde and reduce the formaldehyde emission of wood-based panels. Moreover, some wood extractives are volatile organic compounds (VOC) and insofar also relevant to the emission of VOC from wood and wood-based panels.

Fluxes of CH4 and CO2 from soil and termite mounds in south Sudanian savanna of Burkina Faso (West Africa)

Science.gov (United States)

Brümmer, Christian; Papen, Hans; Wassmann, Reiner; Brüggemann, Nicolas

2009-03-01

The contribution of West African savanna ecosystems to global greenhouse gas budgets is highly uncertain. In this study we quantified soil-atmosphere CH4 and CO2 fluxes in the southwest of Burkina Faso from June to September 2005 and from April to September 2006 at four different agricultural fields planted with sorghum (n = 2), cotton, and peanut and at a natural savanna site with termite (Cubitermes fungifaber) mounds. During the rainy season both CH4 uptake and CH4 emission were observed in the savanna, which was on average a CH4 source of 2.79 and 2.28 kg CH4-C ha-1 a-1 in 2005 and 2006, respectively. The crop sites were an average CH4 sink of -0.67 and -0.70 kg CH4-C ha-1 a-1 in the 2 years, without significant seasonal variation. Mean annual soil respiration ranged between 3.86 and 5.82 t CO2-C ha-1 a-1 in the savanna and between 2.50 and 4.51 t CO2-C ha-1 a-1 at the crop sites. CH4 emission from termite mounds was 2 orders of magnitude higher than soil CH4 emissions, whereas termite CO2 emissions were of the same order of magnitude as soil CO2 emissions. Termite CH4 and CO2 release in the savanna contributed 8.8% and 0.4% to the total soil CH4 and CO2 emissions, respectively. At the crop sites, where termite mounds had been almost completely removed because of land use change, termite fluxes were insignificant. Mound density-based upscaling of termite CH4 fluxes resulted in a global termite CH4 source of 0.9 Tg a-1, which corresponds to 0.15% of the total global CH4 budget of 582 Tg a-1, hence significantly lower than those obtained previously by biomass-based calculations. This study emphasizes that land use change, which is of high relevance in this region, has particularly affected soil CH4 fluxes in the past and might still do so in the future.

Determining termite diversity in arid Namibian rangelands – a ...

African Journals Online (AJOL)

Three methods of sampling termite diversity in arid rangelands were tested in Namibia during the wet (March) and dry (October) seasons of 1998. Six sites were chosen: one pair on each of three farms representing a gradient of land use intensity. At each site, two adjacent plots of 1 ha each were sampled: one plot by a ...

Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite.

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Yuki Mitaka

Full Text Available The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship between division of labor and expression of chemoreceptor genes remains to be explored. Using high-throughput mRNA sequencing (RNA-seq, we found several chemoreceptors that are differentially expressed among castes and between sexes in a subterranean termite Reticulitermes speratus. In total, 53 chemoreception-related genes were annotated, including 22 odorant receptors, 7 gustatory receptors, 12 ionotropic receptors, 9 odorant-binding proteins, and 3 chemosensory proteins. Most of the chemoreception-related genes had caste-related and sex-related expression patterns; in particular, some chemoreception genes showed king-biased or queen-biased expression patterns. Moreover, more than half of the genes showed significant age-dependent differences in their expression in female and/or male reproductives. These results reveal a strong relationship between the evolution of the division of labor and the regulation of chemoreceptor gene expression, thereby demonstrating the chemical communication and underlining chemoreception mechanism in social insects.

Termite nests as an abundant source of cultivable actinobacteria for biotechnological purposes.

Science.gov (United States)

Sujada, Nikhom; Sungthong, Rungroch; Lumyong, Saisamorn

2014-01-01

A total of 118 actinobacterial isolates were collected from the three types of termite nests (mound, carton, and subterranean nests) to evaluate their potential as a source of bioactive actinobacteria with antimicrobial activity. The highest number (67 isolates) and generic abundance (7 known genera) of actinobacterial isolates were obtained from carton nests. Streptomyces was the dominant genus in each type of termite nest. In the non-Streptomyces group, Nocardia was the dominant genus detected in mound and carton nests, while Pseudonocardia was the dominant genus in subterranean nests. A discovery trend of novel species (20% of bioactive actinobacteria that could inhibit the growth of at least one test organism, while 12 isolates, belonging to the genera Streptomyces, Amycolatopsis, Pseudonocardia, Micromonospora and Nocardia, exhibited distinct antimicrobial activities. Streptomyces sp. CMU-NKS-3 was the most distinct bioactive isolate. It was closely related to S. padanus MITKK-103T, which was confirmed by 99% similarities in their 16S rRNA gene sequences. The highest level of extracellular antimicrobial substances was produced by the isolate CMU-NKS-3, which was grown in potato dextrose broth and exhibited a wide range (6.10×10(-4)-1.25 mg mL(-1)) of minimum inhibitory concentrations against diverse pathogens. We concluded that termite nests are an abundant source of bioactive strains of cultivable actinobacteria for future biotechnological needs.

Relationship of vibro-mechanical properties and microstructure of wood and varnish interface in string instruments

Science.gov (United States)

Sedighi Gilani, Marjan; Pflaum, Johanna; Hartmann, Stefan; Kaufmann, Rolf; Baumgartner, Michael; Schwarze, Francis Willis Mathew Robert

2016-04-01

Wood varnish coatings not only are aesthetically important, but also preserve the musical instrument from wear and fluctuations in the ambient humidity. Depending on the thickness, extent of penetration into the wood and the physical and mechanical properties after hardening, varnishes may change the mechanical and also vibro-acoustical properties of the coated wood. Contrary to studies on the chemistry of the varnish and primer used for old and contemporary musical instruments, the physical and mechanical properties of the varnished wood in relation to the geometry of their interface have been poorly studied. We implemented non-destructive test methods, i.e., vibration tests and X-ray tomography, to characterize the hardening-dependent change in the vibrational properties of master grade tone wood specimens after coating with four different varnishes. Two were manufactured in the laboratory, and two were supplied from master violin makers. For a controlled accelerated hardening of the varnish, a UV exposure method was used. It was demonstrated that varnishes increase wood damping, along and perpendicular to the grain directions. Varnishes reduce the sound radiation along the grain, but increase it in the perpendicular direction. Changes in the vibrational properties were discussed together with results of 3D images of wood and varnish microstructure, obtained from a customized tabletop X-ray microtomographic setup. For comparison, the microstructure of the interface of the varnished wood in the laboratory and of specimens from two old violins was analyzed with the same X-ray tomography setup. Laboratory varnishes with various compositions penetrated differently into the wood structure. One varnish of a master grade old violin had a higher density and was also thicker and penetrated weaker into the wood, which is more likely related to a more sophisticated primer and varnish application. The study demonstrates the importance of the vibro-mechanical properties of

Process Damping Parameters

International Nuclear Information System (INIS)

Turner, Sam

2011-01-01

The phenomenon of process damping as a stabilising effect in milling has been encountered by machinists since milling and turning began. It is of great importance when milling aerospace alloys where maximum surface speed is limited by excessive tool wear and high speed stability lobes cannot be attained. Much of the established research into regenerative chatter and chatter avoidance has focussed on stability lobe theory with different analytical and time domain models developed to expand on the theory first developed by Trusty and Tobias. Process damping is a stabilising effect that occurs when the surface speed is low relative to the dominant natural frequency of the system and has been less successfully modelled and understood. Process damping is believed to be influenced by the interference of the relief face of the cutting tool with the waveform traced on the cut surface, with material properties and the relief geometry of the tool believed to be key factors governing performance. This study combines experimental trials with Finite Element (FE) simulation in an attempt to identify and understand the key factors influencing process damping performance in titanium milling. Rake angle, relief angle and chip thickness are the variables considered experimentally with the FE study looking at average radial and tangential forces and surface compressive stress. For the experimental study a technique is developed to identify the critical process damping wavelength as a means of measuring process damping performance. For the range of parameters studied, chip thickness is found to be the dominant factor with maximum stable parameters increased by a factor of 17 in the best case. Within the range studied, relief angle was found to have a lesser effect than expected whilst rake angle had an influence.

Toxicity, Tunneling and Feeding Behavior of the Termite, Coptotermes vastator, in Sand Treated with Oil of the Physic Nut, Jatropha curcas

Science.gov (United States)

Acda, Menandro N.

2009-01-01

Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite. PMID:20053119

Application of the axial tomography computed for the detection of bags of dampness in dry wood of Gmelina arborea (Roxb.)

International Nuclear Information System (INIS)

Moya R, Roger; Munoz A, Freddy; Escalante, Ivan

2006-01-01

Gmelina arborea (Roxb.) is widely used for commercial reforestation in Costa Rica due to its excellent growth rate and productivity. However, during the lumber drying process, the wooden boards show non-uniform values of final moisture content (MC). The low uniformity in final MC is caused by the presence of wet pockets, originated during the growing process of the tree. The regions with wet pockets present zones with a high MC, which are hard to detect with traditional methods for MC measurements during the wood drying process. It is possible to detect and to set the limits of the presence of wet wood in Gmelina arborea boards using scanning computed tomography (CT-scanning), a technique applied in medical diagnostic. A board with wet pockets is shown in the CT-scanning images in clear color and with low values of the Hounsfield Unit (HU) or CT number. When these values were transformed to wood density, it was determined that wet pockets were in a density of around 190 kg/m 3 , a value higher than normal wood. Also, it was possible to observe growth tree rings in the CT-scanning images, an important feature for dendrochronological research. The obtained results allowed showing that it is possible to apply this technique in the process of lumber production, to detect the zones with high MC in kiln dried Gmelina arborea wood. (author) [es

COMPARATIVE ASPECTS OF PLANT-CELL WALL DIGESTION IN INSECTS

NARCIS (Netherlands)

PRINS, RA; KREULEN, DA

Although many phytophagous and wood-eating invertibrates form their own cellulases, there is an overwhelming variety of symbioses between plant- and wood-utilising insects and microorganisms. In one type of symbiosis (endosymbiosis), insects (rhinoceros beetle, cockroach, lower termites) host

Anisotropic damping of Timoshenko beam elements

Energy Technology Data Exchange (ETDEWEB)

Hansen, M.H.

2001-05-01

This report contains a description of a structural damping model for Timoshenko beam elements used in the aeroelastic code HawC developed at Risoe for modeling wind turbines. The model has been developed to enable modeling of turbine blades which often have different damping characteristics for flapwise, edgewise and torsional vibrations. The structural damping forces acting on the beam element are modeled by viscous damping described by an element damping matrix. The composition of this matrix is based on the element mass and stiffness matrices. It is shown how the coefficients for the mass and stiffness contributions can be calibrated to give the desired modal damping in the complete model of a blade. (au)

Comparative Research on Characteristics of the Isolation Systems with Dry Friction Damping and with Vicious Damping under Base Excitation

Science.gov (United States)

Hou, Junfang; jing, Min; Zhang, Weihua; Lu, Yahui; He, Haiwen

2017-12-01

As for the isolation problem of electronic equipments on vehicle, the vibration response characteristics of dry friction damping isolation system under base displacement excitation was analyzed in theory by harmonic balance method, and the displacement response was compared between the isolation systems with dry friction damping and vicious damping separately. The results show that the isolation system with small dry friction damping can’t meet the demands of displacement reduction close to the natural frequency, and it can realize full-frequency vibration isolation by improving dry friction damping when the lock frequency passes beyond the resonance frequency band. The results imply that the damping mechanism of dry friction isolator can’t be described only by dry friction damping, and the composite damping with dry friction and vicious damping is more appropriate.

Dampness in buildings and health. Building characteristics as predictors for dampness in 8681 Swedish dwellings

DEFF Research Database (Denmark)

Hagerhed, L.; Bornehag, Carl-Gustaf; Sundell, Jan

2002-01-01

Questionnaire data on 8681 dwellings included in the Swedish study "Dampness in Buildings and Health" have been analysed for associations between dampness indicators, perceptions of indoor air quality and building characteristics such as time of construction, type of ventilation and type of found......Questionnaire data on 8681 dwellings included in the Swedish study "Dampness in Buildings and Health" have been analysed for associations between dampness indicators, perceptions of indoor air quality and building characteristics such as time of construction, type of ventilation and type...... of "Dry air" in 17.3 and 33.7% respectively. Older buildings and the use of natural ventilation were associated with increased frequency of dampness indicators as well as to increased frequencies of complaints on bad indoor air quality....

Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis

NARCIS (Netherlands)

Fine Licht, de H.H.; Boomsma, J.J.; Aanen, D.K.

2006-01-01

All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be

Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production

Energy Technology Data Exchange (ETDEWEB)

Kartal, S.N. [Istanbul University (Turkey). Forestry Faculty; Imamura, Y. [Kyoto University (Japan). Wood Research Institute; Tsuchiya, F.; Ohsato, K. [JGC Corporation, Yokohama (Japan)

2004-10-01

Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Formitopsis palustris. However the filtrates from sugi wood processed at 270{sup o}C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot. (author)

Approximation of the modal damping coefficients equivalent to material damping by harmonic excitation with ASKA

International Nuclear Information System (INIS)

Edme, R.

1983-01-01

If a dynamic response analysis (harmonic excitation) is carried out with the modal method, the modal damping coefficients must be approximated to match the structural damping. The program ASKA-Damping, which also supplies an error assessment of the approximation, was developed for this purpose. The modal method and the direct method are applied to a test example and their results compared. It is suggested that the ASKA manufacturers extend the spectral earthquake response analysis to take these modal damping coefficients into account so that the results become less conservative. (orig.) [de

Differences between bacterial communities in the gut of a soil-feeding termite (Cubitermes niokoloensis) and its mounds

OpenAIRE

Fall, Saliou; Hamelin, J.; Ndiaye, Farma; Assigbetse, Komi; Aragno, M.; Chotte, Jean-Luc; Brauman, Alain

2007-01-01

In tropical ecosystems, termite mound soils constitute an important soil compartment covering around 10% of African soils. Previous studies have shown (S. Fall, S. Nazaret, J. L. Chotte, and A. Brauman, Microb. Ecol. 28:191-199, 2004) that the bacterial genetic structure of the mounds of soil-feeding termites (Cubitermes niokoloensis) is different from that of their surrounding soil. The aim of this study was to characterize the specificity of bacterial communities within mounds with respect ...

A Preliminary Study on Termite Mound Soil as Agricultural Soil for Crop Production in South West, Nigeria

OpenAIRE

Omofunmi, O. E.; Kolo, J. G.; Alli, A. A.; Ojo, A. S.

2017-01-01

It is a popular belief of the people in the Southern region of Nigeria that a land infested with termite usually brings prosperity to the land owner regardless of the type of its usage.  Therefore, the present study assessed termite mounds soil properties which are important to crop production. Two soil samples were collected and their physical and chemical properties determined in accordance with American Public Health Association (APHA, 2005). Data were analyzed using descriptive stati...

Damped least square based genetic algorithm with Gaussian distribution of damping factor for singularity-robust inverse kinematics

International Nuclear Information System (INIS)

Phuoc, Le Minh; Lee, Suk Han; Kim, Hun Mo; Martinet, Philippe

2008-01-01

Robot inverse kinematics based on Jacobian inversion encounters critical issues of kinematic singularities. In this paper, several techniques based on damped least squares are proposed to lead robot pass through kinematic singularities without excessive joint velocities. Unlike other work in which the same damping factor is used for all singular vectors, this paper proposes a different damping coefficient for each singular vector based on corresponding singular value of the Jacobian. Moreover, a continuous distribution of damping factor following Gaussian function guarantees the continuous in joint velocities. A genetic algorithm is utilized to search for the best maximum damping factor and singular region, which used to require ad hoc searching in other works. As a result, end effector tracking error, which is inherited from damped least squares by introducing damping factors, is minimized. The effectiveness of our approach is compared with other methods in both non-redundant robot and redundant robot

Damped least square based genetic algorithm with Gaussian distribution of damping factor for singularity-robust inverse kinematics

Energy Technology Data Exchange (ETDEWEB)

Phuoc, Le Minh; Lee, Suk Han; Kim, Hun Mo [Sungkyunkwan University, Suwon (Korea, Republic of); Martinet, Philippe [Blaise Pascal University, Clermont-Ferrand Cedex (France)

2008-07-15

Robot inverse kinematics based on Jacobian inversion encounters critical issues of kinematic singularities. In this paper, several techniques based on damped least squares are proposed to lead robot pass through kinematic singularities without excessive joint velocities. Unlike other work in which the same damping factor is used for all singular vectors, this paper proposes a different damping coefficient for each singular vector based on corresponding singular value of the Jacobian. Moreover, a continuous distribution of damping factor following Gaussian function guarantees the continuous in joint velocities. A genetic algorithm is utilized to search for the best maximum damping factor and singular region, which used to require ad hoc searching in other works. As a result, end effector tracking error, which is inherited from damped least squares by introducing damping factors, is minimized. The effectiveness of our approach is compared with other methods in both non-redundant robot and redundant robot

Hospitalitermes krishnai, a new nasute termite (Nasutitermitinae, Termitidae, Isoptera, from southern Sumatra, Indonesia

Directory of Open Access Journals (Sweden)

Syaukani Syaukani

2011-11-01

Full Text Available A new species of nasute termite, Hospitalitermes krishnai sp. n., is described from soldiers and workers discovered in Lampung Province, Sumatra. This species can be distinguished from other related Hospitalitermes species from Southeast Asia by the anterior part of head capsule that is much smaller than the posterior part, head capsule that is moderately constricted behind the antennal sockets, and relatively deep depression between the head and nasus and, finally, the short and robust nasus measuring less than half as long as head capsule. Moreover, in profile the nasus is slightly up-curved but slightly decurved at the apical tip. We name this new species after Professor Kumar Krishna in recognition of his life-long contributions to termite taxonomy, systematics and biology.

Recalculation of compression tests on damping materials in the frame of the research project QUEST; Nachrechnungen von Stauchversuchen an Daempfermaterialien im Forschungsvorhaben Quest

Energy Technology Data Exchange (ETDEWEB)

Schopphoff, E.; Vallentin, R. [Wissenschaftlich-Technische Ingenieurberatung GmbH (WTI), Juelich (Germany); Glutsch, S.; Hueggenberg, R. [GNS Gesellschaft fuer Nuklear-Service mbH, Essen (Germany)

2011-07-01

The mechanical design of packaging containers for radioactive material transport and storage using numerical techniques is a resilient and sufficient exact prediction of the mechanical loads due to drop accident scenarios. The correct simulation of energy dissipation of the involved shock absorbing components and materials is of main importance. The behavior of components and materials is dependent on deformation speed and environmental conditions, esp. temperature. Within the research project QUEST numerical methods based on compression test results from different damping materials are developed for the optimization of mechanical load simulation. Test results are described for polyurethane foam, wood and damping concrete. The finite element based simulation is aimed to develop and verify material models based on the experimental material reference curves.

Wood handbook : wood as an engineering material

Science.gov (United States)

Robert J. Ross; Forest Products Laboratory. USDA Forest Service.

2010-01-01

Summarizes information on wood as an engineering material. Presents properties of wood and wood-based products of particular concern to the architect and engineer. Includes discussion of designing with wood and wood-based products along with some pertinent uses.

Natural Resistance of Eight Sapling Species to Damage by Microcerotermesgabrielis Weidner

Directory of Open Access Journals (Sweden)

A. Sheikhigarjan

2017-12-01

Full Text Available Introduction:The subterranean termites make large damage to wood and cellulosic products. They can have the destroying effects on forest plantations, agriculture crop, and urban landscaping. According to the previous studies, Microcerotermesgabrielis Weidner is the most important termite of the Alborz province belong to the family Termitidae. This species is also reported in the central, the northeastern and the southern regions of Iran. MicrocerotermesvaraminicaGhayourfar, Amitermesvilis (Hagen, A. kharaziiGhayourfar, Anacantthotermesvagan (Hagan have been also reported from Tehran province.Chemical control of termiteis the most conventional method ofcontrol. A few insecticides have acceptable termiticide effects. However more of them have negative effects on the other non-targets organisms in the environment, and may run off into groundwater. Thus we wouldconsiderthe other methods of termite control. Usage of native and natural resistant plant species can be reasonable strategy against termitesinafforestation. Plant species are food sources for termites, however, they differ in their palatabilityand can affect termite preference. There are some studies have reported differences in feeding rates and preferences of termite species amongdifferent species of woody plants. Tree Shalamzar Plantation, encompassing 54 ha in the southern Alborz mountain range have sustained termite damage since 2013. The objective of this study was to evaluate the natural resistance of eight different sapling species to termite´s damage in this region. Materials and Methods: Termites were collected from four infested locations within Shalamzar Plantation, Karaj, Iran. Infested saplings with active termite tunnels were visited and soldier termites collected and transferred to the systematics lab for species identification using a systematic key of Iranian termites. Termite infestation rates were estimatedfor each of 8 sapling species. Ten saplings of each species were

LBA-ECO ND-04 Termite Mound and Soil Characterization, Amazonas, Brazil: 1999-2001

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set reports the results of a comprehensive study of mound building termites at the Embrapa research station in the Distrito Agropecuario da...

LBA-ECO ND-04 Termite Mound and Soil Characterization, Amazonas, Brazil: 1999-2001

Data.gov (United States)

National Aeronautics and Space Administration — This data set reports the results of a comprehensive study of mound building termites at the Embrapa research station in the Distrito Agropecuario da SUFRAMA,...

Hybridization of two major termite invaders as a consequence of human activity.

Science.gov (United States)

Chouvenc, Thomas; Helmick, Ericka E; Su, Nan-Yao

2015-01-01

While hybridization of an invasive species with a native species is a common occurrence, hybridization between two invasive species is rare. Formosan subterranean termites (Coptotermes formosanus) and Asian subterranean termites (C. gestroi) are both ecologically successful and are the two most economically important termite pests in the world. Both species have spread throughout many areas of the world due to human activity; however, their distributions overlap in only three narrow areas because of distinct ecological requirements. In south Florida, where C. formosanus and C. gestroi are both invasive, the dispersal flight seasons of both species overlapped for the first time on record in 2013 and 2014. Pairings of heterospecific individuals were readily observed in the field and C. gestroi males preferentially engaged in mating behavior with C. formosanus females rather than females from their own species. In the laboratory, heterospecific and conspecific pairings had an equal colony establishment rate, but heterospecific incipient colonies had twice the growth rate of conspecific incipient colonies, suggesting a potential case of hybrid vigor. As all pre-zygotic barriers were lifted between the two species in the field, the apparent absence of post-zygotic barriers in the laboratory raises the possibility for introgressive hybridization in south Florida. While laboratory observations remain to be confirmed in the field, and the alate hybrid fertility is currently unknown, our results raise a tangible concern about the hybridization of two major destructive pest species. Such hybridization would likely be associated with a new economic impact.

Fumigant toxicity and acetylcholinesterase inhibitory activity of 4 Asteraceae plant essential oils and their constituents against Japanese termite (Reticulitermes speratus Kolbe).

Science.gov (United States)

Seo, Seon-Mi; Kim, Junheon; Kang, Jaesoon; Koh, Sang-Hyun; Ahn, Young-Joon; Kang, Kyu-Suk; Park, Il-Kwon

2014-07-01

This study investigated the fumigant toxicity of 4 Asteraceae plant essential oils and their constituents against the Japanese termite Reticulitermes speratus Kolbe. Fumigant toxicity varied with plant essential oils or constituents, exposure time, and concentration. Among the tested essential oils, those from Chamaemelum nobile exhibited the strongest fumigant toxicity, followed by those from Santolina chamaecyparissus, Ormenis multicaulis, and Eriocephalus punctulatus at 2 days after treatment. In all, 15, 24, 19, and 9 compounds were identified in the essential oils from C. nobile, E. punctulatus, O. multicaulis, and S. chamaecyparissus, respectively, by using gas chromatography, gas chromatography-mass spectrometry, or open-column chromatography. The identified compounds were tested individually for their fumigant toxicity against Japanese termites. Among the test compounds, trans-pinocarveol, caryophyllene oxide, sabinene hydrate, and santolina alcohol showed strong fumigant toxicity against Japanese termites. Acetylcholinesterase (AChE) inhibition activity of the identified compounds from C. nobile, E. punctulatus, O. multicaulis, and S. chamaecyparissus essential oils were tested to determine the mode of their action. The IC50 values of (+)-α-pinene, (-)-limonene, (-)-α-pinene, β-pinene, and β-phellandrene against Japanese termite AChE were 0.03, 0.13, 0.41, 0.42, and 0.67mg/mL, respectively. Further studies are warranted to determine the potential of these essential oils and their constituents as fumigants for termite control. Copyright © 2014 Elsevier Inc. All rights reserved.

Damping Measurements of Plasma Modes

Science.gov (United States)

Anderegg, F.; Affolter, M.; Driscoll, C. F.

2010-11-01

For azimuthally symmetric plasma modes in a magnesium ion plasma, confined in a 3 Tesla Penning-Malmberg trap with a density of n ˜10^7cm-3, we measure a damping rate of 2s-1plasma column, alters the frequency of the mode from 16 KHz to 192 KHz. The oscillatory fluid displacement is small compared to the wavelength of the mode; in contrast, the fluid velocity, δvf, can be large compared to v. The real part of the frequency satisfies a linear dispersion relation. In long thin plasmas (α> 10) these modes are Trivelpiece-Gould (TG) modes, and for smaller values of α they are Dubin spheroidal modes. However the damping appears to be non-linear; initially large waves have weaker exponential damping, which is not yet understood. Recent theoryootnotetextM.W. Anderson and T.M. O'Neil, Phys. Plasmas 14, 112110 (2007). calculates the damping of TG modes expected from viscosity due to ion-ion collisions; but the measured damping, while having a similar temperature and density dependence, is about 40 times larger than calculated. This discrepancy might be due to an external damping mechanism.

WOOD PROPERTIES AND EFFECT OF WOOD PROPERTIES ON THE WOOD FINISHING

Directory of Open Access Journals (Sweden)

Abdulkadir Malkoçoğlu

2006-04-01

Full Text Available Wood is basic raw material for furniture and joinery industries with wood structures. Wood is a biological material that has widely different properties depending on species, geographic area where the tree grew, the growth condition, size of the tree at harvest, sawing, and other manufacturing processes. Wood properties have been characterized within two groups as natural and manufacturing factors that effects finishing performance. Grow rate, density, knots, moisture content, extractives and juvenile wood are natural characteristics. Grain orientation, texture, drying and performance expectations are manufacturing characteristics. In this review, the effects of natural and manufacturing characteristics are discussed on the surface finishing performance of wood.

effects of rice husk ash and termite hill types on the physical

African Journals Online (AJOL)

PROF EKWUEME

especially in the manufacturing of building materials. A particularly potential ... Cassgrande apparatus with a grooving tool was used for the limit test. ... Lean clay. 2.2.1 Compaction Test. The compaction tests on the termite clay samples were ...

Critical fluid extraction of Juniperus virginiana L. and bioactivity of extracts against subterranean termites and wood-rot fungi.

Science.gov (United States)

F. J. Eller; Carol A. Clausen; Frederick Green; S.L. Taylor

2010-01-01

Eastern red cedar (Juniperus virginiana L.) is an abundant renewable resource and represents a vast potential source of valuable natural products that may serve as natural biocides. Both the wood and needles from J. virginiana were extracted using liquid carbon dioxide (L-CO2) as well as ethanol (EtOH) and the yields determined.Woodblocks were...

Damping in heat exchanger tube bundles. A review

International Nuclear Information System (INIS)

Iqbal, Qamar; Khushnood, Shahab; Ghalban, Ali Roheim El; Sheikh, Nadeem Ahmed; Malik, Muhammad Afzaal; Arastu, Asif

2007-01-01

Damping is a major concern in the design and operation of tube bundles with loosely supported tubes in baffles for process shell and tube heat exchangers and steam generators which are used in nuclear, process and power generation industries. System damping has a strong influence on the amplitude of vibration. Damping depends upon the mechanical properties of the tube material, geometry of intermediate supports and the physical properties of shell-side fluid. Type of tube motion, number of supports, tube frequency, vibration amplitude, tube mass or diameter, side loads, support thickness, higher modes, shell-side temperature etc., affect damping in tube bundles. The importance of damping is further highlighted due to current trend of larger exchangers with increased shell-side velocities in modern units. Various damping mechanisms have been identified (Friction damping, Viscous damping, Squeeze film damping, Support damping. Two-Phase damping, and very recent-Thermal damping), which affect the performance of process exchangers and steam generators with respect to flow induced vibration design, including standard design guidelines. Damping in two-phase flow is very complex and highly void fraction, and flow-regime dependent. The current paper focuses on the various known damping mechanisms subjected to both single and two-phase cross-flow in process heat exchangers and steam generators and formulates the design guidelines for safer design. (author)

Elimination of field colonies of a mound-building termite Globitermes sulphureus (Isoptera: Termitidae) by bistrifluron bait.

Science.gov (United States)

Neoh, Kok-Boon; Jalaludin, Nur Atiqah; Lee, Chow-Yang

2011-04-01

The efficacy of Xterm, which contains 1% bistrifluron, in the form of cellulose bait pellets was evaluated for its efficacy in eradicating field colonies of the mound-building termite Globitermes sulphureus (Haviland) (Isoptera: Termitidae). The termite mounds were dissected at the end of the experiment to determine whether the colonies were eliminated. By approximately 2 mo postbaiting, the body of termite workers appeared marble white, and mites were present on the body. The soldier-worker ratio increased drastically in the colonies, and the wall surface of the mounds started to erode. Colony elimination required at least a 4-mo baiting period. Mound dissection revealed wet carton materials (food store) that were greatly consumed and overgrown by fast-growing fungi. Decaying cadavers were scattered all over the nests. On average, 84.1 +/- 16.4 g of bait matrix (68.9 +/- 13.4%, an equivalent of 841 +/- 164 mg of bistrifluron) was consumed in each colony. Moreover, we found that a mere 143 mg of bistrifluron was sufficient to eliminate a colony of C. sulphureus.

DAMPs, ageing, and cancer: The 'DAMP Hypothesis'.

Science.gov (United States)

Huang, Jin; Xie, Yangchun; Sun, Xiaofang; Zeh, Herbert J; Kang, Rui; Lotze, Michael T; Tang, Daolin

2015-11-01

Ageing is a complex and multifactorial process characterized by the accumulation of many forms of damage at the molecular, cellular, and tissue level with advancing age. Ageing increases the risk of the onset of chronic inflammation-associated diseases such as cancer, diabetes, stroke, and neurodegenerative disease. In particular, ageing and cancer share some common origins and hallmarks such as genomic instability, epigenetic alteration, aberrant telomeres, inflammation and immune injury, reprogrammed metabolism, and degradation system impairment (including within the ubiquitin-proteasome system and the autophagic machinery). Recent advances indicate that damage-associated molecular pattern molecules (DAMPs) such as high mobility group box 1, histones, S100, and heat shock proteins play location-dependent roles inside and outside the cell. These provide interaction platforms at molecular levels linked to common hallmarks of ageing and cancer. They can act as inducers, sensors, and mediators of stress through individual plasma membrane receptors, intracellular recognition receptors (e.g., advanced glycosylation end product-specific receptors, AIM2-like receptors, RIG-I-like receptors, and NOD1-like receptors, and toll-like receptors), or following endocytic uptake. Thus, the DAMP Hypothesis is novel and complements other theories that explain the features of ageing. DAMPs represent ideal biomarkers of ageing and provide an attractive target for interventions in ageing and age-associated diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

EFEITO DO TEOR DE EXTRATIVOS NA RESISTÊNCIA NATURAL DE CINCO MADEIRAS AO ATAQUE DE CUPINS XILÓFAGOS

Directory of Open Access Journals (Sweden)

Juarez Benigno Paes

2016-01-01

Full Text Available When man stopped being nomadic, he had to adapt to new conditions, and started employing wood for energy, hunting and defense instruments and miscellaneous constructive elements. Since then, in the light of usages and rapid growth, the importance of wood has been increasing, primarily by their exploitation assaults less the environment when compared to other non-renewable materials. Although there are several researches about Eucalyptus and Pinus, but studies with other species are incipient mainly about the extractive effects on the wood natural resistance. Thus, this research aimed to assess the influence of extractive contents with the natural resistance of Acacia mangium, Casuarina sp. Eucalyptus cloeziana, Corymbia torelliana and Tectona grandis woods to Nasutitermes corniger xylophagous termite, species of frequent occurrence in several regions in Brazil. From each species, test samples were taken, with dimensions of 2.00 x 10.16 x 0.64 (radial x longitudinal x tangential in four positions in the medulla-sapwood direction (internal core, intermediate core, outer core and sapwood. The woods were exposed to the action of termites for 45 days in a food preference assay. The samples not selected for the test with termites were turned into sawdust and the extractive contents were obtained by using the fraction which passed through the sieve 40 and was retained in 60 mesh. The natural resistance has not been linked to extractive levels present in the wood. The resistance of wood varied in medulla-sapwood direction, with default variable for each species. The more resistant timbers were Tectona grandis and Corymbia torelliana and the most deteriorated was Acacia mangium.

Towards the Automatic Detection of Pre-Existing Termite Mounds through UAS and Hyperspectral Imagery.

Science.gov (United States)

Sandino, Juan; Wooler, Adam; Gonzalez, Felipe

2017-09-24

The increased technological developments in Unmanned Aerial Vehicles (UAVs) combined with artificial intelligence and Machine Learning (ML) approaches have opened the possibility of remote sensing of extensive areas of arid lands. In this paper, a novel approach towards the detection of termite mounds with the use of a UAV, hyperspectral imagery, ML and digital image processing is intended. A new pipeline process is proposed to detect termite mounds automatically and to reduce, consequently, detection times. For the classification stage, several ML classification algorithms' outcomes were studied, selecting support vector machines as the best approach for their role in image classification of pre-existing termite mounds. Various test conditions were applied to the proposed algorithm, obtaining an overall accuracy of 68%. Images with satisfactory mound detection proved that the method is "resolution-dependent". These mounds were detected regardless of their rotation and position in the aerial image. However, image distortion reduced the number of detected mounds due to the inclusion of a shape analysis method in the object detection phase, and image resolution is still determinant to obtain accurate results. Hyperspectral imagery demonstrated better capabilities to classify a huge set of materials than implementing traditional segmentation methods on RGB images only.

Pipe damping

International Nuclear Information System (INIS)

Ware, A.G.; Arendts, J.G.

1984-01-01

A program has been developed to assess the available piping damping data, to generate additional data and conduct seperate effects tests, and to establish a plan for reporting and storing future test results into a data bank. This effort is providing some of the basis for developing higher allowable damping values for piping seismic analyses, which will potentially permit removal of a considerable number of piping supports, particularly snubbers. This in turn will lead to more flexible piping systems which will be less susceptible to thermal cracking, will be easier to maintain and inspect, as well as less costly

Colony Size Affects the Efficacy of Bait Containing Chlorfluazuron Against the Fungus-Growing Termite Macrotermes gilvus (Blattodea: Termitidae).

Science.gov (United States)

Lee, Ching-Chen; Neoh, Kok-Boon; Lee, Chow-Yang

2014-12-01

The efficacy of chitin synthesis inhibitors (CSIs) against fungus-growing termites is known to vary. In this study, 0.1% chlorfluazuron (CFZ) cellulose bait was tested against medium and large field colonies of Macrotermes gilvus (Hagen). The termite mounds were dissected to determine the health of the colony. Individual termites (i.e., workers and larvae) and fungus combs were subjected to gas chromatography-mass spectrometry (GC-MS) analysis to detect the presence of CFZ. In this study, 540.0 ± 25.8 g (or equivalent to 540.0 ± 25.8 mg active ingredient) and 680.0 ± 49.0 g (680.0 ± 49.0 mg active ingredient) of bait matrix were removed by the medium- and large-sized colonies, respectively, after baiting. All treated medium-sized colonies were moribund. The dead termites were scattered in the mound, larvae were absent, population size had decreased by 90%, and the queens appeared unhealthy. In contrast, no or limited effects were found in large-sized colonies. Only trace amounts of CFZ were detected in workers, larvae, and fungus combs, and the population of large-sized colonies had declined by only up to 40%. This might be owing to the presence of large amount of basidiomycete fungus and a drastic decrease of CFZ content per unit fungus comb (a main food source of larvae) in the large-sized colonies, and hence reduced the toxic effect and longer time is required to accumulate the lethal dose in larvae. Nevertheless, we do not deny the possibility of CSI bait eliminating or suppressing the higher termite if the test colonies could pick up adequate lethal dose by installing more bait stations and prolonging the baiting period. © 2014 Entomological Society of America.

Effect of termite activity on soil under different land management strategies

Directory of Open Access Journals (Sweden)

Liane Barreto Alves Pinheiro

2017-03-01

Full Text Available Mound-building termites are important agents of soil bioperturbation, but these species have not been extensively studied thus far. The present study aimed to evaluate the soil particle-size and the chemical attributes of termite mounds and the surrounding soil under different land use strategies. A one-hectare plot was defined for an unmanaged degraded pasture, planted pasture, and for a eucalyptus Corymbia citriodora plantation. In each plot, the top, center, and base sections of five Cornitermes cumulans mounds, and the surrounding soil at the depths of 0-5; 5-10; 10-20 cm, were sampled in the Pinheiral, Rio de Janeiro state. In the three areas, the center of the mounds contained higher clay content, organic carbon, phosphorous, calcium and magnesium, total bases, and cation exchangeable capacity, when compared to the top, base, and the surrounding soils. However, the center had lower values of exchangeable acidity and potassium, of the three areas. In the eucalyptus plantation, the values of pH, total bases, calcium, and magnesium were lower, whereas aluminum, exchangeable acidity, sodium, and cation exchange capacity were higher both in the mounds and in the surrounding soil, in relation to the pastures. There were no differences among the three areas in terms of organic carbon, potassium, phosphorous, and total bases, in the mounds and adjacent soil. Thus, the termite activity altered the clay content and most of the soil chemical properties in all of the studied areas, but only for the center of the mounds. However, the effect of these organisms was different in the eucalyptus plantation in relation to the pasture areas.

Litter-forager termite mounds enhance the ectomycorrhizal symbiosis between Acacia holosericea A. Cunn. Ex G. Don and Scleroderma dictyosporum isolates.

Science.gov (United States)

Duponnois, Robin; Assikbetse, Komi; Ramanankierana, Heriniaina; Kisa, Marija; Thioulouse, Jean; Lepage, Michel

2006-05-01

The hypothesis of the present study was that the termite mounds of Macrotermes subhyalinus (MS) (a litter-forager termite) were inhabited by a specific microflora that could enhance with the ectomycorrhizal fungal development. We tested the effect of this feeding group mound material on (i) the ectomycorrhization symbiosis between Acacia holosericea (an Australian Acacia introduced in the sahelian areas) and two ectomycorrhizal fungal isolates of Scleroderma dictyosporum (IR408 and IR412) in greenhouse conditions, (ii) the functional diversity of soil microflora and (iii) the diversity of fluorescent pseudomonads. The results showed that the termite mound amendment significantly increased the ectomycorrhizal expansion. MS mound amendment and ectomycorrhizal inoculation induced strong modifications of the soil functional microbial diversity by promoting the multiplication of carboxylic acid catabolizing microorganisms. The phylogenetic analysis showed that fluorescent pseudomonads mostly belong to the Pseudomonads monteillii species. One of these, P. monteillii isolate KR9, increased the ectomycorrhizal development between S. dictyosporum IR412 and A. holosericea. The occurrence of MS termite mounds could be involved in the expansion of ectomycorrhizal symbiosis and could be implicated in nutrient flow and local diversity.

Parallel metatranscriptome analyses of host and symbiont gene expression in the gut of the termite Reticulitermes flavipes

Directory of Open Access Journals (Sweden)

Zhou Xuguo

2009-10-01

Full Text Available Abstract Background Termite lignocellulose digestion is achieved through a collaboration of host plus prokaryotic and eukaryotic symbionts. In the present work, we took a combined host and symbiont metatranscriptomic approach for investigating the digestive contributions of host and symbiont in the lower termite Reticulitermes flavipes. Our approach consisted of parallel high-throughput sequencing from (i a host gut cDNA library and (ii a hindgut symbiont cDNA library. Subsequently, we undertook functional analyses of newly identified phenoloxidases with potential importance as pretreatment enzymes in industrial lignocellulose processing. Results Over 10,000 expressed sequence tags (ESTs were sequenced from the 2 libraries that aligned into 6,555 putative transcripts, including 171 putative lignocellulase genes. Sequence analyses provided insights in two areas. First, a non-overlapping complement of host and symbiont (prokaryotic plus protist glycohydrolase gene families known to participate in cellulose, hemicellulose, alpha carbohydrate, and chitin degradation were identified. Of these, cellulases are contributed by host plus symbiont genomes, whereas hemicellulases are contributed exclusively by symbiont genomes. Second, a diverse complement of previously unknown genes that encode proteins with homology to lignase, antioxidant, and detoxification enzymes were identified exclusively from the host library (laccase, catalase, peroxidase, superoxide dismutase, carboxylesterase, cytochrome P450. Subsequently, functional analyses of phenoloxidase activity provided results that were strongly consistent with patterns of laccase gene expression. In particular, phenoloxidase activity and laccase gene expression are mostly restricted to symbiont-free foregut plus salivary gland tissues, and phenoloxidase activity is inducible by lignin feeding. Conclusion To our knowledge, this is the first time that a dual host-symbiont transcriptome sequencing effort

Wood : adhesives

Science.gov (United States)

A.H. Conner

2001-01-01

This chapter on wood adhesives includes: 1) Classification of wood adhesives 2) Thermosetting wood adhesives 3) Thermoplastic adhesives, 4) Wood adhesives based on natural sources 5) Nonconventional bonding of wood 6) Wood bonding.

Screening assays of termite gut microbes that potentially as probiotic for human to digest cellulose as new food source

Science.gov (United States)

Abdullah, R.; Ananda, K. R. T.; Wijanarka

2018-05-01

According to UN, earth population will increase approximately 7.3 billion people up to 11.2 billion from 2015 until 2100. On the other side, food needs are not balance with the availability of food on earth. People of the world need solution for a new food source. By cellulose digesting ability, people analyzed can consume cellulose as the new food source to get glucose. The aims of research is obtaining termite gut cellulase bacteria selected which is potential as probiotic to split cellulose. Method used was as follows; isolation of termite gut microbes, microbial cellulase purification by screening method and probiotic test includes microbial pathogenicity test and human stomach acid and salt osmotic concentration resistance test. The result shows, 3 pure isolates of termite gut microbes can break down cellulose in the medium 1% CMC and 0.1% congo red (indicator of cellulose degradation activity) and life at pH 2- 2.5 and osmotic salt condition. Two isolates show the activity of gamma hemolysis (non-pathogenic in terms of pathogenicity on human blood). In conclusion, there are isolated termite gut microbes can be used as probiotic candidate for human to digest cellulose of the new food source for global food scarcity era.

Modelling of Dampers and Damping in Structures

DEFF Research Database (Denmark)

Høgsberg, Jan Riess

2006-01-01

and the maximum attainable damping are found by maximizing the expression for the damping ratio. The theory is formulated for linear damper models, but may also be applied for non-linear dampers in terms of equivalent linear parameters for stiffness and damping, respectively. The format of the expressions......, and thereby the damping, of flexible structures are generally described in terms of the dominant vibration modes. A system reduction technique, where the damped vibration mode is constructed as a linear combination of the undamped mode shape and the mode shape obtained by locking the damper, is applied....... This two-component representation leads to a simple solution for the modal damping representing the natural frequency and the associated damping ratio. It appears from numerical examples that this system reduction technique provides very accurate results. % Analytical expressions for the optimal tuning...

Sex Pheromone and Trail Pheromone of the Sand Termite Psammotermes hybostoma

Czech Academy of Sciences Publication Activity Database

Sillam-Dusses, David; Hanus, Robert; Abd El-Latif, A. O.; Jiroš, Pavel; Krasulová, Jana; Kalinová, Blanka; Valterová, Irena; Šobotník, Jan

2011-01-01

Roč. 37, č. 2 (2011), s. 179-188 ISSN 0098-0331 R&D Projects: GA ČR GAP506/10/1570 Institutional research plan: CEZ:AV0Z40550506 Keywords : sex pheromone * trail pheromone * Psammotermes hybostoma * termites * Rhinotermitidae Subject RIV: CC - Organic Chemistry Impact factor: 2.657, year: 2011

Functional structure of ant and termite assemblages in old growth forest, logged forest and oil palm plantation in Malaysian Borneo

OpenAIRE

Luke, Sarah H.; Fayle, Tom M.; Eggleton, Paul; Turner, Edgar C.; Davies, Richard G.

2014-01-01

Forested tropical landscapes around the world are being extensively logged and converted to agriculture, with serious consequences for biodiversity and potentially ecosystem functioning. Here we investigate associations between habitat disturbance and functional diversity of ants and termites – two numerically dominant and functionally important taxa in tropical rain forests that perform key roles in predation, decomposition, nutrient cycling and seed dispersal. We compared ant and termite oc...

Surge-damping vacuum valve

International Nuclear Information System (INIS)

Bullock, J.C.; Kelley, B.E.

1977-01-01

A valve for damping out flow surges in a vacuum system is described. The surge-damping mechanism consists of a slotted, spring-loaded disk adjacent to the valve's vacuum port (the flow passage to the vacuum roughing pump). Under flow surge conditions, the differential pressure forces the disk into a sealing engagement with the vacuum port, thereby restricting the gas flow path to narrow slots in the disk's periphery. The increased flow damps out the flow surge. When pressure is equalized on both sides of the valve, the spring load moves the disk away from the port to restore full flow conductance through the valve

Damping in aerospace composite materials

Science.gov (United States)

Agneni, A.; Balis Crema, L.; Castellani, A.

Experimental results are presented on specimens of carbon and Kevlar fibers in epoxy resin, materials used in many aerospace structures (control surfaces and wings in aircraft, large antennas in spacecraft, etc.). Some experimental methods of estimating damping ratios are first reviewed, either in the time domain or in the frequency domain. Some damping factor estimates from experimental tests are then shown; in order to evaluate the effects of the aerospace environment, damping factors have been obtained in a typical range of temperature, namely between +120 C and -120 C, and in the pressure range from room pressure to 10 exp -6 torr. Finally, a theoretical approach for predicting the bounds of the damping coefficients is shown, and prediction data are compared with experimental results.

Hybridization of two major termite invaders as a consequence of human activity.

Directory of Open Access Journals (Sweden)

Thomas Chouvenc

Full Text Available While hybridization of an invasive species with a native species is a common occurrence, hybridization between two invasive species is rare. Formosan subterranean termites (Coptotermes formosanus and Asian subterranean termites (C. gestroi are both ecologically successful and are the two most economically important termite pests in the world. Both species have spread throughout many areas of the world due to human activity; however, their distributions overlap in only three narrow areas because of distinct ecological requirements. In south Florida, where C. formosanus and C. gestroi are both invasive, the dispersal flight seasons of both species overlapped for the first time on record in 2013 and 2014. Pairings of heterospecific individuals were readily observed in the field and C. gestroi males preferentially engaged in mating behavior with C. formosanus females rather than females from their own species. In the laboratory, heterospecific and conspecific pairings had an equal colony establishment rate, but heterospecific incipient colonies had twice the growth rate of conspecific incipient colonies, suggesting a potential case of hybrid vigor. As all pre-zygotic barriers were lifted between the two species in the field, the apparent absence of post-zygotic barriers in the laboratory raises the possibility for introgressive hybridization in south Florida. While laboratory observations remain to be confirmed in the field, and the alate hybrid fertility is currently unknown, our results raise a tangible concern about the hybridization of two major destructive pest species. Such hybridization would likely be associated with a new economic impact.

Morphophysiological study of digestive system litter-feeding termite Cornitermes cumulans (Kollar, 1832).

Science.gov (United States)

de Sousa, Géssica; Dos Santos, Vânia Cristina; de Figueiredo Gontijo, Nelder; Constantino, Reginaldo; de Oliveira Paiva E Silva, Gabriela; Bahia, Ana Cristina; Gomes, Fabio Mendonça; de Alcantara Machado, Ednildo

2017-06-01

Termites are the major decomposers of lignocellulosic biomass on Earth and are commonly considered as biological reactor models for lignocellulose degradation. Despite their biotechnological potential, few studies have focused on the morphophysiological aspects of the termite digestive system. We therefore analyze the morphology, ultrastructure and gut luminal pH of the digestive system in workers of the litter-feeding termite Cornitermes cumulans (Blattodea: Termitidae). Their digestive system is composed of salivary glands and an alimentary canal with a pH ranging from neutral to alkaline. The salivary glands have an acinar structure and present cells with secretory characteristics. The alimentary canal is differentiated into the foregut, midgut, mixed segment and hindgut, which comprises the ileum (p1), enteric valve (p2), paunch (p3), colon (p4) and rectum (p5) segments. The foregut has a well-developed chewing system. The midgut possesses a tubular peritrophic membrane and two cell types: digestive cells with secretory and absorptive features and several regenerative cells in mitosis, both cell types being organized into regenerative crypts. The mixed segment exhibits cells rich in glycogen granules. Hindgut p1, p4 and p5 segments have flattened cells with a few apical invaginations related to mitochondria and a thick cuticular lining. Conversely, the hindgut p3 segment contains large cuboid cells with extensive apical invaginations associated with numerous mitochondria. These new insights into the morphophysiology of the digestive system of C. cumulans reveal that it mobilizes lignocellulose components as a nutritional source by means of a highly compartmentalized organization with specialized segments and complex microenvironments.

Diversity of Termitomyces associated with fungus-farming termites assessed by cultural and culture-independent methods.

Science.gov (United States)

Makonde, Huxley M; Boga, Hamadi I; Osiemo, Zipporah; Mwirichia, Romano; Stielow, J Benjamin; Göker, Markus; Klenk, Hans-Peter

2013-01-01

Fungus-cultivating termites make use of an obligate mutualism with fungi from the genus Termitomyces, which are acquired through either vertical transmission via reproductive alates or horizontally transmitted during the formation of new mounds. Termitomyces taxonomy, and thus estimating diversity and host specificity of these fungi, is challenging because fruiting bodies are rarely found. Molecular techniques can be applied but need not necessarily yield the same outcome than morphological identification. Culture-dependent and culture-independent methods were used to comprehensively assess host specificity and gut fungal diversity. Termites were identified using mitochondrial cytochrome oxidase II (COII) genes. Twenty-three Termitomyces cultures were isolated from fungal combs. Internal transcribed spacer (ITS) clone libraries were constructed from termite guts. Presence of Termitomyces was confirmed using specific and universal primers. Termitomyces species boundaries were estimated by cross-comparison of macromorphological and sequence features, and ITS clustering parameters accordingly optimized. The overall trends in coverage of Termitomyces diversity and host associations were estimated using Genbank data. Results indicate a monoculture of Termitomyces in the guts as well as the isolation sources (fungal combs). However, cases of more than one Termitomyces strains per mound were observed since mounds can contain different termite colonies. The newly found cultures, as well as the clustering analysis of GenBank data indicate that there are on average between one and two host genera per Termitomyces species. Saturation does not appear to have been reached, neither for the total number of known Termitomyces species nor for the number of Termitomyces species per host taxon, nor for the number of known hosts per Termitomyces species. Considering the rarity of Termitomyces fruiting bodies, it is suggested to base the future taxonomy of the group mainly on well

Diversity of Termitomyces associated with fungus-farming termites assessed by cultural and culture-independent methods.

Directory of Open Access Journals (Sweden)

Huxley M Makonde

Full Text Available BACKGROUND: Fungus-cultivating termites make use of an obligate mutualism with fungi from the genus Termitomyces, which are acquired through either vertical transmission via reproductive alates or horizontally transmitted during the formation of new mounds. Termitomyces taxonomy, and thus estimating diversity and host specificity of these fungi, is challenging because fruiting bodies are rarely found. Molecular techniques can be applied but need not necessarily yield the same outcome than morphological identification. METHODOLOGY: Culture-dependent and culture-independent methods were used to comprehensively assess host specificity and gut fungal diversity. Termites were identified using mitochondrial cytochrome oxidase II (COII genes. Twenty-three Termitomyces cultures were isolated from fungal combs. Internal transcribed spacer (ITS clone libraries were constructed from termite guts. Presence of Termitomyces was confirmed using specific and universal primers. Termitomyces species boundaries were estimated by cross-comparison of macromorphological and sequence features, and ITS clustering parameters accordingly optimized. The overall trends in coverage of Termitomyces diversity and host associations were estimated using Genbank data. RESULTS AND CONCLUSION: Results indicate a monoculture of Termitomyces in the guts as well as the isolation sources (fungal combs. However, cases of more than one Termitomyces strains per mound were observed since mounds can contain different termite colonies. The newly found cultures, as well as the clustering analysis of GenBank data indicate that there are on average between one and two host genera per Termitomyces species. Saturation does not appear to have been reached, neither for the total number of known Termitomyces species nor for the number of Termitomyces species per host taxon, nor for the number of known hosts per Termitomyces species. Considering the rarity of Termitomyces fruiting bodies, it is

Damping rates of the SRRC storage ring

International Nuclear Information System (INIS)

Hsu, K.T.; Kuo, C.C.; Lau, W.K.; Weng, W.T.

1995-01-01

The SRRC storage ring is a low emittance synchrotron radiation machine with nominal operation energy 1.3 GeV. The design damping time due to synchrotron radiation is 10.7, 14.4, 8.7 ms for the horizontal, vertical and longitudinal plane, respectively. The authors measured the real machine damping time as a function of bunch current, chromaticity, etc. To damp the transverse beam instability, especially in the vertical plane, they need to increase chromaticity to large positive value. The damping rates are much larger than the design values. Landau damping contribution in the longitudinal plane is quite large, especially in the multibunch mode. The estimated synchrotron tune spread from the Landau damping is in agreement with the measured coherent longitudinal coupled bunch oscillation amplitude

Preliminary Study on the Damping Effect of a Lateral Damping Buffer under a Debris Flow Load

Directory of Open Access Journals (Sweden)

Zheng Lu

2017-02-01

Full Text Available Simulating the impact of debris flows on structures and exploring the feasibility of applying energy dissipation devices or shock isolators to reduce the damage caused by debris flows can make great contribution to the design of disaster prevention structures. In this paper, we propose a new type of device, a lateral damping buffer, to reduce the vulnerability of building structures to debris flows. This lateral damping buffer has two mechanisms of damage mitigation: when debris flows impact on a building, it acts as a buffer, and when the structure vibrates due to the impact, it acts as a shock absorber, which can reduce the maximum acceleration response and subsequent vibration respectively. To study the effectiveness of such a lateral damping buffer, an impact test is conducted, which mainly involves a lateral damping buffer attached to a two-degree-of-freedom structure under a simulated debris flow load. To enable the numerical study, the equation of motion of the structure along with the lateral damping buffer is derived. A subsequent parametric study is performed to optimize the lateral damping buffer. Finally, a practical design procedure is also provided.

Bounce-harmonic Landau Damping of Plasma Waves

Science.gov (United States)

Anderegg, Francois

2015-11-01

We present measurement of plasma wave damping, spanning the temperature regimes of direct Landau damping, bounce-harmonic Landau damping, inter-species drag damping, and viscous damping. Direct Landau damping is dominant at high temperatures, but becomes negligible as v vph / 5 . The measurements are conducted in trapped pure ion plasmas contained in Penning-Malmberg trap, with wave-coherent LIF diagnostics of particle velocities. Our focus is on bounce harmonics damping, controlled by an applied ``squeeze'' potential, which generates harmonics in the wave potential and in the particle dynamics. A particle moving in z experiences a non-sinusoidal mode potential caused by the squeeze, producing high spatial harmonics with lower phase velocity. These harmonics are Landau damped even when the mode phase velocity vph is large compared to the thermal velocity v , since the nth harmonic is resonant with a particle bouncing at velocity vb =vph / n . Here we increase the bounce harmonics through applied squeeze potential; but some harmonics are always present in finite length systems. For our centered squeeze geometry, theory shows that only odd harmonics are generated, and predicts the Landau damping rate from vph / n . Experimentally, the squeeze potential increases the wave damping and reduces its frequency. The frequency shift occurs because the squeeze potential reduces the number of particle where the mode velocity is the largest, therefore reducing the mode frequency. We observe an increase in the damping proportional to Vs2,and a frequency reduction proportional to Vs , in quantitative agreement with theory. Wave-coherent laser induced fluorescence allows direct observation of bounce resonances on the particle distribution, here predominantly at vph / 3 . A clear increase of the bounce harmonics is visible on the particle distribution when the squeeze potential is applied. Supported by NSF Grant PHY-1414570, and DOE Grants DE-SC0002451 and DE-SC0008693.

The distribution, abundance, and the effects of fire on mound building termites (Trinervitermes and Cubitermes spp., Isoptera: Termitidae) in northern guinea savanna West Africa.

Science.gov (United States)

Benzie, John A H

1986-11-01

Termite mound densities in typical guinea savanna, Detarium, and grassland (boval) habitats in northern guinea savanna were determined by random quadratting of 2-3 sites in each habitat (100, 10x10 m quadrats per habitat). Dominant species in guinea savanna were T. geminatus (46 mounds ha -1 ) and T. oeconomus (21 mounds ha -1 ), in Detarium T. geminatus (59 mounds ha -1 ) and C. curtatus (45 mounds ha -1 ) and in boval C. curtatus (72 mounds ha -1 ) and T. geminatus (22 mounds ha -1 ). Only C. curtatus densities and total densities differed significantly between sites within habitats, but all species differed significantly in abundance between habitats. The composition of each community was related to general environment but no particular environmental variable was shown to be a major determinant of termite distribution. Evidence for the limitation of termite populations was obtained from indirect evidence of competition between colonies in Detarium, and by experimental manipulation of fire regimes in the typical guinea savanna habitat. Harvester termites increased four-five fold over two years in fire-protected plots as a result of increased food supplies. Total termite densities in the fire-protected community equilibrated to the new population density (100 mounds ha -1 ) after only two-three years.

Evaluation of chemical, botanical and cultural managements of termites control.

Science.gov (United States)

Dufera, Jiregna Tasisa; Fufa, Tena Gobena

2014-01-15

The study was conducted at Bojdi Dirmaji District, Wollega Zone (Western Ethiopia) using Randomized Complete Block Design with three replications. Eight different treatments of chemical, botanical and cultural control methods independently and in combinations were evaluated to identify the most effective method which is environmentally sustainable and economically feasible in controlling the termite problems. The data were collected over 12 weeks and analysis of variance showed significant difference among the treatments for all parameters. Maesa lanceolata 100 g alone showed lower percent damage between 2-8 weeks (33.3%), later on after 9-12 weeks it become non significant and the destructed mound was recovered. Mound treated with Diazinon 60% EC at the rate of 25 and 20 mL alone and Diazinon 60% EC combination with queen removal at rate of 15 and 10 mL showed significant control overall the treatment. From the results of the study the lower rate of Diazinon 60% EC (10 mL per mound) and queen removal could be better option to manage the termite problem and could be more sustainable and integrated manner in the study area.

Next generation HOM-damping

Science.gov (United States)

Marhauser, Frank

2017-06-01

Research and development for superconducting radio-frequency cavities has made enormous progress over the last decades from the understanding of theoretical limitations to the industrial mass fabrication of cavities for large-scale particle accelerators. Key technologies remain hot topics due to continuously growing demands on cavity performance, particularly when in pursuit of high quality beams at higher beam currents or higher luminosities than currently achievable. This relates to higher order mode (HOM) damping requirements. Meeting the desired beam properties implies avoiding coupled multi-bunch or beam break-up instabilities depending on the machine and beam parameters that will set the acceptable cavity impedance thresholds. The use of cavity HOM-dampers is crucial to absorb the wakefields, comprised by all beam-induced cavity Eigenmodes, to beam-dynamically safe levels and to reduce the heat load at cryogenic temperature. Cavity damping concepts may vary, but are principally based on coaxial and waveguide couplers as well as beam line absorbers or any combination. Next generation energy recovery linacs and circular colliders call for cavities with strong HOM-damping that can exceed the state-of-the-art, while the operating mode efficiency shall not be significantly compromised concurrently. This imposes major challenges given the rather limited damping concepts. A detailed survey of established cavities is provided scrutinizing the achieved damping performance, shortcomings, and potential improvements. The scaling of the highest passband mode impedances is numerically evaluated in dependence on the number of cells for a single-cell up to a nine-cell cavity, which reveals the increased probability of trapped modes. This is followed by simulations for single-cell and five-cell cavities, which incorporate multiple damping schemes to assess the most efficient concepts. The usage and viability of on-cell dampers is elucidated for the single-cell cavity since it

Test and evaluation about damping characteristics of hanger supports for nuclear power plant piping systems (Seismic Damping Ratio Evaluation Program)

International Nuclear Information System (INIS)

Shibata, H.; Ito, A.; Tanaka, K.; Niino, T.; Gotoh, N.

1981-01-01

Generally, damping phenomena of structures and equipments is caused by very complex energy dissipation. Especially, as piping systems are composed of many components, it is very difficult to evaluate damping characteristics of its system theoretically. On the other hand, the damping value for aseismic design of nuclear power plants is very important design factor to decide seismic response loads of structures, equipments and piping systems. The very extensive studies titled SDREP (Seismic Damping Ratio Evaluation Program) were performed to establish proper damping values for seismic design of piping as a joint work among a university, electric companies and plant makers. In SDREP, various systematic vibration tests were conducted to investigate factors which may contribute to damping characteristics of piping systems and to supplement the data of the pre-operating tests. This study is related to the component damping characteristics tests of that program. The object of this study is to clarify damping characteristics and mechanism of hanger supports used in piping systems, and to establish the evaluation technique of dispersing energy at hanger support points and its effect to the total damping ability of piping system. (orig./WL)

Identification of Damping from Structural Vibrations

DEFF Research Database (Denmark)

Bajric, Anela

Reliable predictions of the dynamic loads and the lifetime of structures are influenced by the limited accuracy concerning the level of structural damping. The mechanisms of damping cannot be derived analytically from first principles, and in the design of structures the damping is therefore based...... on experience or estimated from measurements. This thesis consists of an extended summary and three papers which focus on enhanced methods for identification of damping from random struc-tural vibrations. The developed methods are validated by stochastic simulations, experimental data and full-scale measurements...... which are representative of the vibrations in small and large-scale structures. The first part of the thesis presents an automated procedure which is suitable for estimation of the natural frequencies and the modal damping ratios from random response of structures. The method can be incorporated within...

On Landau damping

KAUST Repository

Mouhot, Clément

2011-09-01

Going beyond the linearized study has been a longstanding problem in the theory of Landau damping. In this paper we establish exponential Landau damping in analytic regularity. The damping phenomenon is reinterpreted in terms of transfer of regularity between kinetic and spatial variables, rather than exchanges of energy; phase mixing is the driving mechanism. The analysis involves new families of analytic norms, measuring regularity by comparison with solutions of the free transport equation; new functional inequalities; a control of non-linear echoes; sharp "deflection" estimates; and a Newton approximation scheme. Our results hold for any potential no more singular than Coulomb or Newton interaction; the limit cases are included with specific technical effort. As a side result, the stability of homogeneous equilibria of the non-linear Vlasov equation is established under sharp assumptions. We point out the strong analogy with the KAM theory, and discuss physical implications. Finally, we extend these results to some Gevrey (non-analytic) distribution functions. © 2011 Institut Mittag-Leffler.

Isolation and identification of cellulolytic bacteria from termites gut (Cryptotermes sp.)

Science.gov (United States)

Peristiwati; Natamihardja, Y. S.; Herlini, H.

2018-05-01

The energy and environmental crises developed due to a huge amount of cellulosic materials are disposed of as “waste.” Cellulose is the most abundant biopolymer on Earth. The hydrolysis of cellulose to glucose and soluble sugars has thus become a subject of intense research. Termites are one of the most important soil insects that efficiently decompose lignocelluloses with the aid of their associated microbial symbionts to a simpler form of sugars. The steps of this study consisted of cellulose isolation, cellulolytic bacteria isolation and identification. Cellulose degrading bacteria from termite (Cryptotermes sp.) gut flora were isolated, screened and their identification was studied which showed halo zones due to CMC agar. Among 12 isolates of bacteria, six isolates were cellulolytic. MLC-A isolate had shown a maximum in a cellulolytic index (1.32). Each isolate was identified based on standard physical and biochemical tests. Three isolates were identified in the genus of Clostridium, one isolate be placed in the group of Mycobacteriaceae, Lactobacillaceae or Coryneform and the last one in the genus Proteus.

Prospects of Coir Fibre as Reinforcement in Termite Mound Clay Bricks

Directory of Open Access Journals (Sweden)

Akinyemi Banjo A.

2016-09-01

Full Text Available The study is to develop an appropriate environmental friendly building material that would be sourced, obtained locally and used for construction of structures at a low cost by using termite mound soil, reinforced with 0%, 1%, 2%, 3%. and 4% coir fibres. Physical and mechanical tests were conducted on the different composition samples after curing. The particle size distribution showed that clay had the largest percentage with a moisture content of 3.53%, specific gravity of 2.0, liquid limit of 30.5% and plastic limit value of 25.4. The compressive strength test showed a decrease with increase in fibre content from 1% upward, modulus of rupture test showed that increase in fibre content leads to a corresponding increase in rupture while the modulus of elasticity test showed that from 3% to 4% fibre content, a decrease in the elasticity occurred. It can be concluded that low fibre inclusion into compressed termite mound brick is feasible if fibre content do not exceed 2% and thus can be used for both load and non-loading bearing structures.

Shape memory alloys as damping materials

International Nuclear Information System (INIS)

Humbeeck, J. van

2000-01-01

Shape memory alloys are gaining an increased interest as passive as well as active damping materials. This damping ability when applied in structural elements can lead to a better noise control, improved life time and even better performance of the envisaged tools. By passive damping, it is understood that the material converts a significant part of unwanted mechanical energy into heat. This mechanical energy can be a (resonance) vibration, impact loading or shock waves. This high damping capacity finds its origin in the thermoelastic martensitic phase due to the hysteretic mobility of martensite-variants or different phase interfaces. The damping capacity increases with increasing amplitude of the applied vibration or impact and is almost frequency independent. Special interest exists moreover for damping extreme large displacements by applying the mechanical hysteresis performed during pseudoelastic loading. This aspect is nowadays very strongly studied as a tool for protecting buildings against earthquakes in seismic active regions. Active damping can be obtained in hybrid composites by controlling the recovery stresses or strains of embedded shape memory alloy wires. This controls the internal energy fo a structure which allows controlled modal modification and tuning of the dynamical properties of structural elements. But also impact damage, acoustic radiation, dynamic shape control can be actively controlled. As a consequence improved fatigue-resistance, better performance and a longer lifetime of the structural elements can be obtained. (orig.)

Variability of soil properties within large termite mounds in South Katanga, DRC - origins and applications.

Science.gov (United States)

Erens, Hans; Bazirake Mujinya, Basile; Boeckx, Pascal; Baert, Geert; Mees, Florias; Van Ranst, Eric

2014-05-01

The miombo woodlands of South Katanga (D.R. Congo) are characterized by a high spatial density of large conic termite mounds built by Macrotermes falciger (3 to 5 ha-1). With an average height of 5.05 m and diameter of 14.88 m, these are some of the largest biogenic structures in the world. The mound material is known to differ considerably from the surrounding Ferralsols. Specifically, mound material exhibits a finer texture, higher CEC and exchangeable basic cation content, lower organic matter content, and an accumulation of phosphorous, nitrate and secondary carbonates. However, as demonstrated by the present study, these soil properties are far from uniform within the volume of the mound. The termites' nesting and foraging activity, combined with pedogenic processes over extended periods of time, generates a wide range of physical, chemical, and biological conditions in different parts of the mound. Analysis of samples taken along a cross-section of a large active mound allowed generating contour plots, thus visualizing the variability of soil properties within the mound. The central columns of three other mounds were sampled to confirm apparent trends. The contour plots show that the mounds comprise four functional zones: (i) the active nest, found at the top; (ii) an accumulation zone , in more central parts of the mound; (iii) a dense inactive zone, surrounding the accumulation zone and consisting of accumulated erosion products from former active nests; and (iv) the outer mantle, characterized by intense varied biological activity and by a well-developed soil structure. Intermittent leaching plays a key role in explaining these patterns. Using radiocarbon dating, we found that some of these mounds are at least 2000 years old. Their current size and shape is likely the result of successive stages of erosion and rebuilding, in the course of alternating periods of mound abandonment and recolonization. Over time, termite foraging combined with limited leaching

Identification of Eastern United States Reticulitermes Termite Species via PCR-RFLP, Assessed Using Training and Test Data

Directory of Open Access Journals (Sweden)

Ryan C. Garrick

2015-06-01

Full Text Available Reticulitermes termites play key roles in dead wood decomposition and nutrient cycling in forests. They also damage man-made structures, resulting in considerable economic loss. In the eastern United States, five species (R. flavipes, R. virginicus, R. nelsonae, R. hageni and R. malletei have overlapping ranges and are difficult to distinguish morphologically. Here we present a molecular tool for species identification. It is based on polymerase chain reaction (PCR amplification of a section of the mitochondrial cytochrome oxidase subunit II gene, followed by a three-enzyme restriction fragment length polymorphism (RFLP assay, with banding patterns resolved via agarose gel electrophoresis. The assay was designed using a large set of training data obtained from a public DNA sequence database, then evaluated using an independent test panel of Reticulitermes from the Southern Appalachian Mountains, for which species assignments were determined via phylogenetic comparison to reference sequences. After refining the interpretive framework, the PCR-RFLP assay was shown to provide accurate identification of four co-occurring species (the fifth species, R. hageni, was absent from the test panel, so accuracy cannot yet be extended to training data. The assay is cost- and time-efficient, and will help improve knowledge of Reticulitermes species distributions.

Development of new damping devices for piping

International Nuclear Information System (INIS)

Kobayashi, Hiroe

1991-01-01

An increase of the damping ratio is known to be very effective for the seismic design of a piping system. Increasing the damping ratio and reducing the seismic response of the piping system, the following three types of damping devices for piping systems are introduced: (1) visco-elastic damper, (2) elasto-plastic damper and (3) compact dynamic damper. The dynamic characteristics of these damping devices were investigated by the component test and the applicability of them to the piping system was confirmed by the vibration test using a three dimensional piping model. These damping devices are more effective than mechanical snubbers to reduce the vibration of the piping system. (author)

Chemical systematics of Neotropical termite genera with symmetrically snapping soldiers (Termitidae: Termitinae)

Czech Academy of Sciences Publication Activity Database

Kyjaková, Pavlína; Roy, V.; Jirošová, Anna; Krasulová, Jana; Dolejšová, Klára; Křivánek, Jan; Hadravová, Romana; Rybáček, Jiří; Pohl, Radek; Roisin, Y.; Sillam-Dusses, D.; Hanus, Robert

2017-01-01

Roč. 180, č. 1 (2017), s. 66-81 ISSN 0024-4082 R&D Projects: GA ČR GP13-25354P Institutional support: RVO:61388963 Keywords : chemical defence * frontal gland * termites * chemical systematics * Termitinae Subject RIV: EG - Zoology OBOR OECD: Biodiversity conservation Impact factor: 2.711, year: 2016

Bryan's effect and anisotropic nonlinear damping

Science.gov (United States)

Joubert, Stephan V.; Shatalov, Michael Y.; Fay, Temple H.; Manzhirov, Alexander V.

2018-03-01

In 1890, G. H. Bryan discovered the following: "The vibration pattern of a revolving cylinder or bell revolves at a rate proportional to the inertial rotation rate of the cylinder or bell." We call this phenomenon Bryan's law or Bryan's effect. It is well known that any imperfections in a vibratory gyroscope (VG) affect Bryan's law and this affects the accuracy of the VG. Consequently, in this paper, we assume that all such imperfections are either minimised or eliminated by some known control method and that only damping is present within the VG. If the damping is isotropic (linear or nonlinear), then it has been recently demonstrated in this journal, using symbolic analysis, that Bryan's law remains invariant. However, it is known that linear anisotropic damping does affect Bryan's law. In this paper, we generalise Rayleigh's dissipation function so that anisotropic nonlinear damping may be introduced into the equations of motion. Using a mixture of numeric and symbolic analysis on the ODEs of motion of the VG, for anisotropic light nonlinear damping, we demonstrate (up to an approximate average), that Bryan's law is affected by any form of such damping, causing pattern drift, compromising the accuracy of the VG.

A review of experimental soil-structure interaction damping

International Nuclear Information System (INIS)

Tsai, N.C.

1981-01-01

In soil-structure interaction analysis, the foundation soil is usually represented by impedance springs and dampers. The impedance damping includes the effect of both the material damping and the radiation damping. Because the impedance theory normally assumes a rigid structural base and an elastic bond between the soil and structure, it is generally held that the radiation damping has been overestimated by the theory. There are some published information on the dynamic tests of footings and structures that allow direct or indirect assessments of the validity of the analytical radiation damping. An overview of such information is presented here. Based on these limited test data, it is concluded that for horizontal soil-structure interaction analysis the analytical radiation damping alone is sufficient to represent the combined material and radiation damping in the field. On the other hand, for vertical analysis it appears that the theory may have overestimated the radiation damping and certain reduction is recommended. (orig.)

Mining for hemicellulases in the fungus-growing termite Pseudacanthotermes militaris using functional metagenomics.

Science.gov (United States)

Bastien, Géraldine; Arnal, Grégory; Bozonnet, Sophie; Laguerre, Sandrine; Ferreira, Fernando; Fauré, Régis; Henrissat, Bernard; Lefèvre, Fabrice; Robe, Patrick; Bouchez, Olivier; Noirot, Céline; Dumon, Claire; O'Donohue, Michael

2013-05-14

The metagenomic analysis of gut microbiomes has emerged as a powerful strategy for the identification of biomass-degrading enzymes, which will be no doubt useful for the development of advanced biorefining processes. In the present study, we have performed a functional metagenomic analysis on comb and gut microbiomes associated with the fungus-growing termite, Pseudacanthotermes militaris. Using whole termite abdomens and fungal-comb material respectively, two fosmid-based metagenomic libraries were created and screened for the presence of xylan-degrading enzymes. This revealed 101 positive clones, corresponding to an extremely high global hit rate of 0.49%. Many clones displayed either β-d-xylosidase (EC 3.2.1.37) or α-l-arabinofuranosidase (EC 3.2.1.55) activity, while others displayed the ability to degrade AZCL-xylan or AZCL-β-(1,3)-β-(1,4)-glucan. Using secondary screening it was possible to pinpoint clones of interest that were used to prepare fosmid DNA. Sequencing of fosmid DNA generated 1.46 Mbp of sequence data, and bioinformatics analysis revealed 63 sequences encoding putative carbohydrate-active enzymes, with many of these forming parts of sequence clusters, probably having carbohydrate degradation and metabolic functions. Taxonomic assignment of the different sequences revealed that Firmicutes and Bacteroidetes were predominant phyla in the gut sample, while microbial diversity in the comb sample resembled that of typical soil samples. Cloning and expression in E. coli of six enzyme candidates identified in the libraries provided access to individual enzyme activities, which all proved to be coherent with the primary and secondary functional screens. This study shows that the gut microbiome of P. militaris possesses the potential to degrade biomass components, such as arabinoxylans and arabinans. Moreover, the data presented suggests that prokaryotic microorganisms present in the comb could also play a part in the degradation of biomass within the

Influence of soil pedological properties on termite mound stability

OpenAIRE

Jouquet, Pascal; Guilleux, N.; Caner, L.; Chintakunta, S.; Ameline, M.; Shanbhag, R. R.

2016-01-01

This study investigated the influence of soil properties on the density and shape of epigeous fungus-growing termite nests in a dry deciduous forest in Karnataka, India. In this environment, Odontotermes obesus produces cathedral shaped mounds. Their density, shape (height and volume) and soil physicochemical properties were analyzed in ferralsol and vertisol environments. No significant difference was observed in O. obesus mound density (n = 2.7 mound ha(-1) on average in the vertisol and fe...

1472-IJBCS-Article-Adeduntan S A

African Journals Online (AJOL)

hp

and aluminum which favours termite activity. The soil fairly medium ... length) with a circular saw machine and the wood sample sanded using fine sanding paper ..... flow per unit time and the less the absorption .... economic analysis and discussion of a proposed mechanism. Wood and. Fibre Science, 37(1); 175-184.

The Duffing oscillator with damping

DEFF Research Database (Denmark)

Johannessen, Kim

2015-01-01

An analytical solution to the differential equation describing the Duffing oscillator with damping is presented. The damping term of the differential equation and the initial conditions satisfy an algebraic equation, and thus the solution is specific for this type of damping. The nonlinear term...... of the differential equation is allowed to be considerable compared to the linear term. The solution is expressed in terms of the Jacobi elliptic functions by including a parameter-dependent elliptic modulus. The analytical solution is compared to the numerical solution, and the agreement is found to be very good....... It is established that the period of oscillation is shorter compared to that of a linearized model but increasing with time and asymptotically approaching the period of oscillation of the linear damped model. An explicit expression for the period of oscillation has been derived, and it is found to be very accurate....

EFFECTIVENESS OF A SUPERFICIAL TREATMENT USING BIFENTHRIN TO PROTECT RADIATA PINE FRAMING FROM DAMAGE BY SUBTERRANEAN AND DRYWOOD TERMITES IN INDONESIA

OpenAIRE

Paimin Sukartana; Jim W. Creffield; Agus Ismanto; Neo E. Lelana; Rusti Rushelia

2010-01-01

Various experimental testing procedures were undertaken in Indonesia to determine the effectiveness of a patented superficial (envelope) treatment using bifenthrin to protect radiata pine framing material from damage by two species of subterranean termites (Macrotermes gilvus and Coptotermes curvignathus) and one species of drywood termite (Cryptotermes cynocephalus). Lengths of framing material (Pinus radiata sapwood) were commercially treated to the targeted retention of 0.02% m/m of bifent...

Cord Wood Testing in a Non-Catalytic Wood Stove

Energy Technology Data Exchange (ETDEWEB)

Butcher, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, G. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2014-06-30

EPA Method 28 and the current wood stove regulations have been in-place since 1988. Recently, EPA proposed an update to the existing NSPS for wood stove regulations which includes a plan to transition from the current crib wood fuel to cord wood fuel for certification testing. Cord wood is seen as generally more representative of field conditions while the crib wood is seen as more repeatable. In any change of certification test fuel, there are questions about the impact on measured results and the correlation between tests with the two different fuels. The purpose of the work reported here is to provide data on the performance of a noncatalytic stove with cord wood. The stove selected has previously been certified with crib wood which provides a basis for comparison with cord wood. Overall, particulate emissions were found to be considerably higher with cord wood.

Swing damped movement of suspended objects

International Nuclear Information System (INIS)

Jones, J.F.; Petterson, B.J.; Werner, J.C.

1990-01-01

Transportation of large objects such as nuclear waste shipping casks using overhead cranes can induce pendular motion of the object. Residual oscillation from transportation typically must be damped or allowed to decay before the next process can take place. By properly programming the acceleration of the transporting device (e.g., crane) an oscillation damped transport and swing free stop are obtainable. This report reviews the theory associated with formulating such oscillation damped trajectories for a simply suspended object (e.g., simple pendulum). In addition, the use of force servo damping to eliminate initial oscillation of simply suspended objects is discussed. This is often needed to provide a well defined initial state for the system prior to executing an oscillation damped move. Also included are descriptions of experiments using a CIMCORP XR6100 gantry robot and results from these experiments. Finally, sources of error resulting in small residual oscillations are identified and possible solutions presented

A termite symbiotic mushroom maximizing sexual activity at growing tips of vegetative hyphae.

Science.gov (United States)

Hsieh, Huei-Mei; Chung, Mei-Chu; Chen, Pao-Yang; Hsu, Fei-Man; Liao, Wen-Wei; Sung, Ai-Ning; Lin, Chun-Ru; Wang, Chung-Ju Rachel; Kao, Yu-Hsin; Fang, Mei-Jane; Lai, Chi-Yung; Huang, Chieh-Chen; Chou, Jyh-Ching; Chou, Wen-Neng; Chang, Bill Chia-Han; Ju, Yu-Ming

2017-09-19

Termitomyces mushrooms are mutualistically associated with fungus-growing termites, which are widely considered to cultivate a monogenotypic Termitomyces symbiont within a colony. Termitomyces cultures isolated directly from termite colonies are heterokaryotic, likely through mating between compatible homokaryons. After pairing homokaryons carrying different haplotypes at marker gene loci MIP and RCB from a Termitomyces fruiting body associated with Odontotermes formosanus, we observed nuclear fusion and division, which greatly resembled meiosis, during each hyphal cell division and conidial formation in the resulting heterokaryons. Surprisingly, nuclei in homokaryons also behaved similarly. To confirm if meiotic-like recombination occurred within mycelia, we constructed whole-genome sequencing libraries from mycelia of two homokaryons and a heterokaryon resulting from mating of the two homokaryons. Obtained reads were aligned to the reference genome of Termitomyces sp. J132 for haplotype reconstruction. After removal of the recombinant haplotypes shared between the heterokaryon and either homokaryons, we inferred that 5.04% of the haplotypes from the heterokaryon were the recombinants resulting from homologous recombination distributed genome-wide. With RNA transcripts of four meiosis-specific genes, including SPO11, DMC1, MSH4, and MLH1, detected from a mycelial sample by real-time quantitative PCR, the nuclear behavior in mycelia was reconfirmed meiotic-like. Unlike other basidiomycetes where sex is largely restricted to basidia, Termitomyces maximizes sexuality at somatic stage, resulting in an ever-changing genotype composed of a myriad of coexisting heterogeneous nuclei in a heterokaryon. Somatic meiotic-like recombination may endow Termitomyces with agility to cope with termite consumption by maximized genetic variability.

Identification of the Trail-Following Pheromone of the Pest Termite Amitermes evuncifer (Isoptera: Termitidae)

Czech Academy of Sciences Publication Activity Database

Kotoklo, E. A.; Sillam-Dusses, David; Kétoh, G.; Sémon, E.; Robert, A.; Bordereau, Ch.; Glitho, I. A.

2010-01-01

Roč. 55, č. 2 (2010), s. 579-588 ISSN 0361-6525 Institutional research plan: CEZ:AV0Z40550506 Keywords : dodecatrienol * neocembrene * multicomponent pheromone * termites Subject RIV: CC - Organic Chemistry Impact factor: 0.534, year: 2010

A review of damping of two-phase flows

International Nuclear Information System (INIS)

Hara, Fumio

1993-01-01

Damping of two-phase flows has been recognized as one of the most unknown parameters in analyzing vibrational characteristics of structures subjected to two-phase flows since it seems to be influenced by many physical parameters involved in the physics of dynamic energy dissipation of a vibrating structure, for example, liquid viscosity, surface tension, flow velocity, mass ratio, frequency, void fraction, flow regime and so forth. This paper deals with a review of scientific works done to date on the damping of two phase flows and discussions about what has been clarified and what has not been known to us, or what kinds of research are needed about two-phase flow damping. The emphasis is put on the definition of two-phase fluid damping, damping measurement techniques, damping characteristics in relation to two phase flow configurations, and damping generation mechanisms

Damping Wiggler Study at KEK-ATF

CERN Document Server

Naito, Takashi; Honda, Yosuke; Korostelev, Maxim S; Kubo, Kiyoshi; Kuriki, Masao; Kuroda, Shigeru; Muto, Toshiya; Nakamura, Norio; Ross, Marc; Sakai, Hiroshi; Terunuma, Nobuhiro; Urakawa, Junji; Zimmermann, Frank

2005-01-01

The effects by damping wiggler magnets have been studied at KEK-ATF. The damping ring of the KEK-ATF is a 1.3 GeV storage ring capable of producing ultra-low emittance electron beams. It is significant issue to realize fast damping in the damping ring. The tuning method with 4 sets of wiggler was investigated for the ultra-low emittance beam. The performance on the beam quality, which is related to the transverse (x and y) and the longitudinal (z and dp/p), has been measured by the SR monitor, the laser wire, the streak camera and the energy spread monitor at the extraction line. We report on the operation condition and the measurement results.

Properties of Arboreal Ant and Ground-Termite Nests in relation to Their Nesting Sites and Location in a Tropical-Derived Savanna

Directory of Open Access Journals (Sweden)

B. C. Echezona

2012-01-01

Full Text Available Ecosystem engineers such as ants and termites play an important role in the fertility of tropical soils. Physicochemical analyses were thus carried out on some arboreal ant nests collected from mango (Mangifera indica, bush mango (Irvingia gabonensis, kola (Cola nitida, newbouldia plant (Newbouldia laevis, and oil bean plant (Pentaclethra macrophylla and on ground nest of termite, Odontotermes sudanensis Sjost. (Isoptera: Termitidae in Nigeria. Arboreal nests, particularly those of M. indica, were significantly richer in the chemical constituents sampled, compared to those of ground-termite nests or adjacent unaffected soils. Available water capacity of nests from M. indica (60.0% was significantly higher than those of other sites or locations sampled. While biogenic structures were sandy-loamy in texture, their corresponding adjacent soils were either sandy or sandy-loamy. Soils worked by ants and termites had greater proportions of silt-sized (17.9 versus 9.7 and clay-sized (19.2 versus 9.3 to the detriment of coarse-sized particles (51.2 versus 60.9 and fine-sand-sized particles (11.7 versus 20.1 relative to the adjacent soils. Generally, biogenic structures were about 348% richer in P than their corresponding adjacent soils; an attribute, which holds a strong promise in bioremediation and biofortification of soils especially during amendment.

Multi-functional roles of a soldier-specific volatile as a worker arrestant, primer pheromone and an antimicrobial agent in a termite.

Science.gov (United States)

Mitaka, Yuki; Mori, Naoki; Matsuura, Kenji

2017-07-26

Division of labour in eusocial insects is characterized by efficient communication systems based on pheromones. Among such insects, termites have evolved specialized sterile defenders, called soldiers. Because they are incapable of feeding themselves, it has been suggested that soldiers are sustained by workers and emit the pheromone arresting workers. However, such a soldier pheromone has not been identified in any termite species, and the details of the soldier-worker interaction remain to be explored. Here, we identified a soldier-specific volatile sesquiterpene as a worker arrestant, which also acts as a primer pheromone regulating soldier differentiation and fungistatic agent in a termite Reticulitermes speratus Chemical analyses revealed that (-)- β -elemene is the major component of soldier extract, and its authentic standard exhibited arrestant activity to workers and inhibited the differentiation from workers to soldiers. This compound also showed fungistatic activity against entomopathogenic fungi. These suggest that (-)- β -elemene secreted by soldiers acts not only as a worker arrestant but also as one component of inhibitory primer pheromone and an anti-pathogenic agent. Our study provides novel evidence supporting the multi-functionality of termite soldier pheromone and provides new insights into the role of soldiers and the evolutionary mechanisms of pheromone compounds. © 2017 The Author(s).

Supplementing Blends of Sugars, Amino Acids, and Secondary Metabolites to the Diet of Termites (Reticulitermes flavipes) Drive Distinct Gut Bacterial Communities.

Science.gov (United States)

Huang, Xing-Feng; Chaparro, Jacqueline M; Reardon, Kenneth F; Judd, Timothy M; Vivanco, Jorge M

2016-10-01

Although it is well known that diet is one of the major modulators of the gut microbiome, how the major components of diet shape the gut microbial community is not well understood. Here, we developed a simple system that allows the investigation of the impact of given compounds as supplements of the diet on the termite gut microbiome. The 16S rRNA pyrosequencing analysis revealed that feeding termites different blends of sugars and amino acids did not majorly impact gut community composition; however, ingestion of blends of secondary metabolites caused shifts in gut bacterial community composition. The supplementation of sugars and amino acids reduced the richness significantly, and sugars alone increased the evenness of the gut bacterial community significantly. Secondary metabolites created the most dramatic effects on the microbial community, potentially overriding the effect of other types of compounds. Furthermore, some microbial groups were stimulated specifically by particular groups of compounds. For instance, termites fed with secondary metabolites contained more Firmicutes and Spirochaetes compared to the other treatments. In conclusion, our results suggest that the termite (Reticulitermes flavipes) can be used as a simple and effective system to test the effects of particular chemical compounds in modulating the gut microbiome.

Non-Linear Slosh Damping Model Development and Validation

Science.gov (United States)

Yang, H. Q.; West, Jeff

2015-01-01

Propellant tank slosh dynamics are typically represented by a mechanical model of spring mass damper. This mechanical model is then included in the equation of motion of the entire vehicle for Guidance, Navigation and Control (GN&C) analysis. For a partially-filled smooth wall propellant tank, the critical damping based on classical empirical correlation is as low as 0.05%. Due to this low value of damping, propellant slosh is potential sources of disturbance critical to the stability of launch and space vehicles. It is postulated that the commonly quoted slosh damping is valid only under the linear regime where the slosh amplitude is small. With the increase of slosh amplitude, the critical damping value should also increase. If this nonlinearity can be verified and validated, the slosh stability margin can be significantly improved, and the level of conservatism maintained in the GN&C analysis can be lessened. The purpose of this study is to explore and to quantify the dependence of slosh damping with slosh amplitude. Accurately predicting the extremely low damping value of a smooth wall tank is very challenging for any Computational Fluid Dynamics (CFD) tool. One must resolve thin boundary layers near the wall and limit numerical damping to minimum. This computational study demonstrates that with proper grid resolution, CFD can indeed accurately predict the low damping physics from smooth walls under the linear regime. Comparisons of extracted damping values with experimental data for different tank sizes show very good agreements. Numerical simulations confirm that slosh damping is indeed a function of slosh amplitude. When slosh amplitude is low, the damping ratio is essentially constant, which is consistent with the empirical correlation. Once the amplitude reaches a critical value, the damping ratio becomes a linearly increasing function of the slosh amplitude. A follow-on experiment validated the developed nonlinear damping relationship. This discovery can

Damping Estimation of Friction Systems in Random Vibrations

DEFF Research Database (Denmark)

Friis, Tobias; Katsanos, Evangelos; Amador, Sandro

Friction is one of the most efficient and economical mechanisms to reduce vibrations in structural mechanics. However, the estimation of the equivalent linear damping of the friction damped systems in experimental modal analysis and operational modal analysis can be adversely affected by several...... assumptions regarding the definition of the linear damping and the identification methods or may be lacking a meaningful interpretation of the damping. Along these lines, this project focuses on assessing the potential to estimate efficiently the equivalent linear damping of friction systems in random...

Emittance damping considerations for TESLA

International Nuclear Information System (INIS)

Floettmann, K.; Rossbach, J.

1993-03-01

Two schemes are considered to avoid very large damping rings for TESLA. The first (by K.F.) makes use of the linac tunnel to accomodate most of the damping 'ring' structure, which is, in fact, not a ring any more but a long linear structure with two small bends at each of its ends ('dog-bone'). The other scheme (by J.R.) is based on a positron (or electron, respectively) recycling scheme. It makes use of the specific TESLA property, that the full bunch train is much longer (240 km) than the linac length. The spent beams are recycled seven times after interaction, thus reducing the number of bunches to be stored in the damping ring by a factor of eight. Ultimately, this scheme can be used to operate TESLA in a storage ring mode ('storage linac'), with no damping ring at all. Finally, a combination of both schemes is considered. (orig.)

Assessment of the wood waste resource and its position in the wood / wood-energy sector - Synthesis

International Nuclear Information System (INIS)

Guinard, Ludovic; Deroubaix, Gerard; Roux, Marie-Lise; Levet, Anne-Laure; Quint, Vincent

2015-04-01

The first objective of this study is to obtain a better knowledge of the 'wood wastes' issue, to propose a photography of the wood waste sector (productions, trades, consumptions), and then to elaborate different prospective scenarios on the use of wood waste volumes while taking into account possible evolutions on the medium or short term of the regulation and market of the wood/wood energy sector. The considered wastes come from industrial production, from the use of wood-based products, and from the end of life of products potentially containing wood. The authors present bibliographical sources and the adopted methodology, briefly describe the 'wood waste' system with its actors, and then report their assessment of wood wastes. They propose a global assessment as well as detailed assessments with respect to waste origins: wood trade and distribution, industries, craft, households and communities, building sector, public and private tertiary sector, packaging. They also address the collection and management of wood wastes by public services, and present the different types of valorisation (panel fabrication, energy, and others). They discuss exports, and then present different scenarios: a trend-based scenario, and two prospective scenarios with a priority to energetic valorisation or to material valorisation of wood wastes. These scenarios are compared

Termite enzymes and uses thereof for in vitro conversion of lignin-containing materials to fermentable products

Science.gov (United States)

Scharf, Michael E; Boucias, Drion G; Tartar, Aurelien; Coy, Monique R; Zhou, Xuguo; Salem, Tamer Ibrahim Zaki; Jadhao, Sanjay B; Wheeler, Marsha M

2013-05-21

The disclosure provides isolated nucleic acid molecules derived from the gut of the termite R flavipes, recombinant nucleic acid molecules comprising a vector and an isolated heterologous nucleic acid molecule operably inserted therein, whereby, when transformed into an appropriate host cell system, the heterologous nucleic acid sequence is expressed as a polypeptide having an activity similar to that when expressed in the gut of the termite R. flavipes. The recombinant nucleic acid molecules can comprise more than one heterologous nucleic acid molecule such that more than one polypeptide may be expressed by the host system. The expressed polypeptides may be substantially purified, or used in a substantially unpurified form, to be admixed with a lignocellulose source to be converted to a fermentable product such as a sugar or a mixture of sugars. One aspect of the present disclosure, therefore, encompasses methods of converting a lignified plant material to a fermentable product, the method comprising obtaining a series of isolated polypeptides of a termite, wherein the series of polypeptides cooperate to convert a plant lignocellulose to a fermentable product; and incubating the series of polypeptides with a source of lignified plant material, under conditions allowing the polypeptides to cooperatively produce a fermentable product from the lignified plant material.

Damped Oscillator with Delta-Kicked Frequency

Science.gov (United States)

Manko, O. V.

1996-01-01

Exact solutions of the Schrodinger equation for quantum damped oscillator subject to frequency delta-kick describing squeezed states are obtained. The cases of strong, intermediate, and weak damping are investigated.

Phenomenology of chiral damping in noncentrosymmetric magnets

KAUST Repository

Akosa, Collins Ashu; Miron, Ioan Mihai; Gaudin, Gilles; Manchon, Aurelien

2016-01-01

A phenomenology of magnetic chiral damping is proposed in the context of magnetic materials lacking inversion symmetry. We show that the magnetic damping tensor acquires a component linear in magnetization gradient in the form of Lifshitz invariants. We propose different microscopic mechanisms that can produce such a damping in ferromagnetic metals, among which local spin pumping in the presence of an anomalous Hall effect and an effective “s-d” Dzyaloshinskii-Moriya antisymmetric exchange. The implication of this chiral damping in terms of domain-wall motion is investigated in the flow and creep regimes.

Phenomenology of chiral damping in noncentrosymmetric magnets

KAUST Repository

Akosa, Collins Ashu

2016-06-21

A phenomenology of magnetic chiral damping is proposed in the context of magnetic materials lacking inversion symmetry. We show that the magnetic damping tensor acquires a component linear in magnetization gradient in the form of Lifshitz invariants. We propose different microscopic mechanisms that can produce such a damping in ferromagnetic metals, among which local spin pumping in the presence of an anomalous Hall effect and an effective “s-d” Dzyaloshinskii-Moriya antisymmetric exchange. The implication of this chiral damping in terms of domain-wall motion is investigated in the flow and creep regimes.

Allergy and respiratory health effects of dampness and dampness-related agents in schools and homes

DEFF Research Database (Denmark)

Holst, G; Høst, A; Doekes, G

2016-01-01

was identified based on technical inspection and bedroom dampness on parents' self-report. Classroom and bedroom dust was analysed for seven microbial components. Skin-prick-testing determined atopic sensitisation. Lung function was expressed as z-scores for forced expiratory volume in one second (zFEV1...... ), forced vital capacity (zFVC) and the ratio zFEV1 /zFVC using GLI-2012-prediction-equations. The parents reported children's allergies, airway symptoms and doctor-diagnosed asthma. High classroom dampness, but not bedroom dampness, was negatively associated with zFEV1 (β-coef. -0.71; 95%CI -1.17 - -0...... (ETS) decreased zFEV1 (β-coef. -0.22; 95%CI -0.42- -0.02) and zFEV1 /zFVC-ratio (β-coef. -0.26; 95%CI -0.44 - -0.07) and increased upper airway symptoms (OR1.66; 95%CI 1.03-2.66). In conclusion, dampness in classrooms may have adverse respiratory health effects in pupils, but microbial agents...

Magnon damping in two-dimensional Heisenberg ferromagnetic system

International Nuclear Information System (INIS)

Cheng, T.-M.; Li Lin; Ze Xianyu

2006-01-01

A magnon-phonon interaction model is set up for a two-dimensional insulating ferromagnetic system. By using Matsubara function theory we have studied the magnon damping -I m Σ* (1) (k->) and calculated the magnon damping -I m Σ* (1) (k->) curve on the main symmetric point and line in the Brillouin zone for various parameters in the system. It is concluded that at the boundary of Brillouin zone there is a strong magnon damping. However, the magnon damping is very weak on the zone of small wave vector and the magnon damping reaches maximal value at very low temperature. The contributions of longitudinal phonon and transverse phonon on the magnon damping are compared and the influences of various parameters are also discussed

Evaluation of six techniques for control of the western drywood termite (Isoptera: Kalotermitidae) in structures

International Nuclear Information System (INIS)

Lewis, V.R.; Haverty, M.I.

1996-01-01

Chemical and nonchemical methods for control of western drywood termites, Incisitermes minor (Hager), were evaluated under conditions that simulated infestations in structures. The efficacy of excessive heat or cold, electrocution, microwaves, and 2 fumigants was evaluated. Termite mortality in artificially infested boards was 100% at 3 d after treatment for both fumigant gases. Heating the whole-structure or spot-applications using microwaves resulted in 96 and 90% mortality, respectively, 3 d after treatment. Mortality levels 4 wk after treatment increased to 98% for heat and 92% for microwaves. Spot-applications of liquid nitrogen at 381.8 kg/m3 achieved 100% mortality 3 d after treatment. However, for 122.7 and 57.3 kg/m 3 , mortality levels 4 wk after treatment were 99 and 87%, respectively. Mortality by spot-applications of electricity was 44% 3 d after treatment in the 1st test. Four weeks after treatment drywood termite mortality increased to 81%. In a 2nd electrocution test, using spot-application techniques infrequently used in structures, mortality levels increased to 93% at 3 d and 99% at 4 wk after treatment. The distribution of termite survivors within the test building and test boards varied for some treatment techniques. For naturally infested boards, both fumigants exceeded 99% mortality. Use of heat and microwaves resulted in 100 and 99% mortality levels, respectively, 4 wk after treatment. Applications of liquid nitrogen resulted in mortality greater than or equal to 99.8% at 381.8 and 122.7 kg/m 3 ; however, mortality for 57.3 kg/m 3 was significantly lower (74%). Mortality levels from electrocution were 89 and 95% 4 wk after treatment respectively in the 2 tests. Damage to test boards and the test building did occur. Six test boards were scorched during microwave treatment, 80% of test boards were damaged during electrocution, and visible signs of damage to the test building were noted for whole-structure heating. (author)

Composting of cow dung and crop residues using termite mounds as bulking agent.

Science.gov (United States)

Karak, Tanmoy; Sonar, Indira; Paul, Ranjit K; Das, Sampa; Boruah, R K; Dutta, Amrit K; Das, Dilip K

2014-10-01

The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg(-1) respectively with a bulk density of 0.85 g cm(-3). Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied. Copyright © 2014 Elsevier Ltd. All rights reserved.

Toxicity and anti termite activities of the essential oils from Piper sarmentosum

International Nuclear Information System (INIS)

Chieng, T.C.; Assim, Z.B.; Fasihuddin, B.A.

2008-01-01

The leaves of Piper sarmentosum were hydro distilled using the modified Clevenger-type apparatus, and an average yield of essential oil of 1.10 % (v/ dry weight) was obtained. The leaf oils were analyzed by GC and GC-MS. A total of 31 components were identified. Spathulenol (21.0 %), myristicin (18.8 %), β-caryophyllene (18.2 %) and (E,E)-farnesol (10.5 %) were the major compounds found in the leaf oil. The leaf oil showed inhibitory activity against the larvae of Artemia salina with LC 50 value of 35.2 μg/ mL, and 100 % mortality within two days at 1 % concentration against the subterranean termite (Coptotermes sp.). The crude extract was then subjected to bioassay-guided isolation using silica gel column chromatography, and eluted with hexane containing increasing volumes of ethyl acetate and yielded three pure compounds. Their toxicity and anti termite activities of the three compounds were determined. Compound 2 showed the most potent activity against the larvae of A. salina with LC 50 value of 7.5 μg/ mL, while the LC 50 values for compound 3 and compound 1 were 17.2 μg/ mL and 22.5 μg/ mL respectively. Compound 3 showed the strongest inhibitory activity against the subterranean termite (Coptotermes sp.) with 100 % mortality after 3 days at 0.1 % concentration followed by compound 2 with the same mortality rate at 0.5 % concentration. Compound 1 showed the weakest inhibitory activity with 80 % mortality after 3 days at 2 % concentration. Based on spectroscopic data and comparison with published information, compound 1 and 2 have been identified as caryophyllene and myristicin respectively. Compound 3 is still being studied in order to elucidate its structure. (author)

Termites and large herbivores influence seed removal rates in an African savanna.

Science.gov (United States)

Acanakwo, Erik Francis; Sheil, Douglas; Moe, Stein R

2017-12-01

Seed removal can influence plant community dynamics, composition, and resulting vegetation characteristics. In the African savanna, termites and large herbivores influence vegetation in various ways, likely including indirect effects on seed predators and secondary dispersers. However, the intensity and variation of seed removal rates in African savannas has seldom been studied. We experimentally investigated whether termites and large herbivores were important factors in the mechanisms contributing to observed patterns in tree species composition on and off mounds, in Lake Mburo National Park, Uganda. Within fenced (excluding large herbivores) and unfenced termite mound and adjacent savanna plots, we placed seeds of nine native tree species within small open "cages," accessed by all animals, roofed cages that only allowed access to small vertebrates and invertebrates, and closed cages that permitted access by smaller invertebrates only (5 mm wire mesh). We found that mean seed removal rate was high (up to 87.3% per 3 d). Mound habitats experienced significantly higher removal rates than off-mound habitats. The mean removal rate of native seeds from closed cages was 11.1% per 3 d compared with 19.4% and 23.3% removed per 3 d in the roofed and open cages, respectively. Smaller seeds experienced higher removal rates than larger seeds. Large herbivore exclusion on mounds reduced native seed removal rates by a mean of 8.8% in the open cages, but increased removal rates by 1.7% in the open cages when off-mound habitats were fenced. While removal rates from open cages were higher on active mounds (30.9%) than on inactive mounds (26.7%), the removal rates from closed cages were lower on active vs. inactive mounds (6.1% vs. 11.6%, respectively). Thus, we conclude that large herbivores and Macrotermes mounds influence seed removal rates, though these effects appear indirect. © 2017 by the Ecological Society of America.

Dynamic characteristics of a novel damped outrigger system

Science.gov (United States)

Tan, Ping; Fang, Chuangjie; Zhou, Fulin

2014-06-01

This paper presents exact analytical solutions for a novel damped outrigger system, in which viscous dampers are vertically installed between perimeter columns and the core of a high-rise building. An improved analytical model is developed by modeling the effect of the damped outrigger as a general rotational spring acting on a Bernoulli-Euler beam. The equivalent rotational spring stiffness incorporating the combined effects of dampers and axial stiffness of perimeter columns is derived. The dynamic stiffness method (DSM) is applied to formulate the governing equation of the damped outrigger system. The accuracy and efficiency are verified in comparison with those obtained from compatibility equations and boundary equations. Parametric analysis of three non-dimensional factors is conducted to evaluate the influences of various factors, such as the stiffness ratio of the core to the beam, position of the damped outrigger, and the installed damping coefficient. Results show that the modal damping ratio is significantly influenced by the stiffness ratio of the core to the column, and is more sensitive to damping than the position of the damped outrigger. The proposed analytical model in combination with DSM can be extended to the study of structures with more outriggers.

Chapter 6: Wood energy and competing wood product markers

Science.gov (United States)

Kenneth E. Skog; Robert C. Abt; Karen Abt

2014-01-01

Understanding the effect of expanding wood energy markets is important to all wood-dependent industries and to policymakers debating the implementation of public programs to support the expansion of wood energy generation. A key factor in determining the feasibility of wood energy projects (e.g. wood boiler or pellet plant) is the long-term (i.e. 20-30year) supply...

Struvite for composting of agricultural wastes with termite mound: Utilizing the unutilized.

Science.gov (United States)

Karak, Tanmoy; Sonar, Indira; Nath, Jyoti Rani; Paul, Ranjit Kumar; Das, Sampa; Boruah, Romesh Kumar; Dutta, Amrit Kumar; Das, Kuntal

2015-01-01

Although, compost is the store house of different plant nutrients, there is a concern for low amount of major nutrients especially nitrogen content in prepared compost. The present study deals with preparation of compost by using agricultural wastes with struvite (MgNH4PO4·6H2O) along with termite mound. Among four composting mixtures, 50kg termite mound and 2.5kg struvite with crop residues (stover of ground nut: 361.65kg; soybean: 354.59kg; potato: 357.67kg and mustard: 373.19kg) and cow dung (84.90kg) formed a good quality compost within 70days of composting having nitrogen, phosphorus and potassium as 21.59, 3.98 and 34.6gkg(-1), respectively. Multivariate analysis of variance revealed significant differences among the composts. The four composts formed two (pit 1, pit 2 and pit 3, pit 4) different groups. Two principal components expressed more than 97% of the total variability. Hierarchical cluster analysis resulted two homogeneous groups of composts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wood adhesives : vital for producing most wood products

Science.gov (United States)

Charles R. Frihart

2011-01-01

A main route for the efficient utilization of wood resources is to reduce wood to small pieces and then bond them together (Frihart and Hunt 2010). Although humankind has been bonding wood since early Egyptian civilizations, the quality and quantity of bonded wood products has increased dramatically over the past 100 years with the development of new adhesives and...

Electromagnetic damping of neutron star oscillations

International Nuclear Information System (INIS)

McDermott, P.N.; Savedoff, M.P.; Van Horn, H.M.; Zweibel, E.G.; Hansen, C.J.

1984-01-01

Nonradial pulsations of a neutron star with a strong dipole magnetic field cause emission of electromagnetic radiation. Here we compute the power radiated to vacuum by neutron star g-mode pulsations and by torsional oscillations of the neutron star crust. For the low-order quadrupole fluid g-modes we have considered, we find electromagnetic damping to be considerably more effective than gravitational radiation. For example, a 0.5 M/sub sun/ neutron star with a core temperature approx.10 7 K has a g 1 -mode period of 371 ms; for this mode were find the electromagnetic damping time to be tau/sub FM/approx.0.3 s, assuming the surface magnetic field strength of the neutron star to be B 0 approx.10 12 gauss. This is considerably less than the corresponding gravitational radiation time tau/sub GR/approx.3 x 10 17 yr. For dipole g-mode oscillations, there is no gravitational radiation, but electromagnetic damping and ohmic dissipation are efficient damping mechanisms. For dipole torsional oscillations, we find that electromagnetic damping again dominates, with tau/sub EM/approx.5 yr. Among the cases we have studied, quadrupole torsional oscillations appear to be dominated by gravitational radiation damping, with tau/sub GR/approx.10 4 yr, as compared with tau/sub EM/approx.2 x 10 7 yr

Termite- and mulch-mediated rehabilitation of vegetation on crusted soil in West Africa

NARCIS (Netherlands)

Mando, A.; Brussaard, L.; Stroosnijder, L.

1999-01-01

The rehabilitation of vegetation on structurally crusted soils by triggering termite activity through mulch was studied on three soil types in northern Burkina Faso, West Africa. A split-plot design was used in a fenced environment for the experiment. Insecticide (Dieldrin) was used at a rate of 500

Anti-termite activity of essential oil and its components from Myristica ...

African Journals Online (AJOL)

Michael Horsfall

termite activity test followed the method of (Kang et al. 1990). Samples of 10, 25, and 50 mg of fruit essential oil as well as 1 and 5 mg of each individual compound dissolved in 600 µl of acetone were applied to 1 g filter paper samples (What man #3, 8.5 cm in diam). A piece of filter paper treated with solvent only was used ...

Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)

KAUST Repository

Ngugi, David

2011-11-28

Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using 15N isotope tracer analysis. Living termites emitted N 2 at rates ranging from 3.8 to 6.8nmolh -1 (g fresh wt.) -1. However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of 15N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N 2O, ranging from 0.4 to 3.9nmolh -1 (g fresh wt.) -1, providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

An Empirical Method for Particle Damping Design

Directory of Open Access Journals (Sweden)

Zhi Wei Xu

2004-01-01

Full Text Available Particle damping is an effective vibration suppression method. The purpose of this paper is to develop an empirical method for particle damping design based on extensive experiments on three structural objects – steel beam, bond arm and bond head stand. The relationships among several key parameters of structure/particles are obtained. Then the procedures with the use of particle damping are proposed to provide guidelines for practical applications. It is believed that the results presented in this paper would be helpful to effectively implement the particle damping for various structural systems for the purpose of vibration suppression.

Parametric Landau damping of space charge modes

Energy Technology Data Exchange (ETDEWEB)

Macridin, Alexandru [Fermilab; Burov, Alexey [Fermilab; Stern, Eric [Fermilab; Amundson, James [Fermilab; Spentzouris, Panagiotis [Fermilab

2016-09-23

Landau damping is the mechanism of plasma and beam stabilization; it arises through energy transfer from collective modes to the incoherent motion of resonant particles. Normally this resonance requires the resonant particle's frequency to match the collective mode frequency. We have identified an important new damping mechanism, parametric Landau damping, which is driven by the modulation of the mode-particle interaction. This opens new possibilities for stability control through manipulation of both particle and mode-particle coupling spectra. We demonstrate the existence of parametric Landau damping in a simulation of transverse coherent modes of bunched accelerator beams with space charge.

The origins and radiation of Australian Coptotermes termites: from rainforest to desert dwellers.

Science.gov (United States)

Lee, Timothy R C; Cameron, Stephen L; Evans, Theodore A; Ho, Simon Y W; Lo, Nathan

2015-01-01

The termite genus Coptotermes (Rhinotermitidae) is found in Asia, Africa, Central/South America and Australia, with greatest diversity in Asia. Some Coptotermes species are amongst the world's most damaging invasive termites, but the genus is also significant for containing the most sophisticated mound-building termites outside the family Termitidae. These mound-building Coptotermes occur only in Australia. Despite its economic and evolutionary significance, the biogeographic history of the genus has not been well investigated, nor has the evolution of the Australian mound-building species. We present here the first phylogeny of the Australian Coptotermes to include representatives from all described species. We combined our new data with previously generated data to estimate the first phylogeny to include representatives from all continents where the genus is found. We also present the first estimation of divergence dates during the evolution of the genus. We found the Australian Coptotermes to be monophyletic and most closely related to the Asian Coptotermes, with considerable genetic diversity in some Australian taxa possibly representing undescribed species. The Australian mound-building species did not form a monophyletic clade. Our ancestral state reconstruction analysis indicated that the ancestral Australian Coptotermes was likely to have been a tree nester, and that mound-building behaviour has arisen multiple times. The Australian Coptotermes were found to have diversified ∼13million years ago, which plausibly matches with the narrowing of the Arafura Sea allowing Asian taxa to cross into Australia. The first diverging Coptotermes group was found to be African, casting doubt on the previously raised hypothesis that the genus has an Asian origin. Copyright © 2014 Elsevier Inc. All rights reserved.

Catnip essential oil as a barrier to subterranean termites (Isoptera: Rhinotermitidae) in the laboratory

Science.gov (United States)

C.J. Peterson; J. Ems-Wilson

2003-01-01

The essential oil of catnip, Nepeta cataria (Lamiacae) was evaluated for behavioral effects on two populations of subterranean termite, Reticulitermes flavipes (Kollar) and R. virginicus (Banks) (Isoptera: Rhinotermitidae). The catnip essential oil contained =36: 64 E,Z-nepetalactone and Z,E-nepetalactone,...

Secondary queens in the parthenogenetic termite Cavitermes tuberosus develop through a transitional helper stage

Czech Academy of Sciences Publication Activity Database

Hellemans, S.; Fournier, D.; Hanus, Robert; Roisin, Y.

2017-01-01

Roč. 19, č. 6 (2017), s. 253-262 ISSN 1520-541X Institutional support: RVO:61388963 Keywords : facultative parthenogenesis * replacement queens * termites * asexual queen succession * ontogeny * Cavitermes Subject RIV: EG - Zoology OBOR OECD: Developmental biology Impact factor: 2.243, year: 2016

Wood frame systems for wood homes

Directory of Open Access Journals (Sweden)

Julio Cesar Molina

2010-12-01

Full Text Available The use of constructive systems that combine strength, speed, with competitive differential techniques and mainly, compromising with the environment, is becoming more popular in Brazil. The constructive system in wood frame for houses of up to five stories is very interesting, because it is a light system, structured in reforested treated wood which allows the combination of several materials, besides allowing speed in the construction and total control of the expenses already in the project phase for being industrialized. The structural behavior of the wood frame is superior to the structural masonry in strength, thermal and acoustic comfort. However, in Brazil, the wood frame is still little known and used, due to lack of technical knowledge about the system, prejudice associated the bad use of the wood as construction material, or still, in some cases, lack of normalization. The aim of this manuscript consists of presenting the main technical characteristics and advantages of the constructive system in wood frame homes, approaching the main stages of the constructive process through examples, showing the materials used in the construction, in addition the main international normative recommendations of the project. Thus, this manuscript also hopes to contribute to the popularization of the wood frame system in Brazil, since it is a competitive, fast and ecologically correct system. Moreover, nowadays, an enormous effort of the technical, commercial and industrial section has been accomplished for the development of this system in the country.

BIBLIOMETRICS ON ONE OF THE LARGEST TERMITE INVENTORIES IN THE CERRADO: "STUDIES ON TERMITES FROM THE MATO GROSSO STATE, BRAZIL BY AGA MATHEWS 1977"

Directory of Open Access Journals (Sweden)

HÉLIDA FERREIRA DA CUNHA

2015-01-01

Full Text Available ABSTRACT This paper consists on a bibliometric analysis of the international influences of the book "Studies on termites from the Mato Grosso State, Brazil", by AGA Mathews (1977. The number of citations has increased over the years after the first citation. Mathews book was cited in articles, reviews, theses, dissertations, books, book chapters, abstracts in conference proceedings, comments and scientific notes. Most these studies are empirical and descriptive. The studies were conducted in 35 countries of the Neotropical, Palearctic, Afrotropical, Nearctic, Australasia and Indomalaya regions. 55% of the studies were carried out in Brazil. The journals Sociobiology and Insectes Sociaux, have social insect studies within its scope, and the highest number of articles citing Mathews. Most of the 71 authors that cited Mathews more than twice are Brazilian. Constrictotermes cyphergaster was the most studied in over 80% of the studies addressing Isoptera. The most frequent keywords were termite, Isoptera and taxonomy, generalist terms indexed in most publications carried out in different countries. Most of the research studies were carried out in laboratories and native vegetation areas. Studies in agroecosystems were implemented predominantly in Brazil. This study shows the diversity of application (citations of Mathews' book, and that the number of citations will continue to increase due to the large amount of information presented by the author.

Process Damping and Cutting Tool Geometry in Machining

Science.gov (United States)

Taylor, C. M.; Sims, N. D.; Turner, S.

2011-12-01

Regenerative vibration, or chatter, limits the performance of machining processes. Consequences of chatter include tool wear and poor machined surface finish. Process damping by tool-workpiece contact can reduce chatter effects and improve productivity. Process damping occurs when the flank (also known as the relief face) of the cutting tool makes contact with waves on the workpiece surface, created by chatter motion. Tool edge features can act to increase the damping effect. This paper examines how a tool's edge condition combines with the relief angle to affect process damping. An analytical model of cutting with chatter leads to a two-section curve describing how process damped vibration amplitude changes with surface speed for radiussed tools. The tool edge dominates the process damping effect at the lowest surface speeds, with the flank dominating at higher speeds. A similar curve is then proposed regarding tools with worn edges. Experimental data supports the notion of the two-section curve. A rule of thumb is proposed which could be useful to machine operators, regarding tool wear and process damping. The question is addressed, should a tool of a given geometry, used for a given application, be considered as sharp, radiussed or worn regarding process damping.

Process Damping and Cutting Tool Geometry in Machining

International Nuclear Information System (INIS)

Taylor, C M; Sims, N D; Turner, S

2011-01-01

Regenerative vibration, or chatter, limits the performance of machining processes. Consequences of chatter include tool wear and poor machined surface finish. Process damping by tool-workpiece contact can reduce chatter effects and improve productivity. Process damping occurs when the flank (also known as the relief face) of the cutting tool makes contact with waves on the workpiece surface, created by chatter motion. Tool edge features can act to increase the damping effect. This paper examines how a tool's edge condition combines with the relief angle to affect process damping. An analytical model of cutting with chatter leads to a two-section curve describing how process damped vibration amplitude changes with surface speed for radiussed tools. The tool edge dominates the process damping effect at the lowest surface speeds, with the flank dominating at higher speeds. A similar curve is then proposed regarding tools with worn edges. Experimental data supports the notion of the two-section curve. A rule of thumb is proposed which could be useful to machine operators, regarding tool wear and process damping. The question is addressed, should a tool of a given geometry, used for a given application, be considered as sharp, radiussed or worn regarding process damping.

Damping Identification of Bridges Under Nonstationary Ambient Vibration

Directory of Open Access Journals (Sweden)

Sunjoong Kim

2017-12-01

Full Text Available This research focuses on identifying the damping ratio of bridges using nonstationary ambient vibration data. The damping ratios of bridges in service have generally been identified using operational modal analysis (OMA based on a stationary white noise assumption for input signals. However, most bridges are generally subjected to nonstationary excitations while in service, and this violation of the basic assumption can lead to uncertainties in damping identification. To deal with nonstationarity, an amplitude-modulating function was calculated from measured responses to eliminate global trends caused by nonstationary input. A natural excitation technique (NExT-eigensystem realization algorithm (ERA was applied to estimate the damping ratio for a stationarized process. To improve the accuracy of OMA-based damping estimates, a comparative analysis was performed between an extracted stationary process and nonstationary data to assess the effect of eliminating nonstationarity. The mean value and standard deviation of the damping ratio for the first vertical mode decreased after signal stationarization. Keywords: Damping, Operational modal analysis, Traffic-induced vibration, Nonstationary, Signal stationarization, Amplitude-modulating, Bridge, Cable-stayed, Suspension

Damping-off in forest nurseries

Science.gov (United States)

Carl Hartley

1921-01-01

Damping-off is the commonest English name for a symptomatic group of diseases affecting great numbers of plant species of widely separated phylogenetic groups. It is commonly used for any disease which results in the rapid decay of young succulent seedlings or soft cuttings. Young shoots from underground rootstocks may also be damped-off before they break through the...

The relationship between termite mound CH₄/CO₂ emissions and internal concentration ratios are species specific

OpenAIRE

B. Fest; S. K. Arndt; L. B. Hutley; S. J. Livesley; H. Jamali

2012-01-01

We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e) basis, annual CH4 flux estimate...

Piping system damping data at higher frequencies

International Nuclear Information System (INIS)

Ware, A.G.

1987-01-01

Research has been performed at the Idaho National Engineering Laboratory (INEL) for the United States Nuclear Regulatory Commission (USNRC) to determine best-estimate damping values for dynamic analyses of nuclear piping systems excited in the 20 to 100 Hz frequency range. Vibrations in this frequency range are typical of fluid-induced transients, for which no formal pipe damping guidelines exist. The available data found in the open literature and the USNRC/INEL nuclear piping damping data bank were reviewed, and a series of tests on a straight 3-in. (76-mm) piping system and a 5-in. (127-mm) system with several bends and elbows were conducted as part of this research program. These two systems were supported with typical nuclear piping supports that could be changed from test to test during the series. The resulting damping values were ≥ those of the Pressure Vessel Research Committee (PVRC) proposal for unisulated piping. Extending the PVRC damping curve from 20 to 100 Hz at 3% of critical damping would give a satisfactory representation of the test data. This position has been endorsed by the PVRC Technical Committee on Piping Systems. 14 refs

Offline software for the DAMPE experiment

Science.gov (United States)

Wang, Chi; Liu, Dong; Wei, Yifeng; Zhang, Zhiyong; Zhang, Yunlong; Wang, Xiaolian; Xu, Zizong; Huang, Guangshun; Tykhonov, Andrii; Wu, Xin; Zang, Jingjing; Liu, Yang; Jiang, Wei; Wen, Sicheng; Wu, Jian; Chang, Jin

2017-10-01

A software system has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite-based experiment. The DAMPE software is mainly written in C++ and steered using a Python script. This article presents an overview of the DAMPE offline software, including the major architecture design and specific implementation for simulation, calibration and reconstruction. The whole system has been successfully applied to DAMPE data analysis. Some results obtained using the system, from simulation and beam test experiments, are presented. Supported by Chinese 973 Program (2010CB833002), the Strategic Priority Research Program on Space Science of the Chinese Academy of Science (CAS) (XDA04040202-4), the Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China (NSFC) and CAS (U1531126) and 100 Talents Program of the Chinese Academy of Science

Wood

DEFF Research Database (Denmark)

Unterrainer, Walter

2014-01-01

come from? How is it harvested? How is it manufactured and treated ? How are the buildings detailed and protected against weather during construction to keep them dry and make them long-life ? In a period of climate change, forests are the last lungs of the planet to sequestrate CO2. Their global size......Wood – a sustainable building material ? For thousands of years and all over the planet, wood has been used as a building material and exciting architecture has been created in wood. The fantastic structural, physical and aesthetic properties of the material as well as the fact that wood...

Wood burning

Energy Technology Data Exchange (ETDEWEB)

Winkelmann, H

1955-01-01

Discussed are the use of wood as a fuel, the technique of wood combustion and the operation of wood-burning stoves for cooking and heating. In addition, there is a section which reviews the use of wood stoves in various countries and lists manufacturers of stoves, central heating furnaces and in some cases sawdust burners.

Magnetic damping phenomena in ferromagnetic thin-films and multilayers

Science.gov (United States)

Azzawi, S.; Hindmarch, A. T.; Atkinson, D.

2017-11-01

Damped ferromagnetic precession is an important mechanism underpinning the magnetisation processes in ferromagnetic materials. In thin-film ferromagnets and ferromagnetic/non-magnetic multilayers, the role of precession and damping can be critical for spintronic device functionality and as a consequence there has been significant research activity. This paper presents a review of damping in ferromagnetic thin-films and multilayers and collates the results of many experimental studies to present a coherent synthesis of the field. The terms that are used to define damping are discussed with the aim of providing consistent definitions for damping phenomena. A description of the theoretical basis of damping is presented from early developments to the latest discussions of damping in ferromagnetic thin-films and multilayers. An overview of the time and frequency domain methods used to study precessional magnetisation behaviour and damping in thin-films and multilayers is also presented. Finally, a review of the experimental observations of magnetic damping in ferromagnetic thin-films and multilayers is presented with the most recent explanations. This brings together the results from many studies and includes the effects of ferromagnetic film thickness, the effects of composition on damping in thin-film ferromagnetic alloys, the influence of non-magnetic dopants in ferromagnetic films and the effects of combining thin-film ferromagnets with various non-magnetic layers in multilayered configurations.

Fast damping in mismatched high intensity beam transportation

Directory of Open Access Journals (Sweden)

V. Variale

2001-08-01

Full Text Available A very fast damping of beam envelope oscillation amplitudes was recently observed in simulations of high intensity beam transport, through periodic FODO cells, in mismatched conditions [V. Variale, Nuovo Cimento Soc. Ital. Fis. 112A, 1571–1582 (1999 and T. Clauser et al., in Proceedings of the Particle Accelerator Conference, New York, 1999 (IEEE, Piscataway, NJ, 1999, p. 1779]. A Landau damping mechanism was proposed at the origin of observed effect. In this paper, to further investigate the source of this fast damping, extensive simulations have been carried out. The results presented here support the interpretation of the mechanism at the origin of the fast damping as a Landau damping effect.

Single bunch beam breakup in linacs and BNS damping

International Nuclear Information System (INIS)

Toyomasu, Takanori

1991-12-01

We study a single-bunch beam breakup (BBU) problem by a macro-particle model. We consider both the BBU solution and the Landau damping solution which includes the Balakin-Novokhatsky-Smirnov (BNS) damping. In the BBU solution, we get an analytic solution which includes both the Chao-Richter-Yao solution and the two-particle model solution and which agrees well with simulation. The solution can also be used in a multi-bunch case. In the Landau damping solution, we can be see the mechanism of Landau damping formally and can get some insights into BNS damping. We confirm that a two-particle model criterion for BNS damping is a good one. We expect that the two-particle model criterion is represented by the first order interaction in Landau damping solution of a macro-particle model. (author)

Prognostic and predictive value of DAMPs and DAMP-associated processes in cancer

Directory of Open Access Journals (Sweden)

Jitka eFucikova

2015-08-01

Full Text Available It is now clear that human neoplasms form, progress and respond to therapy in the context of an intimate crosstalk with the host immune system. In particular, accumulating evidence demonstrates that the efficacy of most, if not all, chemo- and radiotherapeutic agents commonly employed in the clinic critically depends on the (reactivation of tumor-targeting immune response. One of the mechanisms whereby conventional chemotherapeutics, targeted anticancer agents and radiotherapy can provoke a therapeutically relevant, adaptive immune response against malignant cells is commonly known as „immunogenic cell death (ICD. Importantly, dying cancer cells are perceived as immunogenic only when they emit a set of immunostimulatory signals upon the activation of intracellular stress response pathways. The emission of these signals, which are generally referred to as „damage-associated molecular patterns (DAMPs, may therefore predict whether patients will respond to chemotherapy or not, at least in some settings. Here, we review clinical data indicating that DAMPs and DAMP-associated stress responses might have prognostic or predictive value for cancer patients.

Monthly fluctuation of termite caste proportions (Isoptera) within fire ant mounds (hymenoptera: formicidae)

Science.gov (United States)

Thomas G. Shelton; J.T. Vogt; Marla J. Tanley; Arthur G. Appel

2003-01-01

Monthly abundance and caste proportions of subterranean termites (Reticulitennes spp.) inhabiting red imported fire ant (Solenopsis invicta Buren) mounds were recorded during 1999 and 2000 from a relatively undisturbed forest edge in Tuskegee, Alabama. Temperature data were also recorded at these mounds; mean air, soil, and mound temperatures followed a sine model over...

Confirmation of soil radiation damping from test versus analysis

International Nuclear Information System (INIS)

Eidinger, J.M.; Mukhim, G.S.; Desmond, T.P.

1987-01-01

The work was performed to demonstrate that soil-structure interaction effects for nuclear plant structures can be accurately (and conservatively) predicted using the finite element or soil spring methods of soil-structure interaction analysis. Further, the work was done to investigate the relative importance of soil radiation versus soil material damping in the total soil damping analytical treatment. The analytical work was benchmarked with forced vibration tests of a concrete circular slab resting on the soil surface. The applied loading was in the form of a suddenly applied pulse load, or snapback. The measured responses of the slap represent the free vibration of the slab after the pulse load has been applied. This simplifies the interpretation of soil damping, by the use of the logarithmic decay formulation. To make comparisons with the test results, the damping data calculated from the analytical models is also based on the logarithmic decay formulation. An attempt is made to differentiate the observed damped behavior of the concrete slab as being caused by soil radiation versus soil material damping. It is concluded that both the traditional soil radiation and material damping analytical simplifications are validated by the observed responses. It is concluded that arbitrary 'conservative' assumptions traditionally made in nuclear plant soil-structure interaction analyses are indeed arbitrary, and not born out by physical evidence. The amount of conservatism introduced by limiting total soil damping to values like 5% to 10% can be large. For the test slab sizes investigated, total soil damping is about 25%. For full size nuclear plant foundations, total soil damping is commonly in the 35% to 70% range. The authors suggest that full soil damping values (the combined radiation and material damping) should be used in the design, backfit and margin assessment of nuclear plants. (orig./HP)

Nonadecadienone, a New Termite Trail-Following Pheromone Identified in Glossotermes oculatus (Serritermitidae)

Czech Academy of Sciences Publication Activity Database

Hanus, Robert; Šobotník, Jan; Krasulová, Jana; Jiroš, Pavel; Žáček, Petr; Kalinová, Blanka; Dolejšová, Klára; Cvačka, Josef; Bourguignon, T.; Roisin, Y.; Lacey, M. J.; Sillam-Dusses, David

2012-01-01

Roč. 37, č. 1 (2012), s. 55-63 ISSN 0379-864X R&D Projects: GA ČR GAP506/10/1570 Institutional research plan: CEZ:AV0Z40550506 Keywords : Glossotermes * Serritermitidae * sternal gland * termites * trail-following pheromone * (10Z,13Z)-nonadeca-10,13-dien-2-one Subject RIV: CC - Organic Chemistry Impact factor: 3.222, year: 2012

Small horizontal emittance in the TESLA damping ring

International Nuclear Information System (INIS)

Decking, W.

2001-01-01

The present TESLA damping ring is designed for a normalized horizontal emittance of 8x10 -6 m. γ-γ collisions at the TESLA linear collider will benefit from a further decrease of the horizontal emittance. This paper reviews the processes which limit the horizontal emittance in the damping ring. Preliminary estimates on the smallest horizontal emittance for the present TESLA damping ring design as well as an ultimate limit of the emittance reachable with the TESLA damping ring concept will be given

Simplified Model of Nonlinear Landau Damping