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Edward L Vargo - One of the best experts on this subject based on the ideXlab platform.
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queen and king recognition in the Subterranean Termite reticulitermes flavipes evidence for royal recognition pheromones
PLOS ONE, 2019Co-Authors: Colin F Funaro, Coby Schal, Edward L VargoAbstract:Royal recognition is a central feature of insect societies, allowing them to maintain the reproductive division of labor and regulate colony demography. Queen recognition has been broadly demonstrated and queen recognition pheromones have been identified in social hymenopterans, and in one Termite species. Here we describe behaviors that are elicited in workers and soldiers by neotenic queens and kings of the Subterranean Termite, Reticulitermes flavipes, and demonstrate the chemical basis for the behavior. Workers and soldiers readily perform a lateral or longitudinal shaking behavior upon antennal contact with queens and kings. When royal cuticular chemicals are transferred to live workers or inert glass dummies, they elicit antennation and shaking in a dose-dependent manner. The striking response to reproductives and their cuticular extracts suggests that royal-specific cuticular compounds act as recognition pheromones and that shaking behavior is a clear and measurable queen and king recognition response in this Termite species.
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queen and king recognition in the Subterranean Termite reticulitermes flavipes evidence for royal recognition pheromones
bioRxiv, 2018Co-Authors: Colin F Funaro, Coby Schal, Edward L VargoAbstract:Royal recognition is a central feature of insect societies, allowing them to maintain the reproductive division of labor and regulate colony demography. Queen recognition has been broadly demonstrated and queen recognition pheromones have been identified in social hymenopterans, but not in Termites. Here we describe behaviors that are elicited in workers and soldiers by neotenic queens and kings of the Subterranean Termite, Reticulitermes flavipes, and demonstrate the chemical basis for the behavior. Workers and soldiers readily perform a lateral or longitudinal shaking behavior upon antennal contact with queens and kings. When royal cuticular chemicals are transferred to live workers or inert glass dummies, they elicit antennation and shaking in a dose-dependent manner. The striking response to reproductives and their cuticular extracts suggests that royal-specific cuticular compounds act as recognition pheromones and that shaking behavior is a clear and measurable queen and king recognition response in this Termite species.
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Effect of Fipronil on Subterranean Termite Colonies (Isoptera: Rhinotermitidae) in the Field
Journal of economic entomology, 2012Co-Authors: Edward L Vargo, Vincent ParmanAbstract:ABSTRACT To assess possible colony-level effects of fipronil, a commonly used nonrepellent termiticide, we conducted a field study of eight houses in the Raleigh, NC, area with infestations of the eastern Subterranean Termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). We installed an extensive grid of in-ground monitoring stations on each property (mean = 68.6 monitors per property) and collected samples from these stations as well as from mud tubes in the structure and wood debris in the yard for ≈6 mo. We genotyped all samples by using microsatellite markers to identify the number and locations of colonies present on each property. Houses were treated with either a full treatment (n = 5) or exterior/localized interior treatment (n = 3). After treatment, the monitors were checked monthly for 3 mo and then quarterly for 3 yr to track the fate of colonies. Wood debris in natural areas was checked semiannually for 3 yr. All 11 of the treated colonies (those attacking structures) disappear...
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Asexual queen succession in the Subterranean Termite Reticulitermes virginicus
Proceedings of the Royal Society B: Biological Sciences, 2011Co-Authors: Edward L Vargo, Paul Labadie, Kenji MatsuuraAbstract:Termite colonies are founded by a pair of primary reproductives. In many species, including Subterranean Termites (family Rhinotermitidae), the primary king and queen can be succeeded by neotenic reproductives that are produced from workers or nymphs within the colony. It is generally believed that these neotenics inbreed within the colony, sometimes for many generations. Here, we show that primary queens of the North American Subterranean Termite, Reticulitermes virginicus, are replaced by numerous parthenogenetically produced female neotenics. We collected functional female neotenics from five colonies of R. virginicus in North Carolina and Texas, USA. Genetic analysis at eight microsatellite loci showed that 91‐100% of the neotenics present within a colony were homozygous at all loci, indicating that they were produced through automictic parthenogenesis with terminal fusion. In contrast, workers, soldiers and alates were almost exclusively sexually produced by mating between the female neotenics and a single king. This is the second Termite species shown to undergo asexual queen succession, a system first described in the Japanese species, Reticulitermes speratus. Thus, the conditional use of sexual and asexual reproduction to produce members of different castes may be widespread within Reticulitermes and possibly other Subterranean Termites.
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polymorphic microsatellite loci in the european Subterranean Termite reticulitermes santonensis feytaud
Molecular Ecology Notes, 2004Co-Authors: Stephanie Dronnet, Anne-geneviève Bagnères, Thomas R Juba, Edward L VargoAbstract:We report on the identification and characterization of two dinucleotide, two trinucleotide and eight tetranucleotide microsatellite DNA loci isolated from the European Subterranean Termite Reticulitermes santonensis . We tested the loci on 51–92 individuals from 46 colonies from different regions of France. Eleven loci were polymorphic with 2–8 alleles per locus and low observed heterozygosities (0.10–0.48). We also tested the loci on 17–20 individuals from 10 colonies in the closely related North American species R. flavipes and found significantly more alleles (2–9 alleles per locus) and higher observed heterozygosities (0.15–0.80) than in R. santonensis . The lower observed heterozygosities in R. santonensis are consistent with higher levels of inbreeding in these colonies due to the presence of numerous inbred replacement reproductives.
Weste L. A. Osbrink - One of the best experts on this subject based on the ideXlab platform.
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foraging distance and population size of juvenile colonies of the formosan Subterranean Termite isoptera rhinotermitidae in laboratory extended arenas
Journal of Economic Entomology, 2017Co-Authors: Weste L. A. Osbrink, Garima Kakkar, Aaron J Mullins, Thomas ChouvencAbstract:The relationship between colony size and foraging distance was examined in extended foraging arenas with juvenile colonies of the Formosan Subterranean Termite, Coptotermes formosanus Shiraki. Our results showed that as long as royal pairs are present, larger colonies foraged at longer distances, and the oldest workers distributed farther away from the central nest. The results agree with the scaling model that predicts a large foraging range for animals of larger body size. An analysis of published data from population survey studies and field trials of bait toxicants showed that field colonies of the eastern Subterranean Termite, Reticulitermes flavipes (Kollar), follow the scaling model, while C. formosanus colonies were inconsistent with the model prediction. Reasons for the inconsistency with field data of C. formosanus are discussed.
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antifeedant and toxicity effects of thiophenes from four echinops species against the formosan Subterranean Termite coptotermes formosanus
Pest Management Science, 2006Co-Authors: Weste L. A. Osbrink, Alan R Lax, Nikolas Fokialakis, Leonid K Mamonov, Nadejda G Gemejieva, Amelia B Mims, A L Skaltsounis, Charles L CantrellAbstract:Over 220 crude extracts from repositories generated from plants native to Greece and Kazakhstan were evaluated for termiticidal activity against the Formosan Subterranean Termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Emerging from this screening effort were bioactive extracts from two Greek species (Echinops ritro L. and Echinops spinosissimus Turra subsp. spinosissimus) and extracts from two Kazakhstan species (Echinops albicaulis Kar. & Kir. and Echinops transiliensis Golosh.). Fractionation and isolation of constituents from the most active extracts from each of the four species has been completed, resulting in the isolation of eight thiophenes possessing varying degrees of termiticidal activity. 2,2':5',2"-Terthiophene and 5'-(3-buten-1-ynyl)-2,2'-bithiophene demonstrated 100% mortality against C. formosanus within 9 days at 1 and 2 wt% concentrations respectively. In addition, all but two of the eight compounds tested were significantly different from the solvent controls in the filter paper consumption bioassay.
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Hydroquinone is not a phagostimulant for the Formosan Subterranean Termite.
Journal of Chemical Ecology, 2005Co-Authors: Ashok K. Raina, John M Bland, Weste L. A. OsbrinkAbstract:It has been suggested that hydroquinone found in the labial glands of a number of Termite species acts as a primary phagostimulating factor. We tested hydroquinone as a phagostimulant using workers from three colonies of the Formosan Subterranean Termite, Coptotermes formosanus, under both laboratory and field conditions. Hydroquinone at concentrations ranging from ca. 0.002–20.0 ng/cm2 did not increase visitation by C. formosanus workers to treated over control filter papers, and was actually repellent at a 20 ng/cm2 dose. No phagostimulant response to hydroquinone was observed in two colonies. In the third, there was a significant increase in feeding on filter paper treated with a 2 ng/cm2 dose, but was significantly lower at a 20 ng/cm2 dose. Furthermore, sand treated with a gradient of hydroquinone, did not evoke increased tunneling activity compared with controls. GC-MS analysis of C. formosanus workers indicated that hydroquinone was present at an average of 41 pg/worker. It was also determined that within one week about 11%hydroquinone in aqueous solution oxidized to 1,4-benzoquinone. Our findings indicate that hydroquinone alone does not act as a phagostimulant but instead may act as a repellent at higher concentrations. The attractant/arrestant of the Formosan Termite may have multiple components of which hydroquinone, at low doses, could be one.
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Potential of entomopathogenic fungi as biological control agents against the formosan Subterranean Termite
2004Co-Authors: M. S. Wright, Weste L. A. OsbrinkAbstract:Tolerance, pathogenicity and transmission studies of the fungi Metarhizium and Beauveria, show that biological control agents can enhance Termite treatment flexibility. Subterranean Termites cause significant damage to wood structures and trees, especially along the Gulf of Mexico coastal region of the United States. A predominant pest species is the Formosan Subterranean Termite, Coptotermes formosanus (Shiraki), which differs from native Termite species in increased colony density and a propensity to destroy living wood. However, in order for Termite control approaches to work they must be non-repellant, transferrable, and have delayed toxicity to allow transfer from foraging workers to their nestmates. An Integrated Pest Management (IPM) approach will be necessary to reduce the impact of these pests. One component of IPM, and the focus of this work, is the development of biological control agents. Environmental conditions in FST nests and sites of infestation, such as living trees, can vary greatly. Some treatment sites require novel treatment methods which fungi may be uniquely suited to provide.
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united states department of agriculture agriculture research service research on targeted management of the formosan Subterranean Termite coptotermes formosanus shiraki isoptera rhinotermitidae
Pest Management Science, 2003Co-Authors: Alan R Lax, Weste L. A. OsbrinkAbstract:The Formosan Subterranean Termite, Coptotermes formosanus Shiraki is currently one of the most destructive pests in the USA. It is estimated to cost consumers over US dollars 1 billion annually for preventative and remedial treatment and to repair damage caused by this insect. The mission of the Formosan Subterranean Termite Research Unit of the Agricultural Research Service is to demonstrate the most effective existing Termite management technologies, integrate them into effective management systems, and provide fundamental problem-solving research for long-term, safe, effective and environmentally friendly new technologies. This article describes the epidemiology of the pest and highlights the research accomplished by the Agricultural Research Service on area-wide management of the Termite and fundamental research on its biology that might provide the basis for future management technologies. Fundamental areas that are receiving attention are Termite detection, Termite colony development, nutrition and foraging, and the search for biological control agents. Other fertile areas include understanding Termite symbionts that may provide an additional target for control. Area-wide management of the Termite by using population suppression rather than protection of individual structures has been successful; however, much remains to be done to provide long-term sustainable population control. An educational component of the program has provided reliable information to homeowners and pest-control operators that should help slow the spread of this organism and allow rapid intervention in those areas which it infests.
Alan R Lax - One of the best experts on this subject based on the ideXlab platform.
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characterization of a new endogenous endo β 1 4 glucanase of formosan Subterranean Termite coptotermes formosanus
Insect Biochemistry and Molecular Biology, 2011Co-Authors: Dunhua Zhang, John M Bland, Alan R Lax, April B AllenAbstract:Abstract The present work characterized a new endogenous cellulase (endo-β-1,4-glucanase) gene, CfEG5, uncovered in the transcriptome of Formosan Subterranean Termite (Coptotermes formosanus). The full-length gene was cloned and sequenced. It is similar to the CfEG3a described earlier ( Zhang et al., 2009 ) but not likely an allelic variant. GenomeWalker™ DNA walking analysis indicated that there may be one copy of CfEG5 and two copies of CfEG3a in the Termite genome. As with CfEG3a, the transcript of CfEG5 was detected predominantly in the salivary gland based on quantitative RT-PCR. Phylogenetic analysis of translated amino acid sequence showed that the CfEG5 is more related to CaEG, derived from an Australian Subterranean Termite (Coptotermes acinaciformis), than CfEG3a and other cellulases from Coptotermes formosanus, Reticulitermes speratus, or Reticulitermes flavipes. Recombinant CfEG5, produced in Escherichia coli, was active against filter-paper cellulose, resulting in mostly cellobiose and cellotriose, similar to the enzymatic and biochemical properties of CfEG3a. These findings would lead to further investigation of both the evolutionary origin of eukaryotic cellulase genes and the evolutionary relationship of Termite species. The cellulose-degrading enzyme is applicable for bioconversion of wood to simple sugars and production of biofuels. The recombinant cellulase should also be useful for designing and screening of inhibitors for the development of target-specific and environment-friendly bio-termicides.
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presence of nitrogen fixing klebsiella pneumoniae in the gut of the formosan Subterranean Termite coptotermes formosanus
Bioresource Technology, 2008Co-Authors: Mark Doolittle, Ashok K. Raina, Alan R Lax, Raj BoopathyAbstract:A gram-negative facultative anaerobic enteric bacterium, Klebsiella pneumoniae was isolated from the hindgut of the Formosan Subterranean Termite (FST). It was characterized using, fatty acid methyl ester (FAME) analysis, BIOLOG assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and biochemical studies. The role of this isolate seems to be nitrogen fixation because the Termite's diet is nitrogen deficient and the isolate produced significant amounts of ammonia when it was grown on nitrogen deficient medium under anaerobic condition with nitrogen gas in the headspace.
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Effect of Orange Oil Extract on the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)
Journal of economic entomology, 2007Co-Authors: Ashok K. Raina, John M Bland, Alan R Lax, Mark Doolittle, Raj Boopathy, Michael FolkinsAbstract:The Formosan Subterranean Termite, Coptotermesformosanus Shiraki (Isoptera: Rhinotermitidae), accidentally brought into the United States, has become a major urban pest, causing damage to structures and live trees. Because of increasing restrictions on the use of conventional termiticides, attention is focused on finding safer alternative methods for Termite management. Oil from citrus peel, referred to here as orange oil extract (OOE), contains -92% d-limonene, and it is generally known to be toxic to insects. In laboratory experiments, 96 and 68% Termites were killed in 5 d when OOE at 5 ppm (vol:vol) was dispensed from the top or bottom, respectively, with Termites held at the opposite end of a tight-fitting plastic container. Apart from high mortality, workers exposed to vapor consumed significantly less filter paper than controls. However, when Termites were exposed to OOE vapor, even at 10 ppm, in the void of a model wall, there was very little mortality. Termites did not tunnel through glass tubes filled with sand treated with 0.2 or 0.4% OOE. Sand treated with OOE was extracted each week for 8 wk to determine the remaining amount of d-limonene. Results indicated that there was a sharp decline in the quantity of d-limonene during the first 3 wk to a residual level that gradually decreased over the remaining period. With a suitable method of application and in combination with other control practices, OOE can be effectively used for the control of Subterranean Termites.
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antifeedant and toxicity effects of thiophenes from four echinops species against the formosan Subterranean Termite coptotermes formosanus
Pest Management Science, 2006Co-Authors: Weste L. A. Osbrink, Alan R Lax, Nikolas Fokialakis, Leonid K Mamonov, Nadejda G Gemejieva, Amelia B Mims, A L Skaltsounis, Charles L CantrellAbstract:Over 220 crude extracts from repositories generated from plants native to Greece and Kazakhstan were evaluated for termiticidal activity against the Formosan Subterranean Termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Emerging from this screening effort were bioactive extracts from two Greek species (Echinops ritro L. and Echinops spinosissimus Turra subsp. spinosissimus) and extracts from two Kazakhstan species (Echinops albicaulis Kar. & Kir. and Echinops transiliensis Golosh.). Fractionation and isolation of constituents from the most active extracts from each of the four species has been completed, resulting in the isolation of eight thiophenes possessing varying degrees of termiticidal activity. 2,2':5',2"-Terthiophene and 5'-(3-buten-1-ynyl)-2,2'-bithiophene demonstrated 100% mortality against C. formosanus within 9 days at 1 and 2 wt% concentrations respectively. In addition, all but two of the eight compounds tested were significantly different from the solvent controls in the filter paper consumption bioassay.
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united states department of agriculture agriculture research service research on targeted management of the formosan Subterranean Termite coptotermes formosanus shiraki isoptera rhinotermitidae
Pest Management Science, 2003Co-Authors: Alan R Lax, Weste L. A. OsbrinkAbstract:The Formosan Subterranean Termite, Coptotermes formosanus Shiraki is currently one of the most destructive pests in the USA. It is estimated to cost consumers over US dollars 1 billion annually for preventative and remedial treatment and to repair damage caused by this insect. The mission of the Formosan Subterranean Termite Research Unit of the Agricultural Research Service is to demonstrate the most effective existing Termite management technologies, integrate them into effective management systems, and provide fundamental problem-solving research for long-term, safe, effective and environmentally friendly new technologies. This article describes the epidemiology of the pest and highlights the research accomplished by the Agricultural Research Service on area-wide management of the Termite and fundamental research on its biology that might provide the basis for future management technologies. Fundamental areas that are receiving attention are Termite detection, Termite colony development, nutrition and foraging, and the search for biological control agents. Other fertile areas include understanding Termite symbionts that may provide an additional target for control. Area-wide management of the Termite by using population suppression rather than protection of individual structures has been successful; however, much remains to be done to provide long-term sustainable population control. An educational component of the program has provided reliable information to homeowners and pest-control operators that should help slow the spread of this organism and allow rapid intervention in those areas which it infests.
Ashok K. Raina - One of the best experts on this subject based on the ideXlab platform.
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presence of nitrogen fixing klebsiella pneumoniae in the gut of the formosan Subterranean Termite coptotermes formosanus
Bioresource Technology, 2008Co-Authors: Mark Doolittle, Ashok K. Raina, Alan R Lax, Raj BoopathyAbstract:A gram-negative facultative anaerobic enteric bacterium, Klebsiella pneumoniae was isolated from the hindgut of the Formosan Subterranean Termite (FST). It was characterized using, fatty acid methyl ester (FAME) analysis, BIOLOG assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and biochemical studies. The role of this isolate seems to be nitrogen fixation because the Termite's diet is nitrogen deficient and the isolate produced significant amounts of ammonia when it was grown on nitrogen deficient medium under anaerobic condition with nitrogen gas in the headspace.
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molting in workers of the formosan Subterranean Termite coptotermes formosanus
Journal of Insect Physiology, 2008Co-Authors: Ashok K. Raina, Yong Ihl Park, Dale B GelmanAbstract:The Formosan Subterranean Termite, Coptotermes formosanus, with its huge colonies, is a major urban pest in several southern states and Hawaii as well as in South Asia. Because of their cryptic nature (underground habitat) and very long life cycle, not much is known about molting in Termite workers. In C. formosanus, the workers stop foraging and lose their gut fauna, respectively, approximately 10 and 5 days prior to ecdysis. In any given colony an average of 1.01% (range 0.6-1.8) of the workers were found to molt each day under laboratory conditions. Workers destined to molt become sluggish and their head capsules develop a mottled texture one day prior to ecdysis. Ecdysis was generally accomplished with the assistance of other workers, which also fed on the exuviae. Immediately after molting worker mandibles were light pink in color and became fully melanized approximately two days later. Gut fauna were acquired on the fourth day after molting. Flagellates were transferred as small encysted cells from other workers through proctodeal feeding. Juvenile hormone III titer ranged between 30-41 pg/mg bodyweight in all stages except in workers sampled 6 days prior to ecdysis. In these workers the titer was 80.5 pg/mg. The high juvenile hormones (JH) titer may also be involved in causing defaunation. Ecdysteroid titer increased from 2.1 pg/mg in non-molting workers to 359.5 and 332.4 pg/mg one and two days following defaunation, respectively. There was a second smaller peak two days prior to ecdysis.
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Effect of Orange Oil Extract on the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)
Journal of economic entomology, 2007Co-Authors: Ashok K. Raina, John M Bland, Alan R Lax, Mark Doolittle, Raj Boopathy, Michael FolkinsAbstract:The Formosan Subterranean Termite, Coptotermesformosanus Shiraki (Isoptera: Rhinotermitidae), accidentally brought into the United States, has become a major urban pest, causing damage to structures and live trees. Because of increasing restrictions on the use of conventional termiticides, attention is focused on finding safer alternative methods for Termite management. Oil from citrus peel, referred to here as orange oil extract (OOE), contains -92% d-limonene, and it is generally known to be toxic to insects. In laboratory experiments, 96 and 68% Termites were killed in 5 d when OOE at 5 ppm (vol:vol) was dispensed from the top or bottom, respectively, with Termites held at the opposite end of a tight-fitting plastic container. Apart from high mortality, workers exposed to vapor consumed significantly less filter paper than controls. However, when Termites were exposed to OOE vapor, even at 10 ppm, in the void of a model wall, there was very little mortality. Termites did not tunnel through glass tubes filled with sand treated with 0.2 or 0.4% OOE. Sand treated with OOE was extracted each week for 8 wk to determine the remaining amount of d-limonene. Results indicated that there was a sharp decline in the quantity of d-limonene during the first 3 wk to a residual level that gradually decreased over the remaining period. With a suitable method of application and in combination with other control practices, OOE can be effectively used for the control of Subterranean Termites.
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Hydroquinone is not a phagostimulant for the Formosan Subterranean Termite.
Journal of Chemical Ecology, 2005Co-Authors: Ashok K. Raina, John M Bland, Weste L. A. OsbrinkAbstract:It has been suggested that hydroquinone found in the labial glands of a number of Termite species acts as a primary phagostimulating factor. We tested hydroquinone as a phagostimulant using workers from three colonies of the Formosan Subterranean Termite, Coptotermes formosanus, under both laboratory and field conditions. Hydroquinone at concentrations ranging from ca. 0.002–20.0 ng/cm2 did not increase visitation by C. formosanus workers to treated over control filter papers, and was actually repellent at a 20 ng/cm2 dose. No phagostimulant response to hydroquinone was observed in two colonies. In the third, there was a significant increase in feeding on filter paper treated with a 2 ng/cm2 dose, but was significantly lower at a 20 ng/cm2 dose. Furthermore, sand treated with a gradient of hydroquinone, did not evoke increased tunneling activity compared with controls. GC-MS analysis of C. formosanus workers indicated that hydroquinone was present at an average of 41 pg/worker. It was also determined that within one week about 11%hydroquinone in aqueous solution oxidized to 1,4-benzoquinone. Our findings indicate that hydroquinone alone does not act as a phagostimulant but instead may act as a repellent at higher concentrations. The attractant/arrestant of the Formosan Termite may have multiple components of which hydroquinone, at low doses, could be one.
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Effects of plant flavonoids on fecundity, survival, and feeding of the Formosan Subterranean Termite.
Journal of Chemical Ecology, 2003Co-Authors: Stephen M. Boue, Ashok K. RainaAbstract:Fecundity, mortality, and food consumption of the Formosan Subterranean Termite, Coptotermes formosanus Shiraki, were evaluated in response to five plant flavonoids (genistein, biochanin A, apigenin, quercetin, and glyceollin). Apigenin fed at 50 μg/primary reproductive pair proved to be the most toxic flavonoid. Biochanin A was most effective in reducing fecundity. Subsequently, these two flavonoids were tested through oral feeding and topical application at 100-μg dose. Significant reduction in the numbers of progeny was evident for biochanin A in both treatment methods. Choice feeding tests with Termite workers showed that initially Termites were attracted to filter paper treated with biochanin A, but over a period of 72 hr, consumed significantly less material when compared to controls. Biochanin A is a promising phytochemical with ability to reduce fecundity in primary reproductives of the Formosan Subterranean Termite, but it does not elicit phagostimulant activity.
Thomas Chouvenc - One of the best experts on this subject based on the ideXlab platform.
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Courtship Behavior Confusion in Two Subterranean Termite Species that Evolved in Allopatry (Blattodea, Rhinotermitidae, Coptotermes)
Journal of Chemical Ecology, 2020Co-Authors: Thomas Chouvenc, David Sillam-dussès, Alain RobertAbstract:Congeneric species that live in sympatry may have evolved various mechanisms that maintain reproductive isolation among species. However, with the spread of invasive organisms owing to increased global human activity, some species that evolved in allopatry can now be found outside their native range and may have the opportunity to interact, in the absence of mechanisms for reproductive isolation. In South Florida, where the Asian Subterranean Termite, Coptotermes gestroi (Wamann), and the Formosan Subterranean Termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae) are invasive, the two species can engage in heterospecific mating behavior as their distribution range and their dispersal flight season both overlap. Termites rely on semiochemicals for many of their activities, including finding a mate after a dispersal flight. In this study, we showed that females of both species produce (3 Z ,6 Z ,8 E )-dodeca-3,6,8-trien-1-ol (DTE) from their tergal glands as a shared sex pheromone. We suggest that both species primarily rely on an inundative dispersal flight strategy to find a mate, and that DTE is used as a short distance pheromone or contact pheromone to initiate and maintain the tandem between males and females. The preference of C. gestroi males for C. formosanus females during tandem resulted from the relatively high amount of DTE produced by tergal glands of C. formosanus females, when compared with those of C. gestroi females. This results in confusion of mating in the field during simultaneous dispersal flights, with a potential for hybridization. Such observations imply that no prezygotic barriers emerged while the two species evolved in allopatry for ~18 Ma.
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foraging distance and population size of juvenile colonies of the formosan Subterranean Termite isoptera rhinotermitidae in laboratory extended arenas
Journal of Economic Entomology, 2017Co-Authors: Weste L. A. Osbrink, Garima Kakkar, Aaron J Mullins, Thomas ChouvencAbstract:The relationship between colony size and foraging distance was examined in extended foraging arenas with juvenile colonies of the Formosan Subterranean Termite, Coptotermes formosanus Shiraki. Our results showed that as long as royal pairs are present, larger colonies foraged at longer distances, and the oldest workers distributed farther away from the central nest. The results agree with the scaling model that predicts a large foraging range for animals of larger body size. An analysis of published data from population survey studies and field trials of bait toxicants showed that field colonies of the eastern Subterranean Termite, Reticulitermes flavipes (Kollar), follow the scaling model, while C. formosanus colonies were inconsistent with the model prediction. Reasons for the inconsistency with field data of C. formosanus are discussed.
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establishment and spread of two invasive Subterranean Termite species coptotermes formosanus and c gestroi isoptera rhinotermitidae in metropolitan southeastern florida 1990 2015
Florida Entomologist, 2016Co-Authors: Thomas Chouvenc, Ruduolf H ScheffrahnAbstract:Abstract This study reports the spread of 2 major invasive Subterranean Termite species (Isoptera: Rhinotermitidae) in metropolitan southeastern Florida: Coptotermes formosanus Shiraki and C. gestroi (Wasmann). Termite records from 1990 to 2015 were analyzed to determine the expansion of their distribution. Our results suggest that the ranges of their distribution have increased exponentially during this time frame. This observation raises concerns about potential structural damage in this urbanized area, which includes 6 million residents. The risk to structures located in an area with known Coptotermes infestation increased from 0.49% in 2000 to 7.3% in 2015, with some species distributional overlap. In addition, several localities that had Coptotermes records before 2000 have registered an increased density of Termite infestation and swarming activity. We argue that the Subterranean Termite problem in metropolitan southeastern Florida is still in its early phase of invasion, and we predict that the dis...
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Territorial Status-Quo Between the Big-Headed Ant (Hymenoptera: Formicidae) and the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)
Florida Entomologist, 2015Co-Authors: Thomas Chouvenc, Aaron J MullinsAbstract:Abstract The big-headed ant, Pheidole megacephala (Fabr.) (Hymenoptera: Formicidae) and the Formosan Subterranean Termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) are 2 invasive species in south Florida, and both have a major economic and ecological impact. Because both species are often associated with man-made structures, we investigated how the 2 species interacted when their tunneling system connected, to determine if the big-headed ant had the ability to predate or displace Subterranean Termite colonies. It was previously suggested that the 2 species had a predator-prey interaction. However in this study we showed that C. formosanus can defend its territory against P. megacephala with minimal loss, and we therefore re-described their interaction as a status quo for habitat competition. It is unlikely that a competitive displacement would take place between C. formosanus and P. megacephala because of their ability to successfully defend their respective nests.
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Molting Process in the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)
Annals of The Entomological Society of America, 2013Co-Authors: Lin Xing, Thomas Chouvenc, Nan-yao SuAbstract:This study describes the behavioral and histological changes that take place during ecdysis in the Formosan Subterranean Termite. The molting process was described in four distinct phases, starting with the peristaltic contraction of the abdomen to the complete shedding of the exuvium. Although individual Termites still managed to go through the molting process when isolated from their nestmates, it required more time for the molting individual to complete the process than when aided by its nestmates. Histological observations were made on Termites during the intermolt period, the premolting or fasting period, the pre-ecdysis and the ecdysis periods, and on newly molted individuals. Symbiotic protozoans were voided at the beginning of the premolting/fasting period. The detachment and reattachment of the muscles of the abdominal segments occurred during pre-ecdysis, and the leg muscle detachment and reattachment occurred during ecdysis. During pre-ecdysis, the abdominal cuticle had a wrinkled texture and two layers of cuticles were observed, one of which was the newly formed cuticle underneath the old one. Finally, the old tracheae were shed from the tracheal system and were pulled out from the spiracular openings of the mesothorax with the help of the nestmates. We concluded that, as social insects, the presence of nestmates during the molting of individual Termites reduced the time necessary to complete the ecdysis, and the histological description of the molting process provides a template for further studies on the effect of chitin synthesis inhibitors on ecdysis in Termites.
