Reticulitermes Flavipes Research Articles

Identification of a queen and king recognition pheromone in the subterranean termite Reticulitermes flavipes

Chemical communication is fundamental to success in social insect colonies. Species-, colony-, and caste-specific blends of cuticular hydrocarbons (CHCs) and other chemicals have been well documented as pheromones, mediating important behavioral and physiological aspects of social insects. More specifically, royal pheromones used by queens (and kings in termites) enable workers to recognize and care for these vital individuals and maintain the reproductive division of labor. In termites, however, no royal-recognition pheromones have been identified to date. In the current study, solvent extracts of the subterranean termite Reticulitermes flavipes were analyzed to assess differences in cuticular compounds among castes. We identified a royal-specific hydrocarbon-heneicosane-and several previously unreported and highly royal enriched long-chain alkanes. When applied to glass dummies, heneicosane elicited worker behavioral responses identical to those elicited by live termite queens, including increased vibratory shaking and antennation. Further, the behavioral effects of heneicosane were amplified when presented with nestmate termite workers' cuticular extracts, underscoring the importance of chemical context in termite royal recognition. Thus, heneicosane is a royal-recognition pheromone that is active in both queens and kings of R. flavipes The use of heneicosane as a queen and king recognition pheromone by termites suggests that CHCs evolved as royal pheromones ∼150 million years ago, ∼50 million years before their first use as queen-recognition pheromones in social Hymenoptera. We therefore infer that termites and social Hymenoptera convergently evolved the use of these ubiquitous compounds in royal recognition.

Spatial and genetic distribution of a north American termite, Reticulitermes flavipes, across the landscape of Paris

Urbanization often negatively impacts biological diversity. Some organisms, however, have traits that are preadapted to urban environments and thus may thrive. Reticulitermes flavipes is one such organism. Indigenous to the Eastern US, it has been introduced into multiple countries. In France, R. flavipes causes major damage to buildings. Although Paris is one of the country’s most infested cities, the factors determining R. flavipes’ distribution and propagation are poorly understood. Using data on termite occurrence, termite genetics, and environmental variables, our study aims to identify factors that explain the distribution and spread of R. flavipes within Paris. First, we explored the association between several environmental variables and the termite’s distribution pattern in Paris; since 2000, a total of 2106 infestations have been recorded. Second, we inferred termite population and colony genetic structure at 66 sample locations using 9 microsatellite loci. Third, we used least-cost models and partial Mantel tests to study the effects of environmental variables on the termite’s population genetic structure. Our analyses revealed that building-related variables were significantly associated with termite infestations and could thus help explain the termite’s spatial distribution pattern. Furthermore, railway networks also explain termite propagation and genetic patterns. Additionally, we found that the termite’s spread is likely driven by budding dispersal, which may be constrained by buildings and roads. Even if budding dispersal could facilitate R. flavipes’ spread in urban areas, it cannot explain the termite’s distribution in Paris all on its own. Indeed, termite propagation seems to be significantly driven by anthropogenic activities.

Termiticidal activity of chitosan against the subterranean termites Reticulitermes flavipes and Reticulitermes virginicus.

Chitosan is a derivative form of chitin, which is the major component of exoskeletons of arthropods and the cell walls of fungi. The antimicrobial activity of chitosan against lepidopterans, aphids, fungi and bacteria has been extensively investigated, but only one report on the termiticidal effect of chitosan on termites has been published. In this study, we examined the termiticidal activity of chitosan by exposing single colonies of Reticulitermes flavipes (Kollar) and Reticulitermes virginicus Banks to wood treated with six different concentrations of chitosan solutions. Termite mortality and percent mass loss of wood samples after exposure to termites for 4 weeks were calculated. High termite mortality (≥ 94%) occurred during exposure of R. flavipes termites to chitosan-treated wood with ≥38 mg g-1 treatment concentrations (≥ 2% chitosan), while <50% termite mortality was observed at lower treatment concentrations (11-15 mg g-1 ; 0.5% and 1% chitosan). For R. virginicus, 100% mortality was observed at all levels of treatment concentrations. A decrease in the percent mass loss of the wood sample was apparent in samples treated with solutions with an increasing chitosan concentration, with a significant difference (P < 0.05) between lower and higher treatment concentrations. Treatment retention in wood samples upon leaching was also determined and showed retention levels of between 0 and 30 mg g-1 chitosan retention. This study investigated the exposure of subterranean termites to chitosan as a wood preservative. The results show that chitosan treatments at sufficiently high loadings could protect wood against termites, preferably under non-leaching conditions. © 2018 Society of Chemical Industry.

Testing for aggression and nestmate recognition in the Eastern subterranean termite (Reticulitermes flavipes)

Social insect colonies typically have well-defined social and physical boundaries but in some cases, colonies may take-on a more diffuse form with no obvious nestmate recognition or inter-colony aggression. Why colonies adopt closed versus open societies is not well understood, but it is presumably related to the genetic or environmental identity of individuals. In this study, we use Canadian populations of the Eastern subterranean termite (Reticulitermes flavipes) to test for evidence of aggression and nestmate recognition. Specifically, we predict that any inter-colony aggression will increase as a function of geographic distance. In short-term, (5-min) Petri-dish trials (varying caste, group size and colony source) we observed no evidence of aggression. However, in 2- and 7-day shared-resource assays, we observed very little inter-colony mixing and a high incidence of mortality in non-nestmate pairings. Our long-term observations imply that subterranean termites sort and potentially compete on the basis of nest origin, and that this recognition is mediated in part by ecological context. This behavior would not be evident from Petri dish-style assays, which lack this context and may explain why prior studies of kin or nestmate recognition in R. flavipes have yielded mixed results.

Measurement of termite resistance of particleboard panels made from Eastern redcedar using nano particle added modified starch as binder

The objective of this study was to evaluate the resistance of experimental particleboard panels exposed to subterranean termites, (Reticulitermes flavipes Kollar). Panels were manufactured from Eastern redcedar (Juniperus virginiana L.) using nano-SiO2 particles added modified starch as a binder. The termite resistance of samples was evaluated using choice and no-choice bioassay approach for 12 weeks. Radiata pine control samples had 87.65% weight loss as compared with 9.92–14.07% weight loss of panel samples. The damage rating index (DRI) of the choice feeding test had the highest value of 4.00 in the case of radiata pine samples and the lowest value of 2.25 resulted from A1 panels having 0.60 g/cm3 density level and 1% of nanoparticles. In no-choice feeding tests, panel samples had less feeding damage compared to that of radiata pine samples and termite worker survival rate was less than 2%, in contrast to 87% survival rate for radiata pine control specimens as a result of 12-week exposure time. The average lowest weight loss value of 9.25% was found for A3 panels, having 0.60 g/cm3 density level and 3% of nanoparticles, and the average highest value of 14.08% was determined for the control samples. Based on the findings in this work it appears that experimental panels manufactured in this study had a certain level of resistance against the damage by subterranean termites.

Characterization of cellulose-degrading microbiota from the eastern subterranean termite and soil

Background: While there have been a lot of studies on the termite gut microbiota, there has been very little research directly on the cellulose-degrading microbiota in termites or their soil environment. This study addresses this problem by profiling cellulose-degrading bacteria and archaea in the selective cellulose cultures of two samples of the eastern subterranean termite (Reticulitermes flavipes) and one soil sample collected at the same location as one of the termite samples. Methods: All the cultures were examined for cell concentration and remaining cellulose after the culture was completed. The 16S rRNA pyrotag sequencing method was used to identify the prokaryotic microbiota for the three cultures and one termite colony without culture. The MOTHUR, SSU-ALIGN, RDPTools, phyloseq, and other R packages were used for sequence and statistical analyses. Results: Biochemical analyses of the cultures suggested high efficiency of cellulose degradation. Comparative analyses between the cultured and uncultured termite gut microbiota revealed a significant difference. Proteobacteria and Firmicutes were found to be the two most abundant phyla of cellulose-degrading bacteria from the three cultures, but different classes within each phylum dominated the different samples. Shared and sample-specific cellulose-degrading taxa, including a core set of taxa across all the cultures, were identified. Conclusions: Our study demonstrates the importance of using selective cellulose culture to study the cellulose-degrading microbial community. It also revealed that the cellulose-degrading microbiota in the eastern subterranean termite is significantly influenced by the microbiota in the surrounding soil environment. Biochemical analyses showed that the microbial communities enriched from all the selective cultures were efficient in degrading cellulose, and a core set of bacteria have been identified as targets for further functional analyses.

Soldier-biased gene expression in a subterranean termite implies functional specialization of the defensive caste.

In a termite colony, reproduction is typically monopolized by a small number of sexuals that are supported by reproductively altruistic soldiers and workers. We expect caste differentiation to be associated with clear-cut differences in gene expression, and for these differences to reflect caste function and development. Here, we use RNA-Sequencing to compare the gene expression profiles of sexual nymphs and two non-reproductive helper castes (i.e., workers and soldiers) of the Eastern subterranean termite Reticulitermes flavipes. We found that of n = 93 genes that are strictly expressed as a function of caste, a majority (78%) show a soldier-specific pattern. This conspicuous soldier-bias in genome-wide expression suggests that this defensively specialized caste is functionally well-differentiated from both the reproductive and the other non-reproductive caste of this species, despite a shared developmental program with workers. Gene ontology analysis supports the notion of functional specialization by soldiers, as soldier-biased gene sets are enriched for novel biological processes. Whether this pattern reflects ancient or more recent bouts of selection for caste novelty at the gene-regulatory level is not known, but because soldiers are sterile and thus have no direct fitness, any selection for novelty must have been mediated indirectly, through reproducing relatives.

Potential spread of the invasive North American termite, Reticulitermes flavipes, and the impact of climate warming

Reticulitermes flavipes is an invasive termite from North America that is found in several European countries, including France from north to south. It feeds on several timber species and can cause major damage when it infests lumber. Termites are urban pests: they are often found in and around towns and their expansion is closely linked to human activity. Although, by law, termite infestations must be reported and treated, R. flavipes continues to spread. To better identify areas that may soon be colonized, it is crucial to understand the mechanisms underlying the termite’s spread at a fine spatial scale. However, the complexity of the species’ dispersal dynamics (i.e., via swarming, budding, or human-mediated transport of infested material) and social organization render this process difficult. The goal of our study was to determine R. flavipes’ potential to expand its current range within a region of France: Centre-Val de Loire. We focused on one administrative department within the region—Indre and Loire—where infestations are common and data on termite presence date back to the 1980s. We developed a spatiotemporal model to study the growth and dispersal of termite colonies within favorable habitat. Habitat favorability was defined based on the density of urbanization and annual mean minimum temperature. First, we modeled temporal population dynamics, using biological parameters describing the transitions between life stages/castes within colonies; we could thus estimate alates production. Then, using this information, we modeled termite dispersal within favorable habitat, and determined the termite’s potential spread. We validated the results by comparing the model’s output with actual data on the termite’s range expansion between 1985 (when the termite was first observed in the region) and 2013. Finally, the model was used to predict the termite’s future spread given climate warming for the period from 2013 to 2030. The results show that an increase in temperature should increase the amount of favorable habitat and, as a consequence, termites could continue to spread within this region. In addition to continuing current control efforts, it will be necessary to enact preventative strategies in newly favorable habitat. In these areas, monitoring efforts should therefore be intensified, as they might be able to slow down the termite’s spread and limit its impact.

An American termite in Paris: temporal colony dynamics.

Termites of the genus Reticulitermes are widespread invaders, particularly in urban habitats. Their cryptic and subterranean lifestyle makes them difficult to detect, and we know little about their colony dynamics over time. In this study we examined the persistence of Reticulitermes flavipes (Kollar) colonies in the city of Paris over a period of 15years. The aim was (1) to define the boundaries of colonies sampled within the same four areas over two sampling periods, (2) to determine whether the colonies identified during the first sampling period persisted to the second sampling period, and (3) to compare the results obtained when colonies were delineated using a standard population genetic approach versus a Bayesian clustering method that combined both spatial and genetic information. Herein, colony delineations were inferred from genetic differences at nine microsatellite loci and one mitochondrial locus. Four of the 18 identified colonies did not show significant differences in their genotype distributions between the two sampling periods. While allelic richness was low, making it hard to reliably distinguish colony family type, most colonies appeared to retain the same breeding structure over time. These large and expansive colonies showed an important ability to fuse (39% were mixed-family colonies), contained hundreds of reproductives and displayed evidence of isolation-by-distance, suggesting budding dispersal. These traits, which favor colony persistence over time, present a challenge for pest control efforts, which apply treatment locally. The other colonies showed significant differences, but we cannot exclude the possibility that their genotype distributions simply changed over time.

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

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.

A Geometric Analysis of the Regulation of Inorganic Nutrient Intake by the Subterranean Termite Reticulitermes flavipes Kollar.

Most studies on termite food selection have focused on a single nutrient per choice, however, termites, like all animals, must balance multiple nutrients in their diet. While most studies that use multi-nutrient approaches focus on macromolecules, the ability to balance the intake of inorganic nutrients is also vital to organisms. In this study, we used the geometric framework to test the effects of multiple inorganic nutrients on termite feeding. We presented the subsets of Reticulitermes flavipes colonies with food enriched with varying in levels of KCl, MgSO4, and FePO4. Each trial varied two of the three nutrients while the third nutrient was kept constant. The amount of food consumed was measured over two weeks. The termites’ feeding patterns during the study suggested that they fed until they reached a limit for MgSO4. This result suggests that the termites were using the rule of compromise such that the termites would over consume KCl or FePO4 in order to avoid overeating MgSO4. Thus, the termite colonies are able to regulate the intake of inorganic nutrients, and by doing so, adjust their intake from multiple resources in order to maintain an intake target.

Efficacy of Chlorantraniliprole in Controlling Structural Infestations of the Eastern Subterranean Termite in the USA.

Subterranean termites are the most economically important structural pests in the USA, and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (Dictyoptera: Rhinotermitidae) is the most widely distributed species. Soil treatment with a liquid termiticide is a widely used method for controlling subterranean termites in structures. We assessed the efficacy of a nonrepellent termiticide, Altriset® (active ingredient: chlorantraniliprole), in controlling structural infestations of R. flavipes in Texas, North Carolina, and Ohio and determined the post-treatment fate of termite colonies in and around the structures. In all three states, microsatellite markers indicated that only one R. flavipes colony was infesting each structure. A single chlorantraniliprole treatment provided effective structural protection as there was no further evidence of termite activity in and on the majority of structures from approximately 1 month to 2 years post-treatment when the study concluded. Additionally, the treatment appeared to either severely reduce the infesting colony’s footprint at monitors in the landscape or eliminate colony members from these monitors. A supplemental spot-treatment was conducted at one house each in Texas and North Carolina at 5 and 6 months post-treatment, respectively; no termites were observed thereafter in these structures and associated landscaping. The number of colonies found exclusively in the landscape (not attacking the structure) varied among the states, with the largest number of colonies in Texas (0–4) and North Carolina (0–5) as compared to 0–1 in Ohio, the most northern state.

Freeze-Thaw Sample Preparation Method Improves Detection of Volatile Compounds in Insects Using Headspace Solid-Phase Microextraction.

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) is commonly used in analyzing insect volatiles. To improve the detection of volatiles in insects, a freeze-thaw method was applied to insect samples before the HS-SPME-GC-MS analysis. Insect samples were first frozen at -80 °C for 10 min and then thawed at 25 °C for 5 min before SPME extraction was performed. The freeze-thaw method clearly improved the detection of volatile compounds for all six tested insect species, including red imported fire ants, Solenopsis invicta Buren, black imported fire ants, Solenopsis richteri Forel, little black ants, Monomorium minimum (Buckley), pharaoh ants, Monomorium pharaonis (Linnaeus), eastern subterranean termites, Reticulitermes flavipes (Kollar), and spotted lady beetles, Coleomegilla maculate De Geer. This method helped identify various volatile compounds in the tested insects which have never been reported previously. This improved method may facilitate the identification of insect derived volatiles such as insect semiochemicals.

Hyperecdysonism in the Formosan Subterranean Termite and Eastern Subterranean Termite (Isoptera: Rhinotermitidae).

Effects of ecdysone, 20-hydroxyecdysone (20E), and an ecdysone agonist, halofenozide, were tested against the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Kollar), in a 12-d no choice assay. Approximately 22-26% of R. flavipes and C. formosanus exhibited symptoms of hyperecdysonism, that is, "jackknife" position, when exposed to ecdysone and 20E at 1,000 ppm, respectively. High mortalities were recorded for both termite species in ecdysone and 20E at 100 and 1,000 ppm, but only at 10,000 ppm for halofenizide. Termites are known to move back to the central nest before the onset of ecdysis, and those that ingested lethal doses of chitin synthesis inhibitors (CSIs) die near the royal pairs, which partially accounts for the success of CSI baits to eliminate subterranean termite colonies. Because ecdysteroids and their agonists induce molting in termites, incorporation of these compounds into baits could potentially achieve the same colony elimination. This study showed that lethal time (12 d) of ecdysteroids and ecdysone agonist is shorter than that of a CSI (45 d); hence, the baiting time should be reduced by more than a month when they are incorporated in termite baits.

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

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 tract physiology, but also on the symbiotic relationship between termites and their intestinal microbiota. The current study was designed to test the possible effects of four heartwood extractives (Tectona grandis, Dalbergia sissoo, Cedrus deodara and Pinus roxburghii) on the mortality, feeding rate and protozoan population in two lower termites, Reticulitermes flavipes and Heterotermes indicola. All wood extractives tested rapidly lowered protozoan numbers in the hindgut of termite workers, which was closely correlated with worker mortality. The average population of protozoans in both termite species was diminished in a dose-dependent manner after fifteen days feeding on treated filter paper. Mortality of termites increased when fed on filter paper treated with T. grandis or D. sissoo heartwood extractives with minimum feeding rate at the maximum concentration (10 mg ml−1). Protozoan number and termite survival was also compared with starved termites and results showed that protozoan populations ware reduced up to 99.60 and 65.71% in R. flavipes and H. indicola, respectively as compared to untreated filter paper controls with ≅ 80% survival for both termite species. Characterizations of heartwood extractives were performed using Gas Chromatography-Mass spectrometry (GC-MS) and chemical profiles were obtained for extractives from each wood species. The largest chemical components, based on percentage of sample, identified from T. grandis were Squalene, 2-methyl-9, 10-Anthracenedione and 1-Methyl-3,4-dihydroisoquinoline. Trismethoxyresveratrol, 1, 3-Diamino-8-n-butyl-5, 6 dihydrobenzoquinazoline and 6, 8-dimethyl-Benzanthracene were the largest components from D. sissoo. The largest percentage components from C. deodara were (E) – Atlantone, Di-epi-alpha-cedrene and alpha-Cuprenene. The main components of P. roxburghii were identified as 1, 2, 3, 4-tetrahydro-5, 8-dimethyl-Acridin-9-amine, 2, 3-dihydro-5, 7-dihydroxy-2phenyl-4H-1-Benzopyran-4-one and 5-hydroxy-7-methoxy-2-phenyl4H-1-Benzopyran-4-one. These are discussed in terms of their termiticidal and protozoicidal properties.

Enhancement of termite (Reticulitermes flavipes L.) resistance in mycelium reinforced biofiber-composites

The increasing demand for sustainable packaging materials with minimal ecological footprint, compatible cost and stable shelf-life has led to a growing interest in biodegradable or compostable cellulosic packaging materials. Since cellulosic fibers are prone to termite (Reticulitermes flavipes) attack, a study was conducted to identify natural and safe termiticides that can be applied to 100% biodegradable composites derived from lignocellulosic fibers and fungus mycelium. The composite material is a patented technology, developed by Ecovative Design LLC (Green Island, NY). Biocomposite boards of two densities were manufactured using kenaf, hemp and corn fibers and bonded by three different strains of fungi Daedaleopsis confragosa, Ganoderma resinaceum, and Tramates versicolor. The resultant biocomposite boards were evaluated for termite resistance using four termiticides: vetiver oil (Vetiveria zizanioides), guayule resin (Parthenium argentatum), cedar oil (Juniperus virginiana), and borax. The treated boards were evaluated for termite resistance in accordance with ASTM D3345-01. The results showed variable impact of different types of termiticides on fungus mycelium bonded cellulosic biocomposites. A heavy to complete mortality was observed in guayule resin and vetiver treated boards. Borax was least effective as a termiticide. Kenaf and hemp boards treated with guayule resin showed maximum repellency to termites, followed by vetiver oil. The weight loss for treated and untreated samples ranged between 17.4%–33.7%, and 19.9%–55.8% respectively. The findings of this study show that vetiver and cedar natural oils and guayule resin can be used as an effective treatment on mycelium bonded cellulosic composites to improve their termite resistance.

Correction for Wertz et al., "Genomic and Physiological Characterization of the Verrucomicrobia Isolate Geminisphaera colitermitum gen. nov., sp. nov., Reveals Microaerophily and Nitrogen Fixation Genes".

Author(s): Wertz, John T; Kim, Eunji; Breznak, John A; Schmidt, Thomas M; Rodrigues, Jorge LM | Abstract: Description of Didymococcus gen. nov. Didymococcus gen. nov. (Di.dy.mo.coc'cus. Gr. fem. n. didymos pair; N.L. masc. n. coccus (from Gr. masc. n. kokkos, grain, seed), coccus; N.L. masc. n. Didymococcus a coccus in pairs). Description of Didymococcus colitermitum sp. nov. Didymococcus colitermitum sp. nov. (co.li.ter'mi.tum. L. n. colon, colon, part of the large intestine; L. n. termes -itis, wood-eating worm, termite; N.L. gen. pl. n. colitermitum, of the gut of termites). Cells are coccoid (0.25 μm to 0.5 μm in diameter) and occur almost exclusively in pairs, with a Gram-negative cell wall morphology that includes an outer membrane. Cells are nonmotile, obligate aerobes and are microaerophilic. The shortest generation times occur in liquid medium under an atmosphere of 2 to 8% O2 (balance N2). On solid R2A medium, colonies are 2 to 4 mm in diameter, have an entire margin and a low convex, mucoid morphology, and are cream colored. Cells do not possess catalase or NADH/ NADPH peroxidase activity. Nitrogenase activity is inferred through growth on nitrogen-free medium. Growth occurs in liquid media between 15 and 35°C (optimum, 30°C); there is no growth at 37°C or 4°C. Growth occurs at a pH range of 5.5 to 7.5 (optimum, 7.0); there is no growth at a pH of ≤5 or ≥8. Substrates utilized as energy sources include starch, D-cellobiose, D-maltose, D-glucose, D-galactose, and one or more components present in yeast extract. Microcrystalline cellulose, methylcellulose, carboxy methylcellulose, xylan, D-fructose, D-mannose, D-trehalose, sucrose, D-ribose, D-xylose, L-arabinose, D-mannitol, D-sorbitol, D-raffinose, DL-lactate, sodium pyruvate, sodium fumarate, sodium acetate, allantoin, D-glucuronate, D-galacturonate, D-gluconic acid, xanthine, tannic acid, resourcinol, vanillic acid, sodium benzoate, and trimethylbenzoate are not utilized. The genome of type strain TAV2 is 5.2 Mb in size, contains 60.5 mol% G+C, and possesses one 16S rRNA gene copy. The type strain, isolated from guts of Reticulitermes flavipes (Kollar) collected in Dansville, MI, is TAV2 (ATCC BAA-2264; DSM 25453).

Foraging Distance and Population Size of Juvenile Colonies of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in Laboratory Extended Arenas.

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.

Carbon Dioxide and Methane Emissions from Different-Sized Groups of Eastern Subterranean Termites

Abstract. Metabolic gas emissions released into the environment from termites contribute to overall soil and air gaseous composition. However, because subterranean termites are not evenly distributed in soil, it is difficult to understand their contribution of gases to the environment. The research presented here includes a method to measure baseline metabolic gas concentrations from subterranean termites in relation to increasing group sizes over time. Metabolic gas emissions were determined from defined numbers (group sizes) of the eastern subterranean termite, Reticulitermes flavipes (Kollar), foraging in laboratory test arenas. Four groups, each with 0, 50, 100, 150, 200, 250, or 300 R. flavipes workers previously collected from three field colonies were analyzed for CO2 and CH4 emissions over time. CO2 and CH4 concentrations in air samples increased linearly as group size increased across all sampling events. CO2 emissions from as few as 50 termites ranged from 442.6 to 660.9 ppm, a net increase of 3...

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

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 in this work was Reticulitermes flavipes, which is a highly efficient lignocellulose digester 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 appear to play roles in CS and SR breakdown.