Search

Insects are the largest and most diverse group of organisms which are typically the overwhelming dominant invertebrate faunal group extensively used in biomonitoring and bioassessment. The aim of this paper was to evaluate the heavy metals levels in insect species collected from Enyigba Community with mining activities in Southeast Nigeria using appropriate standard methods. In this study, three sites namely: Upper Inyia-(SA), Lower Inyia (SB) and the Control Site (SC) were selected and insect specimens were collected and evaluated from July 2022 to February, 2023. The insect groups used were Reticulitermes flavipes (termite), Zonocerus elegans (grasshopper), Acraea acrita (butterfly) and Cremtogaster sp. (Ant). The selected insects' samples were analyzed using atomic absorption spectrophotometer (AAS). The results showed heavy metal accumulations on the selected insects particularly the toxic metals such as Cadmium (Cd), Copper (Cu), Manganese (Mn) and Mercury (Hg). Insects examined were Reticulitermes flavipes, Zonocerus elegans, Acraea acrita, and Crematogaster sp. collected from Enyigba mines. High concentrations of Cd was recorded in Zonocerus elegans at SA (0.13±0.042) and SB (0.17±0.007) which is far above WHO/FAO permissible limit. The result further revealed that there was also high Cd concentration (0.21±0.011) in Reticulitermes flavipes, which is also far above WHO/FAO permissible limit. Grasshopper, termites and butterfly had the highest accumulation of heavy metals among the studied insect groups, highlighting the challenges of mining on agriculture and food security in the region. [ABSTRACT FROM AUTHOR]

Subterranean termites (Family Rhinotermitidae) and drywood termites (Family Kalotermitidae) can be pest species as they have the potential to inflict damage to wooden constructions and can therefore cause a significant economic impact. Some species of these families are highly destructive and are invasive in many parts of the world. New introductions and/or the spread of termites are often caused by import of infested wood, plants or soils. The present study reports the first records of three exotic termite species in Belgium, viz. Cryptotermes brevis and Reticulitermes banyulensis in Brussels (Brussels Capital Region), and Reticulitermes flavipes in Brugelette (Hainaut province; Walloon region). The morphological identification of the specimens (N = 8) was validated by DNA-barcoding. Cryptotermes brevis and Reticulitermes banyulensis infestations are probably of little concern as local climatological conditions make it unlikely for either species to survive in the temperate climate in Belgium. In contrast, it is likely that Reticulitermes flavipes may become established and will spread to other sites in Belgium. [ABSTRACT FROM AUTHOR]

The Featured Creatures collection provides in-depth profiles of insects, nematodes, arachnids and other organisms relevant to Florida. These profiles are intended for the use of interested laypersons with some knowledge of biology as well as academic audiences.

Insects are the largest and most diverse group of organisms which are typically the overwhelming dominant invertebrate faunal group extensively used in biomonitoring and bioassessment. The aim of this paper was to evaluate the heavy metals levels in insect species collected from Enyigba Community with mining activities in Southeast Nigeria using appropriate standard methods. In this study, three sites namely: Upper Inyia-(SA), Lower Inyia (SB) and the Control Site (SC) were selected and insect specimens were collected and evaluated from July 2022 to February, 2023. The insect groups used were Reticulitermes flavipes (termite), Zonocerus elegans (grasshopper), Acraea acrita (butterfly) and Cremtogaster sp. (Ant). The selected insects’ samples were analyzed using atomic absorption spectrophotometer (AAS). The results showed heavy metal accumulations on the selected insects particularly the toxic metals such as Cadmium (Cd), Copper (Cu), Manganese (Mn) and Mercury (Hg). Insects examined were Reticulitermes flavipes, Zonocerus elegans, Acraea acrita, and Crematogaster sp. collected from Enyigba mines. High concentrations of Cd was recorded in Zonocerus elegans at SA (0.13±0.042) and SB (0.17±0.007) which is far above WHO/FAO permissible limit. The result further revealed that there was also high Cd concentration (0.21±0.011) in Reticulitermes flavipes, which is also far above WHO/FAO permissible limit. Grasshopper, termites and butterfly had the highest accumulation of heavy metals among the studied insect groups, highlighting the challenges of mining on agriculture and food security in the region.

BACKGROUND: The Asian needle ant, Brachyponera chinensis, is an invasive ant currently spreading in urban and natural habitats throughout the eastern United States. Recent studies have documented the negative impact of B. chinensis on native ecosystems and human health, yet effective control strategies are lacking. Control difficulties are, in part, due to the unique biology of B. chinensis, which is a predatory ant and a termite specialist. Given that subterranean termites are an important nutritional resource for B. chinensis, the current study evaluated the potential of termite cuticular extract to improve the target‐specificity and efficacy of commercial bait used for B. chinensis control. RESULTS: The efficacy of bait augmented with termite cuticular extracts was evaluated in laboratory and field trials. In laboratory assays, B. chinensis colonies were offered granular bait treated with termite cuticular extract. Results demonstrated that the acceptance of commercial bait is significantly increased by the addition of termite cuticular extract or synthetic (Z)‐9‐pentacosene, a major component of termite cuticular extract. Foraging activity of Asian needle ants was significantly greater on baits augmented with termite cuticular extract or (Z)‐9‐pentacosene relative to standard bait. Furthermore, bait augmented with termite cuticular extract worked substantially faster relative to standard bait. To evaluate population effects, field studies were conducted in forested areas invaded by B. chinensis. Bait treated with termite cuticular extract scattered on the forest floor provided rapid control of B. chinensis and ant densities throughout the treated plots declined by 98% within 14 days. CONCLUSION: The incorporation of termite cuticular extracts and individual cuticular hydrocarbons such as (Z)‐9‐pentacosene into traditional baits used for B. chinensis control may offer a novel tool to manage this increasingly problematic invasive ant. © 2023 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Soil moisture is a critical environmental factor for the survival and behavior of subterranean termites (family Rhinotermitidae). The invasive Formosan subterranean termite, Coptotermes formosanus Shiraki, and the native eastern subterranean termite, Reticulitermes flavipes (Kollar), co-occur in the southeastern United States, while R. flavipes is distributed in a wider geoclimatic range. Previous studies showed that subterranean termites preferred higher soil moisture levels for tunneling and feeding; however, the impacts of constant moisture remained to be characterized to understand their moisture tolerance. In this study, we hypothesized that different soil moisture regimes can alter termite foraging and survival, and that the effects differ between the two species. The tunneling activity, survivorship, and food consumption of termites were documented for 28 days with different sand moisture conditions ranging from no moisture to full saturation (0%, 1%, 5%, 15%, 25%, and 30%). We found that there were no significant differences in the responses between C. formosanus and R. flavipes. In both species, termites did not survive or tunnel with 0% moisture. Termites performed tunneling with only 1% sand moisture, although they did not survive for 28 days. A minimal of 5% sand moisture was required for survival, and there were no significant differences in survivorship, tunneling activity, or food consumption among moisture contents of 5–30%. The results suggest that subterranean termites are resilient to moisture extremes. Colonies can tolerate low moisture conditions in their foraging environment for extended times, which may allow them to tunnel and find new moisture sources for colony survival. [ABSTRACT FROM AUTHOR]

Abstract Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective‐level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony.

Social insect colonies are characterized by an efficient division of labor, allowing high-value individuals (i.e., reproductives and brood) to be sheltered from tasks associated with increased risk of pathogen exposure, such as foraging or corpse disposal. This social organization helps limit the transmission of disease throughout the colony. Further, individuals can actively respond to imminent disease threats by altering their behaviors as a means of social immunity. In subterranean termites, although workers typically avoid detected pathogens, they can be attracted to pathogen cues when a nestmate is infected. Infected termites are usually groomed, but they may instead be cannibalized if the infection has already become lethal. The mechanisms governing these changes in behavior are unclear. We set out to examine immediate changes in individual behaviors, investigating the role that the infected individual plays in communicating its infection status to nestmates. We also assessed gradual changes in social organization after the re-introduction of an infected termite to the colony. Our results reveal that infected termites likely do not signal their infection status to nestmates through shaking behaviors and reduced movements, suggesting the occurrence of other mechanisms used in communicating infection. We also found that infected termites do not self-isolate and may travel to the densest part of the colony, where they can potentially benefit from grooming by large groups of nestmates. These results provide new insights into how individual changes in immune behaviors contribute to overall colony health, highlighting that, at early stages of infection, termites favor a rescuing strategy rather than isolation and/or cannibalization.

Abstract In insect societies, the presence of reproductives or eggs has been shown to shape several biological traits in the colony members. Social interactions are one of these traits that involve modification of the communication system of the entire colony. Many studies described the role of chemical compounds and dominance behaviors in the presence of reproductive but vibratory behaviors received very few investigations. Yet, vibratory behaviors are ideal candidates, particularly for subterranean species like termites, as they could be quickly transmitted through the substrate and could be very diversified (origin, modulation). Here, we investigated whether the presence of reproductives/eggs affects the vibratory behavior (body‐shaking) of workers in the subterranean termite Reticulitermes flavipes. Our results reveal that the presence of reproductives or eggs triggers an increase of workers' body‐shaking, independent of their colony of origin after 24 hr. We hypothesize that vibratory communication could be used to transfer information about the presence of reproductives and eggs to the entire colony, suggesting that vibratory behaviors could serve as an important yet neglected mediator of social regulation.

Standing dead trees (snags) decompose more slowly than downed dead wood and provide critical habitat for many species. The rate at which snags fall therefore influences forest carbon dynamics and biodiversity. Fall rates correlate strongly with mean annual temperature, presumably because warmer climates facilitate faster wood decomposition and hence degradation of the structural stability of standing wood. These faster decomposition rates coincide with turnover from fungal‐dominated wood decomposer communities in cooler forests to codomination by fungi and termites in warmer regions. A key question for projecting forest dynamics is therefore whether temperature effects on wood decomposition arise primarily because warmer conditions facilitate faster decomposer metabolism, or are also influenced indirectly by belowground community turnover (e.g., termites exert additional influence beyond fungal‐plus‐bacterial mediated decomposition). To test between these possibilities, we simulate standing dead trees with untreated wooden posts and follow them in the field across 5 yr at 12 sites, before measuring buried, soil–air interface and aerial post sections to quantify wood decomposition and organism activities. High termite activities at the warmer sites are associated with rates of postfall that are three times higher than at the cooler sites. Termites primarily consume buried wood, with decomposition rates greatest where termite activities are highest. However, where higher microbial and termite activities co‐occur, they appear to compensate for one another first, and then to slow decomposition rates at their highest activities, suggestive of interference competition. If the range of microbial and termite codomination of wood decomposer communities expands under climate warming, our data suggest that expansion will accelerate snag fall with consequent effects on forest carbon cycling and biodiversity in forests previously dominated by microbial decomposers. [ABSTRACT FROM AUTHOR]

Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective‐level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony. [ABSTRACT FROM AUTHOR]

The production of royal pheromones by reproductives (queens and kings) enables social insect colonies to allocate individuals into reproductive and non-reproductive roles. In many termite species, nestmates can develop into neotenics when the primary king or queen dies, which then inhibit the production of additional reproductives. This suggests that primary reproductives and neotenics produce royal pheromones. The cuticular hydrocarbon heneicosane was identified as a royal pheromone in Reticulitermes flavipes neotenics. Here, we investigated the presence of this and other cuticular hydrocarbons in primary reproductives and neotenics of this species, and the ontogeny of their production in primary reproductives. Our results revealed that heneicosane was produced by most neotenics, raising the question of whether reproductive status may trigger its production. Neotenics produced six additional cuticular hydrocarbons absent from workers and nymphs. Remarkably, heneicosane and four of these compounds were absent in primary reproductives, and the other two compounds were present in lower quantities. Neotenics therefore have a distinct 'royal' blend from primary reproductives, and potentially over-signal their reproductive status. Our results suggest that primary reproductives and neotenics may face different social pressures. Future studies of these pressures should provide a more complete understanding of the mechanisms underlying social regulation in termites. [ABSTRACT FROM AUTHOR]

Burgundy oil (BO) from Eastern red cedar provides resistance against termites and wood-decay fungi and is enhanced when combined with an amylose inclusion complex (AIC) containing hexadecylammonium chloride (HAC). Indirect evidence also indicated that a methanol Loblolly pine extract (LPE) was inhibitory against termites. This study compared the effects of HAC and didecyldimethylammonium chloride (DDAC) combined with LPE and BO on termites and wood-decay fungi. Southern pine was treated by vacuum/pressure impregnation and resistance evaluated after exposure to termites and decay fungi. The combination of BO and either HAC/AIC or DDAC/AIC reduced wood mass losses by termites, increased termite mortality, and inhibited all wood-decay fungi. The HAC/AIC and DDAC/AIC resulted in equivalent mass losses by termites and termite mortalities. The DDAC was slightly more inhibitory than the HAC against wood-decay fungi. Given the slight advantage of DDAC over HAC and because DDAC is currently used to preserve wood, DDAC might be preferred over HAC. The LPE had a very minor effect on mass loss by termites, termite mortality, and only a slight inhibitory effect on G. trabeum and T. versicolor, while R. placenta and I. lacteus were unaffected. Higher concentrations of DDAC and/or LPE might improve protection against termites and wood-decay fungi. [ABSTRACT FROM AUTHOR]

Effects of metabolic gas accumulation on termite behavior in tightly sealed laboratory bioassay arenas were compared with arenas with partial air exchange, or open ventilation. Laboratory studies with termites are often conducted in glass or plastic arenas. These studies can last from a few days up to 12-16 weeks or longer. Based on personal observation and published laboratory studies, how tightly study arenas are sealed is not consistent. In some instances arenas are tightly sealed with impermeable rubber stoppers or tight-fitting lids. In other studies, arenas are covered with semi-air-permeable Parafilm®, or loose-fitting aluminum foil or ventilated lids to allow air exchange. Generally, arenas are covered and not completely open to the air, thereby maintaining high moisture requirements needed to avoid termite dehydration. In this study, to determine metabolic gas accumulation and gas effects on termite groups collected from two field colonies, bioassay arenas were capped with either tightly sealed metal lids, semi-air-permeable Parafilm, or stainless steel mesh to allow non-restricted ventilation. Gas concentrations in these arenas and termite behavior and mortality were determined over time. During the study no visible ataxic termite behavior or significant mortality was observed within Parafilm or stainless-steel-mesh capped arenas. In contrast, tightly sealed arenas quickly accumulated significantly more metabolic gases compared with the other arena configurations, causing obvious abnormal termite behavior within 96 hours after these arenas were sealed. Within 8 to 10 days 100% moribund or dead termites occurred in tightly sealed arenas, whereas termites in semi-permeable membrane or non-restricted ventilated arenas were behaving normally. Excess gas accumulation in tightly sealed arenas first elicited negative effects between 96 and 144 hours. Our results show that tightly sealed bioassay arenas must be avoided, even for short-term studies lasting only a few days, as metabolic gases accumulate rapidly, causing negative effects on termites beginning within 4 to 6 days. [ABSTRACT FROM AUTHOR]

In insect societies, the presence of reproductives or eggs has been shown to shape several biological traits in the colony members. Social interactions are one of these traits that involve modification of the communication system of the entire colony. Many studies described the role of chemical compounds and dominance behaviors in the presence of reproductive but vibratory behaviors received very few investigations. Yet, vibratory behaviors are ideal candidates, particularly for subterranean species like termites, as they could be quickly transmitted through the substrate and could be very diversified (origin, modulation). Here, we investigated whether the presence of reproductives/eggs affects the vibratory behavior (body‐shaking) of workers in the subterranean termite Reticulitermes flavipes. Our results reveal that the presence of reproductives or eggs triggers an increase of workers' body‐shaking, independent of their colony of origin after 24 hr. We hypothesize that vibratory communication could be used to transfer information about the presence of reproductives and eggs to the entire colony, suggesting that vibratory behaviors could serve as an important yet neglected mediator of social regulation. [ABSTRACT FROM AUTHOR]

Under a sociogenomic context, the molecular mechanisms underlying gene‐behavior associations are of particular interest. The Drosophila foraging (for) gene has been demonstrated to have a causal role in insect behavioral plasticity. Previous studies of for have revealed many facets of for function, including roles in foraging, energy metabolism, learning and memory, circadian rhythm, and stress resistance. for orthologs have been identified in a variety of insect taxa. However, expression patterns are not consistent across all insects, with for orthologs serving as both positive and negative regulators of foraging behavior. In this study, we cloned two for orthologs, Rffor‐α and Rffor‐β, from the Eastern subterranean termite, Reticulitermes flavipes. Spatial distribution study showed that the termite brain possesses significantly higher expression levels of Rffor‐α and Rffor‐β than other types of tissues, which suggests that for may act on the brain to influence an individual's ability to respond to its environment. The temporal expression profile of Rffor across different developmental stages suggests that Rffor functions as a negative regulator of foraging behavior. However, results from environmental impacts, that is, temperature and photoperiod, do not fit under a model of negative correlation between gene expression and locomotion. Further testing is warranted to better understand the interaction between Rffor expression and the environment. Research highlights: We identified two orthologs of the Drosophila foraging gene in the termite Reticulitermes flavipes. Expression of Rffor‐α and Rffor‐β was highly localized in the brain and showed strong gene × environment interactions, indicative of involvement in behavioral regulation. [ABSTRACT FROM AUTHOR]

Collective constructions are marvels of complexity, composed of networks of tunnels and chambers. However, it is difficult to study subterranean nests without using invasive techniques because the nests are built within pieces of wood and/or in the soil. Using computerized tomography scans and medical imaging software (OsiriX), we were able to observe nest creation, constructions, and architecture of two subterranean termite species. We monitor the nests' growth in three dimensions built by two Reticulitermes species: R. grassei, a species native to Europe, and R. flavipes, an invasive species introduced from North America, over a several month period. Doing so, we wanted to know whether the construction of the nest could participate to the invasive success of R. flavipes. Although the two species displayed some similarities (i.e., nest creation, chamber size, and levels of wood consumption), only R. flavipes built interior structures. Some of these structures changed over time and thus might play a role in the trade-off between wood consumption, colony protection, and environmental homeostasis. [ABSTRACT FROM AUTHOR]

Reticulitermes flavipes, one of the most harmful subterranean termite pests, is reported for the first time from Tenerife (Canary Islands, Spain). Cytochrome oxidase II was sequenced from five specimens in order to confirm the identification. To date, this invasive species has been detected in a limited area in the northeast of the island, affecting buildings, crops and native plant species. Another colony with the identical haplotype found in the southwest, 60 km away from the main population, indicates that this invasive insect may be more widespread over the island. [ABSTRACT FROM AUTHOR]

The eastern subterranean termite, Reticulitermes flavipes, currently inhabits previously glaciated regions of the northeastern U.S., as well as the unglaciated southern Appalachian Mountains and surrounding areas. We hypothesized that Pleistocene climatic fluctuations have influenced the distribution of R. flavipes, and thus the evolutionary history of the species. We estimated contemporary and historical geographic distributions of R. flavipes by constructing Species Distribution Models (SDM). We also inferred the evolutionary and demographic history of the species using mitochondrial (cytochrome oxidase I and II) and nuclear (endo‐beta‐1,4‐glucanase) DNA sequence data. To do this, genetic populations were delineated using Bayesian spatial‐genetic clustering, competing hypotheses about population divergence were assessed using approximate Bayesian computation (ABC), and changes in population size were estimated using Bayesian skyline plots. SDMs identified areas in the north with suitable habitat during the transition from the Last Interglacial to the Last Glacial Maximum, as well as an expanding distribution from the mid‐Holocene to the present. Genetic analyses identified three geographically cohesive populations, corresponding with northern, central, and southern portions of the study region. Based on ABC analyses, divergence between the Northern and Southern populations was the oldest, estimated to have occurred 64.80 thousand years ago (kya), which corresponds with the timing of available habitat in the north. The Central and Northern populations diverged in the mid‐Holocene, 8.63 kya, after which the Central population continued to expand. Accordingly, phylogeographic patterns of R. flavipes in the southern Appalachians appear to have been strongly influenced by glacial‐interglacial climate change. OPEN RESEARCH BADGES: This article has been awarded Open Materials, Open Data Badges. All materials and data are publicly accessible via the Open Science Framework at https://doi.org/10.5061/dryad.5hr7f31. [ABSTRACT FROM AUTHOR]

Parental care is a major component of reproduction in social organisms, particularly during the foundation steps. Because investment into parental care is often costly, each parent is predicted to maximize its fitness by providing less care than its partner. However, this sexual conflict is expected to be low in species with lifelong monogamy, because the fitness of each parent is typically tied to the other's input. Somewhat surprisingly, the outcomes of this tug‐of‐war between maternal and paternal investments have received important attention in vertebrate species, but remain less known in invertebrates. In this study, we investigated how queens and kings share their investment into parental care and other social interactions during colony foundation in two termites with lifelong monogamy: the invasive species Reticulitermes flavipes and the native species R. grassei. Behaviors of royal pairs were recorded during six months using a non‐invasive approach. Our results showed that queens and kings exhibit unbalanced investment in terms of grooming, antennation, trophallaxis, and vibration behavior. Moreover, both parents show behavioral differences toward their partner or their descendants. Our results also revealed differences among species, with R. flavipes exhibiting shorter periods of grooming and antennation toward eggs or partners. They also did more stomodeal trophallaxis and less vibration behavior. Overall, this study emphasizes that despite lifelong monogamy, the two parents are not equally involved in the measured forms of parental care and suggests that kings might be specialized in other tasks. It also indicates that males could play a central, yet poorly studied role in the evolution and maintenance of the eusocial organization. Parental care is a major component of reproduction in social organisms, particularly during the foundation steps. Our results showed that queens and kings in two termites with lifelong monogamy exhibit unbalanced investment in parental care. It also indicates that males could play a central, yet poorly studied role in the evolution and maintenance of the eusocial organization. [ABSTRACT FROM AUTHOR]

RNA interference insecticides have received increasing attention in recent years due to their classification as a reduced-risk biopesticide and their proposed faster path to registration compared with conventional synthetic insecticides. The goal of this study was to synthesize and compare efficacy of 62 double-stranded RNAs (dsRNAs) from 31 target genes against the pest termite species, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). Fifty-seven dsRNAs of ~125 base pairs each were successfully synthesized. First-tier screens using a combination immersion/feeding assay revealed 10 top candidates and also that dsRNAs coming from synthesis reactions with 80–90× yields were the most effective. Follow-up studies using uptake enhancers in combination with top candidate dsRNAs were unsuccessful. Subsequent concentration range feeding assays on the top candidates revealed two lead termiticidal dsRNAs (3ʹ Hexamerin-2 and 3ʹ Glycosyl Hydrolase Family [GHF] 9-2 cellulase) and another that enhanced feeding (5ʹ GHF9-2 cellulase). Testing a matrix of combinations of these three dsRNAs revealed ultimately that the most consistently effective dsRNA combination was the 3ʹ Hexamerin-2 + 3ʹ GHF9-2 cellulase dsRNA combination. These results provide new information on candidate termiticidal dsRNAs and some apparent factors that have a bearing on their efficacy. Despite these successes, further research and development will be necessary to move dsRNA termiticides from pest management theory to real-world application. [ABSTRACT FROM AUTHOR]

We investigated the use of termite baiting, a proven system of targeted colony elimination, in an overall area-wide control strategy against subterranean termites. At two field sites, we used microsatellite markers to estimate the total number of Reticulitermes colonies, their spatial partitioning, and breeding structure. Termite pressure was recorded for two years before and after the introduction of Trelona® (active ingredient novaluron) to a large area of one of the sites. Roughly 70% of the colonies in the treatment site that were present at the time of baiting were not found in the site within two months after the introduction of novaluron. Feeding activity of the remaining colonies subsequently ceased over time and new invading colonies were unable to establish within this site. Our study provides novel field data on the efficacy of novaluron in colony elimination of Reticulitermes flavipes, as well as evidence that an area-wide baiting program is feasible to maintain a termite-free area within its native range.

Reticulitermes flavipes (Kollar) has become the most destructive subterranean termite pest, on urban structures in Nebraska. In this study, we used seven microsatellite loci to infer the colony breeding system and population genetic structure among 20 infested urban structures in Nebraska. Our data revealed that 17 structures were infested by simple family colonies of R. flavipes, while, the remaining three were infested with mixed family colonies. The measure of population differentiation, FCT value (0.459) indicated that all the 20 urban colonies (10 - 410 km apart) represented pronounced levels of genetic differentiation. The Mantel test disclosed a weak and significantly-positive correlation between genetic and geographic distance (slope = 0.0009, P = 0.001). The urban populations of R. flavipes in Nebraska possessed a breeding system characterized by monogamous pairs of outbred reproductives with excessive heterozygosity.

Keywords: Agamomermis termitivoratus n. sp.; collective genus; description; Isoptera; Mermithidae; new species; Reticulitermes flavipes; Rhinotermitidae; subterranean termite; taxonomy Susceptibility of damp wood termites and soil and wood dwelling termites to the entomogenous nematode Neoaplectana carpocapsae. Mites and nematodes associated with three subterranean termite species (Isoptera: Rhinotermitidae). Agamomermis termitivoratus n. sp., collective genus, description, Isoptera, Mermithidae, new species, Reticulitermes flavipes, Rhinotermitidae, subterranean termite, taxonomy. [Extracted from the article]

Workers of three termite species, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae), and Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae), were force-fed with cellulose media pads treated with 20-hydroxyecdysone (20E) alone and in combination with noviflumuron for 3 d to examine their mortality time trends up to 14 d (including 3-d exposure time). Termites exhibited symptoms of hyperecdysonism before the onset of death. The times required for 20E to fully express its effects were 10–13 d for C. formosanus, 13–14 d for C. gestroi, and 11–13 d for R. flavipes. Higher 20E concentrations resulted in higher mortalities at 14 d, and the addition of noviflumuron generally yielded higher mortalities. The lethal time of 20E was similar to chitin synthesis inhibitors such as noviflumuron than metabolic inhibitors, and the 10–14 d lethal time may be sufficient for 20E-affected termites to return to the central nest before the onset of hyperecdysonism and ultimate death. As an active ingredient in baiting systems, 20E has shown potential to reduce the colony elimination time. [ABSTRACT FROM AUTHOR]

Termites evolved eusociality independently from social Hymenoptera. As a common trait, reproductive monopoly is maintained through chemical communication. The queen (and in termites also a king) prevents workers from reproduction by conveying their reproductive status. In termites all soldiers are sterile, but workers’ potential to reproduce differs between species. It ranges from totipotency in wood-dwelling lower termites where workers are a transient stage from which all other castes develop, to sterile workers in some higher termites. Intermediate are species in which workers can develop into replacement sexuals within the nest but not into winged sexuals. I summarize the patchy picture about fertility signaling that we currently have for termites, pointing also to potential conflicts over reproduction that differ from those in social Hymenoptera. Recent findings imply that, similar to many social Hymenoptera, wood-dwelling termites that live in confined nests use long-chain cuticular hydrocarbons (CHCs) as fertility signals. Yet other compounds are important as well, comprising proteinaceous secretions and especially volatiles. For a subterranean termite, two volatiles have been identified as primer pheromones that prevent reproductive differentiation of workers. It requires more data to test whether wood-dwelling termites use CHCs, while species with larger colonies and less confined nests use volatiles, or whether all species rely on multicomponent signals. Ultimately, we need more effort to model and test potential conflicts over reproduction between queens, kings and workers. Here results from social Hymenoptera cannot be transferred to termites as the latter are diploid and commonly inbred. This review illustrates promising future research avenues. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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 [ABSTRACT FROM AUTHOR]

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-SiO 2 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/cm 3 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/cm 3 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 15 years. 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. [ABSTRACT FROM AUTHOR]

Thermal modification is an attractive alternative to improve the decay durability and dimensional stability of wood. However, thermally modified wood is generally not resistant to termite attacks, limiting the field of application of such materials. One way to overcome this drawback is to combine thermal modification treatment with an additional treatment. One such treatment is the impregnation of a boron derivative associated with appropriate vinylic monomers, which takes advantage of the thermal treatment to polymerise these monomers for boron fixation. Using this strategy, we recently showed that an impregnation of borax (2 or 4% boric acid equivalent) dissolved in a 10% aqueous solution of polyglycerolmethacrylate followed by thermal treatment under nitrogen at 220°C protects wood from both termite and decay degradations, even after leaching. Additionally, wood samples treated with a 10% polyglycerolmethacrylate aqueous solution and subjected to thermal treatment at 220°C presented improved resistance to termites while avoiding boron utilization. Based on these results, we investigate the effect of impregnation with two types of vinylic monomers, which are already used in the presence of boron, followed by thermal treatments at different temperatures. We evaluate termite and decay durability of wood to evaluate if thermal modification associated with light chemical modification could be a solution for utilization of thermally modified materials in termite-infested areas.

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. [ABSTRACT FROM AUTHOR]

Colony foundation modes play a key role in social insect societies as they strongly impact colony survival. In subterranean termites, we do not yet know which factors most influence the early stages of colony foundation since studies on the topic are scarce. In the present study, we examined how variation in life-history traits can influence colony foundation success in two European termite species: Reticulitermes grassei, an indigenous, and R. flavipes, an invasive. We conducted an experiment in which we observed the development of colonies founded by 165 royal pairs on a weekly basis over a 6-month period. Several key results emerged: (1) survival rates of royal pairs were lower in R. grassei; (2) R. grassei pairs laid fewer eggs; and (3) all castes contained fewer individuals in R. grassei colonies, but (4) their timing of appearance are similar for both species. Overall, R. grassei pairs seemed less robust and produced fewer offspring. To our knowledge, our study is the first to describe the foundation of R. grassei incipient colonies in detail over a 6-month period. We also discovered new information about R. flavipes' colony foundation. The data suggest that the two species have different levels of colony foundation success, resulting in differences in colony development. This finding could help explain the invasiveness of R. flavipes. Our study contribute to our understanding of the spread of two termite pest species and shed light on critical steps in the colony foundation process. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 10,000ppm 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. [ABSTRACT FROM AUTHOR]

Eastern subterranean termite,Reticulitermes flavipes(Kollar), workers were exposed for 7 days to one of five chitin synthesis inhibitors (CSIs): diflubenzuron, hexaflumuron, lufenuron, noviflumuron, and novaluron in commercially available bait matrices. Following a 7 day exposure period, termite donors (D) were combined with naïve (not exposed) termite recipients (R) at five D:R ratios (20:0, 15:5, 10:10, 5:15, and 1:19) and mortality determined daily for up to 68 days. Lethal time and percent mortality data suggest efficient transfer at all D:R ratios for all CSIs tested, except diflubenzuron at 1:19. Despite the data indicating transfer of lufenuron in bioassay, this material may not be effective in field use based on behavioral observations that include limited movement by donors. We also report frequency of visible evidence of CSI intoxication, including the previously described “jackknife” pose and an additional physical deformity, we term “curled-body”. The implications these data and observations have for laboratory evaluation and field population management using commercial termite baiting systems is discussed. [ABSTRACT FROM PUBLISHER]

Thermal modification is an attractive alternative to improve the decay durability and dimensional stability of wood. However, thermally modified wood is generally not resistant to termite attacks, limiting the field of application of such materials. One way to overcome this drawback is to combine thermal modification treatment with an additional treatment. One such treatment is the impregnation of a boron derivative associated with appropriate vinylic monomers, which takes advantage of the thermal treatment to polymerise these monomers for boron fixation. Using this strategy, we recently showed that an impregnation of borax (2 or 4% boric acid equivalent) dissolved in a 10% aqueous solution of polyglycerolmethacrylate followed by thermal treatment under nitrogen at 220°C protects wood from both termite and decay degradations, even after leaching. Additionally, wood samples treated with a 10% polyglycerolmethacrylate aqueous solution and subjected to thermal treatment at 220°C presented improved resistance to termites while avoiding boron utilization. Based on these results, we investigate the effect of impregnation with two types of vinylic monomers, which are already used in the presence of boron, followed by thermal treatments at different temperatures. We evaluate termite and decay durability of wood to evaluate if thermal modification associated with light chemical modification could be a solution for utilization of thermally modified materials in termite-infested areas. [ABSTRACT FROM AUTHOR]

Invasive ants are considered a significant threat to urban, agricultural, and natural habitats worldwide and the control of invasions is often a priority for conservation management. The spread and impact of invasive ants is often controlled using chemical management tools, predominantly toxic baits. The preferred outcome of such interventions is the recovery of indigenous species following the removal of the alien invader. Nonetheless, management actions may have unintended consequences such as non-target impacts. Non-target impacts are often a significant concern in areawide eradication programs because toxic baits are typically attractive to a wide range of animals and may kill non-target fauna, especially other invertebrates., Development of effective techniques to control populations of invasive ants while protecting the non-target fauna is important for conservation of native biodiversity. This study utilised laboratory and field experiments to evaluate a novel approach for managing invasive Asian needle ants ( Brachyponera chinensis) utilising live, insecticide-treated termite prey. The goal was to examine the potential ecological impact of toxic prey-baiting on native ant fauna and to determine if toxic prey-baiting is adequately selective to be used as a tool for eradicating Asian needle ants while preserving native ant communities. Protein marking was used to track the consumption of termite prey by target and non-target ant species., Results demonstrate that prey-baiting using live, fipronil-treated termites is highly effective against Asian needle ants. Furthermore, prey-baiting is highly specific with detrimental effects against the target species and negligible effects on native ants., Results demonstrate a novel management tool for conservation agencies working to eradicate invasive ants globally. While traditional bait treatments are typically non-selective and eradicate a wide range of non-targets, prey-baiting is highly effective and target specific and may offer an effective alternative to traditional bait treatments. Additionally, prey-baiting may provide environmental benefits with regard to pesticide residues in ecologically sensitive environments and other protected landscapes where invasive ants pose a threat to native organisms and must be carefully managed to avoid non-target effects. [ABSTRACT FROM AUTHOR]

While the impact of predator-induced stress on prey has received considerable attention, there has been far less research into the effect of competitors. Cues from aggressive competitors should be particularly likely to evoke behavioral and/or physiological responses, since they may be indicative of both direct (interference) and indirect (exploitative) threats. The danger posed by such competitors, and the 'fear' they evoke, should be reduced at lower competitor densities and by the presence of individual conspecifics specialized for defense. We assessed how Reticulitermes flavipes termite workers and soldiers were affected by cues from conspecific nestmates, conspecific non-nestmates, and the heterospecific competitor R. virginicus. Competitor cues altered flavipes worker and soldier behavior, decreasing worker growth and increasing their mortality. The presence of flavipes soldiers largely ameliorated these negative impacts: adding even a single soldier (5% of flavipes individuals) decreased worker mortality by 50-80%. Although worker mortality increased with competitor density, increased soldier densities did not increase the benefit to workers. The small number of soldiers required to substantially alter cue-mediated interactions suggests that this caste, in addition to providing direct defense, also occupies a 'keystone role' by providing homeostatic feedback to workers functioning in stressful environments. [ABSTRACT FROM AUTHOR]