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The use of nonrepellent liquid termiticides against subterranean termites has long relied on the assumption that foraging termites in soils could transfer toxicants to nestmates to achieve population control. However, their dose-dependent lethal time can lead to rapid termite mortality in proximity of the treatment, triggering secondary repellency. The current study characterizes the dynamic nature of the "death zone," i.e., the area adjacent to soil termiticides that termites would avoid owing the accumulation of cadavers. Using whole subterranean termite laboratory colonies of Coptotermes gestroi (Wasmann) with 3 × 15 m foraging distances, fipronil was implemented at 1.5 m, 7.5 m, or 12.5 m away from colony central nests, emulating a corrective action against an termite structural infestation. For treatments at 7.5 m and 12.5 m, the death zone stabilized at an average of ~2.56 m away from the treatment after 40 d post-treatment, and colonies suffered as little as 1.5% mortality by 200 d post-treatment. Colonies located 1.5 m away from the treatment minimized the death zone to ~1.1 m and suffered as little as 23.5% mortality. Mortality only occurred within the first few days of treatment from initial exposure, as the rapid emergence of the death zone negated further transfer effects among nestmates over time. In some cases, foraging termites were trapped within the infested structure. While technically nonrepellent, fipronil becomes functionally repellent from the rapid mortality onset near the treatment. Even if diligently implemented to successfully protect structures, surrounding termite colonies are minimally impacted by fipronil soil treatments., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

The western drywood termite, Incisitermes minor (Hagen), causes significant economic damage to wood structures in the United States of America, especially California. When infestation is not widespread, localized insecticide injections may be useful for remedial control. However, the extensive gallery structure of drywood termites and their tendency to aggregate at specific parts of the galleries can impact the efficacy of localized insecticide injection. Chemicals that attract termites from a distance may improve the localized insecticide injection by increasing the number of termites contacting the insecticide residues. Two volatile terpenes, α-pinene and β-pinene, commonly found in many coniferous timber trees, were applied to artificial termite galleries to determine if termites were attracted from their original aggregation site. Furthermore, we examined if adding these pinenes would improve the overall efficacy of some insecticide products for drywood termite control. Behavioral assay results showed that the treatment with pinenes increased the likelihood that drywood termites would leave their original aggregation site and contact the treated part of the gallery. When tested with the pesticide products applied in a small area away from the termite aggregation, β-pinene significantly accelerated the time course of mortality for the aqueous fipronil. The efficacy of disodium octaborate tetrahydrate dust was not influenced by the addition of pinenes. Implications for drywood termite management and future research directions are discussed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Despite providing important ecosystem services, termites are also serious pests of wooden structures. Termites are highly adaptive organisms that cause concern as an invasive species. Predictions of the future spread of their distribution range due to factors such as climate change, urban growth, and global trade present new challenges to our capacity to protect our wood and wood-based materials and structures effectively. Reticulitermes grassei Clément, 1978 (Blattodea: Rhinotermitidae) is a subterranean termite native to the Iberian Peninsula and France, whose global distribution has widened over recent years. This article updates the distribution range of this species, confirming its identification in the Azores, Madeira, and Morocco through molecular analysis. The origin and consequences of these putative invasive populations are discussed in light of previously available data. The resulting network showed a highly structured base consisting of many haplotypes from the southern and southwestern Iberian Peninsula (Spain and Portugal), including those from Morocco (in natural landscapes) and Switzerland (in infrastructures). The more derived part of the network includes the haplotypes from southwest France, the northwest Iberian Peninsula, the United Kingdom, Azores, and Madeira, the last 3 being linked probably to human-mediated transportation events. The potential impacts of invasive subterranean termite populations expanding into new regions are concerning, especially in urban environments, and remain uncertain in natural areas. The challenges posed by these termites could be especially worrying in island ecosystems. Hence, it is crucial to implement early warning systems and monitoring programs in regions susceptible to subterranean termite invasions., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Cyclohexanone is a major precursor for nylon production and is also used as a pesticide solvent. In this study, cyclohexanone was evaluated as a fumigant against rice weevil adults, confused flour beetle adults, western flower thrips larvae and adults, spotted wing drosophila adults, and subterranean termite workers. Cyclohexanone fumigation was effective against all 5 insects, and there were considerable variations in susceptibility to cyclohexanone fumigation among the 5 species. At 20 °C, complete control of spotted wing drosophila adults was achieved in 1-h fumigation with 25 μl/l of cyclohexanone and complete control of eastern subterranean termite workers was achieved in 3-h fumigations with 50 μl/l dose of cyclohexanone. Stored-product insects confused flour beetle, and rice weevil adults were more tolerant to cyclohexanone fumigation. Fumigations of 24 h with 75 μl/l dose of cyclohexanone caused 100% mortality of rice weevil adults and 98% mortality of confused flower beetle adults. Even at a 100 μl/l dose, the 24-h fumigations did not achieve 100% mortality of confused flour beetle adults. At 5 °C, complete control of western flower thrips was achieved in 3- and 6-h fumigations with 100 and 50 μl/l doses of cyclohexanone, respectively. Cyclohexanone vapor concentrations were measured using cyclohexanone detector tubes. Vapor concentrations were far below the expected saturation concentration indicating that most cyclohexanone did not exist as vapor in fumigation chambers. The results of effective control of all 5 insect species suggest that cyclohexanone has the potential to be used as a fumigant for postharvest pest control., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Sulfuryl fluoride (SF) is a fumigant used to eliminate drywood termites (DWT: Kalotermitidae; Froggatt) and other structural pests. Because of its global warming potential, it has been suggested that SF be restricted as a greenhouse gas (GHG). We present an economic model to assess the net social cost of restricting SF. We consider 3 approaches to address DWT control- no treatment, allowing SF fumigation and localized treatments, and only local treatment. Each approach generates private and public benefits and costs. We estimate that the annual damage and home equity loss by DWT in California is US$4.5-16.8 billion without treatment. If fumigation is used on 20% of the houses and local treatments on the others, the combined social cost of treatment, damage, and GHG emissions are between US$1-US$2 billion annually. The annual cost of local treatments only would be between US$3.2 and US$4.9 billion. If the application of SF is severely restricted or banned, the social costs will increase between US$1.43 and US$4.31 billion annually. The implied cost per ton of CO2 eliminated is between US$624 and US$1,465, much above the price range of CO2 in other applications. The restriction/ban has significant equity and environmental effects, impacting low-income individuals living in rented properties and replacing damaged wood in housing will increase GHG emissions. We further recommend the continued use of SF until a comparable whole-structure alternative is developed that fits the parameters of our model., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The traditional stake survey and in-ground (IG) monitoring stations have been ineffective in aggregating the Asian subterranean termite, Coptotermes gestroi (Wasmann) in southeastern Florida. In this study, we used both IG and above-ground (AG) Sentricon stations to monitor and bait C. gestroi, and as expected, none of the 83 IG stations was intercepted. Despite this, AG bait stations with 0.5% noviflumuron were successfully used to eliminate C. gestroi colonies. From 2 field experiments, the mean colony elimination time (±SD) using AG baits were 6.4 ± 3.8 wk (n = 4) and 8.0 ± 2.1 wk (n = 12), respectively. Such results were compatible with baiting studies against field colonies of C. gestroi elsewhere, that is, 4-9 wk. The successful rates in monitoring and baiting of C. gestroi with IG stations in other regions also varied, which may be due to the variabilities in tunnel geometry of this species in different environments. In areas with established C. gestroi populations, routine inspection for signs of activity in structures and surrounding trees can be a critical component for pest control providers for early detection of infestation and colony elimination with AG bait stations., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Reticulitermes flavipes is the most invasive species in its genus and is responsible for causing significant damage to human structures in areas where it has been introduced. Although it has already become established in Chile and Uruguay, it had not previously been reported in Argentina. In this study, we report the first detection of this species in Buenos Aires, the capital of Argentina. The colony was already producing alates, and species identification was confirmed through both morphology and mitochondrial gene 16S rRNA analysis. Our results, while not conclusive, suggest that this introduction was independent from the one that occurred in Chile and Uruguay, and potentially originated from the United States. The detection of R. flavipes in Argentina is significant because it highlights the potential for this species to establish itself in new regions and underscores the need for future research on and control of R. flavipes in this country., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Colleterial glands of female insects are accessory glands responsible for producing secretions associated with egg-laying. Within Dictyoptera, they synthesize compounds of the ootheca. However, their morphology and role in termites are poorly understood. Here, we compared the morphology, development, and secretory activity of the colleterial glands between non- and egg-laying females of the pest termite Coptotermes gestroi under light and transmission electron microscopy. We also provide the first description of these glands for Rhinotermitidae. The glands are paired, divided into anterior and posterior units, which join in a common duct via basal trunks. They are highly developed within egg-laying females, especially the posterior gland, secreting glycoproteins to lubricate the genital chamber and/or stick the eggs together. Ultrastructure revealed glandular epithelia composed of bicellular units of Class 3, whose secretory activity varied between groups and units. Posterior gland of egg-laying females showed richness of mitochondria, rough endoplasmic reticulum, and secretory vesicles, including electron-dense secretory granules, indicating synthesis and transport of contents, especially proteins. The basal trunks were enfolded by muscles, supporting their role in conducting secretion. Morphophysiological modifications occur in the colleterial glands as females mature and lay eggs, and the mechanisms underlying the secretory cycle of the glands are discussed., Competing Interests: Conflict of Interest The authors declare that they have no competing interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Microscopy Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Coptotermes formosanus Shiraki and C. gestroi (Wasmann) are economically important structural pests in urban areas. Due to anthropogenic activity, both species have been introduced into the United States, with their respective invasive ranges now overlapping in Florida, and the two species have the capability to hybridize. The potential for structural damage from subterranean termite colonies primarily depends on colony size. However, long-term colony growth and wood consumption capabilities of hybrid Coptotermes colonies remain to be investigated, to determine the potential pest status of field-established hybrid colonies. In this study, we investigated long-term colony development over four years to determine if aging hybrid colonies display vigor in terms of colony growth. In addition, we compared wood consumption rate of hybrid colonies to compare their potential impact as structural pests with the two parental species. In aging colonies (four-year-old), both hybrid mating types displayed a colony growth equivalent to C. formosanus. However, the wood consumption rates of four-year-old colonies of the two parental Coptotermes species and their hybrids were similar, indicating equal damaging potential. We also found multiple secondary reproductives in hybrid colonies, even in the presence of primary reproductives, which may favor their potential establishment and spread. Although hybrid colonies or hybrid alates have yet to be detected in the field, our results suggest that such hybrid colonies would be an additional termite threat in the future if they were established in the field., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Wood-feeding termites have a nitrogen-poor diet and have therefore evolved nitrogen conservation strategies. However, termite workers molt periodically, and throughout the lifetime of a colony, millions of exuviae, a nitrogen-rich resource, are produced by the colony. In Coptotermes Wasmann, workers foraging at remote feeding sites must return to the central part of the nest to molt, where the queen, king, eggs, and larvae are located. It was hypothesized that this molting-site fidelity is an efficient way to recycle nitrogen for reproduction and colony growth, as nestmates involved in exuviae consumption can directly transfer such resources to individuals engaged in reproduction (the queen) or growth (larvae). This study investigates whether incipient colonies of C. gestroi (Wasmann) can gain additional biomass when they are fed supplementary exuviae. Incipient colonies were reared in nitrogen-poor or nitrogen-rich conditions, and 0, 1, 5, or 10 exuviae were added to 3-month-old colonies. After 6.5 months, colonies reared in nitrogen-poor environments gained significantly more biomass when exuviae were added than colonies with no added exuviae. However, the addition of exuviae had no effect on colony growth for colonies reared in nitrogen-rich environments. In a second experiment, queens from colonies in which exuviae were effectively removed laid fewer eggs than queens from colonies in which exuviae were not removed. Therefore, consumption of exuviae from molting individuals by nestmates is an important part of the nitrogen recycling strategy in Coptotermes colonies, as it facilitates queen oviposition and colony growth, especially when such colonies have limited access to nitrogen-rich soils., (Published by Oxford University Press on behalf of Entomological Society of America 2023.)

Termites are dominant animals of tropical terrestrial ecosystems. Their success is due to their eusocial organization as well as their ability to digest dead plant tissues. While being extremely abundant, the termite diet is poor in crucial nutrients, such as fatty acids. Linoleic acid (LA) is a precursor for many vital biomolecules, and most animals depend on its dietary supply. Termites count among the exceptions known to produce LA de novo, presumably via the action of an unknown Δ12 fatty acyl desaturase (FAD) introducing the second double bond into monounsaturated oleic acid. Here, we search for the evolutionary origin of LA biosynthesis in termites. To this end, we compile the repertoire of FAD homologs from 57 species of termites and their closest relatives, the cockroaches, analyze FAD phylogeny, and identify a potential Δ12 FAD branch, which arose through duplication of a likely Δ9 FAD. We functionally characterize both paralogs and identify the Δ9 activity in the ancestral FAD-A1a and the Δ12 activity responsible for LA biosynthesis in FAD-A1b. Through the combination of homology modeling and site-directed mutagenesis, we pinpoint structural features possibly contributing to the distinct functions, regiospecificities, and substrate preferences of the two enzymes. We confirm the presence of both paralogs in all 36 studied species of the Blattoidea lineage (Blattidae, Lamproblattidae, Cryptocercidae, and termites) and conclude that we identified an evolutionary event important for the ecological success of termites, which took place in their cockroach ancestors roughly 160 My and remained conserved throughout termite diversification into 3,000 extant species., (© The Author(s) 2023. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Information regarding the species composition and dispersal flight season of termites is crucial for termite management. The major obstacles to collecting such information are a lack of access to private buildings and shortage of workers to monitor and report on termite swarming. To overcome these difficulties, we launched a citizen science project in which members of the public and pest management professionals were invited to collect termite samples. We created the website, Taiwan Termite Identification Service, on which populace could log the collection information, and ship termite samples to our laboratory for identification. We also established a Facebook group, called the "Termite Forum," to publicize this project. A total of 3024 samples were collected from 2015 to 2020, and we identified the species of >93% of the samples. Based on 1499 samples collected from buildings, five structural termite pests were identified, and species composition in each county of Taiwan is available. According to 844 dispersal flight events, termite dispersal flight timing peak and degree of centralization were estimated using a Gaussian model. The collected data demonstrated that the invasive termite species, Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae), continued northward expansion. The first intercepted alate of Schedorhinotermes sp. (Blattodea: Rhinotermitidae) indicated that it may be a new invasive pest from Southeast Asia. This study reports on a successful case of a citizen science project where urban pest data were collected on a national scale., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Social insects' constructions are diverse and functionally flexible. We aimed to understand how termites modify their behavior and building material to change the function of a shelter tube. Construction behaviors of three termite species, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), Odontotermes formosanus (Shiraki) (Blattodea: Termitidae), and Nasutitermes takasagoensis (Nawa) (Blattodea: Termitidae), were recorded and analyzed. We measured the thickness and organic matter content of shelter tubes, and further tested their water loss and water drop resistance. All three termite species used a cement-brick construction procedure. The shelter tubes of C. formosanus and N. takasagoensis incorporating of woody material and feces present a strong resistance to water drops. Shelter tubes of the fungus-growing termite, O. formosanus, constructed using only soil and fluid secretion had a weak resistance to water drops. The trade-off between using feces to increase hydrophobicity of shelter tubes and using feces to grow fungus likely occurs in fungus-growing termites. Among intraspecific colonies, increasing the thickness of shelter tube improved resistance to water loss and water drops. This study demonstrated termites employed limited construction material and building behaviors to achieve functional plasticity of foraging shelter., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The present study aimed to isolate and characterize proteolytic Bacillus spp. from termite guts to test the possibility of application for improving the nutritional value and bioactivity of fermented soybean meal (FSBM). Aerobic endospore-forming bacteria were isolated from the gut of the termite Termes propinquus. Ten isolates with high levels of soy milk degradation were selected and tested for extracellular enzyme production. Among them, two isolates, Tp-5 and Tp-7, exhibited all tested hydrolytic enzyme activities (cellulase, xylanase, pectinase, amylase, protease, lipase and phytase), weak alpha hemolytic and also antagonistic activities against fish pathogenic species of Aeromonas and Streptococcus. Both phylogenetic and biochemical analyses indicated that they were closely related to Bacillus amyloliquefaciens. During solid-state fermentation of SBM, Tp-5 and Tp-7 exhibited the highest protease activity (1127.2 and 1552.4 U g-1, respectively) at 36 h, and the resulting FSBMs showed a significant increase in crude protein content and free radical-scavenging ability (P < 0.05), as well as an improvement in the composition of amino acids, metabolites and other nutrients, while indigestible materials such as fiber, lignin and hemicellulose were decreased. The potential strains, especially Tp-7, improved the nutritional value of FSBM by their strong hydrolytic and antioxidant activities, together with reducing antinutritional components., (© The Author(s) 2022. Published by Oxford University Press on behalf of FEMS.)

Colonies of social insects contain large amounts of resources often exploited by specialized social parasites. Although some termite species host numerous parasitic arthropod species, called termitophiles, others host none. The reason for this large variability remains unknown. Here, we report that the evolution of termitophily in rove beetles is linked to termite nesting strategies. We compared one-piece nesters, whose entire colony life is completed within a single wood piece, to foraging species, which exploit multiple physically separated food sources. Our epidemiological model predicts that characteristics related to foraging (e.g., extended colony longevity and frequent interactions with other colonies) increase the probability of parasitism by termitophiles. We tested our prediction using literature data. We found that foraging species are more likely to host termitophilous rove beetles than one-piece nesters: 99.6% of known termitophilous species were associated with foraging termites, whereas 0.4% were associated with one-piece nesters. Notably, the few one-piece nesting species hosting termitophiles were those having foraging potential and access to soil. Our phylogenetic analyses confirmed that termitophily primarily evolved with foraging termites. These results highlight that the evolution of complex termite societies fostered social parasitism, explaining why some species have more social parasites than others., (© 2022 The Authors. Evolution published by Wiley Periodicals LLC on behalf of The Society for the Study of Evolution.)

The edible mushroom Termitomyces is an agaric-type basidiomycete fungus that has a symbiotic relationship with fungus-growing termites. An understanding of the detailed development mechanisms underlying the adaptive responses of Termitomyces sp. to their growing environment is lacking. Here, we compared the transcriptome sequences of different Termitomyces sp. samples and link-stipe grown on fungus combs in situ and monocultured in vitro. The assembled reads generated 8052 unigenes. The expression profiles were highly different for 2556 differentially expressed genes (DEGs) of the treated samples, where the expression of 1312 and 1244 DEGs was upregulated in the Mycelium and link-stipe groups respectively. Functional classification of the DEGs based on both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed an expected shift in fungal gene expression, where stress response genes whose expression was upregulated in link-stipe may adaptively be involved in cell wall hydrolysis and fusion, pathogenesis, oxidation-reduction, transporter efflux, transposon efflux and self/non-self-recognition. Urease has implications in the expression of genes involved in the nitrogen metabolism pathway, and its expression could be controlled by low-level nitrogen fixation of fungus combs. In addition, the expression patterns of eleven select genes on the basis of qRT-PCR were consistent with their changes in transcript abundance, as revealed by RNA sequencing. Taken together, these findings may be useful for enriching the knowledge concerning the Termitomyces adaptive response to in situ fungus combs compared with the response of monocultures in vitro., (© 2021 The Society for Applied Microbiology.)

Subterranean termite control methods using chitin synthesis inhibitors (CSIs) aim at eliminating colonies that feed upon a bait formulation. Several benzoylurea active ingredient formulations are currently commercially available as alternative termite management strategies to liquid termiticides. Individual workers need to molt on a regular basis and CSIs interfere with such molting process, allowing sufficient time for the acquisition of a colony-wide lethal dose prior to widespread mortality. As workers progressively die, the colony eventually collapses, leaving only soldiers and primary reproductives that starve to death. One common observation is that young workers often die early owing to their relatively short molting cycle. However, the absence of brood in dying colonies raises questions about the potential fate of eggs laid by the queen. This study aims to determine if CSI baits also terminate the ability of a colony to produce a new cohort of workers by disabling the ongoing brood development. Incipient termite colonies were used to test the impact of noviflumuron on the queen's ability to lay eggs and on the eggs' ability to hatch. Our results showed that queens in colonies exposed to CSI not only initially laid less eggs than the control queens, but eggs also did not develop and were progressively cannibalized, eventually leading to colony establishment failure. This result implies that queens of mature colonies exposed to CSI would lose the ability to lay viable eggs as the colony collapses, leading to an absence of worker replacement, aiding in colony elimination., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Several species of drywood termites, subterranean termites, and fungus-growing termites cause extensive economic losses annually worldwide. Because no universal method is available for controlling all termites, correct species identification is crucial for termite management. Despite deep neural network technologies' promising performance in pest recognition, a method for automatic termite recognition remains lacking. To develop an automated deep learning classifier for termite image recognition suitable for mobile applications, we used smartphones to acquire 18,000 original images each of four termite pest species: Kalotermitidae: Cryptotermes domesticus (Haviland); Rhinotermitidae: Coptotermes formosanus Shiraki and Reticulitermes flaviceps (Oshima); and Termitidae: Odontotermes formosanus (Shiraki). Each original image included multiple individuals, and we applied five image segmentation techniques for capturing individual termites. We used 24,000 individual-termite images (4 species × 2 castes × 3 groups × 1,000 images) for model development and testing. We implemented a termite classification system by using a deep learning-based model, MobileNetV2. Our models achieved high accuracy scores of 0.947, 0.946, and 0.929 for identifying soldiers, workers, and both castes, respectively, which is not significantly different from human expert performance. We further applied image augmentation techniques, including geometrical transformations and intensity transformations, to individual-termite images. The results revealed that the same classification accuracy can be achieved by using 1,000 augmented images derived from only 200 individual-termite images, thus facilitating further model development on the basis of many fewer original images. Our image-based identification system can enable the selection of termite control tools for pest management professionals or homeowners., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Bark beetles and root weevils can impact forests through tree death on landscape scales. Recently, subterranean termites have been linked to these beetles via the presence of bluestain fungi (Ascomycota: Ophiostomataceae), which are vectored to trees by beetles. However, only a small subset of bluestain species have been examined. Here, we tested whether termite-bluestain association patterns in the field reflect termite feeding preference in laboratory choice trials. We documented the presence of four bluestain fungi (Leptographium procerum (W.B. Kendr.), L. terebrantis (Barras & Perry), Grosmannia huntii (Rob.-Jeffr.), and G. alacris (T.A. Duong, Z.W. de Beer & M.J. Wingf.) in the roots of 2,350 loblolly pine trees in the southeastern United States and whether termites were present or absent on these roots and paired this with laboratory choice feeding trials. Termites were found 2.5-fold on tree roots with at least one bluestain fungus present than tree roots without bluestain fungi. Although termites in this study and others were associated with L. procerum, L. terebrantis, and marginally G. huntii, termites only showed preferential feeding on wood inoculated with G. huntii in laboratory trials. This suggests that increased termite presence on wood with bluestain fungi may be driven by factors other than increased wood palatability. Termites could thus disproportionately affect wood turnover rates for specific pools (e.g., bark beetle and root weevil attacked trees) and in some cases (e.g., G. huntii) accelerate wood decomposition. This study supports the growing evidence that the association between subterranean termites and bluestain fungi is spatially and taxonomically widespread., (Published by Oxford University Press on behalf of Entomological Society of America 2021.)

Termites form one-piece nests in wood that can vary in their moisture content and degree of decomposition, and thus microbial richness. To estimate the microbial load of nests and the potential risk they pose for colony members, we quantified the number of microbes in the nest and on the cuticle of the dampwood termite, Zootermopsis angusticollis, and three drywood termites, Incisitermes minor, I. schwarzi, and Cryptotermes cavifrons. The number of colony forming units (CFUs) cultured from nest material samples and washes of the cuticle of larvae and nymphs were determined. CFUs recorded from nest material was low (fewer than 60 CFUs/g) in the drywood termites and comparatively high in the dampwood species, as more than 800 bacterial and fungal CFUs/g were cultured from the nest material of Z. angusticollis. Similarly, cuticular microbial loads were negligible in the drywood termites sampled, ranging from 0.5 to fewer than 16 CFUs/cm2, whereas approximately 200 CFUs/cm2 were cultured from Z. angusticollis. The nesting and feeding habits of these basal species likely influence colony microbial load and the degree of pathogen exposure, which in turn could favor adaptations to resist disease that vary with termite nesting biology.

In the eastern United States, there are nine species of subterranean termites in three genera: Reticulitermes (six species), Coptotermes (two species), and Prorhinotermes (one species). These species serve as important ecological players by decomposing cellulose material, and some are important structural pests. Many of these species are difficult to discriminate morphologically and require examining the reproductive or soldier castes, which can be difficult to collect. While some genetic tools have been developed for species identification, they are often expensive and time-consuming. To help facilitate identification, we developed a more cost-effective and rapid genetic method to identify Reticulitermes species by screening 10 PCR primers that amplified inter-simple sequence repeats (ISSRs) in other termite species. From these, one primer was amplified in all five focal Reticulitermes species and contained conserved, species-specific fragments. We further screened this identification method on samples of each species covering a diversity of mitochondrial DNA haplotypes and localities. This identification method utilizing ISSRs can be used to quickly identify five species of Reticulitermes subterranean termites in the eastern United States in a matter of hours, providing a useful technique for pest management as well as future ecological research., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Termites, being vulnerable to parasitic or pathogenic infections due to large number of individuals living together in colonies, have evolved various behavioral and physiological tactics to resist the infections by those pathogens. Locomotion can help termites collect information on parasites and accordingly exhibit hygienic behaviors. Termites inevitably encounter entomopathogenic fungi during nesting and foraging. However, how these fungal pathogens influence locomotion of termites and how hygienic behavior benefits their survival remains unknown. Here, we examined locomotion alteration of the termite Reticulitermes chinensis (Isoptera: Rhinotermitidae) after infections with different concentrations of the entomopathogenic fungus Metarhizium anisopliae (Hypocreales: Clavicipitaceae). When R. chinensis was isolated, the low concentration (5 × 103 conidia/ml) significantly increased termite locomotion after 6, 12, and 24 h compared with control. However, the high concentrations (5 × 107, 5 × 109 conidia/ml) significantly decreased termite locomotion after 48 h, and termite survival was also significantly lower at 5 × 107 and 5 × 109 conidia/ml compared with the low concentrations and the control. When R. chinensis was in group, however, the locomotion significantly increased 24 h after exposure to 5 × 103 and 5 × 109 conidia/ml but was normalized after 48 h of exposure compared with the control. Allogrooming was significantly higher at 5 × 103 and 5 × 109 conidia/ml compared with the control. The fungal infection did not result in significantly higher mortality of the group termites probably owing to their allogrooming. These findings enhance our understanding on how a termite species copes with biotic stress (i.e., fungal infections) via adaptive behaviors., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The development of baits for subterranean termite control over the past 25 yr has provided cost-effective alternatives to liquid termiticide treatments. Current bait products use one of the few available benzoylurea chitin synthesis inhibitors (CSIs) labeled for subterranean termites. These insecticides are used because of their nonrepellency, their slow-acting mode of action, and their dose-independent lethal time. Although many studies have provided ample evidence of the efficacy of CSI baits for subterranean termite colony elimination, most have focused on hexaflumuron and noviflumuron. However, bait products using alternative CSIs have not received the same level of scrutiny, limiting the amount of evidence proving their efficacy. One such compound is novaluron, the active ingredient currently used in the Trelona ATBS-Advance Termite Baiting System bait product. The current study independently tested the efficacy of this commercially available bait formulation against whole colonies of Coptotermes gestroi (Wamann) (~63,910 workers) in the laboratory, using an extended experimental setup to simulate a 15-m foraging distance from the central part of the nest to the bait, while having access to alternative food sources. Treated colonies progressively ceased to feed on wood items within 45 d after being provided access to the novaluron bait formulation, with a subsequent progressive collapse of the population, leading to colony elimination by 91 d. This study therefore confirms the efficacy of novaluron baits against subterranean termites, and currently remains one of the few CSIs that can be applied for the successful control of Coptotermes infestations., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Colonies of western drywood termites, Incisitermes minor (Hagen) (Blattodea: Kalotermitidae), are difficult to detect and treat due to their cryptic nature. The use of heated air to create lethal temperatures within infested wood serves as a nonchemical treatment option targeting whole structure or large portions of the structure. However, the presence of hard-to-heat areas and potential risk of damage for heat-sensitive items are recognized as important challenges. Here, we tested if a localized injection of volatile essential oil could be utilized to address the heat sink issue, potentially increasing the overall efficiency of heat treatments against drywood termites. Artificially infested wooden blocks were placed in several locations of the test building, and heat treatments were conducted. For the treatment group, a small amount of essential oil (methyl salicylate) was added in the blocks prior to the heat treatment. All blocks placed in uninsulated wall voids had 92-100% termite mortality by day 7. However, the presence of a large concrete wall in the subarea hindered heating of blocks therein, resulting 36-44% mortality by day 7 when there was no essential oil treatment. Incorporation of the essential oil substantially increased the control efficacy for the subarea, resulting in more than 90% mortality. This approach might also be helpful in reducing the risk of potential heat damage during heat treatment without compromising its control efficacy., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Use of heated air to create lethal temperatures within infested wood serves as a nonchemical treatment option against western drywood termites, Incisitermes minor (Hagen). When treating a whole or large portion of the structure, however, the presence of hard-to-heat areas (structural heat sinks) and potential risk of damaging heat-sensitive items are recognized as important challenges. To address these challenges, we tested if the incorporation of a volatile essential oil would increase the overall efficacy of heat treatments against the drywood termites. To choose an essential oil for use, we tested the volatile action of several candidate compounds against individual termites using a fumigant toxicity assay. As a proof-of-concept experiment, field-collected termites were housed in small wooden arenas and subsequently subjected to 2-h heat treatment at various air temperatures within a gas chromatography oven. A simulated heat sink and essential oil treatment was also included in the experimental design. Analyses of lethal temperatures (LTemp50 and LTemp99 values), probabilities of mortality, and survivorship data over time suggested that 1) the presence of a heat sink significantly increased the minimum air temperature needed for complete kill of the termites and 2) the volatile essential oil added at the site of a heat sink effectively counteracted the impact of the heat sink. The use of volatile essential oils makes it possible to effectively kill drywood termites even in areas which might not reach lethal temperatures (~50°C), potentially improving the overall efficacy of heat treatments while reducing the risk of heat damage., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The infectivity of three species of entomopathogenic nematodes (EPNs) such as Steinernema carpocapsae Weiser (Rhabditida: Steinernematidae), Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), and H. bacteriophora Poinar (IRQ.1 strain) were examined against subterranean termite Microcerotermes diversus (Silvestri) (Blattodea: Termitidae) that is the most economically destructive termite in Iraq. Laboratory and field efficacy of these strains were evaluated to test the feasibility of indigenous EPNs to be used in a biological control program. The biological traits examined included pathogenicity, penetration, and reproduction of EPN species. Filter paper and wood bioassays were conducted using six concentrations: 25, 50, 100, 200, 400, and 600 IJs/termite. In both tests, all strains were virulent against M. diversus workers. The LC50 of S. carpocapsae in both petri dishes and in containers with sawdust was (57.9 and 15.7 IJs/termite) less than both indigenous (274.2 and 60.8 IJs/termite) and commercial (139.6 and 52.6 IJs/termite) Heterorhabditis bacteriophora, respectively. In the field, the percent mortality of the tested workers ranged from 22.5-80 ± 8.3%, 37.5-96.2 ± 8.9%, and 28.7-67.5 ± 6.8% for commercial H. bacteriophora and S. carpocapsae and native H. bacteriophora, respectively. All EPN strains successfully penetrated the M. diversus workers under field conditions, while the results showed that there was a significant difference between the three EPN strains. The percent mortality caused by native H. bacteriophora against termites was higher (43.6 ± 2.7%) than both commercial strains of S. carpocapsae (36.9 ± 1.6%) and H. bacteriophora (29.9 ± 1.4 %). These results highlight the efficiency of EPNs for the control of M. diversus workers., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Termite colony size can influence its foraging activity, reproductive maturity, and, for pest species, potential for structural damage. Estimating colony size of subterranean termite species in field conditions has been challenging owing to their extensive foraging territory and their cryptic nesting habit and has primarily relied on mark-recapture methods. With laboratory-reared colonies in individual containers, determining colony size can be achieved by processing all termites from the nest material, which can be labor intensive and partially destructive. However, with the recent rise in the need of large laboratory colonies for use in colony-wide experimental protocols, there was an imperative to develop a procedure to estimate initial colony sizes without imposing a major stress on colonies before an experiment. In this study, the average daily wood consumption of whole colonies was used to infer the colony size of two Coptotermes, Wasmann (Blattodea: Rhinotermitidae) species and their hybrids in laboratory-rearing conditions. Correlations between the daily wood consumption and several demographic variables within colonies were established. Linear models varied across all species mating types with R2 values greater than 0.8 for all demographic variables. For colonies from all mating combinations, Pearson's correlation coefficient values were greater than 0.94 between their daily wood consumption and both the number of workers and total number of termites, and greater than 0.91 between daily wood consumption and colony mass. Therefore, in colonies with fixed laboratory conditions, their average daily wood consumption determination, which is nondestructive on colonies, can be used to infer colony size of subterranean termites., (Published by Oxford University Press on behalf of Entomological Society of America 2020.)

Damage from termite infestations is economically significant and control can be costly when requiring the widespread use of conventional insecticides. Erythritol, a polyalcohol sweetener that is safe for human consumption, causes increased mortality when ingested by some insects, indicating potential as a safe alternative insecticide. Here, we investigated the applicability of erythritol as a novel toxicant method of termite control. Eastern subterranean termites, Reticulitermes flavipes Kollar (Blattodea: Rhinotermitidae), were fed paper foods treated with increasing concentrations of erythritol and were assessed for mortality and bait consumption. Termite survival to 8 d (the duration of the experiment) significantly decreased as erythritol treatment concentration increased, indicating that the lethal effects of erythritol were concentration-dependent. Termites consumed erythritol-treated paper at all concentrations and did not display avoidance in choice assays, suggesting that erythritol may be practical for use as an ingestible bait. These results provide a basis for further development of erythritol as a safe alternative method of termite control., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Concerns on efficacies of termiticides used for soil treatment to prevent Formosan subterranean termite (Coptotermes formosanus Shiraki) infestations have prompted pest control companies to suggest that retreatments are necessary after flooding of homes. Therefore, to address concerns about the efficacy of termiticides after flooding, we designed a flooding simulation experiment in the laboratory. We used four formulated termiticides containing fipronil, imidacloprid, chlorantraniliprole, or bifenthrin as active ingredients (a.i.) and two colonies of field-collected C. formosanus for this study. Evaluations of each chemical at concentrations of 1, 10, and 25 ppm in both sand and soil were conducted in the laboratory by comparing termite mortalities in no-choice bioassays after exposure to flooded (for 1 wk) and unflooded substrates. Toxicity from bifenthrin and fipronil were not affected by flooding regardless of substrate type except at the lowest concentration tested. Toxicity from chlorantraniliprole was lower in flooded sand at 1 ppm but otherwise similar among flooding treatments. In flooded soil, toxicity from chlorantraniliprole was low at 1 ppm, but unexpectedly high in flooded conditions at 10 and 25 ppm. For all concentrations of imidacloprid-treated sand, mortality of C. formosanus was reduced after a flood. However, like chlorantraniliprole, 10 and 25 ppm of imidacloprid-treated soil in flooded conditions resulted in an increased toxicity on C. formosanus. Our study supports the idea that chemicals with a higher water solubility like imidacloprid may require a home to be retreated with less water-soluble termiticides or baits after a flood., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America.)

As a social insect, termites have different castes and division of labor in a colony. Investigating the social behavior of subterranean termites is a challenge due to the cryptic nature and large colony size. Planar arenas are commonly used to study these termites under laboratory conditions, and have provided several advantages. However, there is no means to designate areas such as a royal chamber or central nest from foraging sites because reproductives can move freely across arenas. In this study, we examined the minimum passing size of different castes of Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), in order to develop a reproductive excluder and correlated minimum passing size with head widths and heights. We found that workers and soldiers of C. formosanus were able to pass through a gap greater than or equal to 0.7 mm. Our results showed that there are significant differences in the head width and height based on castes and head height was more critical than head width to determine passing size. We further confirmed feasibilities of the reproductive excluders using incipient colonies of C. formosanus. Confining reproductives using the excluder in laboratory experiments will provide more chances to study the royal chamber and central nest independently of foraging sites., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

In 2001, Nasutitermes corniger (Motschulsky), common name conehead termite, were discovered near a marina in Dania Beach, FL, where the invasive species was probably transported from its native range in Central and South America or the Caribbean. In January 2016, an infestation was found in Pompano Beach, Florida, approximately 21 km north of the Dania Beach population. This study compares variants in seven microsatellite loci across specimens from 11 nests in Dania Beach and 8 nests in Pompano Beach. Results are consistent with all N. corniger in both locations being descendants of a single introduced colony, spreading within Broward County, FL through human transport of infested materials. No more than four alleles were found at any of the seven microsatellite loci analyzed, inferring that a single Queen and King, or multiple sibling reproductives descended from a monogamous pair, headed the colony that arrived in Florida. The potential economic and environmental impacts of this invasive termite are enormous due to its broad diet, including agricultural crops and orchards, native and ornamental plants, natural landscapes, and structures. Conspicuous tunnels and aboveground nests are the key aspects of N. corniger biology that render colonies vulnerable to discovery and control. The now proven ability of N. corniger to establish breeding populations in the United States, to cause extensive property and landscape destruction, and to spread by human transport underscores the need for continued aggressive efforts toward eradication of known infestations as well as quick operational actions the next time invasive N. corniger are discovered., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Species identification in the genus Reticulitermes is often difficult because of ambiguous morphological characters. Challenges in Reticulitermes spp. recognition have also been encountered in East Asia, including Taiwan. Because of unknown Reticulitermes taxa in Taiwan and the possible origin of alien Reticulitermes kanmonensis Takematsu in Japan and Korea, reexamining Reticulitermes fauna in Taiwan is imperative. To clarify the Reticulitermes fauna in Taiwan, this study applied two mitochondrial genes (cytochrome oxidase subunit II [COII] and 16S rDNA) and morphological characters for species delimitation. Reticulitermes specimens collected from 63 localities across the main and adjacent islands of Taiwan were analyzed. Phylogenetic analyses, morphological comparisons, and ecological traits suggested the existence of three species in Taiwan: Reticulitermes flaviceps (Oshima), R. kanmonensis, and Reticulitermes leptomandibularis Hsia and Fan. Altitudinal distributions among the three Reticulitermes termites tended to differ: R. flaviceps adapted to low hills, but R. kanmonensis and R. leptomandibularis occurred in medium mountainous areas. The combined data, including haplotype diversities and distribution range, suggest that 1) R. flaviceps is an endemic species and only found in Taiwan; 2) R. kanmonensis and R. leptomandibularis are both native species in Taiwan and China; 3) Japanese R. kanmonensis populations originated from southern China and/or Taiwan and that Korean populations were possibly introduced from Japan., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Temperature preference of two invasive subterranean termites, Coptotermes gestroi (Wasmann) and Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), and their hybrids were determined in a horizontal thermal gradient. The activity of workers of four mating combinations: ♀C. gestroi × ♂C. gestroi (C. gestroi), ♀C. formosanus × ♂C. formosanus (C. formosanus), ♀C. gestroi × ♂C. formosanus (Hybrid G), and ♀C. formosanus × ♂C. gestroi (Hybrid F), when placed on the temperature gradients were videotaped and analyzed to determine the mean temperature preference values (mTPV). The temperature ranges for active termites were 21.9-39.5°C for C. gestroi, 11.1-39.5°C for C. formosanus, 25.3-38.2°C for Hybrid G, and 24.9-39.3°C for Hybrid F. There was no significant difference in the mTPV of C. gestroi and both hybrid mating combinations. The mTPV of both Hybrid G and Hybrid F was significantly higher than the parental species C. formosanus. Our results indicate that hybrid populations of C. formosanus and C. gestroi might be more active in tropical than temperate regions, and if established in temperate regions, they will be more active in summer months when the mean temperature exceeds 25°C., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Laboratory studies of Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae) often employ the use of field-collected foraging populations of individuals as defined colonies. The biological relevance of this practice is often called into question, because these colonies lack a full composition of reproductive castes and brood, which may have physiological and behavioral consequences. Rearing intact laboratory colonies can be done; however, it is time-consuming and labor-intensive. The artificial fusion of field-collected foraging populations with a young, laboratory-reared incipient colony may provide whole, intact colonies for laboratory research. The current study measures survivorship of fused colonies using laboratory-reared complete incipient colonies ranging in age from 0 to 5 mo, fused with 100 workers and 10 soldiers from field-collected populations of different colonial origin. Results indicate that 60% of colony fusion was successful when the incipient colony introduced is 5 mo of age. This method of colony fusion will provide researchers with intact colonies using minimal resources., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Ironwood trees (Casuarina equisetifolia subsp. equisetifolia L.) are ecologically and economically important trees in tropical and subtropical regions of the Indo-Pacific. Ironwood is one of the dominant tree species in Guam, but since 2002, this tree has been declining dramatically. A previous study showed that numerous sick or dead trees were under termite attack. However, the species of termites were not identified. As a first step to investigate causal relationships between termites and ironwood tree death, we assigned termites collected from ironwood trees to species using a combination of morphological characters and DNA barcoding of the 12S, 16S, COI, COII, and ITS2 regions. Based on morphology and comparisons to reference sequences in NCBI GenBank, the most likely species assignments were Nasutitermes takasagoensis (Nawa) (Blattodea: Termitidae) found to infest 45 trees, followed by Coptotermes gestroi (Wasmann) (Blattodea: Rhinotermitidae) (2 trees), Microcerotermes crassus Snyder (Blattodea: Termitidae) (2 trees), and an additional unidentified Microcerotermes species (1 tree) with no close sequence match to identified species in NCBI GenBank. However, taxonomic revisions and broader representation of DNA markers of well-curated specimen in public databases are clearly needed, especially for the N. takasagoensis species complex., (© The Author(s) 2019. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aims: To assess phylogenetic and genotypic diversity of Metarhizium anisopliae lineage within diverse agroecosystems in the Karnataka State of India and to compare their chitinase activity and pathogenicity against insect pest of field crops subterranean termite, Odontotermes obesus., Methods and Results: Three phylogenetic and 27 microsatellite markers were used to assess the genetic diversity of M. anisopliae lineage within multiple agroecosystems. Multilocus phylogeny of the Metarhizium isolates identified two species: Metarhizium pingshaense and Metarhizium guizhouense. Multilocus phylogeny and microsatellite markers resolved two phylogenetic species of M. pingshaense, Mp&#95;1 and Mp&#95;2, and one phylogenetic species of M. guizhouense, Mg&#95;1. Phylogenetic species, Mp&#95;2 and Mg&#95;1, were detected with one genotype each and Mp&#95;1 with eleven genotypes. Metarhizium pingshaense GKVK 02&#95;16 isolate caused significantly high mortality of O. obesus in bioassays and detected with high chitinase activity., Conclusions: The study revealed phylogenetic and genotypic diversity of M. anisopliae lineage in agroecosystems of Karnataka State. Findings of pathogenicity and chitinase activity suggest that M. pingshaense GKVK 02&#95;16 isolate provides effective control of O. obesus., Significance and Impact of the Study: The investigation provided an understanding of the genetic diversity and biocontrol efficiency of M. anisopliae lineage in agroecosystem. These data will serve as a resource in the future pest management strategies at a regional scale., (© 2019 The Society for Applied Microbiology.)

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 (3' Hexamerin-2 and 3' Glycosyl Hydrolase Family [GHF] 9-2 cellulase) and another that enhanced feeding (5' GHF9-2 cellulase). Testing a matrix of combinations of these three dsRNAs revealed ultimately that the most consistently effective dsRNA combination was the 3' Hexamerin-2 + 3' 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.

Fungus-growing termites are major contributors to litter decomposition and an agriculture pest in tropical and subtropical Africa and Asia. The foraging behavior of fungus-growing termites was hypothesized to be seasonal and may associate with climatic factors and the occurrence of natural enemies. In this study, we tested the effects of climatic factors and the presence of ants on the foraging activity of the fungus-growing termite Odontotermes formosanus (Shiraki) (Blattodea: Termitidae). Termite-foraging activities were quantified monthly based on the number of wood stakes occupied, amount of wood consumed, and foraging population size. The rate of wood-stake decomposition was measured by monitoring 484 wood stakes in a tropical forest over the course of nearly 6 yr. The results revealed that temperature and rainfall are the major climatic factors influencing the foraging seasonality of O. formosanus. Termites occupied fewer wood stakes during hot-wet seasons when fewer ants were present. The results of a path analysis supported that termite-foraging seasonality correlated mainly with climatic factors rather than the presence of ants. A new foraging hypothesis, the eat-and-run strategy, is proposed to explain the inconsistent seasonal foraging behaviors observed in fungus-growing termites.

Termites and their nests are potential resources for a wide assemblage of taxa including nematodes. During dispersal flight events from termite colonies, co-occurring nematodes in the nest may have phoretic opportunities to use termite alates as transportation hosts. The two subterranean termite species Coptotermes gestroi (Wasmann) and Coptotermes formosanus Shiraki are both invasive and established in south Florida. Alates of both species (n = 245) were collected during dispersal flight events in 2015-2016 from six locations, of which 30 (12.2%) were associated with one or more species of nematodes. Species of Bunonema Jägerskiöld (Rhabditida: Bunonematidae), Halicephalobus Timm (Rhabditda: Panagrolaimidae), and Poikilolaimus regenfussi (Sudhaus) Sudhaus and Koch (Rhabditida: Rhabditidae) were isolated from 5.3, 4.9, and 0.4% of termite alates, respectively, and Bunonema and Halicephalobus were concomitant in 1.6% of alates. Additional C. formosanus alates were field-collected to establish laboratory colonies in sterilized rearing containers (SRC) to determine if alate-associated nematodes would colonize the newly established nest and/or brood. Among 1-yr-old termite colonies reared in SRCs, 26.9% of the colonies were positive for nematodes confirming that within-colony transmission of nematodes occurred. All three isolated nematode genera are free-living bacterivores capable of asexual reproduction. This suggests that these common co-occurring, termite-associated nematodes are opportunistic and facultative symbionts that receive increased opportunities of geographical dispersion through phoresy during termite dispersal flight events.

This study evaluated the impact of a non-repellent liquid termiticide (fipronil) and a chitin synthesis inhibitor (CSI) termite bait (noviflumuron) on whole colonies of Coptotermes gestroi (Wasmann) (Blattodea: Isoptera: Rhinotermitidae) in laboratory conditions, over a 12-m foraging distance. The protocol simulated the implementation of remedial treatment of an infested structure, where the colony has multiple access routes, and where only a portion of the population was directly exposed to the treatment. Within 2 wk after the implementation of fipronil, all termites within 1.5 m away from the treatment died. The accumulation of cadavers near the treated area resulted in secondary repellency and the colonies avoided the treated area for the remaining 10 wk of the experiment, using alternative foraging galleries. At the end of the 12 wk, colonies exposed to fipronil did not have any difference in population size compared with control colonies. Comparatively, colonies exposed to noviflumuron had no change in foraging activity for the first ≈40 d, but then termites progressively ceased their activity throughout their foraging territory. By 12 wk, noviflumuron-exposed colonies were near-elimination, with only a few workers, soldiers remaining, and all colonies were eliminated by 95 d. This study shows that subterranean termite colonies with access to CSI baits are inevitably eliminated, regardless of the position of the bait, while colonies exposed to fipronil are only locally excluded from the area near the treatment, but may maintain their foraging activity in untreated areas, and retain their potential risk for structural damage in the long term.

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.

Imago dispersal by the West Indian drywood termite, Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) potentially initiates or expands structural infestations by the establishment of incipient colonies. The prevention of drywood termite colonization in structures is difficult, but a substantial reduction may be obtainable. In this experiment, seasonal dispersal of C. brevis imagos commenced from infested wood in a laboratory building. A bioassay was developed to determine the efficacy of 100, 50, and 10% label rate applications of a borate (Tim-Bor) and silica (CimeXa) dust or solution against C. brevis colony establishment under these simulated field conditions. All treatments prevented colony establishment at label rate applications, whereas Tim-bor significantly reduced colonization at all exposure rates.

Fluid baits comprised of 10% dry medium (impregnated with 0.5% hexaflumuron) and 90% methylcel solution were injected into foraging galleries of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), in trees and buildings. Elimination times at two of the six baited sites were longer than expected, possibly due to the application disturbance or the presence of an old and declining colony, but fluid bait treatments eliminated all baited colonies. Fluid baits were injected through drill holes behind infested wood surface, and bypassed the difficulties for installing above-ground (AG) bait stations on uneven surface or at tight corners. Because a large quantity of fluid baits could be applied at once, termite control professionals may be able to avoid revisiting the site to add more baits. The absence of unsightly AG station in a house will also make fluid baits more acceptable to homeowners than AG baits. Currently, local applications of liquid termiticides are common practices because termite control professionals are often urged by homeowners to take remedial actions when termites are found in a house, but such treatments only drive termites away from the active loci without affecting the termite colony(s). Remedial treatments with fluid baits would result in immediate bait consumption and shorten colony elimination time with or without the use of in-ground baiting systems. Introduction of fluid baits will add another tool to the termite control industry and will make it more plausible for the homeowners to accept baiting technology., (© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Detecting drywood termites in structures is very challenging. Microwaves technology (Termatrac T3i) is a nondestructive method for detecting drywood termites in structures. Termatrac device and its mobile application provide a bar as well as a line graph when detecting insect movements, but interpreting these graphs is very subjective. In this paper, Termatrac's output signal is quantified using a new method to study the effect of wall layers, wood type, and termite density on signal strength measured as area under curve in a simulated drywall system in laboratory. Two experiments were conducted on Termatrac T3i at its maximum sensitivity (Gain: 10). In experiment I, HEXBUG Nano was used as a source of movement/vibration and two wood types were used in which the wall layers significantly predicted signal strength, but wood type did not. In experiment II, two different densities of live western drywood termites, Incisitermes minor (Hagen) (Isoptera: Kalotermitidae), were used to study the effect of termite density on signal strength. Interestingly, termite density did not significantly predict signal strength. The maximum reliable wood depth for detecting termites was 5 cm. Microwaves produced by Termatrac also showed good penetration into drywall and produced detectable signals even on a single drywood termite which confirms manufacturer's claim. Suggestions on using and improving microwaves technology for detecting termites is provided which can potentially be applied to other types of insects and noninsect animals.

Heartwood extract from white mulberry (Morus alba L.) (Rosales: Moraceae) were investigated for antitermitic activity against Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae) in laboratory experiments. An ethanol:toluene (2:1) solvent system was used to remove extract from heartwood shavings. A concentration-dependent feeding response and mortality were observed for termites exposed to a concentration series range of 1.25 to 10 mg/ml of extract based on their dry weight. Results showed that maximum termite mortality occurred at 10 mg/ml. Based on the concentration series data, LC50 was calculated at 1.71 mg/ml. In filter paper feeding and repellency assays, extract significantly decreased the total number of gut protozoa compared with untreated and solvent controls. After feeding on filter paper treated at 10 mg/ml for 2 wk, protozoan populations were reduced by >55%. In choice and no-choice tests with mulberry heartwood, greater wood loss from termite feeding was found on solvent extracted blocks compared with nonextracted. Complete (100%) mortality was observed after feeding on nonextracted blocks compared with extracted blocks. Heartwood extract from white mulberry imparted resistance to vacuum pressure treated, nondurable southern pine and cottonwood. At every concentration tested, 100% mortality was observed after feeding on extract-treated southern pine or cottonwood. GC-MS analysis of extract showed high levels of the phenol compound, resorcinol. Results indicated that heartwood extract from white mulberry have antitermitic properties and might be potentially valuable in the development of environmentally benign termiticides.