Morphological and functional analyses for investigation of sexually selected legs in the frog legged beetle Sagra femorata (Coleoptera: Chrysomelidae).

Mate choice and male-male combat over successful mating often cause disproportionate exaggeration of male trait relative to body size. However, the exaggeration is often not the only trait involved with male-male combat and mate choice: suites of co-expressed traits may function together as a coordinated unit. When this occurs, dimorphism may be expected for these additional, non-exaggerated, structures. S. femorata males have disproportionately large hind-legs used in male-male combat over females. During the fights, fore- and mid-legs are used to keep males in positions where advantageous for leverage. Because use of the exaggerated hind-legs is coordinated with the other legs, they will coevolve as a functional unit. Here, we show that 1) S. femorata has sexual size differences in all three legs; 2) males show positive allometry in the relative sizes of all three legs; and 3) microstructures of tarsi on the fore- and mid-legs are also sexually dimorphic. Despite these differences in the tarsal microstructure, 4) adhesion forces of the tarsi had no sexual difference in flat surface. The microstructure would be specialized on attaching elytra surface. These results suggest that the three pairs of legs function together during fighting behavior, with hind-legs employed primarily for fighting, and the fore- and mid-legs functioning to grip females, keeping males positioned on the back of the female during combat.

Multiyear study of pollinator efficiency and importance of a wide array of pollinators in a field-cultivated strawberry plot.

Using wild pollinators to pollinate crops without introducing human-managed pollinators is cost-effective and friendly to native ecosystems. To maintain stable, good-quality yields in crops that mainly use wild pollinators, it is essential to determine which flower visitors are important pollinators and their degree of importance. In this study, we observed flower-visiting insects for 5 years in outdoor cultivated strawberries surrounded by a semi-natural environment in central Japan. We estimated the pollination effectiveness and efficiency of the 10 main flower-visiting insect taxa on strawberries by examining the relationship between the number of visits per flower and subsequent achene fertilization rates per berry. Finally, the pollinator importance (%) to the total pollination service was estimated for each of the 10 main taxa and for all others. Among the 10 main insect taxa, 6 were effective pollinators, i.e., they significantly increased achene fertilization rates by increasing their number of visits to a flower. Considering the 5-year mean, these six taxa accounted for the top six important pollinators. Andrena (subgenus Micrandrena) spp. were the most important and three other bee taxa, including Apis mellifera and Ceratina spp., were the next most important pollinators; one fly and one butterfly species were also important pollinators. This indicates that strawberry pollinators were diverse in the study area. The flower-visit frequency and importance of many pollinators fluctuated from year to year, implying that various pollinators pollinate strawberry flowers each year, and in field surveys of crop-pollinator communities multiyear investigations are needed to identify important pollinators and to estimate their importance. To the best of our knowledge, this is the first attempt to quantify the proportional importance of each pollinator to the total pollination service for a crop.

Protein/Lipid ratio of pollen biases the visitation of bumblebees (Bombus ignitus Smith) to male-fertile cultivars of the Japanese pear (Pyrus pyrifolia Nakai).

Bees have been known to visit the male-fertile cultivars of self-incompatible flowering plants more frequently than the male-sterile cultivars, but the origin of this preference is poorly understood. Here, we demonstrate that this preference is driven by the higher protein/lipid ratio of male-fertile pollen compared with male-sterile pollen by way of two caged-behavioral assays with six cultivars. In the first assay, flower-naïve bumblebees (Bombus ignitus Smith) showed a significantly higher flower-visitation rate to male-fertile cultivars (pollen germination rate > 55%; > 14 visits/10 min) of the Japanese pear (Pyrus pyrifolia Nakai) than male-sterile cultivars (pollen germination rate ≤ 20%; > 6 visits/10 min). In the second, bees still preferred the anthers of male-fertile cultivars (5-9 visits/10 min) more than those of male-sterile ones (less than 1 visit in 10 min) even in the absence of all other organs (i.e., petals, pistil, nectar), indicating that pollen is responsible for the preference. We then analyzed the macronutrient content of the pollen and its visual cues, and found that the bee preference was highly correlated with the protein/lipid ratio (0.3-1.6) but not color variables such as (a)chromatic contrast, intensity, and spectral purity. We conclude that the protein/lipid ratio influences the foraging behavior of the bumblebees likely by serving as (1) a chemotactile cue while antennating, (2) a gustatory cue after intake, and (3) an olfactory cue. In addition, the low bee visitation rate to poorly viable pollen could be due to its low protein/lipid ratio.

Diurnal and geographic variations of pollinator importance for Cucurbita maxima Duchesne.

Despite growing awareness of the importance of monitoring wild crop pollinators worldwide, there are still few reports, especially in East Asia. Considering ongoing global warming may change the distribution range and diurnal activity of pollinators, it is necessary to describe current geographic and diurnal patterns. We clarified pollinators of Cucurbita maxima Duchesne (Cucurbitales: Cucurbitaceae) in three geographically distinct (>350 km, minimum) areas in Japan, focusing on diurnal variation. Apis mellifera L. (Hymenoptera: Apidae) and Halictidae (Hymenoptera) were observed in all of the experimental gardens. Apis cerana japonica Radoszkowski (Hymenoptera: Apidae) were mainly observed in Mie and Kagoshima, while Bombus diversus diversus Smith (Hymenoptera: Apidae) were observed only in Ibaraki. The peak time of flower visits depended both on bee taxa and area, and interestingly, did not necessarily synchronize with the timing of the highest pollen loads and the probability of stigma contact. In particular, visits and probability of contacting stigmas of Halictidae tended to increase as time passed, whereas pollen grains on their bodies sharply decreased with time; only a few individuals of Halictidae that visit early can become effective pollinators. There were no differences in yields between supplementary hand and natural pollination in all areas, and flower-enclosure experiments using different mesh sizes clarified that small insects that can go across an approximately 4-mm mesh may not transport sufficient pollen for fruit set. Our study demonstrated that pollination effectiveness, which is usually regarded as a static value, within a taxon can fluctuate in the space of just several hours. Considering such diurnal patterns can be altered by climate change, we need to carefully monitor the diurnal temporal patterns of pollinators worldwide.

Diversity and composition of flower-visiting insects and related factors in three fruit tree species.

Animal-mediated pollination is an essential ecosystem service for the production of many fruit trees. To reveal the community composition of flower-visiting wild insects which potentially contribute to fruit production and to examine the effects of geographic location, local meteorological conditions and locally introduced domesticated pollinators on them, we investigated the community composition of insects visiting the flowers (hereafter, "visitors") of apple, Japanese pear and Oriental persimmon for 1‒3 years at 20 sites around Japan. While most of the variation (82%) of the community composition was explained by tree species with a slight contribution by geographic distance (2%), maximum temperature and tree species contributed 62% and 41% of the variation in total abundance of the visitors, respectively. Though the dominant families of the visitors varied spatiotemporally, the community composition of the visitors of apple and Japanese pear clearly differed from that of Oriental persimmon. While Andrenidae and Syrphidae together accounted for 46%‒64% of the visitors of apple and Japanese pear, Apidae represented 57% of the visitors of Oriental persimmon. The taxonomic richness, diversity and evenness of the visitors were best predicted by locally introduced domesticated pollinators and local meteorological conditions of wind speed and maximum temperature. Amongst these selected factors, locally introduced domesticated pollinators could have the largest impact. It seemed to be strongly related to the reduction of taxonomic richness, diversity and evenness of the visitors, accounting for 41‒89% of the variation. Results suggested that the community composition and total abundance of potential pollinators were predominantly determined by tree species and temperature, but locally introduced domesticated pollinators could have a determinantal pressure on the taxonomic diversity of the community.

Female solitary bees flexibly change foraging behaviour according to their floral resource requirements and foraging experiences.

Intraspecific variation in foraging behaviour is related to the floral resource requirements and foraging experiences of social bees. These behavioural changes influence their pollination efficiency. However, the extent of such behavioural changes in solitary bees, which constitute the majority of bee species, remains largely unknown. As pollen contains essential nutrients for ovarian and offspring development, a relationship between the resource requirements of female bees and their ovarian development is expected. Additionally, wing damage could reflect foraging experiences, as the wings are damaged during foraging. Here, we aimed to clarify the relationships between ovarian development, wing damage, foraging behaviours, and pollination efficiency in female long-horned bees (Eucera nipponensis and Eucera spurcatipes) visiting red clovers. The bee handling times were recorded. Wing damage and pollen load on the hind legs were confirmed and the number of pollen grains on bee's bodies was counted. We then dissected the bees and recorded the presence or absence of nectar and pollen in the digestive tubes, as well as the mature egg number. The mature egg number positively correlated with nectar feeding and pollen collection, whereas handling time decreased with wing damage. Bees with pollen loads on their legs attach more pollen grains to their bodies. Therefore, solitary bees flexibly change their foraging behaviour based on resource requirements and foraging experiences, and these behavioural changes can influence pollination efficiency. The asynchrony of foraging behaviours and pollination efficiency within a bee population may provide stable pollination for flowering plants throughout the season.

Eggs in faeces: defensive mechanisms and effects of faecal coating by a water scavenger beetle, Coelostoma stultum (Coleopterea: Hydrophilidae).

The egg stage in insect development is vulnerable to fluctuations in environmental conditions and attacks by natural enemies. Protective devices are effective means of avoiding both abiotic and biotic damage to eggs. Although some insects use their faeces as a protective device, few studies have focused on using faeces for egg protection, and studies that examined the mechanism are lacking. Females of a water scavenger beetle, Coelostoma stultum, typically lay eggs and coat them with cocoons and their faeces. The efficacy of a double defensive device, however, remains uncertain. Here, we conducted field observations and laboratory experiments to assess the protective effects of cocoons with faecal coating on eggs against predation and determine the duration and mechanisms of this defence. Our findings reveal that the faeces on the egg cocoon protected eggs from predation by the pill bugs, Armadillidium vulgare, and marsh slugs, Deroceras laeve. Laboratory experiments showed that the defensive effect of faecal coating was maintained for three days and decreased daily. The double protective traits with faecal coating on the egg cocoons protected the eggs from instense predation pressure in C. stultum. The behavioural patterns of the pill bugs and egg predation rates indicate that the faecal coating behaviour in C. stultum protects eggs with chemical compounds and textural camouflage in mud when the antennae of the pill bugs touch faeces. It is important to note that for this defence to be effective, the chemistry and texture of the faeces should be similar to that of the oviposition sites.

Acute toxicity data of common agricultural insecticides to Japanese wild bees.

Although numerous ecotoxicological assessments of European honeybee (Apis mellifera L.) have been performed, Japanese wild bees are less well studied in this regard. To address this knowledge gap, we assessed the mortality and acute toxicity (LD50) of 3 common agricultural insecticides (clothianidin, fipronil, and diazinon) on as many as 6 species of Japanese wild bees (Andrena prostomias Perez, Apis cerana japonica Radoszkowski, Bombus deuteronymus Perez, Bombus honshuensis Tkalcu, Bombus hypocrita Perez, and Eucera spp.; all or any of them). The datasets were obtained via standard acute toxicity testing, with assessment of mortality at 24 and 48 h after exposure to the insecticides. These data provide important information regarding the effects of insecticides on Japanese wild bees and their conservation.

The ontogenetic dietary shift from non-dangerous to dangerous prey in predator-eating predators under capture risk.

Evaluating the patterns and generality of ontogenetic dietary shifts (ODSs) contributes to understanding prey-predator interactions and food web dynamics. Numerous studies have focused on predators that target distinctively lower trophic-level organisms. However, the ODS of predators that routinely prey on organisms at similar trophic levels (i.e., predator-eating predators) have been neglected in ODS research. The ODS patterns of predator eaters may not fit into conventional frameworks owing to constraints of potential capture risk (e.g., deadly counterattack from prey) and body size. We aimed to reveal the ODS patterns of predator eaters and determine whether the patterns were affected by body size and capture risk. Assuming that capture risk is a significant factor in ODS patterns, we expected: (1) juvenile araneophagic spiders to forage on non-dangerous prey (insects) and capture larger non-dangerous prey more frequently than dangerous prey (spiders); and (2) as they grow, their prey types will shift from non-dangerous to dangerous prey because larger predators will be able to capture dangerous prey as the optimal food. As a result of field observations, we revealed that the major ODS pattern in these spiders changed from a mixed (both insect and spider) to a spider-dominant diet. The model selection approach showed that this diet shift was partly due to predator size, and the relative importance of predator size was higher than the life stage per se and almost equal to species identity. In these spiders, the body size of spider prey tended to be smaller than that of insects when the predators were small, suggesting that capture risk may be a critical factor in determining the ODS patterns of these predators. Therefore, our study adds to the evidence that the capture risk is crucial in comprehensively understanding the mechanisms determining ODS patterns in natural systems.

Long horns protect Hestina japonica butterfly larvae from their natural enemies.

Animals sometimes have prominent projections on or near their heads serving diverse functions such as male combat, mate attraction, digging, capturing prey, sensing or defence against predators. Some butterfly larvae possess a pair of long frontal projections; however, the function of those projections is not well known. Hestina japonica butterfly larvae have a pair of long hard projections on their heads (i.e., horns). Here we hypothesized that they use these horns to protect themselves from natural enemies (i.e., predators and parasitoids). Field surveys revealed that the primary natural enemies of H. japonica larvae were Polistes wasps. Cage experiments revealed that larvae with horns intact and larvae with horns removed and fitted with horns of other individuals succeeded in defending themselves against attacks of Polistes wasps significantly more often than larvae with horns removed. We discuss that the horns counter the paper wasps' hunting strategy of first biting the larvae's 'necks' and note that horns evolved repeatedly only within the Nymphalidae in a phylogeny of the Lepidoptera. This is the first demonstration that arthropods use head projections for physical defence against predators.

Honeybees with extensive foraging experience rob nectar more frequently.

Not all flower-visiting animals act as pollinators; some visitors engage in foraging nectar without pollen transfer. The tendency to rob nectar is related to visitors' morphological traits and rewards per foraging effort, and drivers of this variation within visitor species are largely unknown. Because foraging behavior is affected by foraging experience, we focused on the relationship between the tendency to rob nectar and the foraging experience of each forager. We investigated five consecutive visits of European honeybee, Apis mellifera L., on comfrey, Symphytum officinale L., in Japan. We estimated the foraging experience of A. mellifera using wing wear, categorized into six groups. Approximately 60% and 40% of A. mellifera foragers engaged in legitimate visits and nectar robbing, respectively. Moreover, most A. mellifera engaged in only one foraging tactic. The proportion of nectar robbing was related to wing wear and was higher in individuals with extensively damaged wings than those with less damaged wings. The present study suggests that extensively experienced honeybee foragers tend towards nectar robbing.

Morphology and sex-specific behavior of a gynandromorphic Myrmarachne formicaria (Araneae: Salticidae) spider.

Behavioral studies of gynandromorphism, also called as sex mosaic, contribute to the understanding of the relationship between morphological gender and sexual identity of an animal. Few studies have focused on the behaviors of gynandromorphic spiders because of a scarcity of gynandromorphic individuals in the field. In this study, we collected a gynandromorphic spider, Myrmarachne formicaria (De Geer 1778) (Araneae: Salticidae), from the field and examined its morphology and sex-specific behavior in the laboratory. The right half of the gynandromorphic spider presented male characteristics and the left half female characteristics. It showed courtship behavior to M. formicaria females and agonistic behavior to the males. These results indicate that the gynandromorphic spider's sexual identity is male. Our findings suggest that a spider can exhibit behaviors of male sexuality, although the external morphology has the characteristics of both sexes. To the best of our knowledge, this is the first report of a gynandromorphic individual and its behavior in the genus Myrmarachne.

First come, first served: precopulatory mate-guarding behavior and male-male contests by a hymenopteran saproxylic parasitoid.

Precopulatory mate-guarding behavior is a common strategy that maximizes male reproductive success when female receptivity to copulation is low. This behavior has been demonstrated in vertebrates, aquatic crustaceans, terrestrial isopods, and some species of insects, but there is very little available information about hymenopteran insects. A few studies have clarified the factor that determines the outcome of a contest between a guarding male and an invader male. We investigated the male-male contest and mating behavior of a saproxylic parasitoid wasp, Ibalia japonica (Hymenoptera: Cynipoidea: Ibaliidae) using field observations in Japan. These observations indicated that I. japonica males show precopulatory mate-guarding behavior and that four types of male-male contests occur on the Magnolia liliiflora (Magnoliales: Magnoliaceae) tree that virgin females emerge from. We show that the arrival order of I. japonica males that found the future emergence point of a female was key factor that allowed males to secure virgin females.

Inbreeding tolerance as a pre-adapted trait for invasion success in the invasive ant Brachyponera chinensis.

Identifying traits that facilitate species introductions and successful invasions of ecosystems represents a key issue in ecology. Following their establishment into new environments, many non-native species exhibit phenotypic plasticity with post-introduction changes in behaviour, morphology or life history traits that allow them to overcome the presumed loss of genetic diversity resulting in inbreeding and reduced adaptive potential. Here, we present a unique strategy in the invasive ant Brachyponera chinensis (Emery), in which inbreeding tolerance is a pre-adapted trait for invasion success, allowing this ant to cope with genetic depletion following a genetic bottleneck. We report for the first time that inbreeding is not a consequence of the founder effect following introduction, but it is due to mating between sister queens and their brothers that pre-exists in native populations which may have helped it circumvent the cost of invasion. We show that a genetic bottleneck does not affect the genetic diversity or the level of heterozygosity within colonies and suggest that generations of sib-mating in native populations may have reduced inbreeding depression through purifying selection of deleterious alleles. This work highlights how a unique life history may pre-adapt some species for biological invasions.

Radiocarbon analysis reveals expanded diet breadth associates with the invasion of a predatory ant.

Invasions are ecologically destructive and can threaten biodiversity. Trophic flexibility has been proposed as a mechanism facilitating invasion, with more flexible species better able to invade. The termite hunting needle ant Brachyponera chinensis was introduced from East Asia to the United States where it disrupts native ecosystems. We show that B. chinensis has expanded dietary breadth without shifting trophic position in its introduced range. Transect sampling of ants and termites revealed a negative correlation between the abundance of B. chinensis and the abundance of other ants in introduced populations, but this pattern was not as strong in the native range. Both termite and B. chinensis abundance were higher in the introduced range than in native range. Radiocarbon (14C) analysis revealed that B. chinensis has significantly younger 'diet age', the time lag between carbon fixation by photosynthesis and its use by the consumer, in the introduced range than in the native range, while stable isotope analyses showed no change. These results suggest that in the introduced range B. chinensis remains a termite predator but also feeds on other consumer invertebrates with younger diet ages such as herbivorous insects. Radiocarbon analysis allowed us to elucidate cryptic dietary change associated with invasion success.

The choosing of sleeping position in the overnight aggregation by the solitary bees Amegilla florea urens in Iriomote Island of Japan.

In addition to the process of joining the sleeping aggregation, the choice of sleeping position is an important night-time behaviour of small diurnal insects because of the increased risk for predator attacks as well as bad weather. The aggregation behaviour of the solitary bee Amegilla florea urens was investigated to elucidate the choice of sleeping position on substrates. Male and female constructed single-sex aggregations on hanging leaves during May and June, respectively. Most individuals tended to form aggregations with other individuals while few individuals slept alone. During the aggregation forming, both the number of individuals that tried to join the aggregation and the completion time of aggregation increased with the number of sleeping individuals, whereas the success rate of joining was unaffected. The sleeping positions of subsequent arrivals on the substrates were higher than those of the first arrivals in female aggregations. Therefore, the first female to arrive tended to be located near the bottom of a hanging substrate. Dissecting sleeping females showed that they contained mature oocytes, indicating that sexually mature individuals formed aggregations. In male aggregations, however, we could not find a clear relationship between the position on substrates and the arrival sequence. We suggest that the purpose for sleeping in aggregations might be a dilution effect for nocturnal predation and that the females that finished both nesting and foraging quickly could choose the optimal positions in the aggregation when they arrived on the sleeping substrates.

Monitoring and Detecting the Cigarette Beetle (Coleoptera: Anobiidae) Using Ultraviolet (LED) Direct and Reflected Lights and/or Pheromone Traps in a Laboratory and a Storehouse.

The cigarette beetle, Lasioderma serricorne (F.), is an important stored-product pest worldwide because it damages dry foods. Detection and removal of the female L. serricorne will help to facilitate the control of the insect by removal of the egg-laying populations. In this manuscript, we examined the responses by L. serricorne to direct and reflected light in transparent cube (50 m3) set in a chamber (200 m3) and a stored facility with both direct and reflected UV-LED lights. The study also examined the responses by the beetles to light in the presence or absence of pheromone in traps that are placed at different heights. Reflected light attracted more beetles than the direct light in the experimental chamber, but the direct light traps attracted more beetles than the reflected light traps in the storehouse. Pheromone traps attracted only males; UV-LED traps attracted both sexes. The UV-LED traps with a pheromone, i.e., combined trap, attracted more males than UV-LED light traps without a pheromone, whereas the attraction of UV-LED traps with and without the pheromone was similar in females. The results suggest that UV-LED light trap combined with a sex pheromone is the best solution for monitoring and controlling L. serricorne.

Long Frontal Projections Help Battus philenor (Lepidoptera: Papilionidae) Larvae Find Host Plants.

Animals sometimes develop conspicuous projections on or near their heads as, e.g., weaponry, burrowing or digging tools, and probes to search for resources. The frontal projections that insects generally use to locate and assess resources are segmented appendages, including antennae, maxillary palps, and labial palps. There is no evidence to date that arthropods, including insects, use projections other than true segmental appendages to locate food. In this regard, it is noteworthy that some butterfly larvae possess a pair of long antenna-like projections on or near their heads. To date, the function of these projections has not been established. Larvae of pipevine swallowtail butterflies Battus philenor (Papilionidae) have a pair of long frontal fleshy projections that, like insect antennae generally, can be actively moved. In this study, we evaluated the possible function of this pair of long moveable frontal projections. In laboratory assays, both frontal projections and lateral ocelli were shown to increase the frequency with which search larvae found plants. The frontal projections increased finding of host and non-host plants equally, suggesting that frontal projections do not detect host-specific chemical cues. Detailed SEM study showed that putative mechanosensillae are distributed all around the frontal as well as other projections. Taken together, our findings suggest that the frontal projections and associated mechanosensillae act as vertical object detectors to obtain tactile information that, together with visual information from lateral ocelli and presumably chemical information from antennae and mouthparts, help larvae to find host plants. Field observations indicate that host plants are small and scattered in southern Arizona locations. Larvae must therefore find multiple host plants to complete development and face significant challenges in doing so. The frontal projections may thus be an adaptation for finding a scarce resource before starving to death. This is the first evidence that arthropods use projections other than true segmental appendages such as antennae, mouthparts and legs, to locate food resources.

Queen-specific volatile in a higher termite Nasutitermes takasagoensis (Isoptera: Termitidae).

In social insect colonies, queen-produced pheromones have important functions in social regulation. These substances influence the behavior and physiology of colony members. A queen-produced volatile that inhibits differentiation of new neotenic reproductives was recently identified in the lower termite Reticulitermes speratus. However, there are no known queen-specific volatiles of this type in any other termite species. Here, we report volatile compounds emitted by live queens of the higher termite Nasutitermes takasagoensis. We used headspace gas chromatography mass spectroscopy (HS GC-MS) to analyze volatiles emitted by live primary queens, workers, soldiers, alates, and eggs collected in a Japanese subtropical forest. Among 14 detected compounds, 7 were soldier-specific, 1 was alate-specific, 1 was egg-specific, and 1 was queen-specific. The queen-specific volatile was phenylethanol, which is different than the compound identified in R. speratus. The identification of this queen-specific volatile is the first step in determining its functions in higher termite social regulation. Comparisons of queen pheromone substances regulating caste differentiation among various termite taxa will contribute to a better understanding of the evolution of social systems in termites.

Identification of a pheromone regulating caste differentiation in termites.

The hallmark of social insects is their caste system: reproduction is primarily monopolized by queens, whereas workers specialize in the other tasks required for colony growth and survival. Pheromones produced by reigning queens have long been believed to be the prime factor inhibiting the differentiation of new reproductive individuals. However, there has been very little progress in the chemical identification of such inhibitory pheromones. Here we report the identification of a volatile inhibitory pheromone produced by female neotenics (secondary queens) that acts directly on target individuals to suppress the differentiation of new female neotenics and identify n-butyl-n-butyrate and 2-methyl-1-butanol as the active components of the inhibitory pheromone. An artificial pheromone blend consisting of these two compounds had a strong inhibitory effect similar to live neotenics. Surprisingly, the same two volatiles are also emitted by eggs, playing a role both as an attractant to workers and an inhibitor of reproductive differentiation. This dual production of an inhibitory pheromone by female reproductives and eggs probably reflects the recruitment of an attractant pheromone as an inhibitory pheromone and may provide a mechanism ensuring honest signaling of reproductive status with a tight coupling between fertility and inhibitory power. Identification of a volatile pheromone regulating caste differentiation in a termite provides insights into the functioning of social insect colonies and opens important avenues for elucidating the developmental pathways leading to reproductive and nonreproductive castes.