Co-evolution-driven cuticular hydrocarbon variation between the slave-making ant Rossomyrmex minuchae and its host Proformica longiseta (Hymenoptera: Formicidae)

Summary. Proformica longiseta exists as two populations in the Sierra Nevada Mountains in Spain, only one of which is parasitized by the slave-maker ant Rossomyrmex minuchae. To investigate the possible effect of co-evolutionary pressures on cuticular hydrocarbon (CHC) profiles (the presumed nestmate recognition cues), we performed a comparative analysis of the CHC of R. minuchae and P. longiseta colonies from both the allopatric and sympatric populations; the latter includes samples of enslaved as well as free-living workers. Discriminant analyses based on these chemical profiles showed two clear profile groups: the first comprised R. minuchae and both enslaved and free-living P. longiseta from the sympatric population; and the second the allopatric P. longiseta workers. As expected, the profiles of the two sympatric P. longiseta groups (enslaved and free-living) were distinct; but, interestingly, those of the enslaved P. longiseta and its parasite R. minuchae were also distinguishable. This indicates that despite their cohabitation each species maintains its own chemical identity. Profile similarity between the sympatric free-living P. longiseta and its parasite may explain the lower than expected aggression observed during raids. We further speculate that in view of the differences between the sympatric and allopatric population of P. longiseta, co-evolutionary pressures have driven changes in the profile of the former to better match that of its parasite R. minuchae. Such an adjustment may have enabled nests of the sympatric P. longiseta to endure multiple raids by the parasite (due to the reduced aggression) and thus to continue to reproduce despite the damage inflicted by the raids.     

Mate preferences in <Emphasis Type="Italic">Drosophila</Emphasis> infected with <Emphasis Type="Italic">Wolbachia</Emphasis>?

The maternally inherited bacterium Wolbachia pipientis generates strong reproductive incompatibilities between uninfected females and infected males (cytoplasmic incompatibility), significantly reducing both female and male reproductive success. Such fitness costs are thought to place selective pressure on hosts to evolve pre-copulatory preferences for mating with compatible mates, thereby enabling them to avoid the reproductive incompatibilities associated with Wolbachia. Therefore, uninfected females are predicted to prefer mating with uninfected males, whereas infected males are predicted to prefer mating with infected females. Despite these predictions, previous investigations of pre-copulatory mate preferences in Wolbachia-manipulated Drosophila have not found evidence of female preference for uninfected or compatible males. However, none of these studies utilised a design where focal individuals are provided with a simple choice in a relatively non-competitive situation. We examined both female and male pre-copulatory mate preference based on mate infection status in Drosophila simulans and D. melanogaster using simple choice assays involving between 30–50 replicates per treatment. Although we found no evidence of female pre-copulatory mate preferences in either species, male D. simulans exhibited some preference for mating with females of the same infection status. However, this preference was not evident when we repeated the experiment to confirm this finding. Consequently, we conclude that neither male nor female D. melanogaster and D. simulans exhibit significant Wolbachia-associated pre-copulatory mate preferences.     

Hibernation clustering and its consequences for associative nest foundation in<Emphasis Type="Italic"> Polistes dominulus</Emphasis> (Hymenoptera Vespidae)

Various studies indicate that cuticular hydrocarbons (CHCs) act as cues for nestmate recognition in paper wasps and other social insects. A recent study showed that associative nest foundation in Polistes dominulus is mainly performed by foundresses coming from the same locality. In the present study, we induced future foundresses of P. dominulus collected in two different localities to hibernate in the laboratory in aggregates of individuals from the same or different localities. After 2 months of hibernation, foundresses from different localities but from the same experimental cluster did not show any preference to associate, at the time of nest foundation, with individuals coming from the same original locality. The cuticular chemical profiles of individuals from the mixed hibernation clusters were quite similar and significantly different from those of individuals which hibernated with other foundresses from the same locality. These findings suggest that, in this species, mechanisms other than nestmate chemical recognition play a major role in the spring association of gynes during the foundation of a new nest.Communicated by R.F.A. Moritz     

Chemical characterization of contact semiochemicals for host-recognition and host-acceptance by the specialist parasitoid <Emphasis Type="Italic">Cotesia plutellae</Emphasis> (Kurdjumov)

Summary. Cotesia plutellae is a specialist parasitoid of Plutella xylostella. This specificity is potentially under the control of several factors before and after oviposition. Thereby, the stimuli that lead female parasitoids to host locations and to oviposition, might be at the basis of the specificity. We explore here the response of C. plutellae females exposed to host cuticular lipids. A total cuticular lipid extract of host caterpillars was fractionated into a hydrocarbon fraction and a non-hydrocarbon fraction. Neither fraction alone had any effect on oviposition behaviour in C. plutellae but the hydrocarbon fraction alone did seem to have a positive effect on the rate of antennal contact by the females. To induce oviposition behaviour, both fractions were necessary and reflect cooperation between at least one compound in each fraction. Identification of cuticular lipids shows that hydrocarbons were dominant (77%). Non-hydrocarbon compounds were mainly represented by 15-nonacosanone (18% of the total lipid extract). This ketone is rare in insect cuticle lipids and is thought to originate from the cabbage epicuticle where it is dominant with n-C₂₉ and 14- and 15-nonacosanol also found among the cuticular lipids of the host caterpillar.     

Asexuals looking for sex: conflict between species and mate-quality recognition in sailfin mollies (Poecilia latipinna)

When two closely related species are sympatric the process of species recognition (identifying conspecifics) and mate-quality recognition (increased fitness benefits) can yield a conflict when heterospecifics resemble high-quality conspecifics. Conflict in species versus mate-quality recognition may serve as a possible mechanism for the persistence of unisexual, gynogenetic Amazon mollies (Poecilia formosa). Amazon mollies require sperm from closely related species (e.g., sailfin mollies, P. latipinna) to start embryogenesis but inheritance is strictly maternal. When choosing mates, male sailfin mollies from populations sympatric with Amazon mollies may rely on traits indicating species identity rather than those indicating mate quality. Conversely, males from allopatric populations may rely more on traits indicating mate quality. Previous work has found that male sailfin mollies in sympatry exhibit a significantly greater mating preference for female sailfin mollies over Amazon mollies compared to males in allopatry. In addition, male sailfin mollies prefer to associate with and produce more sperm in the presence of larger conspecific females, which are more fecund. We hypothesized that male sailfin mollies experience a conflict in species recognition and mate-quality recognition in the presence of Amazon mollies that are relatively larger than female sailfin mollies. To test this hypothesis, we paired males from sympatric and allopatric populations with a larger Amazon molly and a smaller female sailfin molly. We scored the number of mating attempts that males directed to conspecific and heterospecific females. Males in most sympatric and allopatric populations demonstrate no clear preference for conspecifics. In addition, we found some evidence for a difference in mating preference between allopatric and sympatric populations with males from allopatry showing a greater heterospecific mate preference. These results indicate a conflict between species and mate-quality recognition. In sympatry this conflict may contribute to the persistence of gynogenetic Amazon mollies.     

Sequential male mate choice in a fish,the Pacific blue-eye<Emphasis Type="Italic"> Pseudomugil signifer</Emphasis>

Mate choice is not just a female preoccupation. Under some circumstances, males may also be choosy. However, studies of male mate choice have generally been confined to situations where males can make direct comparisons between potential partners. In contrast, sequential male mate choice has largely been overlooked despite its biologically importance, especially if current investment in mate attraction diminishes a males future mating opportunities. Using the Pacific blue-eye fish Pseudomugil signifer, we show that males are capable of exercising sequential mate choice. When presented sequentially with large and small females, males spent more effort courting the former. However, males did not appear to modify the time spent courting a given female based on the size of the female encountered previously. We suggest that greater attention to the sequential choice problem in males may help illuminate similarities and differences between the sexes when it comes to mating decisions.Communicated by T. Czeschlik     

Reproductive success of male bank voles (<Emphasis Type="Italic">Clethrionomys glareolus</Emphasis>): the effect of operational sex ratio and body size

The operational sex ratio (OSR) may influence the intensity of competition for mates and mate choice and is therefore thought to be a major factor predicting the intensity and direction of sexual selection. We studied the opportunity for sexual selection, i.e., the variance in male reproductive success and the direction and intensity of sexual selection on male body mass in bank vole (Clethrionomys glareolus) enclosure populations with experimentally manipulated sex ratios. The opportunity for sexual selection was high among male-biased OSRs and decreased towards female-biased OSRs. Paradoxically, selection for large male body mass was strongest in female-biased OSRs and also considerable at intermediate OSRs, whereas at male-biased OSRs, only a weak relationship between male size and reproductive success was found. Litters in male-biased OSRs were more likely to be sired by multiple males than litters in female-biased OSRs. Our results suggest that the intensity and direction of sexual selection in males differs among different OSRs. Although the direction of sexual selection on male body mass was opposite than predicted, large body mass can be favored by sexual selection. Naturally varying OSRs may therefore contribute to maintain variation in male sexually selected traits.     

Olfactory cues,genetic relatedness and female mate choice in the agile antechinus (<Emphasis Type="Italic">Antechinus agilis</Emphasis>)

Females show mate preferences for males that are genetically dissimilar to themselves in a variety of taxa, but how females choose these males is not clearly understood. In this study, we examined the effects of olfactory stimuli and genetic relatedness on female mate choice in a small carnivorous marsupial, the agile antechinus (Antechinus agilis), during two breeding seasons. Captive female antechinus in oestrus were provided with a combination of male urine and body scent from two novel males, one more genetically similar and one more dissimilar to the females, in a Y-maze olfactometer. Genetic relatedness between females and pairs of males was determined using highly polymorphic, species-specific, microsatellite markers. Females consistently chose to visit the scents of males that were genetically dissimilar to themselves first, spent significantly more time near the source of those scents and showed more sexual and non-exploratory behaviours near those scents. These data demonstrate that chemosensory cues are important in mate choice in the agile antechinus and that females prefer males that are genetically dissimilar to themselves.     

The efficacy of female choice in chimpanzees of the Taï Forest, Côte d’Ivoire

Male–male competition has historically been considered the major force driving sexual selection. However, female choice and inter-sexual conflict are increasingly recognized as important influences affecting differential mating and reproductive success. Many females exhibit preferences for particular males; however, male strategies may conflict with females’ ability to obtain their mate preferences. To influence paternity, females must affect both (1) whether or not sexual interactions occur, particularly during the periovulatory period (POP) and (2) the outcome of sexual interactions. This study focuses on the effectiveness of female choice in wild chimpanzees (Pan troglodytes verus). Over 2,600 h of data were collected on two habituated chimpanzee communities in the Taï National Park, Côte d’Ivoire. Female mate preferences were measured by quantifying proceptive and resistance behavior toward males in both the periovulatory period and non-POP phases of estrus. The efficacy of female preference was measured both (1) by measuring success rates of female proceptivity and resistance behaviors and (2) by determining how well measures of female mate preference (proceptivity and resistance rates) predict male mating success. Though male chimpanzees are clearly dominant to females, the results indicate that females could effectively resist male solicitations and, in most cases, unwanted copulations were averted. Both female proceptivity and resistance rates correlate (positively and inversely, respectively) with male mating success in POP. Outside POP, female proceptivity rates corresponded with male mating success, but resistance rates did not. Males (irrespective of rank) that were preferred by females obtained higher mating success compared to other males during the POP, suggesting that females were effective in their mate choice and that, despite clear male dominance, female choice influences paternity in wild chimpanzees.     

Selected polyandry: female choice and inter-sexual conflict in a small nocturnal solitary primate (<Emphasis Type="Italic">Microcebus murinus</Emphasis>)

Sex-specific interests over the maximization of reproductive success lead to an inter-sexual conflict over the optimal mating system in a species. Traditionally, the outcome of this inter-sexual conflict has been studied from the male perspective but it also depends on female mating strategies, such as manipulating the temporal distribution of sexual activity, advertisement, and mate choice. We used a small nocturnal primate, the gray mouse lemur (Microcebus murinus) to determine the relative importance of female mating strategies on the outcome of this conflict in a species where females are solitary during their activity period. We studied their mating behavior over three consecutive annual mating seasons and determined the genetic relationships among more than 300 study animals to quantify individual reproductive success. We found that most females were receptive asynchronously. Females did not exhibit any obvious direct mate choice, probably due to a highly male-biased operational sex ratio and the corresponding costs of choosiness. However, females exercised indirect choice for multiple matings. They mated with 1–7 males up to 11 times during their single night of receptivity. As a result, mixed paternity was common but heavier males sired more offspring, meaning that indirect female choice for superior males cannot be excluded. Females exhibited a mixed mating strategy, avoiding costly direct mate choice but still counteracting male efforts to monopolize mating, successfully increasing genetic variability among offspring. Thus, females had a major influence on the outcome of the inter-sexual conflict despite male monopolization attempts.Communicated by J. Setchell     

Influence of male harassment and female competition on female feeding behaviour in a sexual–asexual mating complex of mollies (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>, <Emphasis Type="Italic">P. formosa</Emphasis>)

Differential interests between the sexes regarding the number of copulations can result in sexual harassment. Hence, females may have less time available for foraging. Male sexual harassment often leads to fitness reduction in females. We used the mating complex of the bisexual fish Poecilia mexicana and the co-occurring all-female Poecilia formosa to study sexual harassment and its incurred cost on female feeding efficiency. P. formosa is a sperm-dependent parthenogen that requires mating with host males to induce embryogenesis, but the male genes are not used. We therefore predicted P. mexicana males to prefer conspecific females. Hence, costs of male sexual harassment should not occur in unisexuals. While P. formosa are at a disadvantage compared to P. mexicana females due to male mate choice (leading to sperm limitation), this could be traded-off by suffering less from sexual harassment. In our experiment, we found males to direct significantly more pre-copulatory mating behaviour towards conspecific females, whereas actual mating attempts did not differ between species. Contrary to our prediction, both types of females started feeding later and spent less time feeding in the presence of a male partner compared to the time spent feeding with another female, suggesting that females of both species suffer from male harassment. The focal females' feeding time declined with increasing body size of the female competitor, and the same pattern was found when a male was present. We discuss that—besides sexual harassment—other factors such as food competition and female mate choice may affect female feeding efficiency.     

Pheromone-based female mate choice and its effect on reproductive investment in a spitting spider

Numerous studies have focused on whether organisms can signal or perceive pheromones and use chemical signals in species and mate recognition. Recently, there have been an increasing number of studies investigating whether pheromones are used in mate choice. Yet, little attention has been paid in exploring the effects of pheromone-based mate choice on reproductive investment. We first tested this hypothesis by providing virgin Scytodes sp. females with a choice between two virgin males in the presence of chemical signals alone and found strong evidence of an odor-based mate preference. We then examined the consequences of the odor-based mate choice by allowing female Scytodes sp. that had previously made an odor-only mate choice to mate with preferred and non-preferred males, respectively. We measured the success of copulation, mortality of male, pre-oviposition interval, egg-sac weight, egg weight, fecundity, fertility, embryonic period, and size of offspring at hatching. Females that mated with the preferred males produced significantly heavier egg sacs that contained more and larger eggs with a greater fertility. Significantly more non-preferred males than preferred males were killed by spitting. However, pre-oviposition interval, embryonic period, and hatchling size were not affected by female mate choice. This study is the first to demonstrate that female spiders are able to regulate their highly valuable reproductive investment based solely on chemical signals.     

Mate choice plasticity in the field cricket <Emphasis Type="Italic">Teleogryllus oceanicus</Emphasis>: effects of social experience in multiple modalities

Social experience can elicit phenotypically plastic changes in mate choice, but little is known about the degree to which social information from one modality can influence mating decisions based on information from a different modality. I used the field cricket Teleogryllus oceanicus to test whether experience of chemical cues mimicking a high density of sexually mature males causes changes in mate choice based on acoustic signals. T. oceanicus males produce long-range calling songs to attract females for mating, but they also produce waxy, non-volatile hydrocarbons on their cuticle (CHCs) which, when deposited on a substrate, can be detected by females and may provide demographic information. I manipulated female experience of substrate-bound male CHCs and then performed acoustic mate choice trials. When CHCs were present on the substrate during trials, females showed greater motivation to respond to male calling song. This effect diminished with repeated exposure to male songs, demonstrating that the importance of olfactory cues in altering acoustic mate choice decreased with increasing exposure to acoustic signals. However, the temporal nature of CHC experience mattered: previous experience of CHCs did not alter subsequent female choice for male calling song traits. Exposure to male song increased the threshold of mate acceptance over time, and individuals varied considerably in overall levels of responsiveness. Taken together, the results demonstrate that mate choice is dependent on social context mediated by multiple modalities in T. oceanicus, but they do not support the idea that prior experience of social cues in one modality necessarily influences later mating decisions based on other signalling modalities.     

Audience effect alters male but not female mating preferences

Males often face strong mating competition by neighboring males in their social environment. A recent study by Plath et al. (Anim Behav 75:21–29, 2008a) has demonstrated that the visual presence of a male competitor (i.e., an audience male) affects the expression of male mating preferences in a poeciliid fish (Poecilia mexicana) with a weaker expression of mating preferences when an audience male observed the focal male. This may be a tactic to reduce sperm competition, since surrounding males likely share intrinsic preferences for female traits or copy mate choice decisions. Here, we examined the hypothesis that a same-sex audience would affect female mate preferences less than male mating preferences. Our hypothesis was based on the assumptions that (1) competition for mates in a fashion that would be comparable in strength to sperm competition or overt male–male aggression is absent among Poecilia females, and (2) P. mexicana females typically form female-biased shoals, such that almost any female mate choice in nature occurs in front of a female audience. Poecilia females (P. mexicana, surface and cave form, and the closely related gynogenetic Poecilia formosa) were given a choice between a large and a small male, and the tests were repeated while a conspecific, a heterospecific, or no audience female (control) was presented. Females spent more time in the neutral zone and, thus, less time near the males during the second part of a trial when an audience was presented, but—consistent with predictions—females showed only slightly weaker expression of mate preferences during the second part of the tests. This decline was not specific to the treatment involving an audience and was significantly weaker than the effect seen in the male sex.     

Worker policing and nest mate recognition in the ant <Emphasis Type="Italic">Formica fusca</Emphasis>

A conflict over male production arises in social insects where workers are able to lay unfertilized male eggs. This happens because each female (queen or worker) is most closely related to her own sons and is thus predicted to reproduce. The conflict is modulated by worker policing where workers prevent each other from reproducing by aggression or egg cannibalism. In this study, we show that in the ant Formica fusca, worker policing occurs by egg cannibalism rather than by overt aggression among workers. Furthermore, we show that, contrary to bees, wasps and other ant species, egg discrimination in F. fusca is not based only on a universal queen signature chemical and that nest mate recognition of eggs occurs.     

Why are larvae of the social parasite wasp <Emphasis Type="Italic">Polistes sulcifer</Emphasis> not removed from the host nest?

A challenge for parasites is how to evade the sophisticated detection and rejection abilities of potential hosts. Many studies have shown how insect social parasites overcome host recognition systems and successfully enter host colonies. However, once a social parasite has successfully usurped an alien nest, its brood still face the challenge of avoiding host recognition. How immature stages of parasites fool the hosts has been little studied in social insects, though this has been deeply investigated in birds. We look at how larvae of the paper wasp obligate social parasite Polistes sulcifer fool their hosts. We focus on cuticular hydrocarbons (CHCs), which are keys for adult recognition, and use behavioral recognition assays. Parasite larvae might camouflage themselves either by underproducing CHCs (odorless hypothesis) or by acquiring a chemical profile that matches that of their hosts. GC/MS analyses show that parasite larvae do not have lower levels of CHCs and that their CHCs profile is similar to the host larval profile but shows a reduced colony specificity. Behavioral tests show that the hosts discriminate against alien conspecific larvae from different colonies but are more tolerant towards parasite larvae. Our results demonstrate that parasite larvae have evolved a host larval profile, which overcomes the host colony recognition system probably because of the lower proportion of branched compounds compared to host larvae. In some ways, this is a similar hypothesis to the odorless hypothesis, but it assumes that the parasite larvae are covered by a chemical blend that is not meaningful to the host.     

Major histocompatibility complex and mate choice in a monogamous rodent

A growing number of studies indicate that females can increase the viability of their offspring by gaining direct benefits such as parental care or genetic advantages through selective mating with certain males. Among the best candidates for the genetic basis of mate choice in vertebrates are the genes of the major histocompatibility complex (MHC) because these highly polymorphic genes may increase offspring viability and provide direct cues for mate choice. A free-ranging, pair-living rodent was used as an example to investigate MHC-dependent mate choice in an obligate monogamous species, the Malagasy giant jumping rat Hypogeomys antimena. Two possible mechanisms of mate choice were tested. First, mate choice may occur to increase the heterozygosity of MHC genes in the progeny and, second, mates might choose each other according to the degree of dissimilarity of their functional MHC DRB (exon 2) proteins in order to maximise the allelic divergence in their offspring. Analyses of 65 Hypogeomys couples failed to confirm associations of mating patterns with the MHC genotype to increase heterozygosity or MHC allelic divergence in the progeny. Also, no evidence for mechanisms to increase the allelic divergence was found in sex-specific analyses where a male or female, respectively, migrated to and was accepted by a territory and burrow holder of the opposite sex. However, the frequency distribution of 0, 1 or 2 new alleles potentially available for the progeny differed significantly when a new male was chosen by a territory-holding female. In contrast to current models, genetically similar instead of dissimilar mates seem to be the preferred choice. This is the first study investigating the role of the MHC in mate selection in an obligate monogamous rodent.Communicated by G. Wilkinson     

Bat serenades—complex courtship songs of the sac-winged bat (<Emphasis Type="Italic">Saccopteryx bilineata</Emphasis>)

Vocalisations of many songbirds, anurans, and insects are shaped by sexual selection. Males acoustically compete for territories, and females choose their mates by means of male courtship songs. In courtship, richness and complexity of elements are often favoured characters. Only a few examples of complex songs are known in mammals. Males of the harem-polygynous sac-winged bat (Saccopteryx bilineata, Emballonuridae) have an uncommonly complex vocal repertoire, and different song types of males are used in the context of territorial defence and in courting females. We classified the daytime vocalisations of 16 male S. bilineata from a colony in Costa Rica, both on the basis of their acoustical properties and the social context in which they occurred. Seven vocalisation types were differentiated: echolocation pulses, barks, chatter, whistles, screeches, territorial songs and courtship songs. Territorial songs were short, rather stereotyped and not obviously directed towards a certain conspecific. They appear to be of importance in male competition for harem territories, in which females roost during the day. Courtship songs were exclusively observed when males displayed towards a female; they were long and complex, and consisted of highly variable elements (calls). We classified the calls in courtship songs of six males into call types, based on acoustical properties, mainly spectral purity and duration. Four call types are described in detail: trills, noise-bursts, short tonal calls, and quasi constant frequency calls. Twelve parameter values were extracted from the most common call type, the trill. Discriminant function analysis of trills showed that different males had different repertoires. This could allow females to use trill parameters for recognition of individual males and thus for mate choice.Communicated by G. Wilkinson     

Absence of status signalling by structurally based ultraviolet plumage in wintering blue tits (<Emphasis Type="Italic">Cyanistes caeruleus</Emphasis>)

Structurally based ultraviolet (UV)-reflective plumage parts can be important cues in mate choice. However, it remains largely unknown if UV plumage variation can also function as a signal of social status during competitive interactions. In blue tits (Cyanistes caeruleus), the UV-reflective crown plumage functions as a female mate choice cue that probably indicates male quality, as males with higher UV reflectance have been shown to have better chances of over-winter survival. Possibly, the UV crown plumage acts as a status signal in the competition over scarce food sources during winter. To test this idea, we related dominance of individuals at an artificial food source during adverse winter conditions to spectrophotometric measurements of their crown plumage. However, while controlling for the confounding effects of sex, age, and distance from territory, we found no significant effect of crown UV reflectance on dominance. Consistent with this result, we also found no relation between crown UV reflectance and over-winter survival. We conclude that the structurally based UV reflectance of the blue tit crown feathers plays little role in competition between individuals during winter despite its importance as a cue in mate choice.     

Diet-induced chemical phytomimesis by twig-like caterpillars of Biston robustum Butler (Lepidoptera: Geometridae)

Summary. Polyphagous caterpillars of the giant geometer Biston robustum resemble the twigs of their respective food sources in color and shape. Common predatory ants, including Lasius and Formica, were often observed to freely prowl directly on caterpillars bodies, even after antennal contact. This suggests that the cuticular chemicals of the caterpillars resemble those of the twigs of the foodplants, so we analyzed both by GC and GC-MS. The chemical compositions differed among caterpillars fed on a cherry, Prunus yedoensis, a chinquapin Castanopsis cuspidata, and a camellia Camellia japonica. The cuticular chemicals of the caterpillars resembled those of their corresponding food sources. When the caterpillar diets were switched from the cherry to camellia or chinquapin at the 4^th instars, the caterpillars cuticular chemicals changed after molting to resemble those of their respective foods. Caterpillars also changed their cuticular chemicals when they perched on cherry twigs and fed on camellia or chinquapin leaves, but not when they perched on camellia or chinquapin twigs and fed on cherry leaves. The chemical similarities between the caterpillars and the twigs were due to the digestion of host leaves, which indicates that this is a diet-induced adaptation.