What are the Mechanisms Behind a Parasite-Induced Decline in Nestmate Recognition in Ants?

Social insects have developed sophisticated recognition skills to defend their nests against intruders. They do this by aggressively discriminating against non-nestmates with deviant cuticular hydrocarbon (CHC) signatures. Studying nestmate recognition can be challenging as individual insects do not only vary in their discriminatory abilities, but also in their motivation to behave aggressively. To disentangle the influence of signaling and behavioral motivation on nestmate recognition, we investigated the ant Temnothorax nylanderi, where the presence of tapeworm-infected nestmates leads to reduced nestmate recognition among uninfected workers. The parasite-induced decline in nestmate recognition could be caused by higher intra-colonial cue diversity as tapeworm-infected workers are known to exhibit a modified hydrocarbon signature. This in turn may broaden the neuronal template of their nestmates, leading to a higher tolerance towards alien conspecifics. To test this hypothesis, we exchanged infected ants between colonies and analyzed their impact on CHC profiles of uninfected workers. We demonstrate that despite frequent grooming, which should promote the transfer of recognition cues, CHC profiles of uninfected workers neither changed in the presence of tapeworm-infected ants, nor did it increase cue diversity among uninfected nestmates within or between colonies. However, CHC profiles were systematically affected by the removal of nestmates and addition of non-nestmates, independently from the ants’ infection status. For example, when non-nestmates were present workers expressed more dimethyl alkanes and higher overall CHC quantities, possibly to achieve a better distinction from non-nestmates. Workers showed clear task-specific profiles with tapeworm-infected workers resembling more closely young nurses than older foragers. Our results show that the parasite-induced decline in nestmate recognition is not due to increased recognition cue diversity or altered CHC profiles of uninfected workers, but behavioral changes might explain tolerance towards intruders.     

Juvenile Hormone III Influences Task-Specific Cuticular Hydrocarbon Profile Changes in the Ant <Emphasis Type="Italic">Myrmicaria eumenoides</Emphasis>

We investigated the influence of juvenile hormones (JH) on the composition of cuticular hydrocarbons (CHCs) and the division of labor in colonies of the African ant Myrmicaria eumenoides. CHCs have long been implicated in nestmate recognition in social insect colonies. In M. eumenoides, the CHC profiles also vary with the task performed from brood-tender-type to forager type. The endocrine factors regulating the task allocation as well as the intracolonial recognition cues are not well understood, but JHs are prime candidates. Only JH III was identified in the hemolymph of M. eumenoides workers. Foragers had significantly higher JH III titers than brood tenders. The application of exogenous JH III and a JH analogue (methoprene) to M. eumenoides workers did not result in an observable acceleration of task change in our study. However, longevity of the focus workers, and thus the observational period, was reduced by the applications. Changes from a brood-tender-type to a forager-type CHC profile were accelerated by the application of JH III and methoprene, resulting in brood-tending workers that displayed forager-type CHC profiles. We present the first data supporting that recognition cues of an eusocial Hymenopteran are influenced by JH III, which could thus play a major role in the regulation of the dynamic nature of social insect colonies. JH III is connected to at least two key processes: the acceleration of CHC changes and the more long-term modulation of task shifting. Moreover, this indicates that changes in CHC recognition cues do not trigger task allocation in social insect colonies.     

Diet-Related Modification of Cuticular Hydrocarbon Profiles of the Argentine Ant, <Emphasis Type="Italic">Linepithema humile</Emphasis>, Diminishes Intercolony Aggression

Territorial boundaries between conspecific social insect colonies are maintained through a highly developed nestmate recognition system modulated by heritable and, in some instances, nonheritable cues. Argentine ants, Linepithema humile, use both genetic and environmentally derived cues to discriminate nestmates from nonnestmates. We explored the possibility that intraspecific aggression in the Argentine ant might diminish when colonies shared a common diet. After segregating recently field-collected colony pairs into high or moderate aggression categories, we examined the effect of one of three diets: two hydrocarbon-rich insect prey, Blattella germanica and Supella longipalpa, and an artificial (insect-free) diet, on the magnitude of aggression loss. Aggression diminished between colony pairs that were initially moderately aggressive. However, initially highly aggressive colony pairs maintained high levels of injurious aggression throughout the study, independent of diet type. Each diet altered the cuticular hydrocarbon profile by contributing unique, diet-specific cues. We suggest that acquisition of common exogenous nestmate recognition cues from shared food sources may diminish aggression and promote fusion in neighboring colonies of the Argentine ant.     

Desiccation Resistance and Micro-Climate Adaptation: Cuticular Hydrocarbon Signatures of Different Argentine Ant Supercolonies Across California

Cuticular hydrocarbons (CHCs), the dominant fraction of the insects’ epicuticle and the primary barrier to desiccation, form the basis for a wide range of chemical signaling systems. In eusocial insects, CHCs are key mediators of nestmate recognition, and colony identity appears to be maintained through a uniform CHC profile. In the unicolonial Argentine ant Linepithema humile, an unparalleled invasive expansion has led to vast supercolonies whose nestmates can still recognize each other across thousands of miles. CHC profiles are expected to display considerable variation as they adapt to fundamentally differing environmental conditions across the Argentine ant’s expanded range, yet this variation would largely conflict with the vastly extended nestmate recognition based on CHC uniformity. To shed light on these seemingly contradictory selective pressures, we attempt to decipher which CHC classes enable adaptation to such a wide array of environmental conditions and contrast them with the overall CHC profile uniformity postulated to maintain nestmate recognition. n-Alkanes and n-alkenes showed the largest adaptability to environmental conditions most closely associated with desiccation, pointing at their function for water-proofing. Trimethyl alkanes, on the other hand, were reduced in environments associated with higher desiccation stress. However, CHC patterns correlated with environmental conditions were largely overriden when taking overall CHC variation across the expanded range of L. humile into account, resulting in conserved colony-specific CHC signatures. This delivers intriguing insights into the hierarchy of CHC functionality integrating both adaptation to a wide array of different climatic conditions and the maintenance of a universally accepted chemical profile.     

Colony-Specific Cuticular Hydrocarbon Profile in Formica argentea Ants

The cuticular hydrocarbons of the ant Formica argentea were identified by gas chromatography/mass spectrometry. Behavioral bioassays tested the role of each class of cuticular hydrocarbon in nestmate recognition, and statistical analyses looked for potential colony-specific signatures. The cuticular hydrocarbons of F. argentea consist of n-alkanes, alkenes, and methyl-branched alkanes. Behavioral bioassays demonstrated that changes in the alkene and methyl-branched alkane signature of F. argentea increased aggression, but changes in alkanes did not. Statistical analyses demonstrated that F. argentea workers present a colony-specific hydrocarbon profile based on their methyl-branched C₂₉ alkane signature. Using this signature alone, it is possible to group worker ants statistically by nest, suggesting that methyl-branched C₂₉ alkanes may be important in nestmate recognition for this species. These results support the idea that variation in positional isomers of cuticular hydrocarbons of the same carbon chain length may provide enough information for nestmate recognition. Although the addition of alkenes increased aggression in F. argentea, alkenes did not provide a colony-specific signature. This study reinforces the idea that investigators studying nestmate recognition should not examine cuticular hydrocarbon profiles as a whole but rather, should look for colony-specific signatures embedded in parts of the profile.     

Cuticular Hydrocarbon Compounds in Worker Castes and Their Role in Nestmate Recognition in <Emphasis Type="Italic">Apis cerana indica</Emphasis>

Differences in cuticular hydrocarbons (CHCs) among worker castes and colonies were examined in Apis cerana indica. The roles of tetracosanoic acid, hexadecanoic acid, pentacosane, and (Z)-9-tricosene in nestmate recognition were studied. The CHC profiles of different castes, i.e., newly emerged bees, nurse bees, and forager bees, were found to differ among colonies. The CHC profiles of nurse bees were similar across different colonies, but forager bees in all colonies had significantly greater amounts of alkanes. In nestmate recognition experiments, guard bees reacted significantly more aggressively to foragers treated with tetracosanoic acid, hexadecanoic acid, and (Z)-9-tricosene. Pentacosane provoked no such effect.     

A Review of Ant Cuticular Hydrocarbons

We compared the published cuticular hydrocarbon (CHC) profiles of 78 ant species across 5 subfamilies. Almost 1,000 CHCs have been described for these species, composing 187 distinct homologous series and ten hydrocarbon groups. In descending order of occurrence were: n-alkanes > monomethylalkanes > dimethylalkanes > alkenes > dienes>> trimethylalkanes>> methylalkenes > methylalkadienes > trienes > tetramethylalkanes. Odd chain lengths and positions of methyl or double bonds at odd carbon numbers were far more numerous than even chain-length compounds or bond positions. Although each species possess its own unique pattern of CHCs, we found no association between CHC profile and phylogeny. The production of the biosynthetically complex compounds (e.g., methyl branched dienes) by the most primitive living ant suggests that the basic genetic architecture required to produce the rich diversity of CHCs was already present prior to their adaptive radiation. Unlike the ubiquitous n-alkanes and monomethylalkanes, there is a huge diversity of species-specific dimethylalkanes that makes them likely candidates for species and nest-mate discrimination signals.     

Nestmate and Task Cues are Influenced and Encoded Differently within Ant Cuticular Hydrocarbon Profiles

Insect cuticular hydrocarbons (CHCs) are primarily antidesiccation agents, but they also play crucial roles in intra- and interspecific communication, especially among social Hymenoptera. The complex CHC profiles of social insects have often been compared among individuals, kin, nestmates, colonies, and species. In the ant Formica exsecta, only the (Z)-9-alkene part of the CHC profile encodes the nestmate signal. Here, we showed that the other major part of the CHC profile with n-alkane components is influenced strongly by the task a worker performs (foraging vs nonforaging). This part of the profile is independent of the nestmate signal. Therefore, the CHC profile of F. exsecta workers is composed of two independent parts: a colony-specific (Z)-9-alkene profile under genetic influence and an environmentally influenced task-related n-alkane profile. The dissociating of the CHC profile into two or more independent parts has implications for the analysis and interpretation of past and future CHC studies.     

Acceptance Threshold Hypothesis is Supported by Chemical Similarity of Cuticular Hydrocarbons in a Stingless Bee, Melipona asilvai

The ability to discriminate nestmates from non-nestmates in insect societies is essential to protect colonies from conspecific invaders. The acceptance threshold hypothesis predicts that organisms whose recognition systems classify recipients without errors should optimize the balance between acceptance and rejection. In this process, cuticular hydrocarbons play an important role as cues of recognition in social insects. The aims of this study were to determine whether guards exhibit a restrictive level of rejection towards chemically distinct individuals, becoming more permissive during the encounters with either nestmate or non-nestmate individuals bearing chemically similar profiles. The study demonstrates that Melipona asilvai (Hymenoptera: Apidae: Meliponini) guards exhibit a flexible system of nestmate recognition according to the degree of chemical similarity between the incoming forager and its own cuticular hydrocarbons profile. Guards became less restrictive in their acceptance rates when they encounter non-nestmates with highly similar chemical profiles, which they probably mistake for nestmates, hence broadening their acceptance level.     

Harvester Ants Utilize Cuticular Hydrocarbons in Nestmate Recognition

Cuticular hydrocarbons appear to play a role in ant nestmate recognition, but few studies have tested this hypothesis experimentally with purified hydrocarbon extracts. We exposed captive colonies of the harvester ant Pogonomyrmex barbatus to small glass blocks coated with whole cuticular lipid extracts and the purified hydrocarbon portion of extracts from nestmate and nonnestmate workers. As an estimate of agonistic behavior, we measured the proportion of ants in contact with blocks that flared their mandibles. Blocks coated with cuticular extracts from nonnestmates were contacted by more workers in one of two experiments and elicited higher levels of aggression in both experiments than blocks bearing extracts from nestmates. The cuticular hydrocarbon fraction of extracts alone was sufficient to elicit agonistic behavior toward nonnestmates. The results demonstrate that harvester ants can perceive differences in cuticular hydrocarbon composition, and can use those differences in nestmate recognition.     

Genetic Distance and Age Affect the Cuticular Chemical Profiles of the Clonal Ant Cerapachys biroi

Although cuticular hydrocarbons (CHCs) have received much attention from biologists because of their important role in insect communication, few studies have addressed the chemical ecology of clonal species of eusocial insects. In this study we investigated whether and how differences in CHCs relate to the genetics and reproductive dynamics of the parthenogenetic ant Cerapachys biroi. We collected individuals of different ages and subcastes from several colonies belonging to four clonal lineages, and analyzed their cuticular chemical signature. CHCs varied according to colonies and clonal lineages in two independent data sets, and correlations were found between genetic and chemical distances between colonies. This supports the results of previous research showing that C. biroi workers discriminate between nestmates and non-nestmates, especially when they belong to different clonal lineages. In C. biroi, the production of individuals of a morphological subcaste specialized in reproduction is inversely proportional to colony-level fertility. As chemical signatures usually correlate with fertility and reproductive activity in social Hymenoptera, we asked whether CHCs could function as fertility-signaling primer pheromones determining larval subcaste fate in C. biroi. Interestingly, and contrary to findings for several other ant species, fertility and reproductive activity showed no correlation with chemical signatures, suggesting the absence of fertility related CHCs. This implies that other cues are responsible for subcaste differentiation in this species.     

Colony Fusion in Argentine Ants is Guided by Worker and Queen Cuticular Hydrocarbon Profile Similarity

Introduced populations of the Argentine ant, Linepithema humile, have experienced moderate to severe losses of genetic diversity, which may have affected nestmate recognition to various degrees. We hypothesized that cuticular hydrocarbons (CHC) serve as nestmate recognition cues, and facilitate colony fusion of unrelated L. humile colonies that share similar CHC profiles. In this study, we paired six southeastern U.S. L. humile colonies in a 6-month laboratory fusion assay, and determined if worker and queen CHC profile similarity between colonies was associated with colony fusion and intercolony genetic similarity. We also compared worker and queen CHC profiles between fused colony pairs and unpaired controls to determine if worker and queen chemical profiles changed after fusion. We found that colony fusion correlated with the CHC similarity of workers and queens, with the frequency of fusion increasing with greater CHC profile similarity between colonies. Worker and queen CHC profile similarity between colonies also was associated with genetic similarity between colonies. Queen CHC profiles in fused colonies appeared to be a mix of the two colony phenotypes. In contrast, when only one of the paired colonies survived, the CHC profile of the surviving queens did not diverge from that of the colony of origin. Similarly, workers in non-fused colonies maintained their colony-specific CHC, whereas in fused colonies the worker CHC profiles were intermediate between those of the two colonies. These results suggest a role for CHC in regulating interactions among mutually aggressive L. humile colonies, and demonstrate that colony fusion correlates with both genetic and CHC similarities. Further, changes in worker and queen chemical profiles in fused colonies suggest that CHC plasticity may sustain the cohesion of unrelated L. humile colonies that had fused.     

Hydrocarbons on Harvester Ant (<Emphasis Type="Italic">Pogonomyrmex barbatus</Emphasis>) Middens Guide Foragers to the Nest

Colony-specific cuticular hydrocarbons are used by social insects in nestmate recognition. Here, we showed that hydrocarbons found on the mound of Pogonomyrmex barbatus nests facilitate the return of foragers to the nest. Colony-specific hydrocarbons, which ants use to distinguish nestmates from non-nestmates, are found on the midden pebbles placed on the nest mound. Midden hydrocarbons occur in a concentration gradient, growing stronger near the nest entrance, which is in the center of a 1–2 m diameter nest mound. Foraging behavior was disrupted when the gradient of hydrocarbons was altered experimentally. When midden material was diluted with artificial pebbles lacking the colony-specific hydrocarbons, the speed of returning foragers decreased significantly. The chemical environment of the nest mound contributes to the regulation of foraging behavior in harvester ants.     

DIET-MEDIATED INTER-COLONIAL AGGRESSION IN THE FORMOSAN SUBTERRANEAN TERMITE <Emphasis Type="Italic">Coptotermes formosanus</Emphasis>

In most social insects, intercolonial and interspecific aggression are expressions of territoriality. In termites, cuticular hydrocarbons (CHCs) have been extensively studied for their role in nestmate recognition and aggressive discrimination of nonnest-mates. More recently, molecular genetic techniques have made it possible to determine relatedness between colonies and to investigate the influence of genetics on aggression. In the Formosan subterranean termite, Coptotermes formosanus, however, the role of CHCs and genetic relatedness in inter-colony aggression has been ambiguous, suggesting the involvement of additional factors in nest-mate recognition. In this study we assess the range of aggression in this termite species and characterize the influence of genetic relatedness, CHC profiles and diet on aggression levels. We collected four colonies of C. formosanus, feeding either on bald cypress or birch, from three locations in Louisiana. Inter-colony aggression ranged from low to high. Differences in CHC profiles, as well as genetic distances between colonies determined by using microsatellite DNA markers, showed no significant correlation with aggression. However, termite diet (host tree) played a significant role in determining the level of aggression. Thus, two distantly related colonies, each feeding on different diets, showed high aggression that significantly diminished if they were fed on the same wood in the laboratory (spruce). Using headspace solid phase microextraction, we found three compounds from workers fed on birch that were absent in workers fed on spruce. Such diet-derived chemicals may be involved in the complex determination of nest-mate recognition in C. formosanus.     

<Emphasis Type="Italic">Tetramorium tsushimae</Emphasis> Ants Use Methyl Branched Hydrocarbons of Aphids for Partner Recognition

In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid’s CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes.     

Hydrocarbons in the Ant <Emphasis Type="Italic">Lasius niger</Emphasis>: From the Cuticle to the Nest and Home Range Marking

The cuticular hydrocarbons (CHCs) of the ant Lasius niger are described. We observe a high local colony specificity of the body cuticular profile as predicted for a monogynous and multicolonial species. The CHCs show a low geographical variation among different locations in France. The CHCs on the legs also are colony specific, but their relative quantities are slightly different from those on the main body. For the first time, we demonstrate that the inner walls of the ant nest are coated with the same hydrocarbons as those found on the cuticle but in different proportions. The high amount of inner-nest marking and its lack of colony-specificity may explain why alien ants are not rejected once they succeed in entering the nest. The cuticular hydrocarbons also are deposited in front of the nest entrance and on the foraging arena, with a progressive increase in n-alkanes relative amounts. Chemical marks laid over the substrate are colony specific only when we consider methyl-branched alkanes. Our data confirm that these “footprint hydrocarbons” are probably deposited passively by the contact of ant tarsae with the substrate. These results suggest that the CHCs chemical profiles used by ants in colony recognition are much more complex than a single template: ants have to learn and memorize odors that vary depending on their context of perception.     

Role of cuticular hydrocarbons of aphid parasitoids in their relationship to aphid-attending ants

Lysiphlebus cardui, the dominant aphidiid parasitoid of the black bean aphid,Aphis fabae cirsiiacanthoidis (Afc), on creeping thistle, is able to forage in ant-attended aphid colonies without being attacked by ants. Several behavioral observations and experimental studies led to the hypothesis thatL. cardui mimics the cuticular hydrocarbon profile of its host aphid. Chemical analysis of the cuticular extracts revealed that bothL. cardui and Afc exclusively possess saturated hydrocarbons:n-alkanes, monomethyl (MMA), dimethyl (DMA), and trimethyl alkanes (TMA). Comparison of the hydrocarbon profiles of parasitoid and aphid showed great qualitative resemblance between parasitoid and host:L. cardui possesses almost all host-specific compounds in addition to species-specific hydrocarbons of mainly higher molecular weight (>C₃₀). However, there is a lesser quantitative correspondence between parasitoid and host aphid. Furthermore, we analyzed the cuticular hydrocarbon profile of another parasitoid of Afc,Trioxys angelicae. This aphidiid species is vigorously attacked and finally killed by honeydewcollecting ants when encountered in aphid colonies. Its cuticular hydrocarbon profile is characterized by the presence of large amounts of (Z)-11-alkenes of chain lenghts C₂₇, C₂₉, C₃₁, and C₃₃, in addition to alkanes and presumably trienes. The role of the unsaturated hydrocarbons onT. angelicae as recognition cues for aphid-attending ants is discussed.     

Lack of intraspecific aggression in the ant Tetramorium bicarinatum: a chemical hypothesis

Tetramorium bicarinatum(Myrmicinae) is an ant species frequently found in tropical and subtropical areas, particularly in Africa, Southeast Asia (Japan), and South America (Brazil). The species is polygynous, reproduces by budding, and has sterile workers. Since the nests are widely distributed in a given area, the problem arises of territorial defense against conspecifics. Because not all ants defend territories, we assessed the defensive behavior of T. bicarinatumworkers through intraspecific and interspecific aggressiveness tests. A detailed behavioral study of the interactions between workers from several different colonies of T. bicarinatum(originating from Japan and Brazil) showed that workers do not discriminate against conspecific nonnestmate individuals, but they are highly aggressive towards allospecifics (Myrmica rubra, Myrmicinae). The results suggest that each colony from this ant species possesses a similar colonial odor. Chemical analyses of the cuticular hydrocarbons of these species were made with gas chromatography coupled to mass spectrometry. Results showed that the different colonies of T. bicarinatumpossess a common chemical profile mainly composed of straight-chain alkanes and alkenes, while M. rubrapossess more methyl-branched alkanes. We suggest that methyl alkane cues play a determining role in colonial recognition and that these results could explain the underlaying basis of the lack of intraspecific aggressiveness in T. bicarinatum.     

Deciphering the Chemical Basis of Nestmate Recognition

Social insects maintain colony cohesion by recognizing and, if necessary, discriminating against conspecifics that are not part of the colony. This recognition ability is encoded by a complex mixture of cuticular hydrocarbons (CHCs), although it is largely unclear how social insects interpret such a multifaceted signal. CHC profiles often contain several series of homologous hydrocarbons, possessing the same methyl branch position but differing in chain length (e.g., 15-methyl-pentatriacontane, 15-methyl-heptatriacontane, 15-methyl-nonatriacontane). Recent studies have revealed that within species these homologs can occur in correlated concentrations. In such cases, single compounds may convey the same information as the homologs. In this study, we used behavioral bioassays to explore how social insects perceive and interpret different hydrocarbons. We tested the aggressive response of Argentine ants, Linepithema humile, toward nest-mate CHC profiles that were augmented with one of eight synthetic hydrocarbons that differed in branch position, chain length, or both. We found that Argentine ants showed similar levels of aggression toward nest-mate CHC profiles augmented with compounds that had the same branch position but differed in chain length. Conversely, Argentine ants displayed different levels of aggression toward nest-mate CHC profiles augmented with compounds that had different branch positions but the same chain length. While this was true in almost all cases, one CHC we tested elicited a greater aggressive response than its homologs. Interestingly, this was the only compound that did not occur naturally in correlated concentrations with its homologs in CHC profiles. Combined, these data suggest that CHCs of a homologous series elicit the same aggressive response because they convey the same information, rather than Argentine ants being unable to discriminate between different homologs. This study contributes to our understanding of the chemical basis of nestmate recognition by showing that, similar to spoken language, the chemical language of social insects contains “synonyms,” chemicals that differ in structure, but not meaning.     

The Social Integration of a Myrmecophilous Spider Does Not Depend Exclusively on Chemical Mimicry

Numerous animals have evolved effective mechanisms to integrate into and exploit ant societies. Chemical integration strategies are particularly widespread among ant symbionts (myrmecophiles), probably because social insect nestmate recognition is predominantly mediated by cuticular hydrocarbons (CHCs). The importance of an accurate chemical mimicry of host CHCs for social acceptance recently has been demonstrated in a myrmecophilous silverfish. In the present study, we investigated the role of chemical mimicry in the myrmecophilous spider Gamasomorpha maschwitzi that co-occurs in the same host, Leptogenys distinguenda, as the silverfish. To test whether spiders acquire mimetic CHCs from their host or not, we transferred a stable isotope-labeled hydrocarbon to the cuticle of workers and analyzed the adoption of this label by the spiders. We also isolated spiders from hosts in order to study whether this affects: 1) their chemical host resemblance, and 2) their social integration. If spiders acquired host CHCs, rather than biosynthesizing them, they would be expected to lose these compounds during isolation. Spiders acquired the labeled CHC from their host, suggesting that they also acquire mimetic CHCs, most likely through physical contact. Furthermore, isolated spiders lost considerable quantities of their CHCs, indicating that they do not biosynthesize them. However, spiders remained socially well integrated despite significantly reduced chemical host similarity. We conclude that G. maschwitzi depends less on chemical mimicry to avoid recognition and aggressive rejection than the silverfish previously studied, suggesting that the two myrmecophiles possess different adaptations to achieve social integration.