RESEARCH ARTICLE Males and females of the social wasp Ropalidia marginata do not differ in their cuticular hydrocarbon profiles and do not seem to use any long-distance volatile mate attraction cues A. Mitra 1,2 • R. Palavalli Nettimi 1,3 • A. Ramachandran 1,4 • P. Saha 1 • R. Gadagkar 1,5 Received: 29 January 2014 / Revised: 21 March 2015 / Accepted: 24 March 2015 / Published online: 21 April 2015 Ó International Union for the Study of Social Insects (IUSSI) 2015 Abstract Sex pheromones are vital in communication between individuals belonging to opposite sexes and form an integral part of the reproductive biology of various spe- cies. Among insects, sexual dimorphism in CHCs has been reported from diverse taxa spanning seven different orders, and thereby CHCs have been implicated as sex pheromones. Because males and females of the primitively eusocial wasp Ropalidia marginata touch each other with their antennae during mating, before engaging in sperm transfer, a sex pheromone that is perceived via contact chemosensation through the antennae can possibly exist in this species. Since CHCs have been implied as sex pheromones in various in- sects (including hymenopterans), and since sexual dimorphism of CHCs should be an obligatory prerequisite for them to act as sex pheromones, we investigated whether males and females of R. marginata differ in their CHC profiles. We found only nonvolatile CHCs, and our results show absence of sexual dimorphism in CHCs, suggesting that CHCs do not function as sex pheromone in this species. A behavioral assay failed to show presence of mate attrac- tion at a distance, thereby showing the absence of volatile long-distance mate attraction cues (that may originate from sources other than and in addition to CHCs). Keywords Cuticular hydrocarbons Á Sexual dimorphism Á Sex pheromone Á Mate attraction Á Ropalidia marginata Introduction Sex pheromones play an important role in communication between individuals belonging to different sexes, serving various functions such as mate attraction, courtship, sex recognition, and mate choice, thereby forming an indis- pensable part of the reproductive biology of various animal species (Wyatt 2003). Among insects, sex pheromones often comprise of volatile compounds that serve to attract mates at a distance, helping members of opposite sexes to locate each other, and consequently eliciting courtship and mating behavior (Jacobson 1972). Semivolatile and non- volatile compounds such as cuticular hydrocarbons (CHCs) have also been implicated as sex pheromones in various species, and sexual dimorphism in CHCs has been reported from diverse taxa ranging from apterygotes such as Collembola to various pterygotes such as beetles, bugs, flies, mosquitoes, aculeate and nonaculeate wasps, ants, moths, crickets, and grasshoppers (Cuvillier-Hot et al. 2001; Porco et al. 2004; Ferveur 2005; Steiger et al. 2008; Coc- chiararo-Bastias et al. 2011; reviewed in Howard and Blomquist 2005; Thomas and Simmons 2008). Sexual di- morphism in CHCs has been reported from over 100 species Electronic supplementary material The online version of this article (doi:10.1007/s00040-015-0408-4) contains supplementary material, which is available to authorized users. & A. Mitra mitra.aniruddha@gmail.com 1 Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India 2 Laboratoire Evolution, Ge ´nomes, Comportement, Ecologie, Centre National de la Recherche Scientifique, 1, avenue de la Terrasse, Batiment 13, 91198 Gif Sur Yvette, France 3 Indian Institute of Science Education and Research, Pune 411008, India 4 Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, India 5 Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India Insect. Soc. (2015) 62:281–289 DOI 10.1007/s00040-015-0408-4 Insectes Sociaux 123