Mate recognition and sex differences in cuticular hydrocarbons of the diurnal firefly ellychnia corrusca (Coleoptera: Lampyridae)

Abstract

There are several genera of diurnally active fireflies (Coleoptera: Lampyridae), and these adults generally do not produce bioluminescent signals. We investigated whether contact sex pheromones play a role in mate recognition in the diurnal firefly Ellychnia corrusca (L.). In laboratory behavioral assays, after antennal contact >70% of males attempted copulation with freeze-killed females, whereas no copulation attempts occurred when freeze-killed females had been washed with hexane. This shows that E. corrusca mate recognition relies on contact chemoreception and suggests that male mating responses are mediated by contact sex pheromones on the female cuticle. Using direct contact solid phase microextraction (SPME) and solvent extraction, we sampled cuticular hydrocarbons (CHCs) from both sexes of E. corrusca adults. Gas chromatography-mass spectrometry showed that SPME was more effective than solvent extraction in detecting CHCs (a two-fold increase in the number of compounds detected). Although E. corrusca males and females showed similar CHCs profiles, we documented several quantitative and qualitative differences between the sexes that may play a role in mate recognition. This report provides the first behavioral evidence for the existence of contact sex pheromones in any diurnal firefly. © 2010 Entomological Society of America.