Dynamic changes in volatile emissions of breeding burying beetles

Abstract

AbstractBurying beetles reproduce on small vertebrate carcasses by exhibiting elaborate biparental brood care. Partner recognition in breeding Nicrophorus species (Coleoptera: Silphidae) relies substantially on information encoded in cuticular hydrocarbon profiles. Until recently, it was unknown whether breeding burying beetles also produce volatile low molecular weight substances and, if so, which functions can be attributed to such volatiles. The present study reports a survey of the volatiles released by males and females of Nicrophorus vespilloides Herbst in nonbreeding status and at different stages of breeding. Headspace analyses are performed by using solid phase micro‐extraction fibres and gas chromatography–mass spectrometry. The volatiles released by nonbreeding males and females include phenolic compounds, alcohols, aldehydes and ketones and are quite similar in both sexes. With the onset of breeding, the volatile profiles of males and females become distinct, with a number of female‐specific compounds occurring. An analysis of the anal secretions reveals the presence of some of the compounds previously detected in the headspace analysis. The specific chemical properties suggest that some of the volatiles may function against competitors and parasites, such as bacteria, fungi, nematodes and arthropods at the carcass breeding resource. By contrast, the emission of 4‐methyl branched esters by the females closely parallels the emission of the terpenoid methyl geranate and they may function together as a complex signal by the females. Signalling traits associated with biparental care and specific constraints associated with the ephemeral nature of the breeding resource may explain the occurrence of both groups of compounds in the volatile profiles.