The importance of carcass volatiles as attractants for the hide beetle Dermestes maculatus (De Geer).

A decaying cadaver emits volatile organic compounds that are used by necrophilous and necrophagous insects in order to find their brood substrate. Although volatile organic compounds (VOCs) that are released by carcasses have been identified, little is known about the specific compounds that are used by these insects while searching for a brood substrate. Therefore, we have investigated the chemical ecology involved in the attraction of the necrophagous hide beetle Dermestes maculatus, which feeds as an adult and larva upon decomposing carcasses. Our aims have been to identify the responsible compounds in the odours of the carcass that are important for the attraction of the beetles. Furthermore, we have studied sex- and age-related differences in beetle attraction and tested whether the hide beetle can distinguish between various stages of decomposition by means of the emitted odours. Headspace collection of volatiles released from piglet carcasses (bloated stage, post-bloating stage, advanced decay and dry remains), coupled gas chromatography-mass spectrometry (GC-MS), gas chromatography with electroantennographic detection (GC-EAD) and bioassays were conducted to identify the volatiles responsible for the attraction of the beetles. Freshly emerged male beetles were attracted by the odour of piglets in the post-bloating stage (9 days after death; T(mean) = 27 °C) and the EAD-active compound benzyl butyrate. Statistical analysis revealed a higher relative proportion of benzyl butyrate in the odour bouquet of the post-bloating stage in comparison with the other stages. We therefore conclude that this compound plays an important role in the attraction of hide beetles to carcass odour. This underlines the potential use of D. maculatus for the estimation of the post mortem interval. The decomposition stage at which the female beetles are attracted to the odour of a cadaver remains unknown, as does the nature of this attraction. Pheromones (sexual or aggregation pheromones) might play an essential role correlated with their attraction to carrion and consequently with their attraction to the substrate for mating and ovipositioning.