Electrophysiological responses of Chrysomya rufifacies (Diptera: Calliphoridae) to active volatile organic compounds released by human and pig decomposition
Abstract
Forensic entomology is an important discipline which utilizes the developmental and behavioural patterns of insects which colonize decomposing tissue in a medicolegal context, most commonly to determine the post-mortem interval (PMI). Chryosmya rufifacies (Macquart) (Diptera: Calliphoridae) is a secondary colonizer of human decomposition in North America and its predatory behaviour can affect successional data, and therefore alter PMI estimations. Determining the specific volatile organic compounds which induce a response in C. rufifacies could mitigate the effects of this predatory species by providing empirical indications of the behaviourally active compounds released by decomposition. The specific compounds which cause a response in this species were isolated and identified via GC-MS, electroantennography (EAG) and GC-EAG. Electrophysiologically active volatile organic compounds (VOCs) derived from human and pig decomposition were analysed and compared, indicating that pigs are an acceptable human analogue. Six EAG-active compounds were identified via coupled GC-EAG of the VOC samples; BAME, DMDS, DMTS, ethanol, indole and phenol. Dose response testing was conducted, confirming DMTS and BAME as EAG-active compounds. Ethanol was determined to not be EAG-active in C. rufifacies.