"Fingerprint" cuticular hydrocarbons for identifying and ageing forensically important blowflies

Determining a reliable PMI can be problematic even for the most experienced of Forensic Entomologists and more scientifically supported research is needed to compliment current methods used in the field. Research in social insects has shown that hydrocarbons found on the cuticle are species-specific.  This has also been proven in studies of flies and could be a promising tool for identifying and ageing forensically important blowflies in Forensic Entomology. Cuticular hydrocarbons have been successfully extracted from all life stages of the three blowfly species, Lucilia sericata, Calliphora vicina and Calliphora vomitoria. Our results showed that there were some distinguishing changes of the cuticular hydrocarbon profile over time so not only can they be used to identify the blowfly species, but more importantly they have the potential to be used to age the life stage (Moore et al., 2012). This technique therefore yields a relatively straightforward source of identification using Gas Chromatography-Mass Spectrometry (GC-MS) analysis and statistical analysis in the form of Principal Component Analysis (PCA). Results from the three forensically important blowflies mentioned will be discussed in more detail. Preliminary results of future developments of hydrocarbon analysis in the form of rapid identification provided by Direct Analysis in Real Time Mass Spectrometry (DART-MS) and Artificial Neural Networks (ANN) will also be presented.