A comparison of carcass decomposition and associated insect succession onto burnt and unburnt pig carcasses
AIM To use forensic entomological approach to estimate the post mortem interval (PMI) in burnt remains. METHODS Two experiments were performed in a field in the outskirts of Milan, in winter and summer 2007. Four 60-kg pigs were used: two for each experiment. One pig carcass was burnt until it reached the level 2-3 of the Glassman-Crow scale and the not-burnt carcass was used as a control. In order to describe the decomposition process and to collect the data useful for minimum PMI estimation, macroscopic, histological, and entomological analyses were performed. RESULTS In the winter part of the experiment, the first insect activity on the burnt carcass began in the third week (Calliphora vomitoria) and at the beginning of the fourth week an increase in the number of species was observed. In the summer part, adult flies and first instar maggots (Phormia regina) appeared a few minutes/hours after the carcass exposure. Both in winter and summer, flies belonging to the first colonization wave (Calliphoridae) appeared on burnt and control pigs at the same time, whereas other species (Diptera and Coleoptera) appeared earlier on burnt pigs. CONCLUSION In forensic practice, burnt bodies are among the most neglected fields of entomological research, since they are supposed to be an inadequate substratum for insect colonization. Entomological approach for PMI estimation proved to be useful, although further studies on larger samples are needed.