Prospection entomologique et bio-écologie des insectes nécrophages sur deux substrats mammifères – importance médico-légale des coléoptères (Insecta: Coleoptera)

Abstract

Forensic or medico-legal entomology is one of the oldest disciplines, but remains little known. It represents the tool that stages insects to solve a criminal investigation. Forensic entomology is used to determine the postmortem interval (MPI), which is the time elapsed between death and the discovery of the corpse. In Algeria, works on forensic entomology are in their first steps, especially for both Coleoptera on which no work has been done yet. That’s why we have chosen to deal with this subject, by choosing eight dead animals, for adult dogs, a puppy and three rabbits. The study was led in during the four seasons of the year 2012/2013, in an open area localized near the Biosystematic and Ecology of Arthropods laboratory, Chaabat Erssas Constantine, Algeria. The two corpses of every season were put in two separate cages to protect them from any possible predators. A few hours later the two animal cadavers were already visited by insects on which they begin to lay. After the capture of insects, the identification revealed that they belong to two major insect orders which are flies and beetles. These insects partly constitute the necrophagous fauna. Our daily sampling has allowed us to collect a total a total of 2654 necrophagous insects, of which 44.73% are Diptera and 55.27 are Coleoptera. The analysis of the results reveals a better diversity of necrophagous insects on the adult dog of spring, and unlike large corpses, the number of beetles harvested on small bodies is higher than that of Diptera except for the two cadavers assessed in winter Where this result is reversed About the life cycle of Silpha rugosa and Dermestes peruvianus, we could recognize all stages of development and found the influence of temperature on different stages. Furthermore, we confirm the influence of the size of the corpse and climatic parameters (temperature) on the degradation of the bodies and their Colonization by necrophagous insects. Finally, the species Silpha rugosa and Dermestes peruvianus actively involved in the decomposition of the corpses would have interest in the forensic sciences.