Alterações no perfil químico cuticular de coleópteros são importantes em investigações forenses?

Abstract

The application of studies with entomofauna in criminal investigations and civil proceedings is known as Forensic Entomology. Its importance relates to the fact that insects are usually the first to find a decomposing body, being attracted by odors and gases released after death. The most important order for forensic entomology is the Diptera, because they are the first to find a decomposing body. On the other hand, coleoptera are considered as the second most important group for forensic entomology, as they can also answer various questions and consequently assist in the field of criminal proficiency. This dissertation is divided in two chapters and in the first one we tested the hypothesis that, through the analysis of the cuticular chemical profile of males and females of the species of Euspilotus azureus, it would be possible to distinguish cuticle samples of these insects coming from different types of environments, the use of these compounds as a complementary tool to evaluate if corpses may have suffered displacement from the place where death occurred. The results show that cuticle samples from the E. azureus beetle are useful tools to assist in investigating where the crime may have occurred, or even cases of cadaveric translocation in the attempt to conceal, since the composition varies significantly in function, especially of specific local conditions. The compounds derived from the sexual dimorphism of the cuticle of this species prove that males may be more reliable for this type of investigation and should be taken into account when collecting evidence on the corpse. In the second chapter we verified the hypothesis that the insecticide contamination will affect the chemical profile of beetles of forensic interest. The results show that the Cuticular Hydrocarbons can be affected by the contamination by the insecticide thiamethoxam, with a qualitative and quantitative alteration of the cuticular chemical composition of the beetle samples. This points to the use of a new tool to assess whether the cause of death may have been by poisoning or even if the corpse is in the culture area, if there has been possible contamination of the corpse, which may then affect the development of insects and thus make it difficult to determine the postmortem interval using this type of samples.