Efeito da contaminação por disparo de arma de fogo sobre a assembleia de himenópteros em carcaças de suínos

Abstract

The decomposition of cadavers is a complex process influenced by a variety of environmental factors. Among the biological factors, one of the most important is the role of insects, which actively participate in this process by consuming the carcass or preying on other invertebrates that do so. Therefore, elements that may contaminate a carcass can potentially interfere with the activity or even the occurrence of these insects. Contamination by elements present in firearm discharge can trigger a series of changes in cadaveric decomposition and, consequently, in the associated insect community. In this study, we investigated whether contamination by gunshot residues in pig carcasses (Sus scrofa) affects the decomposition time, species richness, and composition of Hymenoptera. Three carcasses were used in the treatment group, each of which received three close-range gunshots, while three additional carcasses, which were not shot, served as the control group. All carcasses were monitored daily in the field from installation to the final stage of decomposition. Hymenoptera specimens were collected both actively—using forceps and an entomological net—and passively, via Pitfall traps. Carcasses in the treatment group took an average of 13.3 ± 3.21 days to reach the final stage of decomposition, compared to 13 ± 3.46 days for the control group, with no statistically significant difference in decomposition time. Species richness of Hymenoptera was higher in the later stages of decomposition; however, there was no significant difference between the treatment and control groups, nor between the different decomposition stages. Regarding abundance, of the 3,692 Hymenoptera collected, 70.72% were found in the control carcasses, and only 29.28% in the treated carcasses—a statistically significant difference. The species composition throughout the decomposition stages and between the treatment and control groups also differed significantly, which may be related to the influence of firearm discharge residues. Therefore, we infer that in investigations involving deaths caused by firearm discharge, the effects of gunshot residues on the cadaveric decomposition process should be considered, as they may affect the colonization dynamics of Hymenoptera associated with the carcasses.