Forensic Entomology Insights: Effects of Cocaine and Carbamate on Cadaveric Entomofauna and Postmortem Interval Estimation

Forensic entomology utilizes insect succession patterns to estimate the postmortem interval (PMI), a vital tool in criminal investigations, especially for corpses in advanced decomposition. This study explored how toxic substances—cocaine and carbamate ("chumbinho")—influence decomposition and entomofauna succession in pig carcasses (Sus scrofa domesticus) in an urban setting in São Paulo, Brazil. Three carcasses (two experimental, one control) were euthanized, intoxicated accordingly, and exposed in cages with interception traps from July to September 2016. Over this period, 15,870 adult insects (Diptera, Coleoptera, Hymenoptera, Lepidoptera) and 1,952 immature insects (Diptera, Hymenoptera) were collected and analyzed. Cocaine accelerated larval colonization within 24 hours, compared to Day 2 in the control, while carbamate delayed it until Day 15, suggesting differential toxicological impacts on insect behavior. The cocaine-exposed carcass showed the highest insect attraction, though species visitation did not differ significantly across models. Decomposition phases progressed synchronously in all carcasses, unaffected by the toxins. These substances altered PMI estimation: cocaine shortened it, while carbamate extended it, potentially skewing forensic timelines. The findings underscore the need to account for toxicological factors in PMI calculations, enhancing the reliability of entomological evidence in death investigations involving drug overdoses or poisoning. This research bridges applied biosciences and forensic science, offering practical insights for criminalistics.