Dipterofauna de importância forense associada a cadáveres humanos no estado do Tocantins, Brasil

Abstract

Insects maintain a series of relationships with humans and can even be used as tools in the investigation of crimes and other legal issues within the scope of Forensic Entomology. Scavenger flies (Diptera) are the most important group for this area, due to their high ability to perceive odors and move around, thus being the first to colonize carcasses and corpses. In Brazil, the first studies with insects of forensic importance date back to the beginning of the 20th century, however, it was only from the 1980s that research related to this area began to grow. Despite this growing research in the area, this is the first study on Forensic Entomology in the state of Tocantins with collections of insects directly from human corpses. This work aimed to identify species of Diptera of forensic importance for Legal Medicine, associated with human corpses in the state of Tocantins. The collection of eggs and larvae took place from January 2021 to February 2022, in a total of 40 human corpses received by the Instituto Médico Legal de Palmas/TO, from 20 municipalities in the state of Tocantins. The collected material was placed in plastic pots containing beef-based food substrate to guarantee the complete development of the specimens until the adult stage for later identification at a specific level. Information on temperature, humidity, and accumulated rainfall available from INMET's automatic meteorological stations were collected to analyze the influence of these variables on this group. Our results confirm the existence of a high richness of Diptera of forensic importance for the state of Tocantins, for the North region of the country and for the Cerrado biome, even indicating a higher number than other works of inventories of colonizing fauna of human corpses already carried out so far in Brazil. We recorded the occurrence of six families and 18 species of forensic importance, all new records for the state of Tocantins, with 16 new records for the northern region of the country. We highlight here the record of Retrocitomyia mizuguchiana, this being the first record of the species colonizing human corpses, thus confirming the importance of the species for Forensic Entomology. Finally, we indicate Chrysomya albiceps, Chrysomya megacephala and Hydrotaea aenescens as the most important species for forensic use in the Cerrado of Tocantins because they occur in high abundance, every year in different environments. The first two are important indicators for the initial stages of decomposition and the third for the final stages.