Efeitos da refrigeração no desenvolvimento de dípteros califorídeos de importância forense

Abstract

This study investigated the effects of continuous and discontinuous refrigeration on the development and survival of forensically important calliphorid dipterans. The primary objective was to assess how exposure to low temperatures, both constant and intermittent, affects the different developmental stages of these flies (eggs, 1st, 2nd, and 3rd instar larvae, and pupae) and the implications for estimating the post-mortem interval (PMI). In Chapter I, experiments were conducted with continuous refrigeration (4 ± 2 ºC) on four forensically relevant species: Chrysomya megacephala, Chrysomya putoria, Hemilucilia segmentaria, and Lucilia cuprina. The results demonstrated a significant delay or cessation of development, with high mortality in eggs and first instar larvae, while third instar larvae showed greater tolerance, entering quiescence. Chapter II evaluated the effects of discontinuous refrigeration on third instar larvae of the same species, with alternating cycles of cold and rewarming. It was observed that discontinuous refrigeration also induced quiescence, leading to a considerable increase in total development time and a reduction in survival. In Chapter III, larval development was assessed on refrigerated human corpses (4 ± 2 ºC) at the Afrânio Peixoto Forensic Medical Institute, with the collection of larvae from various species, including Chrysomya albiceps, C. megacephala, Peckia (Peckia) chrysostoma, H. segmentaria, and Synthesiomyia nudiseta. The results confirmed a significant delay in larval development under refrigeration, affecting the estimation of the oviposition day and highlighting potential inaccuracies in the minimum PMI. The study xi concludes that refrigeration is a critical factor that significantly interferes with the development of calliphorid dipterans, impacting the accuracy of PMI estimation. There is a pressing need for further research on the thermal biology of these species at low temperatures, especially for tropical and subtropical species, to improve methodologies.