Bionomia e morfologia dos estágios imaturos de Hermetia Illucens (Linnaeus, 1758) (Diptera: Stratiomyidae) de interesse forense em Manaus, Amazonas, Brasil

Abstract

Hermetia is composed by 78 species worldwide, from which 54 occur in the neotropics, 22 in Brazil. In particular, Hermetia illucens displays potential forensic importance and its biological records may be useful in medico-legal circumstances and for economic activities. We recorded bionomic data on the development of H. illucens on swine decomposition in an Amazonian landscape. We described the immature morphology, and used larval body dimensions to estimate biomass through different regression models. The study was conducted in an urban forest fragment in Manaus City, State of Amazonas, Brazil. We used a swine carcass to attract and function as substrate for the flies. We collected pregnant females ofH. illucens for posterior oviposition. For the morphological description, we used both stereomicroscopy and scanning electronic microscopy. For the estimation of biomass and obtaining of the best fitting model, we took four measurements of 20 individual larvae and tested three regression models. Our results showed that females prefered to lay the eggs on sheltered areas. . Eggs tool four to seven days to hatch. The larvae grew in humid zones, preferentially under the swine skin. The pupae completed their development on the substrate, rather than buried underground. Immature stage lasted from 53 to 82 days, and comprised six instars and the pupal stage. The eggs stage lasted 4-7 days. Duration of the immature stage: first instar = 1 –2 days; second instar = 2–3 days; third instar = 3–7 days; fourth instar = 8–13 days; fifth instar = 9–15 days; sixth instar = 11 –15 days; pupal stage = 15–20 days. Eggs are elliptical, elongated, color varying from white to yellowish. Hermetia illucens is identified by the combination of the following set of characters: (1) head elongated, its width never superior to its height; (2) dorsal and ventral chaetotaxy of the cephalic capsule, thorax and abdomen; (3) sixth abdominal segment with a spot on the sternum; (4) morphology of the anterior and posterior spiracles. The pupae is adectica and coarctata, tegument dark brown, with setae varying from light brown to golden. The body measurements that best predicted biomass were overall body length and width of the largest abdominal segment. The exponential regression model best fitted body dimensions and biomass of larvae. We provided information on bionomy, morphology and biomass of H. illucens in the Amazon Region, which can be employed to economic and forensic activities.