Bionomy of Hermetia illucens (Diptera: Stratiomyidae) on Decomposing Swine Carcass in an Urban Area of Central Amazon

Biological data on development of Hermetia illucens (Linnaeus, 1758) is useful to calculate the postmortem interval (PMI), thus being important for solving crimes. We aimed at gathering bionomic information on H. illucens, during the decomposition of a Sus scrofa, in the urban zone of Manaus, Amazonas State. Mature females and eggs were collected on the swine carcass. After hatching under natural conditions, larvae were observed daily. Different instars were fixed in ethylic alcohol to determine instar duration by the evaluation of the frequency distribution of cephalic capsule measurements and the principal components analysis (PCA). Females laid 620-700 eggs per posture in concealed locations preferentially, such as cranial cavities and slots on the metal cage. The larvae were found under the swine skin and on bones. After feeding, the larvae of H. illucens began to move slowly to pupate, did not seek for drier sites to do it, and buried themselves into the carcass instead. Pupae were observed as of the 60th day after death. H. illucens completed its life cycle in 53-82 d, which encompassed six larval instars and the pupa. About 93% of the eggs hatched, 11% reached the adult stage and the sex ratio was 0.49. Our results are complementary to the biological information of this species in Central Amazon, since most of the data were not known yet. This should render PMI calculation more accurate, even for corpses in advanced decomposition stages, as H. illucens spends relatively more time on the carcasses than most dipterans.