XIV Meeting of the European Association for Forensic Entomology, Treviso 8-10 giugno 2017

The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), a slender, wasp-like dipteran of forensic relevance, is often used to estimate postmortem interval. Investigations by scanning electron microscopy (SEM) were conducted on adults of both sexes of H. illucens, examining, in detail, the sensilla and microtrichia of the three regions of the antenna (scape, pedicel and flagellum). Three different types of sensilla and four types of microtrichia were found on the antennal structures. Chaetic sensilla and hair-like microtrichia were detected on the scape and pedicel. Different sensorial structures were detected on the flagellomeres according to their position: two types of pit sensilla on flagellomeres 1 to 6, and trichoid sensilla in an oval depression on flagellomeres 4 to 6. Lanceolate microtrichia were present on flagellomeres 1 to 6, scimitar-like microtrichia on flagellomeres 7 and 8, and finely tapered microtrichia in the depression of the eighth flagellomere. The pit sensilla were of two types: a complex sensillum with an arbor-like structure and a grooved one, and a simpler sensillum with digitiform structures. Sex-related differences were detected in the length of chaetic sensilla of the pedicel: three different lengths were found in males and two in females. These ultrastructural studies represent the basis for further investigations on the electrophysiology and molecular biology of these sensorial structures in H. illucens, probably involved in the ability of this species in finding corpses on which to develop.