Investigations on molecular mechanisms and morphology of structures involved in chemoreception in black soldier fly larvae Hermetia illucens (Diptera: Stratiomydae)

Insects use chemical perception to interact with other insects and with their environment. The perception of volatile substances, linked to the processes of feeding, mating and escape from predators, is related to gene families encoding for proteins belonging to Odorant Binding Proteins (OBPs), Olfactory Receptors (ORs), Ionotropic Receptors (IRs) and Chemosensory Proteins (CSPs). The larval stages of the black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae) are generalist detritivores which feed on decomposing organic materials of both animal and vegetal origin. Hermetia illucens has a highly sensitive olfactory system, specialized in perceiving molecules linked to the decomposition of organic materials. Investigations on molecular mechanisms involved in feeding source recognition mediated by OBPs, through the perception of volatile attractants and the study of the structures involved in olfactory perception may contribute to the description of ethological details of this species (e.g. acceptance or rejection of organic material by larvae). An identification of the protein profile has been conducted based on the generation and annotation of a H. illucens larval de novo transcriptome and subsequent identification of transcripts encoding proteins involved in processes mediating olfactory perception. The OBPs and other predicted proteins involved in olfactory perception mechanisms were identified using BLAST searches and protein domain signatures. A parallel investigation by scanning electron microscopy (SEM) has been conducted on H. illucens larvae to identify structures possibly related to the olfactory perception. The preliminary data obtained by the two experimental approaches will be useful to increase knowledge about physiology of this insect.