Sensory Morphology, Investment and Plasticity in the Black Soldier Fly (Hermetia illucens)

Abstract

The importance of sensory traits, such as the development of the antennae and compound eyes, can be seen in the wide range of reproductive life history strategies employed by insects. Despite this, few studies have investigated the scaling relationships of sensory traits and body size which may give insight into the selective pressures driving this diversity. The commercially important species Hermetia illucens, or black soldier fly, was used to investigate the following: (1) the ultrastructural morphology of the antennae in H. illucens through the use of scanning electron microscopy; (2) the allometry of sensory traits and a dispersal trait (wing size) in the black soldier fly and a comparison of the allometries of the sexes and between two separate populations, (3) the effects of larval density on developmental phenotypic plasticity of sensory traits. I discovered a wide range of allometries that shed light on potential strategies utilised by the species to improve fitness. Some traits also showed sexual dimorphism and were explained by the unusual lek-like mating behaviour exhibited by adult males. Finally, I found that lower larval densities resulted in larger antennae suggesting that this species predicts future environmental conditions based on larval rearing conditions and adapt their adult morphology to maximise fitness.