All About Lekking: A Comprehensive Examination of Lekking and the Lek Mating System in the Black Soldier Fly, Hermetia illucens (Diptera: Stratiomyidae)

The black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), is an economically important fly that is now mass-reared globally to produce livestock protein and frass that can serve as sustainable alternatives to conventional fishmeal and synthetic fertilizer. The species’ mating system has repeatedly been described as lekking, though there have been doubts raised as to the appropriateness of this terminology, especially for captive populations. Hence, the purpose of this review is to formally evaluate the mating system of the black soldier fly using Bradbury’s expanded criteria for lekking species to better understand what indeed the natural mating system and behavior of the black soldier fly is. From an applied perspective, accurately describing the mating system is important for understanding whether the industrial breeding system is inducing (unintentional) phenotypic changes. However, it is also important to point out that because the black soldier fly are not being mass-reared for release into the wild, as would be the case for those reared for Sterile Insect Technique (SIT), unless a particular mating system can be linked to an increase in fertile egg production, then there is a very limited reason why that mating system should be preserved in favor of the more productive one, other than perhaps the discovery of correlated genetic erosion or through the desire to promote insect-welfare, which places an emphasis on emulating a natural environment, maintaining natural behaviors, and reducing stress of confined animals.