Evaluating entomopathogenic nematode production on injured black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae)

Previous results established that black soldier fly larvae, Hermetia illucens (L.) (Diptera: Stratiomyidae) are not an optimal host to rear entomopathogenic nematodes due to very low infection rate. In a preliminary experiment, injuring the larvae increased the infection rate and damaging the cadaver increased the number of emerging nematodes for Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae). Our first objective determined if injuring the fly larvae changed the infectivity of four entomopathogenic nematodes: Heterorhabitis bacteriophora Poinar (Rhabditida: Heterorhbditidae), S. carpocapsae (Weiser), S. feltiae, and S. riobrave Cabanillas, Poinar & Raulston. Our second objective determined if damaging the cadavers affects the number of nematodes that emerge. In the first of two experiments, we injured 5^th instars and exposed them to infective juveniles. Mortality was assed daily for five days, then cadavers were frozen and dissected to innumerate nematodes that entered the hosts. In the second experiment, fly larvae were injured before infection and cadavers were injured again a week later.  Infective juveniles were harvested and counted to determine the number of infective juvenile nematodes emerging per gram of host. Injuring the black soldier fly dramatically increased mortality rate when infected with Steinernema spp., but not H. bacteriophora. Only one or two injured larvae died in the no nematode control.  We harvested H. bacteriophora and S. carpocapsae from 60% of the black soldier fly larvae that were injured pre- and post-infection. Steinernema feltiae and S. riobrave were harvested from ≤ 21% of the infected fly larvae. Injuring black soldier fly larvae does not make them more of a suitable host to rear entomopathogenic nematodes.