Understanding olfactory cues in host location of the filth fly parasitoid Spalangia cameroni (Hymenoptera:Pteromalidae) to improve release methods on livestock operations

Pupal parasitoids (Hymenoptera:Pteromalidae) are often used as a sustainable biological control option for filth fly pests on livestock operations. An understanding of the behavior and biology of the biological control agent is necessary for a successful biological control program. However, though pupal parasitoids are sold commercially, very little is known about host-attraction by these parasitoids which could affect release methods. Additionally, historical monitoring for parasitoids has relied on the use of sentinel puparia traps or wild-collected puparia, but attraction to hosts may vary by species. The purpose of this project was to improve understand the olfactory cues associated with host location by the pupal parasitoids Spalangia cameroni to improve release and monitoring techniques. A two-way olfactometer was used to determine responses of S. cameroni toward odors associated with fly host development habitat substrates, host larvae and pupae reared in host habitat, and combinations of these variables. Spalangia cameoni was attracted to all odor-producing habitat over clean air, but was significantly more attracted to the substrate containing developing larvae over all other treatments. Larvae and puparia removed from the substrate were not attractive over the control or host habitat, but were significantly more attractive over the puparia that were removed from substrate. Those substrates eliciting positive responses are currently being evaluated by GC-EAD. The results of this research can be used to optimize monitoring for endemic and released parasitoid species by using appropriate sentinel traps or the development of a monitoring lure. Additionally, release strategies may be improved by releasing parasitoids need habitats where flies are currently developing.