Differential host-seeking cues used by the filth fly parasitoids Spalangia cameroni and Muscidifurax raptor (Hymenoptera: Pteromalidae)

Pupal parasitoids (Hymenoptera:Pteromalidae) are used as biological control agents for filth flies on livestock operations. Though pupal parasitoids are sold commercially, very little is known about host-seeking by these parasitoids which could affect release methods. Historical monitoring for parasitoids has relied on the use of sentinel pupae traps or wild-collected pupae, but host seeking cues may vary by species. The purpose of this project was to improve the understanding of host location by the common pupal parasitoids Spalangia cameroni and Muscidifurax raptor to improve release and monitoring techniques. A two-way olfactometer was used to determine responses parasitoids toward odors associated with fly hosts and development habitat. Spalangia cameoni was attracted to the substrate containing developing larvae over all other treatments. Muscidifurax raptor was more attracted to substrates containing pupae than larvae. The results of this research show that host seeking differs by parasitoid species. These data can be used to optimize monitoring for parasitoids by using appropriate techniques for each species or the development of a monitoring lure. Individualizing monitoring by species could improve fly control by releasing endemic species and increasing knowledge of baseline parasitism.