Comparison of the olfactory preferences of four species of filth fly pupal parasitoid species (Hymenoptera: Pteromalidae) for hosts in equine and bovine manure

Authors: MACHTINGER, ERIKA - University Of Florida; Geden, Christopher - Chris

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2015
Publication Date: 7/29/2015
Citation: Machtinger, E.T., Geden, C.J. 2015. Comparison of the olfactory preferences of four species of filth fly pupal parasitoid species (Hymenoptera: Pteromalidae) for hosts in equine and bovine manure. Environmental Entomology. pgs 1-8. doi: 10.1093/ee/nvv120.

Interpretive Summary: House flies and stable flies are common pests in equine and cattle facilities. Biological control is an important element in successful fly management, and parasitic wasps that attack and kill fly pupae are the most commonly used fly biocontrol agents. There are about a half-dozen species that farmers and ranchers can purchase from commercial insectaries, which advertize their products in agricultural trade magazines and on the internet. Which species works best? Research over the past couple of decades has helped to characterize the which species are most effective under condition choices such as wet vs. dry, light vs. dark, indoor vs. outdoor, etc. Most of this research has been conducted using fly breeding substrates found on cattle and poultry farms. Little is known about how the different species respond to breeding sites on horse farms, even though such operations are important consumers of these biocontrol agents. In this study, scientists at USDA’s Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and the University of Florida examined the preferences of four commercially important parasitic wasp species for horse vs. cattle manure under a variety of test conditions. They found that two species, Spalangia cameroni and S. endius, were attracted to both types of manure, especially when immature flies were present in them. In sharp contrast, the other two species (Muscidifurax raptor and M. zaraptor), were not attracted to horse manure under any test conditions. The results suggest that horse owners should try to find suppliers of parasitic wasps that can provide Spalangia alone or as the major constituent of species mixtures if pure species are impractical.

Technical Abstract: House flies (Musca domestica L.) and stable flies (Stomoxys calcitrans (L.)) (Diptera: Muscidae) are common pests in equine and cattle facilities. Pupal parasitoids primarily in the genera Spalangia and Muscidifurax (Hymenoptera: Pteromalidae) can be purchased for biological control of these flies. However, little is known about the host-habitat preferences associated with host-seeking by these parasitoids. The preferences of two Spalangia and Muscidifurax species to odors associated with house fly hosts in equine and bovine manure were investigated in the laboratory using a Y-tube olfactometer. Odor stimuli from manure without developing flies, 3rd instar house flies in manure, and fly host puparia in manure were evaluated. In choice tests, S. cameroni and S. endius were strongly attracted to odor associated with equine manure against clean air. Although S. cameroni was attracted to all bovine treatments against clean air, S. endius was only attracted to the bovine manure with 3rd instar flies. There were no significant differences between the Spalangia species in overall odor response. Neither Muscidifurax species were attracted to any equine treatments and were only attracted to the bovine manure with puparia over clean air. In manure comparison studies, bovine treatments with developing flies were more attractive than the equivalent equine treatments to both Muscidifurax species The data suggest that coexistence between the competing pteromalid parasitoids might be promoted by different host-seeking behavior. Additionally, manure preferences may indicate parasitoid suitability for releases on different livestock and equine facilities.