Volatile Cues from Fresh Cattle Dung Can Drive Horn Fly Egg-Laying and Fecal Attraction to Horn Flies, Haematobia irritans (Diptera: Muscidae)

Abstract

The horn fly is one of the most important ectoparasites of cattle worldwide. Insecticides are commonly used to mitigate this plague, thought resistance to conventional insecticides and its environmental impact are problematic; hence, new approaches for management are being investigated. The use of chemical cues involved in horn fly behavior is promising because these cues are naturally and specifically detected by horn flies, avoiding the development of resistance. In this work, the effects of volatile blends and compounds emitted from cattle dung on the olfactory response and oviposition of horn flies were evaluated. The olfactory response and the egg-laying of horn flies were influenced by volatile cues emanated from cattle feces. Volatile cues from fresh cattle dung were preferred by flies of both sexes and by flies for egg-laying. Moreover, females were attracted to p-cresol and α-pinene which elicited a higher oviposition. Therefore, p-cresol and α-pinene may be responsible, in part, for the dung selection by female horn flies searching for oviposition sites. These results can be valuable for the development of new approaches for the control of the horn fly using semiochemicals as lures in fly traps and simultaneously emitting repellents from cattle as part of a “push-pull” strategy.