Behavioural responses of bethylid parasitoid species of the coffee Berry borer to chemicals cues from host and non-host dust/frass

The bethylid wasps Cephalonomia stephanoderis Betrem and Prorops nasuta Waterston are parasitoids of the coffee berry borer, Hypothenemus hampei (Ferrari), the most serious insect pest of coffee worldwide. Recent studies on the host location behaviour of these parasitoids have shown that females are attracted to volatile compounds released by immature stages and dust/frass of H. hampei. Also, these studies have reported that the locomotory behaviour of parasitoids is influenced by contact chemical cues from host dust/frass. In this study, we investigated the responses of females of both species to volatiles and contact cues from dust/frass from different sources. Volatiles from dust/frass from H. hampei-infested coffee and maize infested with Sitophilus sp were attractive to P. nasuta females. In contrast, C. stephanoderis females were only attracted to the volatiles from dust/frass from H. hampei-infested coffee. Volatiles from an artificial diet used for rearing H. hampei were not attractive to females of both species. The effect of methanolic extracts from dust/frass from different sources on the patch-searching time of parasitoids was analysed using the Ethovision software. P. nasuta females spent more time in the patches treated with extracts of dust/frass from H. hampei-infested berries, artificial diet, and from maize infested with Sitophilus sp than on patches treated with dry coffee extract or solvent control. C. stephanoderis females spent more time on patches treated with dust/frass extracts from H. hampei-infested berries and artificial diet than on patches treated with an extract of dust/frass from maize infested with Sitophilus sp, an extract of dry coffee, and methanol control.