Single sensillum responses in Trissolcus basalis females to companion plant volatiles

Abstract

In food resources location and selection, parasitoid females spend considerable time examining the substrate with their antennae, where chemosensory, mechanosensory and thermo-hygroreceptive sensilla exist. Olfaction and perception of plant volatiles play a basic role in recognition of nutritional resources. For Trissolcus basalis, an egg parasitoid of the green stink bug Nezara viridula, previous electroantennography and behavioural experiments tested the parasitoid’s response to extracted headspace volatiles and a synthetic blend of buckwheat volatiles indicated that T. basalis females have sensitive and selective olfactory responses some major buckwheat, Fagopyrum esculentum, flower volatiles, such as 3-methylbutanoic and 2-methylbutanoic acids. This suggests that antennal olfactory sensilla play an important role in bukwheat volatile compounds perception. Based on these finding results we examined the sensitivity of antennal olfactory sensilla to seven individuals compounds of buckwheat plant volatiles to determine the major active component using single sensilluim recording technique (SSR). All seven buckwheat volatiles elicited responses from some ORNs but 3-Methylbutanoic acid and p-benzoquinone were the most active compound which were showing consistant responses. These results represent a first step toward the identification of specialized ORN’s for T. basalis which could help in enhancing its activity in the field as a biological control agent using ‘attract and reward’ strategies where synthetic companion plant volatiles are provided from dispensers to attract the egg parasitoid to the crop.