Cashew volatiles mediate short-range location responses in Pseudotheraptus wayi (Heteroptera: Coreidae)

Abstract

Pseudotheraptus wayi Brown (Heteroptera: Coreidae) is a major pest of cashew in East Africa, but little is known about its chemical ecology. Here, we show by using behavioral assays and chemical analysis that some components of cashew leaf volatiles are attractants for male P. wayi. By using a petri dish arena-EthoVision video-tracking assay, males oriented closer to crude cashew leaf odor than females. In coupled gas chromatography-electroantennographic detection analysis, we found that four components of cashew leaf volatiles that were identified by coupled gas chromatography-mass spectrometry and confirmed with authentic standards as (E)- and (Z)-β-ocimene, allo-ocimene, and (Z)-3-hexenyl butyrate appeared to elicit stronger and more consistent responses in male than female antennae. We recorded electroantennograms from antennae of either sex, which confirmed that antennal responses of males to synthetic components of the cashew leaf odor were stronger than those of females. In the petri dish arena-EthoVision video-tracking assay, males oriented closer to the synthetic cashew leaf monoterpenes than females. Our results suggest that specific monoterpenes in cashew leaf volatiles may serve as candidate kairomones for males.