Male-produced sex attractant pheromone of the green stink bug, Acrosternumhilare (Say)

Sexually mature virgin adult males of the green stink bug, Acrosternum hila re attracted sexually mature virgin adult females in laboratory bioassays u sing a vertical Y-tube. There was no indication that males attracted other males. or that females attracted either sex. These results suggested that A . hilare males produce a sex pheromone, Extracts of odors collected from se xually mature males contained compounds that were not present in extracts f rom females or sexually immature males. (4S)-Cis-(Z)-bisabolene epoxide ((4 S)-cis-Z-BAE) was the major sex-specific component of the extract. The crud e extract was attractive to female A. hilare, but when separated into four fractions, only the portion containing (4S)-cis-Z-BAE and the minor compone nt (4S)-trans-Z-BAE was attractive to females, This fraction was as attract ive as the crude extract, suggesting that the former contained all the pher omone components. Neither synthetic (4S)-cis-Z-BAE nor (4S)-trans-Z-BAE alo ne was attractive to females, but a 95:5 cis:trans blend, mimicing the rati o naturally produced by males, was attractive to females in Y-tube bioassay s. Bioassays in a field cage showed that significantly more A. hilare femal es were attracted to cotton string lures treated with I mg of a 95:5 blend of (4S)-cis-Z-BAE and (4S)-trans-Z-BAE placed inside a bouquet of alfalfa t han to an alfalfa bouquet containing a pentane-treated control. In field ca ge studies, attraction of females was greatest during the late afternoon an d evening hours, and female A. hilare approached the synthetic pheromone so urce almost exclusively by walking.