Limoniic acid is a sex attractant pheromone component of Limonius agonus (Coleoptera: Elateridae)

Recently, (E)-4-ethyloct-4-enoic acid (limoniic acid) has been reported as the major sex attractant pheromone component of L. canus and L. californicus (Coleoptera: Elateridae) in western North America. Our objective was to determine whether limoniic acid is also a sex attractant pheromone component of the eastern field wireworm, Limonius agonus (Say). In gas chromatographic-electroantennographic detection (GC-EAD) analyses of headspace volatiles from L. agonus females, antennae from male L. agonus responded to limoniic acid as a trace component. In field experiments, traps baited with synthetic limoniic acid, or its analog (E)-5-ethyloct-4-enoic acid, afforded captures of male L. agonus 3.6- to 8.9-times greater than unbaited control traps. In long-term field trapping studies, emergence and captures of L. agonus males fluctuated with temperature for more than 5 weeks, with distinctively different emergence patterns at the two study sites. Compared to previous studies with L. canus and L. californicus, limoniic acid as a trap lure afforded relatively low captures of L. agonus males, suggesting that L. agonus populations were low or that other L. agonus pheromone components are yet to be identified.