Concurrent effects of induced host volatiles and plant-based resources on host plant attraction and predation behaviors in the omnivorous western bigeyed bug, Geocoris pallens

Both induced plant volatiles and plant-based resources may facilitate antagonistic interactions between insect predators and herbivores.  However, because the former trait conveys information while the latter provides resource, each trait may be perceived and utilized differently by insect predators.  We hypothesized that plant-based resources may interact with induced volatiles to increase the attraction of insect predators to damaged plants but also reduce subsequent predation against herbivores by the same predators.  We performed a series of manipulative field experiments over two consecutive years to measure the concurrent effects of plant-based resources and induced volatiles on predation and colonization behaviors in the omnivorous western bigeyed bug (Geocoris pallens).  G. pallens local density was enhanced in the presence of suitable plant-based resources, but predation against herbivore eggs was reduced, regardless of the volatile production treatment.  These findings indicate that suitable plant-based resources can positively augment or conflict with the potential effects of co-occurring induced volatiles on individual aspects of insect predator behavior.  Research into how different plant cues are perceived and utilized by omnivorous insects, especially when encountered in unison, can provide valuable information regarding the manipulation and implementation of these insects as biocontrol agents in agricultural systems.