Investigating the role of olfaction in host plant selection of harlequin bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae)

Harlequin bug, Murgantia histrionica Hahn, is an important pest of cole crops in Virginia. There is potential for its control through trap cropping, or drawing pest pressure away from a protected crop by providing a nearby planting of something preferred by the insect. Choice test experiments conducted in field cages revealed that harlequin bug numbers were significantly higher on mustard (Brassica juncea) over collards (Brassica oleracea) or bean (Phaseolus vulgaris). In order to better understand the mechanisms of host plant selection in this species, olfactometer bioassays were conducted to evaluate the role of plant and insect-derived volatiles in attracting harlequin bug adults. Field-collected bugs were offered odors from bean and mustard versus clean air and in assays where plants were paired against each other. In addition, bugs were offered odors from virgin males feeding on each plant versus plant odors alone. Male participants were attracted to odors from mustard and bean as well as virgin males feeding on mustard, while males were not attracted to odors from virgin males feeding on bean. Female participants were attracted to odors from virgin males feeding on mustard, but not attracted to odors from mustard, bean, or virgin males feeding on bean. These studies illustrate the likely importance of male-produced pheromones for host plant finding and colonization by harlequin bug.