The role of vision in host selection of Warren root collar weevil, Hylobius warreni

Warren root collar weevil, Hylobius warreni, is a native insect found throughout Canada’s boreal forest. In British Columbia, the weevil’s primary host is lodgepole pine, Pinus contorta. While adults inflict minimal damage upon their hosts, larval feeding can girdle young trees, potentially causing tree death. Little is known about the weevil’s mechanisms of host selection. We examined the use of vision in weevil host choice in field assays using plastic Christmas trees and ABS pipe “trunks.” In one experiment, movement of blinded and non-blinded weevils towards conifer tree silhouettes was compared. In a second experiment, four treatments comparing the effects of different silhouettes were investigated: plastic silhouettes of a tree trunk; tree foliage; full trees; and blank controls. Results indicate that visual cues influence host selection. Findings from this study may aid in the development of management strategies in plantations that are at high risk of weevil-induced mortality. Such plantations may become more numerous in the central interior of British Columbia due to landscape changes as a result of the mountain pine beetle epidemic.