Adult Movement and Host-Orientation Behaviour of Warren Root Collar Weevil, Hylobius warreni Wood (Coleoptera: Curculionidae).

Warren root collar weevil, Hylobius warreni Wood, is a native insect found throughout Canada's boreal forest. In British Columbia, the weevil's primary host is lodgepole pine, Pinus contorta var. latifolia. While adults inflict minimal damage upon their hosts, larval feeding can girdle young trees, potentially causing tree death. Little is known about weevil host-orientation, particularly with respect to timing and extent of movement among host plants. I examined movement of adult weevils in different habitats using harmonic radar, and found that the highest movement rates occurred in areas without trees. Insect movement decreased with decreasing ambient air temperature and increasing time since release. In separate experiments in field arenas, I found that these flightless insects would walk toward vertical silhouettes in the shape of a tree. Blinding the insects obscured this behavior, suggesting that adult insects primarily use visual cues rather than chemical cues in host-finding behaviour. These findings may aid in the development of management strategies in plantations at high risk of weevil-induced mortality. --P. ii.