Rapid differentiation of the sexes of adult Mecinus janthinus (Coleoptera: Curculionidae) based on external leg morphology

The stem-boring weevil, Mecinus janthinus Germar (Coleoptera: Curculionidae), was introduced from Europe to Canada in 1991 to control the noxious weeds Dalmatian toadflax, Linaria dalmatica (L.) P. Mill., and yellow toadflax, Linaria vulgaris P. Mill. (Scrophulariaceae) (De Clerck-Floate and Harris 2002; McClay and De Clerck-Floate 2002). Since its release, M. janthinus has established well on Dalmatian toadflax in British Columbia (BC) and, to a lesser extent, southern Alberta (De Clerck-Floate and Miller 2002), and it is beginning to show promise as a successful control agent against this weed (De Clerck-Floate and Harris 2002). However, it appears that M. janthinus has not thrived on yellow toadflax in Alberta (McClay and De Clerck-Floate 2002).