An improved trap for large wood-boring insects, with special reference to Monochamus scutellatus (Coleoptera: Cerambycidae)
Commercially available multiple funnel traps have three potential limitations for trapping large wood-boring insects: (i) escape by captured insects from the dry collecting cup, (ii) low catches of insects that fall outside the trap, and (iii) poor visual orientation to the narrow funnel column. To test the importance of these limitations, we compared conventional multiple funnel traps to multiple funnel traps with water-filled collecting cups or large bottom funnels and to crossvane traps with a prominent silhouette. The experiment was conducted in a mill yard in the southern interior of British Columbia between 5 July and 2 October 2000. Differences in catch among different trap types indicated that the first and third of the three potential limitations were important for the capture of most target species. Crossvane traps captured significantly greater numbers of most Cerambycidae and Siricidae, and similar numbers of most Buprestidae, compared with the other traps. Of the two most abundant species, Xylotrechus longitarsus Casey was captured in consistently greater numbers in crossvane than in other traps, but Monochamus scutellatus (Say) showed little discrimination early in the flight season and much higher captures in crossvane traps late in the season. The change in behaviour of M. scutellatus may be related to a transition from maturation feeding to searching for oviposition sites.