Host selection byAgrilus planipennis(Coleoptera: Buprestidae): inferences from sticky-band trapping

Sticky-band trapping experiments were undertaken in 2003–2006 to examine the host-seeking behaviour of the emerald ash borer,Agrilus planipennisFairmaire, in woodlots in southwestern Ontario, Canada. The female proportion ofA. plannipennisemerging from host logs ranged from 0.414 to 0.582. Landings on sticky-band traps varied more with the female proportion, ranging from 0.392 to 0.889, with the majority in the upper range, suggesting behavioural differences between the sexes. Correlations between landing density and tree size measured as diameter at breast height were positive or showed no relationship. In some locations more beetles were captured on the south side of the tree than on the north side; however, there was no difference between these cardinal directions at other locations. Numbers of captured beetles were never significantly greater on the north side of boles. We observed greater landing densities of adults of both sexes on traps on trees along the edges of woodlots than on trees within the woodlots. When given a choice under natural conditions, beetles landed almost exclusively on host trees (Fraxinus pennsylvanicaMarsh. (Oleaceae)) rather than on other common trees species (Carya ovata(Mill.) K. Koch (Juglandaceae),Tilia americanaL. (Tiliaceae), and species ofAcerL. (Aceraceae)) found in the same woodlots. Our data suggest thatA. planipennismake host-selection decisions while in flight rather than landing randomly. Implications for monitoringA. plannipennisusing sticky-band traps and understanding its host-seeking behaviour are discussed.