Host acceptance behaviour of the jack pine tip beetle, Conophthorus anksianae and the red pine cone beetle, C. resinosae

Abstract

The jack pine tip beetle, Conophthorus banksianae McPherson (Coleoptera: Scolytidae) and the red pine cone beetle, C. resinosae Hopkins, are doubtful sibling species. However, it is possible that these two taxa are valid species that maintain reproductive isolation because they accept different hosts. In a series of laboratory and field cage experiments, the host acceptance behaviours of these two species under choice and no choice conditions were compared. The field experiments demonstrated that the two species have a similar propensity to accept jack pine cones and shoots for feeding, but differ consistently in their acceptance of red pine cones, and variably in their acceptance of red pine shoots. However, the laboratory experiments did not indicate a difference between the two species in their propensity to accept red pine cones for feeding. In field cages, C. resinosae accepted significantly more red pine cones for oviposition than C. banksianae; the situation was reversed for jack pine shoots. In comparison to C. banksianae, C. resinosae is a more generalist feeder. The results from this study suggest that host acceptance behaviour is a permeable barrier unable to ensure reproductive isolation between the two species. Although there are differences in the host acceptance behaviours between C. banksianae and C. resinosae, we conclude that these differences do not necessarily support their designation as distinct species.

Breeding performance and longevity of Tomicus destruens on Mediterranean and continental pine species

“…Nevertheless, in a no-choice experiment, starved beetles may be forced to infest tree species that are not included in their usual diet (de Groot & Borden, 1992). Adults showed no host preference during bark colonization, although there were differences in tunnel length in the various species.…”

“…Adults showed no host preference during bark colonization, although there were differences in tunnel length in the various species. Nevertheless, in a no-choice experiment, starved beetles may be forced to infest tree species that are not included in their usual diet (de Groot & Borden, 1992). Scolytid adults bore galleries into bark for feeding and breeding, or just to find protection from enemies and dehydration, and oviposition is only the last step in a long process of host selection (Byers, 1995).…”