Monday, December 10, 2007 - 8:41 AM

Potential host range of an invasive bark beetle, Orthotomicus erosus

Abigail Walter, somm0136@umn.edu1, Robert C. Venette, rvenette@fs.fed.us2, and Stephen A. Kells, kells002@umn.edu1. (1) University of Minnesota, Entomology, 1980 Folwell Ave Room 219, St Paul, MN, (2) USDA Forest Service, Northern Research Station, 1561 Lindig St, St. Paul, MN

Orthotomicus erosus Wollaston, the Mediterranean pine engraver, was first detected in North America in 2004. This bark beetle appears to utilize any tree in the genus Pinus, but its potential interactions with closely related genera are unclear. The ability to predict host use is critical to estimate the occurrence and impact of O. erosus in North America. Generally, when an herbivore invades a region, it is expected to utilize plants closely related to its native hosts. Thus, we hypothesize that phylogenetic relationships within the Pinaceae can be used to predict potential host use by O. erosus. Specifically, we speculate that O. erosus will be more likely to utilize plants that are more closely related to Pinus. Two components of host use, gustatory acceptance and offspring production, were measured in no-choice assays under quarantine conditions for: red pine, balsam fir, white spruce, tamarack, and eastern hemlock in the Pinaceae, and alder and paper birch as negative controls. The beetles reproduced most successfully in pine and failed to reproduce in fir, hemlock, alder, and birch. Reproduction was intermediate on spruce and tamarack. Adult beetles occasionally bored into the bark of all species tested, but the tree species that were acceptable in the gustatory assay were different from the tree species supporting development. Acceptability of and developmental potential on the various tree species are compared to the phylogeny of the Pinaceae to estimate the extent that plant phylogeny influences host use by this bark beetle.

Species 1: Coleoptera Curculionidae Orthotomicus erosus (Mediterranean pine engraver)