Spatial and Temporal Attack Dynamics of the MountainPine Beetle: Implications for Management
Integrating Cultural Tactics into the Management ofBark Beetle and Reforestation Pests
J. C Gregoire, A.M. Liebhold, F.M Stephen, K.R. Day,and S.M. Salom
Colonization of a host tree by the mountain pine beetle, MPB (Dendroctonus ponderosae Hopkins, Coleoptera: Scolytidae), involves a complex, synergistic interaction between host-produced chemicals and beetle-produced pheromones. This system of chemical communication enables a massive aggregation of beetles on a single resource, thereby ensuring host death and subsequent beetle population survival. Because a single host tree is a limited food and breeding resource, MPB populations have evolved mechanism(s) for termination of colonization on a tree at optimal beetle densities, with a concomitant shift of attacks to nearby trees. Several hypothesis attempt to explain this pheromone-mediated phenomena. In an effort to more fully understand the entire colonization process, including the switch of attacks among trees, we observed the daily spatial and temporal attack process of MPB (non-epidemic) attacking lodgepole pine (Pinus contorta Douglas var. latifolia Engelmann). Our results from this preliminary study suggest that beetles switch attacks to a new host tree before the original focus tree is fully colonized, and that verbenone, an anti-aggregating pheromone, may be acting within a tree rather than between trees. Results from this and additional on-going studies are being used for parameterization of a spatially explicit model of MPB dispersal. Alternative hypotheses for MPB colonization and management implications are discussed.
B.J. Bentz, J.A. Logan and J.A. Powell. “Spatial and Temporal Attack Dynamics of the Mountain Pine Beetle: Implications for Management.” IN Integrating Cultural Tactics into the Management of Bark Beetle and Reforestation Pests; Editors: J. C Gregoire, A.M. Liebhold, F.M Stephen, K.R. Day, and S.M. Salom; USDA Forest Service GTR-NE-236, pp: 153-162, 1996.