Canadian Forest Service Publications
Environmental effects on host selection and dispersal of mountain pine beetle. 2007. Reid, M. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Mountain Pine Beetle Initiative Working Paper 2007-07. 14 p.
Issued by: Pacific Forestry Centre
Catalog ID: 26811
We investigated the influence of landscape heterogeneity on processes that could influence the dispersal of mountain pine beetle, Dendroctonus ponderosae. Host tree quality, as measured by tree diameter, resin production, monoterpenes and phloem thickness, did not differ greatly among stands, including sites that had been thinned or burned. Live trees in the highest burn classes produced the least resin and had the thinnest phloem, and were unattractive to single beetles placed on the trees (pioneers). Pioneers entered moderately burned trees significantly more often than less or more burned trees, but this could not be attributed to tree size, resin or phloem thickness. Naturally arriving beetles were more likely to colonize trees with higher resin production and more limonene, and did so earlier on trees with more myrcene; the probability that a pioneer beetle would recruit a mass-attack was higher with higher resin flow for larger beetles. These results suggest that constitutive tree "defences" may act as attractants. Overall, larger females and those in better condition were more likely to enter trees than were smaller beetles, despite mortality costs and relatively low prospects of recruitment. We also examined the dispersal of beetles through a pine forest and an intensively burned forest in a mark-recapture study. The burned stand was warmer and windier than the pine stand during the beetles' midday flight period. Beetles tended to disperse further in the burned stand than in the intact stand. Movement of beetles across the landscape is likely determined more by host tree availability, in turn influencing beetle energetic condition, and less by host tree quality.