J. Powell et al., THEORETICAL-ANALYSIS OF SWITCHING IN A LOCALIZED MODEL FOR MOUNTAIN PINE-BEETLE MASS ATTACK, Journal of theoretical biology, 194(1), 1998, pp. 49-63
The dynamic interaction between mountain pine beetles (MPB) and hosts
(generally lodgepole pine) is reviewed briefly. In particular, success
ful ''switching'' from initial foci of attack to nearby hosts which ma
y be higher-quality resources is a potentially critical element initia
ting the transition from endemic to epidemic population levels. A coup
led partial differential equation model for MPB dispersal and host res
ponse is reviewed. The equations are decoupled making an adiabatic ass
umption for MPB chemotaxis, and a ''local'' projection is made using t
he leading eigenfunction for the MPB density equation. This projection
yields a system of ordinary differential equations for the spatio-tem
poral responses at individual trees. These equations are analysed to d
etermine what factors control successful ''switching'' in a two-tree m
odel. The results suggest that stand thinning ameliorates outbreaks ma
inly through interference with the chemical ecology via a change in mi
cro-climate, rather than by altering host vigor. (C) 1998 Academic Pre
ss.