Site Characteristics and the Population Dynamics of the Pine Looper Moth

1. Data from 27 populations of Bupalus piniaria L. (Lepidoptera, Geometridae) spanning a minimum of 22 years are used to estimate the parameters of a simple difference model of the moth's population dynamics. 2. The resulting parameter estimates are compared with the `site characteristics' of the forest in which each population exists. 3. The per capita net rate of increase is found to be positively correlated with latitude, while the shape parameter in the function describing immediately density-dependent mortality is inversely related to local rainfall. 4. Possible physiological and behavioural mechanisms underlying these correlations are discussed.