Invasive populations of Anoplophora glabripennis (Motschulsky) threaten forested systems across the globe. Eradication programs in North America can span hundreds of square kilometers, yet eradication efforts are carried out at the individual tree or stand scale. An A. glabripennis infestation was discovered in South Carolina in 2020; within this landscape, a small island was found on which 85% of A. glabripennis host trees were infested. The removal of all infested trees from the island in 2021 provided an opportunity to use this discrete population as a natural microcosm in which the spatial locations for the 14,615 oviposition sites and 1,611 exit holes in the population were documented. Data show A. glabripennis population growth rates varied substantially among individual trees. At the scale of the island, beetle density increased exponentially over time, while the number of infested trees on the island increased at a more moderate rate. The spatial and temporal patterns suggest several causal mechanisms and highlight the need for additional studies including the potential that female preference drives variation among host tree preference and beetle performance. The severity of the A. glabripennis infestation within trees was an inconsistent predictor of the age of an infestation, which is a key assumption used in landscape scale models of A. glabripennis dispersal. However, overall differences between predicted A. glabripennis movement and behavior were similar to that predicted from current risk models, supporting the utility of the landscape scale reconstructions currently used to model A. glabripennis spread and risk.
Bean et al. (Tue,) studied this question.