Mountain pine beetle is considered the most significant mortality agent in pine ecosystems of western North America, where it attacks and kills trees. The current distribution of mountain pine beetle is limited by climate, and pines extend further north, east, and south. Migration north in British Columbia and Alberta has occurred with warming in the past few decades. What will happen with continued warming? Will the frequency of population activity increase within the current distribution? What is the likelihood of migration south into Mexico?
Decades of research on mountain pine beetle response to varying temperatures in the laboratory and field facilitated the development of mechanistic simulation models that can be used to predict population response to thermal regimes. We used temperature projections that were derived from Global Climate Models in conjunction with our mountain pine beetle models to explore potential effects of warming throughout this century on population success within and beyond the current distribution. It is important to note that our models do not include the potential for genetic adaptation in mountain pine beetle lifecycle traits to rapidly warming temperatures. Genetic adaptations that keep pace with warming could allow for continued population persistence.
Although mountain pine beetle migration north in Canada is projected to continue, warming will disrupt lifecycle traits that synch populations with their environment in parts of the historical distribution. Range retraction in the US may occur.
To be successful in southern pine habitats, mountain pine beetle will need to adapt a new lifecycle pathway of two generations in a single year. Currently, one generation in a year (univoltine) occurs throughout the historical range.
Models project thermal suitability for migration south into pine habitats of Mexico, assuming two generations in a single year is viable ecologically.
Pine habitats in Europe were also projected to be thermally suitable for mountain pine beetle highlighting the need for continued forest insect monitoring at international ports.