The role of temperature in the dispersal capacity of emerald ash borer (Agrilus planipennis) and its parasitoid, Tetrastichus planipennisi

The success of classical biological control programs, which aim to reunite invasive pests with natural enemies from their native range, often hinges on sufficient climate matching for introduced natural enemies. The effect of temperature on developmental rate, survival and performance (fecundity, parasitism rates) has received significant attention in biological control research. However, temperature also mediates the willingness of insects to initiate and maintain flight. Non-synonymous flight metrics of pests and their natural enemies at different temperatures may lead to suboptimal dispersal patterns and attack rates. Agrilus planipennis (Coleoptera: Buprestidae) is a wood-boring beetle from Asia that is currently causing widespread mortality of ash trees in North America. Tetrastichus planipennisi (Hymenoptera: Eulophidae) is a gregarious larval endoparasitoid that has been introduced against emerald ash borer at various locations throughout the eastern United States and American Midwest. We used computer-monitored flight mills to study the flight capacity of hosts and female parasitoids at temperatures between 8-42° C. Maximum flight occurred at 27.9° C and 26.5° C for emerald ash borer and Tetrastichus planipennisi, respectively. Finally, we linked temperatures associated with maximum flight capacity to 10-year averages of landscape temperatures at 15 locations throughout the continental United States and estimated the maximum flight periods for emerald ash borer and T. planipennisi based strictly on thermal impacts on flight energetics.