Influence of Temperature and Precipitation Anomaly on the Seasonal Emergence of Invasive Bark Beetles in Subtropical South America.

Several invasive bark beetle species have caused major economic and ecological losses in South America. Accurate predictions of beetle emergence times will make control efforts more efficient and effective. To determine whether bark beetle emergence can be predicted by season, temperature, or precipitation, we analyzed trapping records for three introduced pest species of bark beetles in Uruguay. We used trigonometric functions as seasonal predictors in generalized linear models to account for purely seasonal effects, while testing for effects of temperature and precipitation. Results show that all three beetle species had strong but unique seasonal emergence patterns and responded differently to temperature and precipitation. Cyrtogenius luteus (Blandford) emerged in summer and increased with precipitation but was not affected by temperature. Hylurgus ligniperda (Fabricius) emerged in winter and increased with temperature but was not affected by precipitation. Orthotomicus erosus (Wollaston) had a primary emergence in spring, and a smaller emergence in early summer, but showed no significant relationship with temperature or precipitation. This study shows that the emergence of these bark beetle species in Uruguay is influenced by seasonality more than by temperature and precipitation fluctuations. It also shows how seasonality can be easily incorporated into models to make more accurate predictions about pest population dynamics.