Resumen
The pine processionary moth, Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae) is known as the most defoliating insect in Pinus and Cedrus in many countries. In the last three decades, climate change has led to a substantial expansion of its range and high attack rates in previously unaffected areas were observed. A 3-year analysis of the effect of several climatic elements on the T. pityocampa adult emergence was made and one climatic change scenario was tested in order to predict the insect?s behaviour in the future. Results showed that mean air temperature was the climatic element with the best single regression fit to adult emergence, whereas minimum air temperature and relative humidity provided the best multiple regression fits. Results also demonstrated that higher emergence of adults is often related to a maximum temperature above 30°C, a mean temperature above 23°C, a minimum temperature above 17°C, relative humidity lower than 60% and precipitation values lower than 10 mm. Using the same thresholds for future climatic conditions simulated by the COSMO-CLM model, the period for pine processionary moth emergence will be expanded, starting much sooner. Contrasting with the actual emergence period, the insect is projected to have favorable climatic conditions to start emerging in May. This might have serious implications in forest ecosystems, concerning not only ecological issues, but also forest management.