Climate change can alter insect population dynamics in several ways, including in the number of generations per year and Spring emergence date. We explore changes in grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae),  seasonality that may occur with climate projections developed from the climate models (GFDL, HadCM3 and PCM) based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on emission scenarios in North East, Pennsylvania. Previous studies have quantified the relationship between environmental factors such as temperature and photoperiod, and diapause termination, diapause initiation, and temperature dependent development in P. viteana. Based on historical climate data from 1960, and predicted downscaled daily climate data until 2099 under both high (A1fi) and low (B1) greenhouse gas emission scenarios of the IPCC, we used concepts of P. viteana biology to develop estimates of the number of generations per year and Spring emergence date using an individual-based Monte Carlo approach. 

Results/Conclusions

Under the low emission scenario, we observed a shift in voltinism from currently 2.6 to 3.1 generations per year and significant earlier emergence dates in all generations. Under the high emission scenario, up to 3.6 generations per year were predicted by the end of this century and each generation had been reported to advance almost 30 days. The number of generation increased linearly under the low emission condition and nonlinearly under the high emission condition. By the middle of this century, our projections suggested that some GBM could even have a 5^th generation which was not seen in the study area currently. This study was not only to assess the impact of climate change on a specific species but also to propose an easy to use software framework to deal with a variety of insect species in different locations.These life history changes in this and other pest species due to climate change will likely cause significant economic impacts.