Differences in thermal tolerances between two soybean pests may differently affect their voltinism under climate change

Abstract

Abstract Insect development is affected by temperature which in turn influences population growth. The thermal limits tolerated by insects vary depending on the species which can have important consequences for their voltinism in a climate‐changing world. This study used a multicriteria approach to select the best among six nonlinear models to describe the temperature‐dependent development rate of Anticarsia gemmatalis and Spodoptera cosmioides, two important soybean pests. The best models for each species were employed to estimate their voltinism under current and future climate conditions predicted for southern Brazil. According to the selected models, A. gemmatalis showed high upper lethal threshold (42.4°C) than S. cosmioides (32.3°C). Such disparity in the tolerance to high temperatures resulted in pronounced differences in the species' voltinism in southern Brazil, especially under future climate conditions. While an increase in the voltinism of A. gemmatalis of up to 32.3% was predicted in the entire study area, a decrease in the voltinism of S. cosmioides of up to 33.1% was predicted in warmer regions where temperatures more often exceeded the species' optimum. The species, location, and interaction between these two factors explained 96.0% of the total variation observed in the voltinism. Our findings suggest that disparity among species in their tolerance to high temperatures may differently influence their voltinism and population growth, leading to potential changes in their status as a pest in some regions due to climate change.