Anthropogenic CO2 is rising in the atmosphere and will lead to an increase in temperature which in turn will increase plant productivity. However, previous studies have shown that elevated CO2 levels decrease plant defenses, increase the palatability of soybean to Japanese Beetles (JB), and increase the life span and fecundity of (JB). An increase in temperature will increase insect metabolic rates, possibly resulting in even greater damage in the field under future climate conditions. To understand how an increase in CO2 and temperature will affect soybean defenses, plants were grown under two levels of CO2 and temperature representative of current conditions and ambient conditions expected by 2050. Plants were infested in growth chambers and at the SoyFACE research facility located in central Illinois. Tissue was collected 24 hours after mechanical damage and JB feeding and was analyzed for plant defenses—specifically proteinase inhibitors (PIs) and polyphenol oxidase (PPO). Additional experiments examined beetle consumption rates under varying temperatures and preference to tissue grown under different treatments
Results/Conclusions Elevated temperature increased beetle consumption rate and PI activity in soybean. Despite this increase in soybean defenses, high levels of consumption were present on plants located in both high temperature plots. These results suggest that temperature may play a more important role in determining the interactions between these two species in combination with other aspects of global change.