Climate change is likely to increase average temperatures by 2 6˚ C over the next century. Unfortunately, scientists lack the data necessary to make accurate predictions about the effects of this increase on biological communities. Most experiments on warming have focused on single species. In contrast, this project will test effects of increasing temperatures on multiple plant, herbivore, and predator species. To examine whether temperature alters effectiveness of how plants defend themselves against insect pests, plants will be grown under different temperatures and exposed to insect herbivores at different times. To examine whether rising temperatures can increase the rate at which the same insects are eaten by their predators, entire communities of plants, herbivores and predators will be reared under current and future temperature conditions. The ability of predatory insects to control populations of herbivorous insects will then be measured. These two experiments will identify how climate change might affect complex interactions between plants and insects, which will aid researchers in developing predictive models. Invasive insect species are responsible for considerable damage to economically important crop species. Importantly, many of the herbivores used in the two experiments described here are agricultural and horticultural pests or are closely related to such pests. The results of the first experiment will determine whether economically important plants will be able to adequately defend themselves against insect pests under warmer climates. Likewise, the second experiment will determine whether predators can control population sizes of agricultural pests, which could be important in preventing pest outbreaks.