Thermal stress on monarch butterfly caterpillars

Ongoing climate change will continue to increase the frequency and intensity of extreme climate events, such as heat waves and droughts, with potentially wide-ranging consequences for species interactions. Temperature and moisture availability strongly affect the development of both monarch butterflies and their milkweed host plants, but the role of extreme climate events is less well characterized.

Two plausible hypotheses in the monarch-milkweed system center on heat waves: