 Global warming has a strong effect on butterfly populations.
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Camille Parmesan , assistant professor of integrative biology at the University of Texas in Austin, cares about butterflies, so she's concerned: Global warming is bugging her beloved insects. Three years ago, Parmesan reported that Edith's checkerspot butterfly had moved northward along the west coast of North America over the past century.1 Specifically, local populations were four times more likely to go extinct in Mexico, at the southern end of Edith's range, than at the northern end in Canada, as predicted if global warming were at work. Alaskan glaciers and Greenland ice sheets are melting in the face of record warmth, much of it caused by human activity,2 but how global warming affects biology is uncertain. That's why Edith's checkerspot was a proverbial coal mine canary. "Dozens of different papers ... at some level have shown distribution changes," says Parmesan. Her study ...