Butterflies Adjust Flight Pattern Based on Temperature

After studying more than 100 years of climate records, Canadian researchers have discovered that butterflies are changing their flight season timing as temperature fluctuates.

The researchers -- from University of British Colombia, the Université de Sherbrooke and the University of Ottawa -- looked at collections of more than 200 species of butterflies and matched them with 130 years weather station data, finding a widespread temperature sensitivity in the dozens of butterfly species.

The butterflies, it turns out, adjusted their flight season an average of 2.4 days earlier per each degree Celsius of temperature increase.

"With warmer temperatures butterflies emerge earlier in the year, and their active flight season occurs earlier," said Heather Kharouba, lead author of the paper published this week in Global Change Biology.

"This could have several implications for butterflies. If they emerge too early, they could encounter frost and die. Or they might emerge before the food plants they rely on appear and starve," Kharouba said, adding: "Butterflies are also a bell-weather, and provide an early warning signal for how other wildlife may respond to climate change."

To make their assessments and estimate the flight season timing of each species, Kharouba and her team compared historical weather data with data of when the butterfly specimens were collected.

"Museum collection records are an under-exploited resource of ecological data and can provide a window into the past, and potentially the future," Kharouba said. "We should invest in efforts to properly database and centralize more of these records."