Butterflies are showing us how wildlife will cope with climate change

As warm-weather species flutter further toward the poles, we will end up with far fewer kinds of butterfly. Here’s what that means for biodiversity across the animal kingdom

By Madeleine Finlay

THE long-tailed blue butterfly, named for the stringy “tails” on its wings and its iridescent azure colour, is common across Africa and southern Europe. It has rarely ventured as far north as the UK. In fact, for most of the time since one was first recorded on the south coast of England in 1859, only a few dozen more had been spotted there. But over the past decade or so, the long-tailed blue (pictured above) has been arriving in the country during the late summer in greater and greater numbers. Last year, eagle-eyed gardeners saw at least 50 adults and hundreds of eggs.

The sight of such exotic visitors is a thrill for butterfly enthusiasts. For conservationists, it is something else entirely: a worrying confirmation that butterflies are already feeling the effects of human-induced global warming. “This isn’t something that’s 50 years ahead. This is happening right now,” says Dan Hoare, an ecologist and director at UK-based charity Butterfly Conservation. Although the long-tailed blue is taking advantage of rising temperatures by expanding its range, most wildlife won’t have it so good. “The long-tailed blue should make us think twice about how nature is going to be able to adapt,” says Hoare.

As it happens, watching butterflies is one of the best ways to answer that question because these fragile, transient creatures are bellwethers. When it comes to understanding how climate change is affecting wildlife and ecosystems, their lifestyles and famous visibility make them uniquely revealing. So, as temperatures rise, what is becoming of butterflies? And what do their various fates tell us about how climate change will …