How to help protect butterflies: give them some shade

If you want to help protect butterflies from climate change, provide them with more shady places to keep cool, according to a new study from the University of Cambridge. The scientists report that the butterfly species which rely on finding shady areas to regulate their body temperature are the most vulnerable to global warming.

The study showed significant variations in the ability of different UK butterfly species to maintain a suitable body temperature. 

The researchers found that larger butterflies which are pale in color, including the Brimstone and the Large White, have the best adaptive strategies to handle climate change. These butterflies have large wings which they can use to reflect the sun’s heat either away from, or onto, their bodies. 

The larger and paler butterflies examined for the study were found to have stable or growing populations. By contrast, the larger butterfly species that are more colorful such as the Peacock and Red Admiral have greater difficulty controlling their body temperature, and are therefore more vulnerable to environmental changes.

The study revealed that some butterfly species must seek out a microclimate, or an area with suitable temperatures, in order to control their body temperature. 

Around two-thirds of UK butterfly populations are in a state of decline as a result of habitat loss and fragmentation, and the landscape modifications have eliminated many of the microclimates that butterflies need to survive. Climate change is making matters much worse by causing more extreme weather events and greater fluctuations in temperature.

“Butterfly species that aren’t very good at controlling their temperature with small behavioural changes, but rely on choosing a micro-habitat at the right temperature, are likely to suffer the most from climate change and habitat loss,” said study first author Dr. Andrew Bladon.

“We need to make landscapes more diverse to help conserve many of our butterfly species. Even within a garden lawn, patches of grass can be left to grow longer – these areas will provide cooler, shady places for many species of butterfly. In nature reserves, some areas could be grazed or cut and others left standing. We also need to protect features that break up the monotony of farm landscapes, like hedgerows, ditches, and patches of woodland.”

The research, which involved the analysis of nearly 4,000 wild butterflies and their surroundings, shows that butterflies are either thermal generalists or thermal specialists. However, this classification does not always correspond with the roles they play in their habitats.

“As we plan conservation measures to address the effects of climate change, it will be important to understand not only the habitat requirements of different butterfly species, but also their temperature requirements,” said lead investigator Dr. Ed Turner.

“With this new understanding of butterflies, we should be able to better manage habitats and landscapes to protect them, and in doing so we’re probably also protecting other insects too.”

In recent decades, the ranges that are suitable for species adapted to cooler environments are shrinking, and many butterflies have expanded their ranges northward. This study is the first to track how individual butterflies respond to small temperature changes.

The findings can be used to predict how climate change will impact certain butterfly communities, and may ultimately improve the conservation strategies designed to protect them.

“I like to think of butterflies as the gateway drug,” said Dr. Bladon. “If we can get people involved in butterfly conservation, that’s the first step to getting them to care about insects more broadly.”

The study is published in the Journal of Animal Ecology.

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By Chrissy Sexton, Earth.com Staff Writer