Butterfly populations in Catalonia in northern Spain are better than their UK counterparts at regulating their body temperature by basking in the sunshine, but rising global temperatures due to climate change may put Spanish butterflies at greater risk of extinction. An international study, led by the University of Cambridge and the Institut de Biologia Evolutiva (IBE) in Barcelona, found that butterflies use different methods to regulate their body temperature. In Catalonia, butterflies tend to angle their wings towards the sun to warm up at lower temperatures, while British butterflies rely more on finding warm microclimates.

In a study published in 2020, several of the same researchers showed that there are significant variations in the ability of different UK butterfly species to maintain a suitable body temperature. Species that rely mostly on shade to keep cool are at greatest risk of population decline, due to climate change and habitat loss. In Spain, butterflies spend much more time at their optimum temperature since it's warmer, but there's also a greater risk of overheating," said Dr Andrew Bladon from Cambridge's Department of Zoology, the study's senior author.

The researchers say that beyond rising temperatures, butterflies are also at risk from associated climate impacts, such as droughts or heatwaves. These extreme weather events can not only push butterflies past their thermal limits, but it can kill the plants which their caterpillars rely on. Climate change is a two-pronged attack that can take out both adult butterflies and their caterpillars, Climate change and biodiversity loss go hand-in-hand, and we urgently need to address both if we're going to protect important species like butterflies.