Light-Colored Butterflies and Dragonflies Thrive as European Climate Warms and Changes

Climate change is impacting our world in unprecedented ways. Now, scientists have found that it may be influencing the evolution of insects across Europe. As temperatures warm, communities of butterflies and dragonflies consist of more lighter-colored species.

As with lizards and snakes, the color of an insect's body plays a key role in how much energy it absorbs from the sun. Heat is crucial for fueling flight, as well as regulating their body temperature. While darker colored insects absorb more heat, lighter colored insects reflect it.

In order to see whether warmer temperatures might be influencing the coloration of species, the scientists looked at 366 butterfly species and 107 dragonfly species across Europe. They found a clear pattern of lighter insects dominating the warmer south of Europe and darker insects dominating the cooler north.

Yet this didn't tell them whether climate change has influenced the insects. The scientists therefore examined changes in species distributions over an 18-year period from 1988 to 2006. In the end, they found that on average, insects were becoming lighter in color. In addition, darker-colored insects shifted toward the cooler areas in Western margins of Europe, the Alps and the Balkans.

"We now know that lighter-colored butterflies and dragonflies are doing better in a warmer world, and we have also demonstrated that the effects of climate change on where species live are not something of the future, but that nature and its ecosystems are changing as we speak," said Carsten Rahbek, one of the researchers, in a news release.

Previous research has suggested that climate change is having an impact on insect populations and the distribution of species. Yet this latest study shows a direct link between climate change and its influence on insects.

"When studying biodiversity, we lack general rules about why certain species occur where they do," said Dirk Zeuss, one of the researchers, in a news release. "With this research we've been able to show that butterfly and dragonfly species across Europe are distributed according to their ability to regulate heat through their color variation. Until now we could only watch the massive changes in the insect fauna during the last 20 years. Now we have an idea of what could be a strong cause of the changes."

The findings are published in the journal Nature Communications.