This butterfly, which also lives in the Netherlands, may have adapted its appearance due to climate change

Scientists have long wondered why brown sandeyes have varying amounts of spots on their wings. New research now suggests it has to do with temperature.

Research shows that just a few extra degrees can have a big impact. This occurs during the period when the caterpillar is still in the cocoon and eventually becomes a butterfly. The research shows that butterflies exposed to a temperature of 11 degrees during that period have an average of six points, while butterflies exposed to a temperature of 15 degrees at the same life stage have only three points. Therefore, the research suggests that climate change may cause the dots to disappear.

Custom camouflage
Scientist Richard French Constant contributed to the research. He said: “Our results suggest that butterflies adapt their camouflage based on the environment. For example, in this case it is possible that brown sand eyes with fewer dots are harder to see on dry brown grass. This brown grass is more common during warm weather. The research has been published In the magazine Environment and evolution.

Catching butterflies
For the research, British scientists collected butterflies daily from a field near Cornwall during the flying season. They then compared their contemporary observations with what they see in butterflies in historical collections. This indicates that female butterflies in particular are sensitive to the loss of spots on the back of their hind wings (see box). “We did not see this effect strongly in male butterflies,” says French Constant. “This is probably because males need their position to attract females.”

forward and backward
Brown sandeyes have two pairs of wings. There are always two large dots inside the front pair. There are several small dots on the back of the back pair. Ffrench-Constant explains: “The large spots on the front wings are likely intended to deter animals from hunting. The spots on the hind wings are much smaller and are particularly good for camouflage. It is mainly these small spots that can hide them.”

Therefore, the world expects that brown sand springs in the future will have fewer points as their temperature rises. French Constant concludes: “This is an unexpected consequence of climate change. We often expect animals to move northward slowly. So in this case we see a species changing its appearance.”