Along Christa Leste-Lasserre Male flame skimmer dragonfly (Libellula saturata)Danita Delimont / Alami
At Living Earth Collaborative and the University of Washington in St. Louis, Missouri, his colleagues examined hundreds of thousands of records of dragonflies representing 319 species in North America and compared them to the climate of animal homes. They found that the cooler the area, the darker and more elaborate the male feathers of each species.
The team then focused on 10 species of dragonflies that have a particularly wide geographic area throughout North America. They examined 2700 photos of these species uploaded to the iNaturalist community science platform. This revealed that even within one dragonfly species, males had less colorful wings in warmer climates.
This makes sense because colorful wings absorb more sunlight and warm up than colorless wings. In fact, the colored pattern raises the temperature of the wing by more than 2 ° C, which can damage the tissue of the wing and even die from overheating.
However, this also suggests that as the climate warms, male dragonflies are most likely to survive if they do not have colorful wings.
“Dragonflies adapt to the rise in temperature that accompanies climate change, so it’s very likely that they will lose their feather color moderately,” Moore says. “It’s a matter of cost-benefit.”
Finally, researchers scrutinized how the last 10 focal species have changed. They found that male dragonflies, photographed between 2005 and 2019, tend to have less colorful wings in warmer years and more colorful wings in cooler years. This means that only light-colored male dragonflies survive when it is hot.
Female dragonflies also have colorful wings, but they are less likely to lose color in hot weather. This may be because females prefer to hide in the shade while males fly in the sun.
However, it suggests that dragonflies may face problems in the future. Moore says that if colorful females find the bland males less attractive, they may refuse to mate with them. To make matters worse, females may begin to struggle to recognize males of their own species and accidentally start mating with males of another species.
“It already happens from time to time, and the offspring don’t work very well, so that’s going to have pretty detrimental consequences,” says Moore.
Journal Reference: PNAS , DOI: 10.1073 / pnas.2101458118
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