Light pollution may be causing urban moths to evolve smaller wings

Moths trying to survive in bright cities may have evolved smaller wings to limit the amount of light they absorb.

Artificial lights that shine at night disrupt the lives of many insect species, diverting them from their habitats and mates, and exposing them to predators. Ecological changes due to light pollution may also have caused evolutionary changes, but clear examples are hard to find.

In search of such changes, evert van de shoot Researchers from the Catholic University of Leuven in Belgium analyzed the wing and body sizes of 680 spindle-shaped stoat moths.Yoponomeuta cañajera). These moths are previous experiment Test your reaction to light.

In their experiment, the researchers collected moth larvae from bright urban and dark rural locations in France and Switzerland and raised the moths together in the same garden. In the ‘flight to light’ test, urban moths were captured in 30 percent fewer light traps than rural moths, suggesting that they were less responsive to light.

Van de Schoot and his colleagues may have found an explanation for this. Careful measurements of the insects’ bodies revealed that moths in urban environments had slightly smaller wings on average than moths in rural areas. In both urban and rural populations, this small wing size correlated with a weak response in light trap experiments.

“What’s really surprising is that despite small changes in plumage, there are differences in rural and urban moth populations,” he says. Samuel Fabian At Imperial College London. He said the study’s focus on flight mechanics adds a new dimension to thinking about the effects of light on insects. “Nature is not static,” he says. “Nature adapts to us.”

Small wings can limit the distance and speed these moths can disperse to find mates and food. But if the trade-off makes moths less susceptible to the negative effects of being sensitive to light, it could be a beneficial adaptation in urban ecosystems, van de Scoot says.

The researchers say they cannot rule out the possibility that this change was driven by other differences between urban and rural areas, such as more fragmented habitats. Changes in visual acuity may also contribute to urban moths’ reduced response to light. Other insect species may also be affected differently.

But if such shifts in mobility were widespread, they could separate insect populations from each other and from the plants they pollinate, van de Scoot says. “It could be important for the entire ecosystem.”