John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
The strategy supposedly prevents them from being burned to death or gobbled up.
Everyone knows that moths love light. But what you love can kill you, as proven by the millions of flying insects that immolate themselves on hot lights, or are gobbled up by predators in well-illuminated environments.
For that reason, some moths have evolved to avoid artificial lights, according to new research from Swiss zoologists. Researchers trekked around Basel collecting thousands of young, small ermine moths from dark areas (villages) and ones bathed in light pollution (cities). They then raised the bugs into adulthood and tested their reactions to light. The result: Moths descended from generations in heavily lit places tended to avoid human light, or as their study in Biology Letters phrases it, showed a “significant reduction in the flight-to-light behaviour.”
These altered instincts could be good and bad news for the insects, as well as organisms that depend on them, like plants in need of pollination. Here’s more from the study:
The reduced attraction to light sources of ‘city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks.