Light-colored insects are better adapted to warmer climates than their darker cousins, according to a new study.
As average temperatures rise around the world, lightly colored insects are multiplying in Europe. Investigators from the Imperial College London, University of Copenhagen and Philipps-University Marburg in Germany studied dragonflies and butterflies.
They discovered both light- and dark-hued species were moving their habitats northward. Still, this results in dark insects dominating northern regions of the continent, and light-colored species finding their homes in the south.
"[B]eing dark is only advantageous in cool climates. In areas with high temperatures and insolation, insects need to protect themselves against overheating. At high temperatures, [cold-blooded] species with light colouration can be active for a longer period than species with dark colouration, and may be able to use a broader thermal range of habitats," researchers wrote in the article announcing their results.
The dainty damselfly is one of the insects exhibiting a change in habitat. This skinny, light-blue species was recently seen in Great Britain for the first time in 57 years.
Researchers used digital image analysis to make precise determinations of the color of collected insects. This data was then compared to the location where the insect was found.
"We now know that lighter-coloured butterflies and dragonflies are doing better in a warmer world, and we have also demonstrated that the effects of climate change... are changing as we speak," Carsten Rahbek, from the University of Copenhagen, said.
A total of 107 dragonfly species and 366 types of butterflies were examined by investigators. While collecting information, they examined data on the distribution of species around Europe from 1988 to 2006. This study showed darker insects are moving toward mountainous regions in the Alps and Balkans.
Movement of species in warming temperatures has been observed before, including distribution of plant varieties. This is the first study to specifically trace those changes to global warming.
"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," Dirk Zeuss, lead author of the article detailing the investigation, told the press.
Insects outnumber humans by a ratio of around 200 million-to-1, and their biomass, or total weight, is 50 times higher than that of our own species. There are around 1,800 insects for every square foot on Earth, including oceans.
The study of insects, and how color assists the animals in adapting to global warming, was published in the journal Nature Communications.
