Light Colored Insects Surviving Warming Conditions in Europe

Lighter colored species of butterflies and dragonflies are adapting themselves better to the warming climate than the dark colored insects, a new study reveals.

The study, reported in Nature Communication, found that light colored butterflies and dragonflies are out-competing the dark-colored insects as the climate across Europe undergoes drastic change.  The darker colored species are seen moving back northwards to cooler regions whereas the lighter colored species are seen shifting their geographical range norht as climate warms across Europe.

This collaborative study was conducted by researchers at the Imperial College London, Philipps-University Marburg and University of Copenhagen.

The dragonfly species that have been on the move and immigrated to Germany include the Southern Migrant Hawker (Aeshna affinis), the Scarlet Darter (Crocothemis erythraea) and the Dainty Damselfy (Coenagrion Scitulum. In 2010m, for the first time in 50 years, the Dainty Damselfy was seen in England. 

Butterfly species like the Southern Small White (Pieris Mannii) that prefer the warmer climates are being seen in Germany in the last ten years and continue to shift northwards.

It is the color of an insect's body that determined the amount of energy they absorb from the sun and this helps in fueling their flight along with regulating body temperatures.

Compared to the light colored insects, the dark colored insects absorb more light to elevate the body temperature and they are generally spotted in cooler climates. On the other hand, insects thriving in warmer climates need to shield themselves from the risk of overheating. The insects seen in hotter climates are the light colored insects because they can reflect the light to avoid overheating of the body and stay active for longer durations.

Professor Carsten Rahbek, at Imperial College London said, "For two of the major groups of insects, we have now demonstrated a direct link between climate and insect color, which impact their geographical distribution. We now know that lighter-colored butterflies and dragonflies are doing better in a warmer world, and we have also demonstrated that the effects of climate change on where species live are not something of the future, but that nature and its ecosystems are changing as we speak."

To check the association between color and temperature, the researchers studied 366 butterfly species and 107 dragonfly species across Europe. They displayed a clear pattern of light-colored insects dominating the north when the temperature was cooler.

To check if warming had triggered the shift, they analyzed the variations that occurred in the distribution of species over an 18-year period from 1988-2006. They noticed that on an average, insects turned lighter in color and the darker colored insects were moving toward cooler regions on Western margins of Europe, the Alps and the Balkans.

Though studies earlier showed how climate change is causing an impact on distribution of species, this study highlights a direct relationship and confirms that climate change does affect the pattern of biodiversity.