Ladybugs Changed Color in Response to Climate Change
A warming climate and fewer sunny days might be driving a shift in ladybug color—from black with red spots to red with black spots—in the Netherlands.
Paul Brakefield, an ecological geneticist at the University of Cambridge in the United Kingdom, and colleagues have studied the two-spot ladybugs for decades. In 1980, 10% of the ladybugs living near the coast were black with red spots, or melanic, whereas 90% were red with black spots, or nonmelanic. In contrast, 40 kilometers inland, 40% of the ladybugs were melanic and 60% were nonmelanic. The color difference was likely an adaptation: darker melanic ladybugs can stay warm in cooler inland climes, whereas a lighter color prevents the nonmelanic bugs from getting too hot on the coast.
But over the past 25 years, Brakefi eld and his colleagues have noticed a change to more nonmelanic bugs, even when sampling inland. In 2004, they found that only 20% of the ladybugs in any area were melanic. The trend seemed to fit with temperature data over the period, which showed that the entire area had been consistently warming, the researchers report in the December issue of Heredity. http://scim.ag/ladybugchange