“From a pest perspective it’s an important issue.”
Two butterfly species, the small heath (left) and common blue (right), have become more likely since 1980 to have multiple generations in Central Europe in the same year, as a long-term warming trend has picked up pace:
Ecologist Florian Altermatt of the University of California, Davis has studied 44 species of moths and butterflies in Central Europe. He published the results December 22 in the science journal, Proceedings of the Royal Society B article, “Climatic warming increases voltinism in European butterflies and moths” (which is available online for free for a few more days). “Voltinism” refers to the number of breeding cycles in a year.
As the region has warmed since the 1980s, some of these species have added an extra generation during the summer for the first time on record in that location. Among the 263 species already known to have a second or third generation there during toasty times, 190 have grown more likely to do so since 1980.
Since the journal article is a tough read, I’m excerpting the Science News story (which is also the source of the pictures):