Universitat Autònoma de Barcelona (UAB) researchers have found that the rise in temperatures and heat waves have accelerated the presence of high-temperature tolerant flies commonly found in European forests, the Drosophila subobscura. 

The report shows that the evolutionary response to the past two decades of increasing heat happened in already existing species and not new ones, and has accelerated, implying that "global warming may have put at risk species with lower levels of genetic variation."

The results, published in Nature Climate Change, confirm that more flies have the mutation that makes them heat tolerant, the proportion of inversions favoring cold tolerance has diminished, and that "species with broad geographic ranges, large population sizes, and high genetic diversity may have the evolutionary potential to cope with climate change."

Researchers from the UAB Department of Genetics and Microbiology Francisco Rodríguez-Trelles Astruga and Rosa Tarrío Fernández studied the different genetic variations of the fly.

In this species, climate adaptation is mediated by a type of genetic variation known as a chromosomal inversion polymorphism. Certain inversions or mutations that change the fly's "orientation of genome segments," provide the insect with either a higher tolerance to cold temperatures or more tolerance to heat.

If a greater effort is not put into mitigating global warming, the central European populations of this species will become genetically indistinguishable from populations in southern Europe by 2050.

The researchers gathered samples in Vienna, Austria; Leuven, Belgium; Lagrasse, Montpellier and Villars, France; Tübingen, Germany; Groningen, the Netherlands; Leuk, Switzerland; Malaga, Punta Umbria, Riba-roja de Túria and Queralbs, Spain.