Wiley, Evolution: International Journal of Organic Evolution, 5(55), p. 1063-1068, 2007
DOI: 10.1111/j.0014-3820.2001.tb00623.x
Wiley, Evolution: International Journal of Organic Evolution, 5(55), p. 1063, 2001
DOI: 10.1554/0014-3820(2001)055[1063:cctamc]2.0.co;2
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Most drosophilid species can be classified either as temperate or tropical. Adults of species were submitted to a cold treatment (0 degrees C) and then brought back to ambient temperature. They generally exhibited a chill coma and the time needed to recover was measured. We found in a set of 26 temperate species that recovery was rapid (average 1.8 min, range 0.15-4.9). In contrast, a long recovery time (average 56 min, range 24-120) was observed for 48 tropical species. A few species, like Drosophila melanogaster, are cosmopolitan and can proliferate under temperate and tropical climates. In 9 of 10 such species, slight genetic differences were found: a shorter recovery in temperate than in tropical populations. Comparing physiological data to phylogeny suggests that chill-coma tolerance has been a recurrent adaptation that is selected for in cold climates but tends to disappear under a permanently warm environment. This major climatic adaptation, evidenced in drosophilids, seems to occur in other insect groups also.