Resistance to cold temperature stress in populations of Drosophila melanogaster and D. simulans

Abstract

Populations of D. melanogaster and D. simulans were tested for resistance to the cold-temperature stress of - 1ºC. Mean mortalities after 48 h followed the sequence D. melanogaster (Townsville) > D. simulans (Townsville) > D. simulans (Melbourne), which were all considerably greater than D. melanogaster (Melbourne). These differences can be related to differences between the sub- tropical climate of Townsville and the temperate climate of Melbourne. The physiological (and genetic) bases of resistance to cold temperature and desiccation differ considerably. The simultaneous genetic study of both traits would be advantageous in understanding the distribution and abundance of natural populations of Drosophila.