The effect of developmental temperature on population flexibility in Drosophila melanogaster and D. simulans

Abstract

Ten strains each of D. melanogaster and D. simulans were derived from single inseminated females of the same population. For each strain the influence of developmental temperatures in the range 12-30ºC was considered for developmental time, egg to adult development percentage, sex ratio, longevity of adults, mating speed, fecundity and fertility. The species showed similar responses for all characters, although for the latter four D. simulans was more affected by extreme temperatures. Analyses of variance demonstrated temperature, strain, and temperature x strain effects to be generally significant. For sex ratio, however, temperature effects alone were significant. The results are discussed in relation to the level of genetical integration existing in a population and how such integration allows for considerable population flexibility.