Rapid loss of stress resistance in Drosophila melanogaster under adaptation to laboratory culture

We investigate changes in resistance to desiccation and starvation during a daptation of Drosophila melanogaster to laboratory culture. We test the hyp othesis that resistance to environmental stresses is lost under laboratory adaptation. For both traits, there was a rapid loss of resistance over a th ree-year period. The rapidity of the response suggested that mutation accum ulation could not account for it. Rather, resistance to environmental stres ses appeared to be lost as a correlated response to selection on another tr ait,. such as early fertility, with which stress resistance is negatively g enetically correlated. These results suggest that caution is needed when ex trapolating from evolution of stress resistance in long-established laborat ory stocks to patterns of responses and correlated responses in natural pop ulations.