Thermal adaptation in Drosophila serrata under conditions linked to its southern border: Unexpected patterns from laboratory selection suggest limited evolutionary potential

Abstract

To investigate the ability of Drosophila serrata to adapt to thermal conditions over winter at the species southern border, replicate lines from three source locations were held as discrete generations over three years at either 19°C (40 generations) or temperatures fluctuating between 7°C and 18°C (20 generations). Populations in the fluctuating environment were maintained either with an adult 0°C cold shock or without a shock. These conditions were expected to result in temperature-specific directional selection for increased viability and productivity under both temperature regimes, and reduced development time under the fluctuating-temperature regime. Selection responses of all lines wer..