Genetic variation for egg‐to‐adult survival in Drosophila melanogaster in a set of recombinant inbred lines reared under heat stress in a natural thermal environment

Abstract

Quantitative trait loci (QTL) for thermotolerance were previously identified for adult flies in several mapping populations of Drosophila melanogaster Meigen (Diptera: Drosophilidae) in the laboratory. However, laboratory assays may not necessarily reflect the performance under heat stress in the field. For instance, do the heat‐resistance QTL regions in the field match the QTL for thermotolerance in laboratory studies? To address this and related questions we used a set of recombinant inbred lines (RIL), which were originally used to identify QTL in the laboratory. We tested egg‐to‐adult survival (EAS) QTL in a field experiment under naturally varying heat‐stress temperatures in fly cultures reared on a rotting fruit (banana) in summer. EAS under heat stress was found to be 3–6× lower (depending on RIL) in the field than in the corresponding control at benign temperature (25 °C). Five QTL for EAS were significant in the field experiment under heat stress, four of them co‐located with plasticity QTL, and none of the QTL was significant at control temperature. All significant QTL overlapped (co‐localized) with thermotolerance QTL previously identified in the laboratory. A previously found QTL in the middle of chromosome 2 explained near 30% of the phenotypic variance in EAS under heat stress in previous studies in the laboratory, but this QTL explained only 8% of the EAS variation in our field assay. The largest effect on EAS was found for an X‐linked QTL (cytological range 7B3‐10C3) in the heat‐stress field experiment, explaining a high percentage (14–45%) of the phenotypic variation in EAS. The ecological relevance of QTL implicated in this study is discussed.

Heat knockdown resistance and chill‐coma recovery as correlated responses to selection on mating success at high temperature in Drosophila buzzatii

“…High temperature can affect the reproduction, abundance, and distribution of species in contemporaneous wild environments under heat stress (Franks & Hoffmann, ; Hoffmann & Sgrò, ). In addition, the ability of individuals to respond to adverse environmental conditions such as thermal stress is highly relevant for adaptation to climate changes including global warming (Borda, Sambucetti, Gomez, & Norry, ; Deutsch et al, ; Franks & Hoffmann, ; Huey et al, ; Kellermann, Heerwaarden, Sgrò, & Hoffmann, ; Kellermann et al., ; Kingsolver et al, ; Rebaudo & Rabbi, ; van Heerwaarden, Kellermann, & Sgrò, ). Diverse fitness‐related traits, including mating success at stressing temperatures, can be direct phenotypic targets of selection for thermal adaptation (Hoffmann, Sørensen, & Loeschcke, ; Kellermann et al, ; Sambucetti & Norry, ).…”