Genetic variation for egg-to-adult survival in Drosophila melanogaster (Diptera: Drosophilidae) in a set of recombinant inbred lines reared under heat stress in a natural thermal environment

BORDA MIGUEL; SAMBUCETTI P,; GOMEZ F; NORRY F

Entomologia experimentalis et applicata

Wiley

Año: 2018 p. 863 - 872

1570-7458

Quantitative trait loci (QTL) for thermotolerance were previously identified for adult fliesin several mapping populations of Drosophila melanogaster Meigen (Diptera:Drosophilidae) in the laboratory. However, laboratory assays may not necessarily reflectthe performance under heat stress in the field. For instance, do the heat-resistance QTLregions in the field match the QTL for thermotolerance in lab studies? To address this andother related questions we used a set of recombinant inbred lines (RIL), which wereoriginally used to identify QTL in the lab. We tested egg-to-adult survival (EAS) QTLs in afield experiment under naturally varying heat-stress temperatures in fly cultures reared on arotting fruit (banana) in summer. EAS under heat stress was found to be 3 to 6 times 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, fourof them co-located with plasticity QTL, and none of the QTL was significant at controltemperature. All significant QTL overlapped (co-localized) with thermotolerance-QTLpreviously identified in the lab. A previously found QTL in the middle of chromosome 2explained near 30% of the phenotypic variance in EAS under heat stress in previous studiesin the lab, but this QTL explained only 8 % of the EAS variation in our field assay. Thelargest effect on EAS was found for an X-linked QTL (cytological range 7B3 ? 10C3) inthe heat-stress field experiment, explaining a high proportion (14 to 45%) of the phenotypicvariation in EAS. The ecological relevance of QTL implicated in this study is discussed.