Thermal‐specific patterns of longevity and fecundity in a set of heat‐sensitive and heat‐resistant genotypes of Drosophila melanogaster

Abstract

Fitness‐related traits are often affected by temperature. Heat‐resistant genotypes could influence the dependence of fitness traits on temperature, which should be important in adaptation to directional changes in temperature including global warming. Here, we tested temperature‐dependent variation in longevity and fecundity between Drosophila melanogaster Meigen (Diptera: Drosophilidae) genotypes that differ in heat‐resistance QTL. Longevity and fecundity were affected by heat‐resistance genotypes at constant moderate and high temperature. However, these differences between heat‐resistant and heat‐sensitive genotypes disappeared in a cyclic thermal regime. Analysis with the logistic mortality function indicated that mortality patterns are dependent on temperature and genotype. The results suggest that genotype*temperature interactions are substantial for senescence‐related traits. In particular, fluctuating temperatures can drastically reduce any differences in life‐history traits between heat‐resistance genotypes, even if such genotypes differentially affect the traits at constant temperatures.

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

“…natural variation of high temperature and humidity in the field (Stazione et al, 2017). Several thermotolerance QTL were previously found in laboratory studies both in larvae and adults, and most of them co-localized with QTL in the present field study.…”

“…Egg‐to‐adult survival at elevated temperature is expected to be an important fitness component, particularly under a possible global warming scenario. One major aim in the present study was to test for QTL effects under natural variation of high temperature and humidity in the field (Stazione et al., ). Several thermotolerance QTL were previously found in laboratory studies both in larvae and adults, and most of them co‐localized with QTL in the present field study.…”

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“…Consequently, in some studies stress resistance was deemed an indicator of organisms' great fitness (Johnson et al 2002;Lithgow & Walker 2002;Rea et al 2005). This notion was supported by some researchers, who claimed that selected lines of long-lived animals always have better performance when experiencing stress, including starvation and high temperature or vice versa (Zwaan et al 1995;Norry & Loeschcke 2003;Stazione et al 2017), although it is not always the case. Our study finds no evidence that the females highly tolerant to starvation lived longer than males.…”