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.