Summary Thermal limits of ectotherms have been studied extensively and are believed to be evolutionarily constrained, leaving ectotherms at risk under future climate change. Phenotypic plasticity may extend the thermal limits, but we lack detailed characterizations of thermal limit reaction norms as well as an understanding of the interspecific variation in these reaction norms. Here, we investigated the interspecific variation in phenotypic plasticity of thermal limits in 13 Drosophila species. We obtained high‐resolution reaction norms for upper and lower thermal limits across the permissive developmental thermal range (12·5–30 °C). The estimated phenotypes were then associated (while accounting for phylogeny) with climatic parameters from the species’ distributional range. All species showed linear reaction norms for cold tolerance (CTmin) and heat tolerance (CTmax) across developmental acclimation temperatures. We observed strong beneficial cold acclimation to lower temperatures in all species. Conversely, the heat acclimation response was non‐existent in some species, and decreasing or increasing with increasing developmental acclimation temperatures in other species. The degree of phenotypic plasticity of CTmin and CTmax was related neither to the basal thermal limits (trade‐off hypothesis) nor to climatic parameters connected to latitudinal distributions (latitudinal hypothesis). A substantial and linear developmental plasticity of lower thermal limits is a general characteristic of Drosophila species, which allows for straightforward application in species distribution models. In general, upper thermal limits also show linear norms of reaction, but their adaptive significance is limited and highly variable among species, making general predictions across species rather impossible. High‐resolution estimates of norms of reaction of thermal limits can considerably increase our understanding of the capacity of ectotherms to acclimate to different thermal environments. However, our understanding of the environmental drivers of the evolution of phenotypic plasticity and thus of the interspecific differences remains ambiguous, potentially constrained by limited microclimate information. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12782/suppinfo is available for this article.

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The contribution of insect fat body to multiple processes, such as development, metamorphosis, activity, and reproduction results in trade-offs between life history traits. In the present study, age-induced modulation of storage lipid composition in Drosophila melanogaster longevity-selected (L) and non-selected control (C) lines was studied and the correlation between total body fat mass and lifespan assessed. The trade-offs between fecundity, locomotor activity, and lifespan were re-evaluated from a lipid-related metabolic perspective. Fewer storage lipids in the L lines compared to the C lines supports the impact of body fat mass on extended lifespan. The higher rate of fecundity and locomotor activity in the L lines may increase the lipid metabolism and enhance the lipolysis of storage lipids, reducing fat reserves. The correlation between neutral lipid fatty acids and fecundity, as well as locomotor activity, varied across age groups and between the L and C lines. The fatty acids that correlated with egg production were different from the fatty acids that correlated with locomotor activity. The present study suggests that fecundity and locomotor activity may positively affect the lifespan of D. melanogaster through the inhibition of fat accumulation.