Heat-induced longevity extension in Drosophila. I. Heat treatment, mortality, and thermotolerance.

Survival data were collected on a total of 28,000 Drosophila melanogaster adults in order to investigate mortality patterns and induced physiological responses after a mild thermal stress. A brief, nonlethal heat treatment extends adult life span at normal temperatures by an average of 2 days (64), compared to nontreated controls of the same genotypes. Life expectancy is extended as a demographic consequence of reduced age-specific mortality over a period of up to several weeks after the heat treatment. Heat treatment also increases tolerance to subsequent, more severe thermal stress. Observations on single-sex populations suggest that heat-induced longevity extension is independent of the suppression of reproductive activity.