HEAT-INDUCED LONGEVITY EXTENSION IN DROSOPHILA .1. HEAT-TREATMENT, MORTALITY, AND THERMOTOLERANCE

Survival data were collected on a total of 28,000 Drosophila melanogas ter adults in order to investigate mortality patterns and induced phys iological responses after a mild thermal stress. A brief, nonlethal he at treatment extends adult life span at normal temperatures by an aver age of 2 days (64), compared to nontreated controls of the same genoty pes. Life expectancy is extended as a demographic consequence of reduc ed age-specific mortality over a period of up to several weeks after t he heat treatment. Heat treatment also increases tolerance to subseque nt, more severe thermal stress. Observations on single-sex populations suggest that heat-induced longevity extension is independent of the s uppression of reproductive activity.