Abstract
It has been demonstrated in several animal models that a brief non-lethal application of high temperature is capable of inducing an increased longevity. It is also known that an even briefer exposure to a non-lethal elevated temperature enables some organisms to subsequently survive what would normally be a lethal exposure to high temperature. Our long-lived La strain is significantly resistant to oxidative stress due to an enhanced expression of certain antioxidant defense genes and enzyme activities. We collected survival data on 12, 463 adults of normal-lived and long-lived strains of Drosophila melanogaster in order to determine if animals selected for extended longevity also had an enhanced resistance to heat shock, and whether they exhibited thermotolerance as well. We find that normal-lived animals exhibit a heat-induced longevity extension but that long-lived animals already resistant to oxidative stress exhibit a heat-induced longevity shortening. The effects of temperature stress on longevity are strain dependent and are separable from thermotolerance effects. The trait of extended longevity based on an increased resistance to oxidative stress in the adult may be purchased at the price of a decreased fitness of the adult to other important environmental parameters.