Drosophila selected for extended longevity are more sensitive to heat shock

It has been demonstrated in several animal models that a brief non-lethal a pplication of high temperature is capable of inducing an increased longevit y. It is also known that an even briefer exposure to a nonlethal elevated t emperature enables some organisms to subsequently survive what would normal ly be a lethal exposure to high temperature, Our long-lived La strain is si gnificantly resistant to oxidative stress due to an enhanced expression of certain antioxidant defense genes and enzyme activities. We collected survi val data on 12, 463 adults of normal-lived and long-lived strains of Drosop hila melanogaster in order to determine if animals selected for extended lo ngevity also had an enhanced resistance to heat shock, and whether they exh ibited thermotolerance as well. We find that normal-lived animals exhibit a heat-induced longevity extension but that long-lived animals already resis tant to oxidative stress exhibit a heat-induced longevity shortening. The e ffects of temperature stress on longevity are strain dependent and are sepa rable from thermotolerance effects. The trait of extended longevity based o n 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 enviro nmental parameters.