Subjecting flies to a mild stress at a young age may increase longevity and protect against strong stresses occurring at middle age. The purpose of this article is to test whether a mild stress could also increase survival time of flies living in stressful conditions. Flies were transferred at middle age in vials where they could only feed on a saccharose solution without any other nutrient. This poor medium is known to decrease longevity and it was hypothetized that adding hydrogen peroxide to it could minimize this negative effect. While high doses of hydrogen peroxide decreased further longevity, a low dose increased it in 4-week-old males and, only in some experiments, in females. This low dose had however not any positive effect on behavioral aging, resistance to heat and starvation. The positive effect of hydrogen peroxide appeared not to be due to a sanitary action upon the environment. Rather, it seems that hydrogen peroxide was a mild stress helping flies to cope with the negative effects of saccharose on longevity. Therefore, it is concluded that hydrogen peroxide, beyond the deleterious effects of high doses, could have positive effects in organisms when used at a low dose, particularly in stressful living conditions.
Adaptation, Physiological Aging