Effect of X-irradiation at larval stage on adult lifespan in Drosophila melanogaster

The effects of X-ray irradiation at larval stage with doses of 1.2, 2.1, 4.2, 7.5 and 17.1 Gy on adult longevity and fecundity inDrosophila melanogaster fruit flies we restudied. A significant negative trend with increasing dose of irradiation was detected for the median lifespan in both sexes. In all experimental groups, both male and female mortality rates in irradiated flies were above control levels approximately for one month after emergence, and below control levels at older ages. The irradiation with 1.2 and 2.1 Gy resulted in 11.5% and 12.7% increase of male maximum lifespan, respectively. Irradiated females had in most cases a lower fecundity than control females. In all studied age groups, the decrease of fecundity was dose-related, and the negative effect of irradiation on fecundity was no longer observed in flies older than two weeks of age. Mean fecundity for the 4–25-day period of the irradiated females was shortened and dose-related [one-way ANOVA: F(5,414) = 10.56,P < 0.001], but significant differences from control were observed only for flies irradiated with doses of 4.2, 7.5 and 17.1 Gy. Mean fecundity for females irradiated with doses of 1.2 and 2.1 Gy did not differ from that of control females.