The median and maximum life spans of Zaprionus paravittiger are 43 and 79 days, respectively, for males and 52 and 91 days for females at 24 ± 2°C. Sodium selenite (SS), an antioxidant, feeding prolongs the median as well as maximum life span of both the sexes. Antioxidative enzymes, catalase and peroxidase showed greater activity during the developmental stages. Females, at most of the age intervals, exhibited greater enzymatic activities as compared to their age-matched males. Both the sexes showed a statistically significant increase in the baseline activity of these enzymes as consequent upon SS feeding. It is suggested that SS acts by strengthening the antioxidative enzymes, namely catalase and peroxidas