The present study found significant difference in the ROS levels of the two populations but no effect of parental age was seen on the progeny in both the control and competitive condition with rest to ROS levels. In the parental generation, the female flies from the selected populations had on an average 60 (relative Optical Density) of ROS compared to 128 (relative Optical Density) in their ancestral control populations. The study indicates that ROS production is dependent on the immediate environment rather than the long term genetic effects.