anastrepha fraterculus (wied.) shows a populational fluctuation related to the year season in southern brazil. adults cannot be colected by means of conventional methods of capture in the winter. even with the use of special traps, a very low number of adults is caught. two hypothesis are pointed out to explain the increase of the population at spring: a) adults migrate from neighbouring areas with temperature more favourable during winter, and b) some individuals that can survive the critical period develop a differential metabolic regulation. in this paper the second hypothesis was tested by studying the effect of four temperatures (9, 13, 20 and 25oc) on ovarian maturation and longevity of the females. only at 25 and 20oc ovarian maturation has occurred. the life expectancy was larger in the intermediate temperatures (20 and 13oc) than in the extreme temperatures (25 and 9oc). the relation between ovarian maturation and longevity was observed at 25 and 20oc, although at 25oc the ovarian maturation was faster, but the life expectancy was lower. therefore, the hypothesis of developmental regulation cannot be discarded as a populational mechanism in a. fraterculus for its populational increase in the months subsequent to the winter.