According to the University of Arizona, the average life span of fruit flies is determined by the environmental conditions in which they live. In the lab, female fruit flies have a life span of approximately 26 days, while male fruit flies live approximately 33 days.
Under optimum conditions, fruit flies can live between 80 and 153 days, while fruit flies existing in crowded conditions only live about 12 days. Fruit flies go through four phases in their life cycle, which include egg, three larval stages, pupa and adult. The rate of development is affected by temperature. Flies in ideal circumstances can reach the adult stage in seven days.