The life span of a fruit fly will vary depending mostly on the temperature. If the fruit fly is in a relatively stable environment, it will have an average life span of about 40-50 days.

24 hours

The fruit fly life span is 20-30 days. If the temperature gets cold for them they will die before that time.

Fruit fly labs demonstrate life cycles since their life span is so short. It can also demonstrate genetic mutations in a population.

Provided there aren't sudden temperature drops, a fruit fly can be expected to survive between forty to fifty days. During that lifespan, a female fruit fly can lay repeat batches of eggs that could infest a house in that short period of time.