The life span of a fruit fly is relatively short compared to many other organisms. Fruit flies, also known as Drosophila melanogaster, are small insects that belong to the family Drosophilidae. They are commonly found in households and are often attracted to ripe or decaying fruits.

The life cycle of a fruit fly can be divided into four main stages: egg, larva, pupa, and adult. Each stage plays a crucial role in the development and ultimate life span of a fruit fly.

1. Egg Stage:
Fruit flies begin their life as eggs, which are laid by adult female flies. These eggs are usually laid on the surface of ripe or decaying fruits, where the larvae will have a food source once they hatch. The egg stage typically lasts for about 1-2 days.

2. Larva Stage:
After hatching from the eggs, fruit flies enter the larva stage. During this stage, they are commonly referred to as maggots. The larvae feed on the decaying fruit, consuming the nutrients necessary for their growth and development. The larva stage typically lasts for about 4-6 days.

3. Pupa Stage:
Once the larvae have completed their feeding and growth, they enter the pupa stage. During this stage, the larvae undergo a process called metamorphosis, where they transform into adult flies. Inside the pupa, the larval tissues are reorganized and transformed into the structures of an adult fly. The pupa stage typically lasts for about 4-6 days.

4. Adult Stage:
After the pupa stage, adult fruit flies emerge from the pupal case. They have fully developed wings and reproductive organs. The adult fruit flies are capable of reproducing, and this is the stage where they mate and lay eggs to continue the life cycle. The adult stage usually lasts for about 7-10 days.

Considering the duration of each stage, the average life span of a fruit fly is around 20-30 days. However, it is important to note that various factors such as temperature, humidity, and availability of food can influence the life span of fruit flies. Under optimal conditions, fruit flies may have a slightly longer life span, while unfavorable conditions can shorten their life cycle.

The average natural life span of fruit fly adults in optimal temperatures is 40 to 50 days. The life span of the fruit fly is heavily influenced by temperature.