Queensland Fruit Fly Life Cycle
Courtesy Agriculture Victoria
Knowing the QFF life cycle makes it easier to control.
An adult female fly only needs to mate once and can lay up to 500 eggs in its lifetime. It only takes a couple of minutes to lay 6-20 eggs in a host fruit.
These eggs can develop into adult flies in less than a month if the conditions are right. Because of the fly’s rapid breeding cycle, there can be multiple generations in one season resulting in a population of over 700,000 flies.
QFF require warmth and moisture to complete their lifecycle. Ideal conditions for QFF development is around 26 degrees Celcius. Extreme heat, frost and dry conditions will naturally reduce fly numbers but will not destroy all flies.
It is not clear how long flies can live in the wild but it is thought that they are able to survive over winter suggesting they may live for at least 3 or more months.
As with many insects, there are four stages in the life cycle: egg, larva, pupa and the adult fly.
1. Eggs - white in colour and banana shaped. Eggs are so small they are unlikely to be seen by the naked eye.
2. Larvae (maggots) - soon after the eggs have been laid within the fruit, they hatch and a small maggot emerges from each. As the maggot feeds, it increases in size. It has cutting jaws which help it to tear off pieces of the fruit small enough for it to swallow. Maggots tend to eat toward the centre of the fruit. This promotes rotting of the fruit, although it may appear to be in good condition from the outside. As the maggot completes its growth, it chews its way out of the fruit (which by then, has usually fallen) and burrows into the soil.
3. Pupae - in the soil, larvae become inactive and change into an oval, brown, hard pupa.
4. Adult fly - the fly develops within the pupa and then bursts open the pupal case and tries to find a food source e.g. bird droppings and bacteria on leaves. Both males and females need to feed on protein to become sexually mature. This is especially important for the female in order to produce viable eggs. The more protein she can find the more eggs she is able to lay.
After feeding, the flies mate, and each female then searches for ripening fruit, which she punctures and lays her eggs in.