Did you know that there are more than 110,000 species of flies around the world? Some, such as the vinegar fly (Drosophila melanogaster ), play important roles, serving as ‘model species’ in numerous scientific research studies, while others, such as the house fly ( Musca domesticus ), appear to simply hover around food leftovers. Knowing more about their curious life cycles and finding out when and how flies are born can sometimes be of great importance, helping to prevent infections in plant crops (such as pests) and even in animals and people (since they are carriers of numerous diseases).
What is the life cycle of flies like?
The interesting life cycle of flies is based on 4 different phases or stages, very similar to the famous life cycle of butterflies , with metamorphosis included! Do you want to know what exactly happens at each stage? Let’s look at it stage by stage:
- Stage or egg stage: since flies are oviparous animals (except for some species as an exception), the first step in the life cycle consists of the deposition of eggs by females. These fly eggs have already been previously fertilized by the male during mating, and the female, depending on the species of fly, will deposit them either in decomposing organic remains, in excrement, or even in fruits. It is truly amazing that females lay up to 100 or 500 eggs per clutch! The number will depend, again, on the species of fly, as well as the time it takes to hatch, although it is usually a fairly rapid hatching.
- Phase or stage of larvae: after hatching, some elongated larvae and yellowish-white color hatch from the eggs. At that time, and depending on where the flies previously lay their eggs, they will begin to feed quickly to have the energy and food necessary to grow and move to the next stage of the cycle.
- Pupal phase or stage: After having ingested enough organic debris (be it excrement, fruit pulp or decomposing animals and other food), the larvae of the flies begin to develop into what are commonly called ‘pupae’. They are more rigid dark structures, like capsules, that cover the body of the larva and prepare it for the amazing process of the metamorphosis of flies.
- Phase or adult stage: the apparently inactive metamorphosis gives rise to a new individual much more complex than the larva: it is the adult. Adult flies have three well differentiated anatomical parts: head, thorax and abdomen, in which the limbs are found in the form of legs and wings. In this fourth and last stage, the new adults close the life cycle, carrying out the reproduction process again with the consequent formation of new eggs that will enter each and every one of the phases of the cycle. Reproduction takes place here, thus starting the life cycle again.
As we have mentioned previously, flies are oviparous animals that reproduce through the mating of a male individual and a female individual, thus following sexual reproduction .
The act of mating can last about 10 minutes, from which the first stage of the life cycle begins through the deposition of eggs by the female. This life cycle or reproductive cycle enjoys an incredible speed compared to that of other animals, since completing each and every one of the phases of the cycle can take between 3 and 7 days for flies, depending on the species or types of flies .
In addition, to attribute a greater speed to the reproduction of flies, they are capable of laying up to 500 eggs in a single cycle , being able to repeat this process up to 3 or 4 times during their life as an adult fly.
This dizzying speed of reproduction and of completing their life cycles has allowed different species of flies to colonize the entire planet.
In the previous sections we saw how quickly flies reproduce and complete their life cycles, but how long does a fly last? How many days of life are we talking about exactly?
This question does not have a single answer, since each species of fly tends to live a certain number of days. House flies ( Musca domestica ), for example, normally live between 15 and 25 days , while the famous fruit fly ( Drosophila spp. ) Only lives between 8 and 10 days .