Life cycle

An adult mosquito generally lives for 2 to 4 weeks. The mosquito's life cycle is made up of 4 different stages:

1. Egg-laying stage: the eggs must be laid in a suitable breeding site. Depending on the species, the eggs will be laid individually (some Anopheles species) or in groups (some Culex, Culiseta and Coquillettidia species), on the water surface or at the water's edge on a solid surface (some Anopheles, Aedes and Culiseta species). Mosquito eggs are elongated, fusiform and opaque (see photos below).

2. Larval stage: once the eggs have been laid, the embryo develops over 2 or 3 days, depending on the temperature. Once this development is complete, the egg shell breaks open and a larva emerges (see left-hand photo below). The larval stage comprises 4 stages, with a moult at the end of each stage. The larva has a tube attached to the surface of the water, enabling it to breathe. It feeds by means of mouth parts, with which it filters algae and surrounding micro-organisms (see photo on the right below).

3. Nymph stage: this is the final aquatic phase. During this stage, respiration takes place through two short breathing tubes and the nymph no longer absorbs food. In 1 or 2 days, the nymph transforms into an adult mosquito (see photo below).

4. Adult stage: during this last stage, the nymph's skin opens, the adult mosquito emerges and floats on the surface of the water for several hours until its skeleton has hardened. The adult mosquito then flies away.

On average, the time taken between fertilisation and the mosquito's flight is 2 weeks. Depending on the sex of the adult mosquito, the rest of the cycle will be different. While the sole purpose of the male mosquito is to mate, females also have other vital tasks. Mosquitoes mate a few days after reaching the adult stage. The fertilised females then go in search of a host An organism that can carry a pathogen Micro-organism capable of causing disease. . In the context of mosquito ecology, for example a human or animal host, this term refers to the organism from which the mosquito seeks to feed. to feed on their blood, which is necessary for the maturation of the eggs. Once she has finished her blood meal, the female looks for a place to rest and digest. This resting period lasts 2 to 3 days in tropical regions and up to two weeks in temperate regions. After this, the female begins to look for a suitable place to lay her eggs, after which she can repeat the cycle.

In autumn, when temperatures fall and the days get shorter, mosquitoes enter "hibernation" mode. Some species hibernate as eggs (many species of Aedes) or larvae (some species of Aedes, Anopheles and Culex) and can remain in this state for several months. Other species hibernate as adults in houses and cellars (for example, the common house mosquito, Culex pipiens, and the large ringed mosquito, Culiseta annulata).