Life cycle of the dengue mosquito

Aedes aegypti is the mosquito that transmits dengue, Zika, Chikungunya and yellow fever and its life cycle is divided into 4 phases: egg, larva, pupa and developed mosquito. The cycle begins when an adult female lays her eggs on the walls of the reservoirs with clean, still water and normally after 7 days, the larva grows into pupae and, 2 days later, the mosquito is fully formed and ready to bite.

Mosquito eggs are very resistant and survive even for 1 year in a dry place and when this place receives clean water, in about half an hour of submersion this egg can develop. This mosquito takes an average of 10 days to develop and lives for 30 days. A single female produces 60 to 120 eggs in each reproductive cycle and can have more than 3 cycles during her life.

4 Stages of Aedes aegypti

The Aedes aegypti mosquito needs both water and land to survive if its life cycle in the aquatic phase includes eggs, larvae and pupae and in the terrestrial phase, the mosquito that when it bites humans can transmit dengue.

The 4 stages of mosquito life are:

1. Egg

The female of Aedes lays her eggs in standing water or at the edge of a spot that may eventually get wet. They prefer to deposit their eggs in containers that can accumulate water, but a little above the water line, such as on the edge of buckets, basins, garbage cans, swimming pools that are not treated with chlorine, an open water box, bromeliads and dishes of plants, for example.

Sometimes the female lays her eggs in the water, but she often prefers to lay the eggs close to the water line to ensure the growth of new mosquitoes months later, ensuring the development and survival of her offspring. It is at this stage that the mosquito is most resistant and the only way to eliminate it is by washing the place with soap and water, using a little bottle to scrub the place. To ensure that the egg is destroyed you can add a little chlorine to the water while cleaning the container.

2. Larva

Upon contact with the water, the egg turns into a larva in just 2 or 3 days and these larvae are quite active and move in the water, being easily recognized. Although the mosquito prefers clean water to reproduce, it can grow even in dirty water and domestic sewage and feeds on protozoa, bacteria and fungi present in this water. During this phase the larva comprises 4 stages of its development, where it increases in size.

3. Pupa

In about 7 to 10 days the larva turns into a pupa and adopts a comma shape and this stage is shorter and lasts only 2 days, until the mosquito is ready to 'be born'. They don't eat at this stage, they just breathe and move around a lot.

4. Adult mosquito

The pupa turns into a mosquito and it comes out of its 'cocoon' and is ready to fly and needs to feed. Normally Aedes aegypti mosquitoes feed on fruits and juices of some vegetables, but after copulation, the female needs blood to make her eggs mature. After feeding on blood in 3 days she lays her eggs. The average life span of an adult mosquito is 30 days and during this period each female can lay about 3000 eggs.

These 4 phases can last from 5 to 10 days and the higher the temperature in the environment, the faster the mosquito develops and is ready to bite. The bite of the Aedes aegypti mosquito can happen at any time of the day, however the mosquito avoids the strong sun and outdoors, prefers the shade but usually bites in the morning or in the late afternoon and evening between 7 am and 10 am: 00h and between 16:00 and 19: 00h.

How it breeds

The reproduction of the dengue mosquito occurs through copulation between the male and the female. Mating can happen during flight or on a flat surface. Then, for the maturation of their eggs, the female needs human or animal blood that will provide the necessary nutrients for the development of the eggs.

The female lays her eggs little by little, stacking them in different places. It has already been observed that a female can lay only 1 or 2 eggs in one place, depositing the others in several other places, over a distance of more than 1 km. This indicates that when the female does not find an appropriate place to lay her eggs, she can fly long distances in search of the ideal environment, spreading the disease.

How to fight the mosquito

There are several ways to fight the mosquito and everyone can help in this fight by adopting some measures such as:

• Use of insecticides that can be applied to water deposits, drains and plant dishes. See how to make a homemade insecticide. Avoid the accumulation of standing water inside and outside the house; Putting chlorine and treating the water in the pools that remain open; Cleaning and capping the water boxes and cisterns; Removing all accumulated garbage.

Through simple measures like these it is possible to interrupt the life cycle of Aedes avoiding all the diseases that it can cause.

Aedes Aegypti in Brazil

Aedes aegypti is originally from North Africa and arrived in the Americas during its colonization and is present in several tropical countries, being very common in Brazil, especially in the summer where temperatures are higher and there are periods of rain and tropical storms that they lead to the flooding of the streets and the easy pooling of water, facilitating their reproductive cycle.

Dengue is an arbovirus, as are Zika, Chikungunya and yellow fever because they are transmitted by the bite of an insect, in this case the mosquito Aedes aegypti . Until the year 2000 in Brazil there were only dengue types 1 and 2, but in 2001 type 3 emerged and in 2010 type 4 was found in Roraima. Learn more about the Types of Dengue in Brazil.