Learn about the behavior of the Aedes aegypti mosquito and understand why this small insect is taxed in this way
You must have heard that the Aedes aegypti It is a mosquito with opportunistic habits. For what reason? It is a domestic mosquito, which lives in or around homes or other places frequented by people, such as commercial establishments, schools or churches, for example. It has preferably diurnal habits and feeds on human blood, especially at dawn and dusk. But can it also sting at night? Yes. He doesn't let the opportunity pass.
As it is a mosquito that lives close to humans, its presence is more common in urban areas and the infestation is more intense in regions with high population density - mainly, in urban spaces with occupation�� the disordered, where the females have more opportunities for feeding and have more breeding sites to spawn. Mosquito infestation is always more intense in the summer, due to rising temperatures and increased rainfall - factors that encourage the hatching of mosquito eggs. To avoid this situation, it is necessary to adopt permanent measures to control the vector, throughout the year, based on preventive actions to eliminate vector outbreaks. As the mosquito has domestic habits, this action depends mainly on the commitment of the population.
Main breeding sites
Research carried out in the field indicates that large reservoirs, such as water tanks, gallons and barrels (widely used for storing water for domestic use in places with poor urban infrastructure), are the breeders that produce the most A. aegypti and therefore the most dangerous. This does not mean that the population can neglect paying attention to small reservoirs, such as potted plants, clogged gutters, bottles, open-air garbage, air-conditioning trays, elevator shafts , between others. The alert is for greater care to be taken with larger reservoirs, as it is in them that the mosquito surely finds the best conditions to develop from egg to adult. In some suburban neighborhoods of the State of Rio de Janeiro, these large breeding sites produce almost 70% of the total number of adult mosquitoes.
Lifecycle
Find out what are the factors that affect the life cycle of the vector and what it feeds on
From egg to adult form, the life cycle of the A. aegypti varies according to temperature, food availability and number of larvae existing in the same breeding place, since the competition of larvae for food (in the same breeding place with little water) is an obstacle to the maturation of the insect to the adult stage. Under favorable environmental conditions, after the egg hatches, the development of the mosquito to the adult form can take a period of 10 days. Therefore, the elimination of breeding sites must be carried out at least once a week: in this way, the mosquito's life cycle will be interrupted.
Genilton Vieira/IOC
the larvae of A. aegypti are reduced in size, approximately that of a sewing needle head
The highest rates of infestation by A. aegypti are recorded in neighborhoods with high population density and low vegetation cover, where the mosquito finds feeding targets more easily. Another important factor is the lack of infrastructure in some locations. Without a regular supply of water, residents have to store the supply in large containers, which most of the time do not receive the necessary care and, because they are not completely sealed, end up becoming mosquito foci.
food
effeminate males Aedes aegypti they feed on sugary substances such as nectar and sap. Only the female bites the man to suck blood (hematophagy), food necessary for the maturation of the eggs. Generally, hematophagy is more voracious from the second or third day after the emergence of the pupa and mating with the male.
reproduction and spawning
Understand the reproductive cycle of the mosquito that transmits the dengue virus
the mating of Aedes aegypti it occurs in or around houses, usually in the first days after the mosquito reaches the adult stage. Only one dome is needed for reproduction to take place, as the female stores the sperm in the spermatheca. After mating, the females need to undergo hematophagy (blood feeding), which is important for the complete development of the eggs and their maturation in the ovaries. Aedes aegypti they are able to lay eggs three days after ingestion of blood, and then start looking for a place to spawn.
Spawning takes place preferably in breeding grounds with clean, still water. The eggs are deposited on the walls of the breeding site, very close to the surface of the water, but not directly on top of the liquid. Hence the importance of washing, with a brush or steel wool, the walls of containers that cannot be disposed of, where the egg can remain stuck.
Eggs
A female can breed 1.000 mosquitoes in her lifetime. The eggs are distributed by different breeding grounds, a strategy that guarantees the dispersion and preservation of the species. If the female is infected with the dengue virus when laying eggs, there is the possibility that daughter larvae will already be born with the virus, in a process called vertical transmission.
Initially, the eggs are white in color and, over time, they darken due to contact with oxygen. the egg of A. aegypti measures approximately 0,4 mm in length and is difficult to observe.
Genilton Vieira/IOC
In nature, A. aegypti eggs can survive up to 450 days out of water.
Eggs acquire resistance to drying out very quickly, in just 15 hours after laying. From then on, they can withstand long periods of desiccation - up to 450 days, according to studies. This resistance is a great advantage for the mosquito, as it allows the eggs to survive for many months in dry environments, until the next rainy and hot period allows them to hatch.
Under favorable conditions of humidity and temperature, the development of the mosquito embryo is completed within 48 hours. Resistance to desiccation also allows eggs to be transported over long distances in dry containers. This important aspect of the mosquito's life cycle demonstrates the need for continued combat against breeding sites, in all seasons of the year.
*All contents were reviewed by researchers at Instituto Oswaldo Cruz (IOC/Fiocroz)
