dengue 1ILLUSTRATIONS: Erika Onodera
It has special eyes and salivary glands to detect humans and an imperceptible sting – in other words, it is a perfect agent of infection. So much so that Aedes aegypti transmits yellow fever, dengue, zika and chikungunya (and can carry the viruses of the last three and infect a person with all of them at the same time). He lives 30 days as an adult, enough to infect about 300 people. Only the female bites, as she needs blood to nourish her eggs – the male feeds on fruit sap. The eggs can withstand up to 400 days without contact with water and the larvae take only a week to reach the adult stage, being then able to go out biting people around.
1) BRISTLES
With them, the males detect the vibration of the females’ wings, locating potential mates. For females, the bristles have a tactile function: they help the animal to feel the human skin and see if it is suitable for the bite (free of hair and smooth)
2) PALPS
They help the Aedes to maintain balance when landing and create stability when inserting the proboscis. They are divided into five segments and allow to differentiate between males and females, since the former have larger palps.
3) PROBOSCIDE
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It is the proboscis that contains the mandible, trachea and other parts. The female uses it to penetrate the skin in search of blood. It has two channels: the hypopharynx inserts saliva (contaminated with viruses) and the labrum sucks blood.
SPITTLE
At the time of the attack, the Aedes injects its saliva into the victim, which contains anticoagulant substances (to maintain constant blood flow) and anesthetics (to momentarily block the sensation of pain). That’s why we only feel the sting much later
TASTE BUDS
After identifying possible targets, the Aedes is guided by the odors emitted by the human body and by the CO2 released in breathing. These components are detected by the taste buds, located near the proboscis
4) WINGS
The wings are covered with dark scales. Females reach a frequency of 400 beats per second, while males can reach 600 beats. The sound of flight, however, is virtually inaudible to us.
5) WHITE STAINS
Typical marks of Aedes aegypti, the white spots (which are actually small scales) are scattered throughout the body, but do not play any important role in the insect’s life.
EYES
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They are composed of up to 492 ommatidia, tiny “lenses” that are extremely sensitive to light. Through them, the Aedes has a field of view of 225°, which is essential for the first step of its hunting: the perception of our silhouette in the environment.
EGGS
O aedes aegypti it lays the eggs on the walls of the breeding grounds (any reservoir with still and clean water). They are placed very close to the water depth and wait for the next rain to hatch. They are 1 mm long
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2) Larva – Pupate in about 5 days
3) Pupa – 2 to 3 days to become an adult
4) Adult – Lives for about 30 days
THE STING
dengue 41) In the sting, a pair of jaws pierces the skin with up and down movements, like a saw.
two) When the blood vessel is reached, the movement stops. Hypopharynx injects saliva
3) The blood is then sucked through the labrum into the mosquito’s stomach.
MALE AND FEMALE
Know how to differentiate. Females are bigger and only they bite
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SOURCES Articles Ultrastructural variations in the anal papillae of Aedes aegypti (L.) at different environmental salinitiesby Rajindar Sohal and Eugene Copeland, Aquaporin homologs and water transport in the anal papillae of the larval mosquito, Aedes aegyptiby Jesmilavathani Marusalin, Brieanne Matier, Mark Rheault and Andrew Donini, book Main Mosquitoes of Sanitary Importance in Brazilby Rotraut Consoli and Ricardo Oliveira
CONSULTANCY Carlos Fernando Andrade, professor at the Institute of Biology at Unicamp
READ MORE
– What is the anatomy of a mosquito?
– Where do mosquitoes go in the winter?
– Why can’t Brazil detonate with dengue?