He mosquito Aedes aegypti uses infrared to detect and achieve its goal of biting humans, according to a study published in the journal Nature.
This mosquito is one of the main vectors for transmitting viruses such as dengue, yellow fever, Zika and chikungunya, collateral damage to its main objective: feeding on blood, preferably human blood.
To achieve this, several detection methods are simultaneously integrated, according to the study carried out by researchers at the University of California at Santa Barbara.
Aedes aegypti first detects the slightest fluctuation of carbon dioxide (CO2) in the aircaused by the breathing of a human being. This detection is made at more than ten meters from the subject.
According to the study, published on Wednesday, this “increases their locomotor activity and increases their reactivity to other stimuli from the host,” particularly olfactory signals characteristic of human scent, detectable at a distance of one to two meters.
Since Aedes aegypti has “poor visual acuity”, the effectiveness of these signals is reduced by possible air currents.
The insect knows that it is close to reaching its target when it is less than ten centimetres from human skin, as it detects humidity and heat.
The University of California team, led by Professor Craig Montell, investigated whether Aedes aegypti It could also use the infrared radiation emitted by all living beings to fine-tune its position.
The researchers conducted an experiment by placing 80 female mosquitoes in a cage, a few centimetres from two plates, one at room temperature of 29.5ºC, typical of a warm country, and the other at human skin temperature: 34ºC.
This device also allowed the emission of a discreet cloud of CO2 and the diffusion of the smell of human sweat coming from an old glove.
The researchers observed that a single signal, whether CO2, odor, or infrared radiation from the plate at skin temperature, elicited a very weak response. This was noticeably stronger with a combination of odour and CO2, and maximal when combining infrared radiation, odour and CO2.
The authors assume that “infrared detection could be widely used by mosquitoes to target warm-blooded hostsIf so, the researchers mention the possibility of designing “more effective traps.”