Scientists uncover how mosquitoes sniff humans before biting

July 18, 2015: Ever wondered why the mosquito can always find you no matter where you hide? It is now that researchers have been able to know how the blood sucking insect can zero on to its target for its bloody meal. The mosquito employs a variety of senses to hunt its prey.

A study has been published on how the mosquito can find its prey. On summer evenings when most people would like to savor the cool breeze outside, mosquitoes make this almost impossible.

We use bug repellents and burn Citronella sticks, but it is effective only for some time. The blood-sucking pest has evolved a triple process of visual, olfactory and thermal cues to zero on its target.

A study has been published on how the mosquito can find its prey.

The first step in this process is sniffing out its prey. Once they can smell you, they try to see and once they are close enough, seek the warmest part of the body where they could land and use their proboscis to suck blood.

The researchers were able to unravel a complex methodology by which the mosquito seeks out its prey. Step one involves detecting CO₂ possibly through the breath of the person.

The CO₂ activates the mosquito’s visual senses and the insect then look for identifiable human or animal features. Once the mosquito is near the person, it seeks thermal clues to guide it to the optimal place to start its bloody meal.

The study revealed that a mosquito can see its prey from a distance of 5 to 15 meters. However, mosquitoes can sniff out CO₂ from a distance greater than 15 meters.

The information will be useful for devising ways by which mosquitoes can be kept away from homes. Details could be found in the paper titled “Mosquitoes Use Vision to Associate Odor Plumes with Thermal Targets” was published with Science Direct and is written by Floris van Breugel, Jeff Riffell, Adrienne Fairhall, and Michael H. Dickinson


  1. In the 1970s the scientists had established that nano-gram quantities of female sex hormones (estrogens) excreted through the human skin acted as the causative factor for attraction by mosquitoes. Since women invariably excrete more estrogens, they were / are bitten preferentially than men when both are present in a gathering even in a closed door room. It was further found that since fair-skinned women excrete more estrogens that dark-skinned females the former are bitten more preferentially and furiously than the latter. Since men excrete mostly male sex hormones (androgens), and extremely tiniest amount of estrogens from their skin, the mosquitoes exhibit second preference for biting them. This theory of the 70s now deserves to be retested in the light of current one.