Have you ever wondered why some of us are mosquito magnets? It is well established that only female mosquitoes bite because they need protein from our blood to nourish their eggs. And, they are picky about their blood meal; look for several factors in their target before digging their proboscis.
Science is still figuring out the complex mechanisms behind their bias, and it turns out to be no less than rocket science.
Research shows that the female mosquitoes employ ‘coincidence detection’ or multiple smelling pathways and collate those signals to choose their target.
They have a special organ in their antennae called the maxillary palp that contains olfactory (odour) receptors. A receptor called Ir8a is particularly sensitive to carbon dioxide and sniffs it out in human scent from as far as 30 feet. It is seen that pregnant women, overweight individuals, and alcohol consumers expel more carbon dioxide, making them more vulnerable to mosquito bites.
Ir8a is also sensitive to volatile acids in sweat such as lactic acid, uric acid, and ammonia and once the mosquito lands on the skin, their feet begin to taste the sweat. Evidently, the more sweaty we are, the more we attract mosquitoes. Furthermore, they like warmer body temperatures.
Based on genetic factors, about 85% of us secrete special chemicals in our skin that reveals the type of blood antigen or blood group we have -- that is, A, B, AB, or O. A study found that mosquitoes sense these blood signals and generally are attracted to those who have these secretions more than the non-secretors. In addition, in a controlled-group experiment, researchers noticed that the mosquitoes seem to find type O people more meal-worthy.
Besides, certain types of bacteria that reside on our skin attract mosquitoes (the reason why most bites are around the ankles and feet, which are naturally bacteria prone).
Last but not least, reportedly mosquitoes also combine vision to locate their prey. They appear to find targets clothed in darker shades more inviting.