It’s rare to attend an outdoor party in warm weather without hearing people complain about mosquitoes. They swat away, sit in campfire smoke, cover up with blankets and eventually just give up and go indoors. On the other end of the spectrum, there are plenty of people who don’t seem bothered by mosquitoes in the slightest.As a medical entomologist who’s worked with mosquitoes for more than 40 years, I’m often asked why some people seem to be mosquito magnets while others are oblivious to these blood-feeding pests buzzing all around them.Most mosquito species, along with a host of other arthropods – including ticks, fleas, bedbugs, blackflies, horseflies and biting midges – require the protein in blood to develop a batch of eggs. Only the female mosquito feeds on blood. Males feed on plant nectar, which they convert to energy for flight.AdvertisementAdvertisementBlood-feeding is an incredibly important part of the mosquito’s reproductive cycle. Because of this, a tremendous amount of evolutionary pressure has been placed on female mosquitoes to identify potential sources of blood, quickly and efficiently get a full blood meal, and then stealthily depart the unlucky victim. If you check some, or all, of the mosquito’s search boxes, then you may find that you are a mosquito magnet.[embedded content]This video by Deep Look explains some of the ways mosquitoes feed on blood.Sensing CO2 and scent signalsDepending on when during the day they are active, mosquitoes use sight, sound and olfactory cues to identify a potential source of blood. Most night-active species rely on olfactory or receptor cues. The most important chemical cue is the carbon dioxide that all vertebrates, including humans, release with each breath and through their skin.Mosquitoes are very sensitive to CO2 and can sense a CO2 source that is many meters away. Receptor cells on the mosquito’s antennae and legs bin …
