9 Things You Didn't Know About Mosquitoes

Anopheles maculipennis (malaria mosquito) standing on a leaf
Paul Starosta / Getty Images

Mosquitoes are well-known and widely disliked for their tendency to siphon blood from any sliver of exposed skin at twilight, leaving behind a red bump that itches incessantly for days on end. Not only are they annoying — with the buzzing and the biting — but they can also be deadly when they carry diseases like Zika, West Nile, and malaria. With climate change bringing more heat and humidity to the Midwest and East Coast, the mosquito season is getting increasingly longer. Learn more about these insects with which you're likely to become even more acquainted as time goes on.

1. Mosquitoes Sniff Out Their Victims

Natural body odors and the carbon dioxide humans exhale excite and attract mosquitoes, which is why we so often hear them buzzing around our heads. In fact, they can sniff out a host from 100 feet away. But researchers have found that certain scents — some of them minty, others fruity, one like caramelized chocolate — can actually inhibit the animals' carbon dioxide-sensitive neurons, thus making it harder for them to find their next meal. This is how lemon eucalyptus, aka citronella, works. Wind can also aid in masking mosquito-attracting odors.

2. Male Mosquitoes Don't Bite

A mosquito on a flower
Tahreer Photography / Getty Images

The Centers for Disease Control and Prevention (CDC) says only female mosquitoes bite. They rely on the protein from blood meals to produce their eggs, but they also drink it to stay hydrated. The thirstier they are, the more aggressive they become. Males, on the other hand, feed exclusively on flower nectar, plant sap, honeydew, and anything else containing the sugars required for energy and survival.

3. They Become Better Hunters When Infected

Female mosquitoes are already unquenchably bloodthirsty, but researchers have found that those infected with the dengue virus, which they can transmit to humans, are even hungrier for the red stuff. The virus equips them with the perfect cocktail for blood consumption: It manipulates the insect's genes to make it thirstier while also enhancing the mosquito's sense of smell, in turn increasing its ability to detect potential hosts.

4. Mosquitoes With Parasites Are Even More Bloodthirsty

Not only do parasites live and feed on mosquitoes, but the clever moochers can also manipulate their host's behavior to increase their odds of spreading. Research has shown that mosquitoes infected with the malaria parasite want longer and more frequent blood meals than noninfected mosquitoes, all to better the chance of obtaining a human host. Other research has found that mosquitoes with malaria are also drawn to the smell of human sweat, as was proven by experiments using well-worn socks.

5. Their Spit Leaves Skin Itchy

When a mosquito sets her sights on a target, she hones in, divebombs, and inserts her microscopic proboscis into the victim's skin. As she sucks blood, she leaves behind a dollop of saliva, which serves as an anticoagulant (to prevent clotting) so that she may feast more efficiently. Most humans have a natural immune response to mosquito slobber that results in histamines and itchiness up to seven days post-bite. Contrary to popular belief, not many people are allergic to mosquito saliva.

6. Not All Mosquitoes Can Carry West Nile Virus

Of the thousands of known mosquito species, West Nile virus has been found in just around 65 of them. (It's also found in more than 200 vertebrates.) The virus usually cycles between Culex mosquito species and common urban birds, like robins, northern cardinals, and house sparrows. Nearly 80 percent of people who are infected with the virus will not show any symptoms, which range from mild irritation and stupor to coma and death.

7. They May Be the Reason Alexander the Great Died

Alexander the Great, king of Macedonia and conqueror of the Persian Empire, never lost a battle and is considered to be one of history's most successful commanders, but he is thought to have ultimately been defeated at the age of 32 by a mosquito infected with West Nile encephalitis. Previous theories surrounding his death involved poisoning and infection, but more recent research points to a lone mosquito as the probable cause of death.

8. They're Quite Slow

Mosquitos against the sky
Martin Botvidsson / Getty Images

Vicious as the man-eaters may be, they move at a surprisingly pokey pace. The average mosquito weighs 2 to 2.5 milligrams, seemingly enabling them to fly swiftly, but not so. Instead, they fly at speeds between 1 and 1.5 miles per hour, making them one of the slowest flying insects of all. A dragonfly, for comparison, can go about 35 miles per hour.

9. Mosquitoes Are the Deadliest Animals in the World

Beware the dangers of tigers, sharks, and snakes? Nay, fear the mosquito, the most lethal creature on the planet. More deaths are caused by mosquitoes than any other animal, thanks to the insects' aid in spreading malaria, dengue fever, yellow fever, encephalitis, and a wealth of other deadly diseases. A single malarial mosquito can infect more than 100 people. According to the World Health Organization, malaria kills a child every minute in Africa.

Protect Yourself From Mosquito Bites

  • The CDC recommends wearing clothing that covers the arms and legs fully, and covering small children's strollers and carriers with mosquito netting.
  • Use an EPA-registered insect repellent such as oil of lemon eucalyptus (OLE) to repel mosquitoes while outside, especially at dawn and dusk. Keep in mind that some natural repellents aren't EPA-registered and the CDC does not know the effectiveness of them.
  • While some mosquito-borne illnesses like Zika and dengue cannot be prevented by a vaccine, others can. If you plan to travel to a high-risk area such as remote parts of Africa and Asia, the CDC recommends (and some countries require) getting vaccinated for yellow fever and taking malaria medication during and after your trip.
View Article Sources
  1. "Mosquito Season Getting Longer." Climate Central.

  2. Vinagaur, Clement, et al. "Visual-Olfactory Integration in the Human Disease Vector Mosquito Aedes aegypti." Current Biology, vol. 29, no. 15, 2019, pp. 2509-2516, doi:10.1016/j.cub.2019.06.043

  3. Ultra-prolonged activation of CO2-sensing neurons disorients mosquitoes

    Turner, Stephanie, et al. "Ultra-Prolonged Activation of CO2-Sensing Neurons Disorients Mosquitoes." Nature, vol. 474, 2011, pp. 87-91, doi:10.1038/nature10081

  4. Sim, Shuzhen, et al. "Dengue Virus Infection of the Aedes aegypti Salivary Gland and Chemosensory Apparatus Induces Genes that Modulate Infection and Blood-Feeding Behavior." PLOS Pathogens, vol. 8, no. 3, 2012, pp. e1002631, doi:10.1371/journal.ppat.1002631

  5. Smallegange Renate, et al. "Malaria Infected Mosquitoes Express Enhanced Attraction to Human Odor." PlosOne, vol. 8, no. 5, 2013, pp. e63602, doi:10.1371/journal.pone.0063602

  6. Vogt, Megan, et al. "Mosquito Saliva Alone has Profound Effects on the Human Immune System." PLOS Neglected Tropical Diseases, vol. 12, no. 5, 2018, pp. e0006439, doi:10.1371/journal.pntd.0006439

  7. "Mosquito." Minnesota Pollution Control Agency.

  8. "Mosquito Control." New Hampshire Department of Health and Human Services.

  9. "The Most Incredible Insects." The Smithsonian Institute.

  10. "Fighting the World's Deadliest Animal." Center for Disease Control.

  11. "A Child Dies Every Minute from Malaria in Africa." World Health Organization.