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Macro Photo of Yellow Fever, Malaria or Zika Virus Infected Mosquito Insect Bite on Green Background

Andrew Huang, Writer

Mosquitoes have been around the Earth for about 210 million years. In comparison, the modern human has only been around for 300,000 years. Humans hate these pesky insects. They are known for the itchy, swelling bumps they leave after they bite. Mosquitos are also known for spreading deadly diseases, like malaria, killing at least 725,000 people every year. How do these insects track you down? Why do they bite? Why do they leave an itchy bump afterwards?

Mosquitoes have an array of devices to use when tracking their prey. First off, they can sense carbon dioxide in the air. Mammals (like humans) give off this gas as a waste product through their breathing. Secondly, mosquitoes can also detect heat; this allows them to find warm-blooded animals very easily. Finally, mosquitoes can also sense their surroundings visually. This means that if you wear clothing that contrasts greatly with the background, these troubling insects are more likely to hone in on you. Mosquito repellents work to chemically confuse mosquitoes by blocking your carbon dioxide scent.

When a mosquito bites, it uses its proboscis to dig into your skin and suck blood from your capillaries. These insects suck your blood to serve as nutrition for their young. The mosquito keeps the blood from clotting by releasing anticoagulants in their saliva. These molecules interfere with the clotting process that usually occurs when there is a tear in your circulatory system. The saliva also includes lots of proteins and other molecules which cause your body’s immune system to react and create those dreaded red, itchy bumps. Even worse, the saliva is also the main way that mosquitoes transmit diseases.

Next time you go on that hiking trip, or take a walk in the park, be sure to remember the mosquito spray.