Written by: on June 15, 2020 @ 6:00 am

Why are mosquitos so religious? Because they prey on you!

When making a list of the most dangerous creatures on our planet, what do you think of? A menacing shark with 3,000 teeth? A hungry, slithering, 30-foot long anaconda? What about a buzzing, blood sucking mosquito? Mosquitos may not maul you like a vicious tiger, but instead carry diseases such as malaria, dengue fever, Zika, yellow fever, and encephalitis. Mosquitos bites are estimated to be responsible for the deaths of more than 2 million people annually, causing 300 to 500 million cases of malaria each year. Mosquitos are the deadliest animals on the planet, followed by human beings and snakes.

After you feel the itch of a mosquito bite, have you ever wondered why mosquitos feast on us? Raccoons, snakes, frogs, and birds like crows or ducks are also subject to the thirst of a mosquito.  To locate their next source of blood, mosquitos track exhaled carbon dioxide, movement, and body odor and temperature. Male mosquitos do not possess the necessary anatomy to suck blood, so female mosquitos are to blame.  Mosquitos need the proteins our blood contains to produce their eggs.  While the average mosquito’s lifespan is 2 weeks to 6 months, a single female mosquito can lay thousands of eggs within a month! Mosquitos can drink three times their weight in blood!

Female mosquitos use their straw-like mouth called a proboscis to pierce the skin and access blood. The proboscis has a sharp tip to piece the skin, much like a doctor’s needle, to draw blood up into its mouth. The itching associated with mosquito bites is caused by mosquito saliva, which the mosquito injects into its prey when biting. Mosquito saliva is an anticoagulant, which inhibits blood clotting, so the mosquito can get the most blood per bite. Our bodies recognize mosquito saliva as a foreign liquid, and the swelling is a response from our immune system to flush out this chemical. Scratching mosquito bites make the itching worse by increasing the inflammation of this immune system reaction.

The first human malaria case can be dated back to 450 C.E.; the disease is rumored to have killed half of all humans who have ever lived, making it the deadliest disease of all time. Malaria is also deadly for 125 species of animals, including mammals, birds, and reptiles. Prior to the age of germ theory, malaria was named after the assumed cause, “bad air.” Mosquitos lay their eggs directly on top of water, making mosquitos populations rampant in swamps and marshes, earning the name bad air from the heavy, humid air of these areas. Malaria is caused by a single-celled parasite called Plasmodium Falciparum, which enters the blood stream through mosquito saliva. Once this parasite is inside the blood stream, it makes its way to our liver, compromising the liver cells and multiplying rapidly.

It is believed that Alexander the Great, Genghis Khan, and Christopher Columbus were all victims of malaria. Malaria infection causes flu-like symptoms like fever, headaches, muscle, and joint paint; symptoms typically begin after a 10-14-day incubation of the parasite. It is estimated that malaria has evolved with humans, making it as old as 60 to 80,000 years old. It was not until 1897 when Dr. Ronald Ross, an army doctor in India, was able to prove that the malaria parasite was found in the gut of a mosquito and transferred to a malaria patient after they had been bitten. German chemists in 1934 invented a new antimalarial drug, the first drug proven to kill the plasmodium species. Today malaria is of little threat to most U.S. citizens, but people in underdeveloped areas of the world are highly susceptible to the disease. There is no malaria vaccination currently, so the disease is fought with preventative measures such as insecticide and covering beds with mosquito nets.

 While mosquitos are easy to hate, from the itchy bites they leave to the disease they spread, mosquitos have been of huge benefit to science research. Their proboscis, or needle mouths, have helped scientists to design better, less painful needles for doctors. The resilience of mosquitoes is fascinating, and if mosquitoes can find food they will persist. While there are over 3,500 species of mosquito, only 200 of those species prey on humans. Keep your bug spray handy this summer!

Learn to love insects through entomology, the study of insects! Catch mosquitos by making a pheromone trap from mosquitos that may prey on you! Find the Bugs of Summer experiment at: https://sciencemadefun.net/downloads/bugs_summer.pdf

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