Picture this: a cool moonlit summer evening, relaxing after a tough day and then you hear it. It begins as a distant high pitched whiny noise. The noise moves closer, seemingly zeroing in. And then you feel the lightest of caresses, brushing up against your skin. Too late you swat, and within minutes your skin begins to itch. Mosquitos! They are worse in some areas than others, but everyone has been victimized by them at one time or another.
But how does a mosquito find you in the first place? If you guessed that they are not smart enough to hang around doorways, you'd be right. Mosquitos are not that smart. Instead they use a basic sensory organ, they smell you. When we breath, we exhale carbon dioxide gas. Mosquitos can smell this gas from as much as fifty feet away! If that doesn't thrill you, you'll also be delighted to know that they smell the lactic acid which routinely oozes from glands in your skin. From these odors the mosquito can tell whether you are a tasty human as opposed to a bird, dog or horse.
There are about 150 species of mosquitoes in North America. Worldwide, about 3,000 species of mosquitoes have been described by scientists, and it is very likely that many more exist. Just which animal a kind of mosquito prefers to dine on depends on the mosquito.
You have undoubtedly heard of the dreaded sickness called malaria which is most common in Africa but does occur other places and more recently there have been a few cases in the US. This sickness is caused by a disease carrying species of mosquito called Anopheles Gambiae. This mosquito prefers humans as its main source of food and has been known to fly past thousands of cattle to bite the herdsman! Only when they cannot find humans will this insect dine on cattle.
You have probably noticed that some people seem more tasty to mosquitos than other folks. If there is a group of people sitting outside, it is not uncommon to see one or two people get the majority of bites while often there is one person who gets none! Our tastiness is related to natural differences in our body chemistry though we do not understand the specifics. Certain fragrances found in shampoos, soaps and powders will mask your natural scent but may make you even more attractive to the mosquito!
It is a common belief that mosquitos are either attracted or repelled by certain colours. It is not that mosquitos prefer blues to reds however, but more so that dark colours absorb more heat which in turn makes you more attractive to the hungry mosquito.
Actually, it is only the female mosquito that you need worry about, for only she dines on animals. Male mosquitos dine only on nectar. The females need the protein rich blood in order to produce eggs. The female requires one blood meal for each batch of eggs. If she is not interrupted by a slapping hand, the female will suck two or three times her weight in blood. Her body tells her when she has had enough when stretch receptors in her abdomen sense she has reached her limit. Scientists performed tests where these receptors were deactivated. The females continued to drink until they literally exploded!
When the female is full of food she is so heavy she may have some trouble flying. She looks for a safe place like under a leaf and processes the meal over the next few hours. See the image at the bottom of the page for the complete mosquito cycle.
When you do get bitten by a mosquito you usually get a red bump that itches for a period of time which varies from severity of bite as well as from person to person. Some people only itch for a few hours, while others keep a red itchy bump for weeks! The red bump is caused by an allergic reaction to mosquito saliva. The mouth of the female mosquito is designed much like a needle in a syringe. When she bites you she buries the syringe into your skin and begins to suck blood. While she is doing this however, some of her saliva flows into the wound.
The mosquito saliva causes an allergic reaction which kicks in your immune system. Antibodies are produced by the body and chemicals are released to protect us from infection. It is this which causes the initial swelling. When our immune cells gather around the bite area, it makes the lump get hard.
It is the itch which annoys most people. Calamine lotion helps some, as does a tiny drop of ammonia. If you are wondering about the suggestion of ammonia, there is a commercial product called "Afterbite" which can be used for bee stings and mosquito bites, but the only active ingredient is ammonia!
Sometimes when someone is bitten many times, they develop a natural immunity to the saliva, but it usually takes a lot of bites. Other people (like myself) have an allergy to them which makes the bites last as long as two weeks!