Mosquito Types, Traits, Lifecycle and Repellants

By: Craig Freudenrich, Ph.D. & Mack Hayden  | 
mosquito swollen with blood standing on a finger tip
Mosquitoes have been around for over 30 million years. Ick. Paul Starosta / Getty Images

Nobody loves getting a mosquito bite. But that itchy inconvenience can quickly turn into a deadly threat when you consider the severity of that buzzy bug transmitting a mosquito-borne disease.

Here, we'll take a close-up look at mosquitoes: how they breed, how they bite, what diseases they carry (including those transmitted by the inland floodwater mosquito) and what you can do to control these pests.

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Mosquito Anatomy

Like all insects, adult mosquitoes have three basic body parts.

A mosquito's main body parts.
HowStuffWorks
  • Head: This is where all the sensors are, along with the biting apparatus. The head has two compound eyes, two antennae to sense chemicals, and mouth parts called the palpus and the proboscis (only the female mosquito has the proboscis for biting).
  • Thorax: This segment is where the two wings and six legs attach. It contains the flight muscles, compound heart, some nerve cell ganglia and ­trachioles.
  • Abdomen: This segment contains the digestive and excretory organs.

So, you have a sensor package, a motor package, and a fuel processing package — a perfect design!

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Mosquito Senses

Mosquitoes are insects that have been around for more than 30 million years. And it seems that, during those millions of years, mosquitoes have been honing their skills so that they are now experts at finding people to bite. Mosquitoes have a battery of sensors designed to track their prey, including:

  • Chemical sensors: Mosquitoes can sense carbon dioxide and lactic acid up to 100 feet (36 meters) away. Mammals and birds give off these gases as part of their normal breathing. Certain chemicals in sweat also seem to attract mosquitoes (people who don't sweat much don't get nearly as many mosquito bites).
  • Visual sensors: If you are wearing clothing that contrasts with the background, and especially if you move while wearing that clothing, mosquitoes can see you and zero in on you. It's a good bet that anything moving is "alive," and therefore full of blood, so this is a good strategy.
  • Heat sensors: Mosquitoes can detect heat, so they can find warm-blooded mammals and birds very easily once they get close enough.

Something with this many sensors sounds more like a military aircraft than an insect. That's why mosquitoes are so good at finding and biting you. One of the only ways to stop mosquitoes from finding you is to confuse their chemical receptors with something like DEET.

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3 Common Types of Mosquitoes

There are more than 2,700 species of mosquitoes in the world, and there are 13 mosquito genera (plural for "genus") that live in the United States. Of these genera, most mosquitoes belong to one of these three, but species such as the cattail mosquito (Coquilettidia perturbans) are becoming more prevalent pests as humans invade their habitats.

1. Aedes

Aedes mosquito
Aedes mosquito.
Joao Paulo Burini / Getty Images

These are sometimes called "floodwater" mosquitoes because flooding is important for their eggs to hatch. Aedes mosquitoes have abdomens with pointed tips. They include such species as the yellow-fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus).

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They are strong fliers, capable of travelling great distances (up to 75 miles/121 km) from their breeding sites. They persistently bite mammals (especially humans), mainly at dawn and in the early evening. Their bites are painful.

2. Anopheles

Anopheles mosquito
Anopheles mosquito.
Paul Starosta / Getty Images

These tend to breed in bodies of permanent fresh water. Anopheles mosquitoes also have abdomens with pointed tips. They include several species, such as the common malaria mosquito (Anopheles quadrimaculatus), which can spread malaria to humans.

3. Culex

Culex mosquito
Culex mosquito.
Paul Starosta / Getty Images

These tend to breed in quiet, standing water. Culex mosquitoes have abdomens with blunt tips. They include several species such as the northern house mosquito (Culex pipiens).

They are weak fliers and tend to live for only a few weeks during the summer months. They persistently bite (preferring birds over humans) and attack at dawn or after dusk. Their bite is painful.

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How Mosquitoes Live and Breed

Like all insects, mosquitoes hatch from eggs and go through several stages in their mosquito life cycle before becoming adults. The females lay their eggs in water, and the larva and pupa stages live entirely in water. When the pupa change into adults, they leave the water and become free-flying land insects.

The mosquito life cycle can vary from one to several weeks depending upon the species (the adult, mated females of some species can survive the winter in cool, damp places until spring, when they will lay their eggs and die).

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The word "mosquito" is Spanish for "little fly," and its use dates back to about 1583 in North America (Europeans referred to mosquitoes as "gnats").

Mosquitoes belong to the order Diptera, true flies. Mosquitoes are like flies in that they have two wings — but unlike flies, their wings have scales, their legs are long and the females have a long mouth part (proboscis) for piercing skin.

Egg

All mosquitoes lay eggs in water, which can include large bodies of water, standing water (like swimming pools) or areas of collected standing water (like tree holes or gutters).

Females lay their eggs on the surface of the water — except for Aedes mosquitoes, which lay their eggs above water in protected areas that eventually flood.

The eggs can be laid singly or as a group that forms a floating raft of mosquito eggs. Most eggs can survive the winter and hatch in the spring.

Larva

The mosquito eggs hatch into larvae or "wigglers," which live at the surface of the water and breathe through an air tube or siphon.

The larvae filter organic material through their mouth parts and grow to about 0.5 to 0.75 inches (1 to 2 cm) long; as they grow, they shed their skin (molt) several times. Mosquito larvae can swim and dive down from the surface when disturbed.

The larvae live anywhere from days to several weeks depending on the water temperature and mosquito species.

Pupa

After the fourth molt, mosquito larvae change into pupae, ­or "tumblers," which live in the water anywhere from one to four days depending on the water temperature and species. The pupae float at the surface and breathe through two small tubes (trumpets).

Although they do not eat, pupae are quite active. At the end of the pupal stage, the pupae encase themselves and transform into adult mosquitoes.

Adult

Inside the pupal case, the pupa transforms into an adult mosquito. The adult uses air pressure to break the pupal case open, crawls to a protected area and rests while its external skeleton hardens, spreading its wings out to dry. Once this is complete, it can fly away and live on the land.

One of the first things that adult mosquitoes do is seek a mate, mate and then feed. Male mosquitoes have short mouth parts and feed on plant nectar. In contrast, female mosquitoes have a long proboscis that they use to bite animals and humans and feed on their blood. The blood provides proteins that the females need to lay eggs.

After they feed, females lay their eggs (they need a blood meal each time they lay eggs). Females continue this cycle and live anywhere from many days to weeks (longer over the winter); males usually live only a few days after mating. The life cycles of mosquitoes vary with the species and environmental conditions.

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Mosquito Bites

This female Anopheles gambiae mosquito is feeding. You can see the blood swelling her abdomen.
Photo courtesy Centers for Disease Control & Prevention, photographer Jim Gathany

Only female mosquitoes bite animals. They are attracted by several things, including heat (infrared light), light, perspiration, body odor, lactic acid and carbon dioxide.

The female lands on your skin and sticks her proboscis into you (the proboscis is very sharp and thin, so you may not feel it going in). Her saliva contains proteins (anticoagulants) that prevent your blood from clotting. She sucks your blood into her abdomen (about 5 microliters per serving for an Aedes aegypti mosquito).

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If she is disturbed, she will fly away. Otherwise, she will remain until she has a full abdomen. If you were to cut the sensory nerve to her abdomen, she would keep sucking until she burst.

Why Mosquito Bites Itch

After she has bitten you, some saliva remains in the wound. The proteins from the saliva evoke an immune response from your body. The area swells (the bump around the bite area is called a wheal), and you itch, a response provoked by the saliva.

Eventually, the swelling goes away, but the itch remains until your immune cells break down the saliva proteins.

Treating Mosquito Bites

To treat mosquito bites, you should wash them with mild soap and water. Try to avoid scratching the bite area, even though it itches. Some anti-itch medicines such as Calamine lotion or ­over-the-counter cortisone creams may relieve the itching.

Typically, you do not need to seek medical attention (unless you feel dizzy or nauseated, which may indicate a severe allergic reaction to the bite).

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4 Diseases Mosquitoes Carry

An infected mosquito can carry many types of diseases that are caused by bacteria, parasites or viruses. These diseases include:

1. Malaria

Malaria is caused by a parasite that is transmitted by an Anopheles mosquito. The parasite grows in your bloodstream and can produce symptoms that develop anywhere from six to eight days to several months after infection.

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The symptoms include fever, chills, headaches, muscle aches and general malaise (similar to flu symptoms). Malaria is a severe disease that can be fatal, but can be treated with antimalarial drugs. Malaria is prevalent in tropical or subtropical climates.

2. Yellow Fever

Yellow fever no longer occurs in the United States or Europe, but it is prevalent in Africa and parts of South America. Yellow fever produces symptoms similar to malaria, but also includes nausea, vomiting and jaundice.

Like malaria, yellow fever can be fatal. There is no treatment for the disease itself, only the symptoms. Yellow fever can be controlled by vaccination and mosquito control.

3. Encephalitis

Encephalitis is caused by viruses that are transmitted by mosquitoes ­such as the Aedes mosquitoes or Culiseta mosquitoes. The symptoms of encephalitis include high fever, stiff neck, headache, confusion and laziness/sleepiness.

There are several types of encephalitis that can be transmitted by mosquitoes, including St. Louis, Western equine, Eastern equine, La Crosse and West Nile.

4. Dengue Fever

Dengue fever is transmitted by the Asian tiger mosquito, which is native to East Asia and was found in the United States in 1985. It is also transmitted by Aedes aegypti in the tropics.

Dengue fever is caused by a virus that produces a range of illnesses, from viral flu to hemorrhagic fever. It is especially dangerous for children.

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Mosquito Repellents

The best way to reduce mosquito-borne diseases and prevent mosquito bites is through mosquito control and personal protection.

Personal Protection

You can do a few things to reduce the number of mosquito bites that you get while enjoying the outdoors.

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  • First, wear clothing that covers most of your body, if temperatures permit.
  • Second, use a mosquito repellent that contains NN-diethyl-meta-toluamide (DEET) at a concentration of 7.5 percent to 100 percent.

Lower concentrations are sufficient for most outdoor protection, and a 15-percent concentration is recommended for children. Avon's original Skin-So-Soft is a weak, short-lasting (less than 20 minutes) mosquito repellent, although there are newer Skin-So-Soft formulations that include EPA-recognized insect repellents.

Note that permethrin, an effective pesticide, is for use on clothing only.

Eliminating Breeding Grounds

Beyond mosquito repellents and clothing, you can try to control the mosquito population.

Mosquitoes need water to breed and will use any source of standing water. So, to reduce the mosquito population, eliminate sources of standing water in your yard. Empty watering cans, remove old tires and cover rain barrels.

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