It all begins in the water.
Female mosquitoes lay their eggs in water. And some species don’t need much water: an old tire, a discarded cup from someone’s fast food lunch, a birdbath, a hole in a tree. Others hatch in still lakes or sewage ponds.
The larvae grow to be one-tenth to one-fourth-inch long, float to the top of the water, and are called “wrigglers.” They breathe air through a snorkel-like device (called a siphon) that they poke out of the water. They are filter feeders, sifting out organic debris and small animals. Larvae eat constantly,
The larvae become pupae. Mosquito pupae are different from most insects at this stage because they can move.
Although mosquito larvae and pupae provide lunch for many different animals, there are still many left to emerge as adults.
Adult mosquitoes live in many places according to their species. Almost all are active and bite at dusk, but a few also attack during the day.
Blood for mosquitoes is not food. Both males and females seek plant nectar and juices containing sugars for food. Only the female takes blood; she needs animal blood protein to complete the development of her eggs. This is when she may transmit disease to humans or animals.
Public Enemy #1
When an infected mosquito bites, she injects saliva and the parasite that causes disease. The person becomes sick as the organisms multiply in the body. Other mosquitoes bite the infected animal or person and take in the parasite with the blood needed for egg development. The cycle begins again when the mosquito bites another animal or person.
Certain mosquitoes spread many diseases in this way. Malaria is carried from the sick to a well person by about 70 species of the Anopheles mosquito. Persons with malaria have muscle pains, chills, and fever–and many die.
In Europe and North America, malaria has been generally conquered. Travelers to malaria areas, however, bring about 1,000 cases to North America each year. In some areas of Africa, Asia, and South America, malaria is not only a serious health problem, but also a threat to economic development.
Yellow fever and dengue are also serious diseases carried by mosquitoes. In the early 1900s, the southern coast of the United States was considered a bad place to live. Many villages and towns were quarantined because of outbreaks of yellow fever. Improved living standards (screens, using piped water) and pesticides controlled the problem.
In 1986, the tiger mosquito, a kind that can transmit encephalitis, dengue, and other viral diseases to humans, was introduced into the United States via shipments of used tires. When cases of encephalitis were diagnosed, several Florida towns canceled outdoor football games because of the fear of spreading the disease. These mosquitoes are now found in 24 states. They breed around houses in old tires and bird baths.
Your pets also may get diseases from mosquitoes. Horses get a type of encephalitis, and your dog may get heartworm.
Obviously, the main thing is to keep away from them and keep them away from you. Check around your house. Find old tires, cups, or cans? You can help by getting rid of them. Also, if you have a bird bath, change the water each week.
But mosquitoes may travel for miles, and you may not be able to avoid them. Spray! Yes, but beware when you bug off .
Sprays are powerful insecticides, but they can be dangerous to humans as well. In 1940, the insecticide DDT was introduced. People sprayed and it killed insects, bugs, and mosquitoes. But DDT later was found to have dangerous side effects, harming animals and threatening humans. In 1972, the U.S. government banned DDT. But, it is still used to control diseases in many parts of the world because of its low cost.
Look at your bug repellent. You will probably see the chemical DEET (diethyltoluamide) listed as the active ingredient. DEET is an effective repellent. But it too can harm people if it is not used properly.
What’s the answer? Natural oils have been used as insect repellents throughout history. Some companies are experimenting with products containing herbal oils such as citronella, cedarwood, eucalyptus, and lemongrass. The oils smell pleasant to humans, but insects hate them.
Scientists are developing innovative techniques, including new biodegradable chemicals. Releasing biological controls–parasites that kill mosquitoes in the various stages of development–is promising.
One scientist is building a better skeeter through genetic engineering. The genes are programmed so the mosquito cannot carry the malaria parasite. Only one problem: It will still bite.