Alaska's State Insect
The mosquitoes are with us again. It is always a special pleasure in the early spring to swat those big, slow-moving ones because they are usually fertilized females who, having wintered over in chinks of tree bark or buildings, will soon be about their business of laying eggs to produce more of their own kind. Depending on the species of mosquito (and Alaska has many), the egg-laying can take place in pools of stagnant water, in tree holes or on moist ground.
Some species of Alaskan mosquitoes do not hibernate, but lay their eggs the previous year and leave the little darlings unattended to overwinter as best they can. They usually do pretty well. Although most varieties have a life span of only a few weeks to a few months, they can produce several generations over the course of a summer.
At this time of the year, the questions always arise: How do they find us and what can we do to keep them away? Many people have their own ideas of how to best combat this nasty little beast. They may range from burning incense to eating a tablespoon of brewer's yeast each day. Some have merit; some may not.
One of the most authoritative sources of information on the subject is an article by R. H. Wright in the July 1975 issue of Scientific American. According to Dr. Wright, the female mosquito (only the female feeds on blood--the males prefer plant juices) tracks its quarry by a "sniffing" mechanism which monitors heat, moisture and carbon dioxide content in the air. If a mosquito is downwind from a creature (such as a human) who emits these qualities, it will zig-zag upstream in the air flow until it finds the source. Mosquitoes do not have very good long range vision, and sight is not really a factor; but even if it were, the insect does not have the brains to distinguish between an animate and an inanimate object on the basis of sight alone. This is why we observe most mosquito "clouds" lying downwind from us. If a mosquito should wander out of the air flow passing our bodies, we have effectively eluded it, and it must start over again.
This is why mosquito repellents work. It is not that they smell bad to the insect--it is because the molecules which they contain block the sensing mechanisms that the mosquito carries in its antennae to detect heat, moisture and carbon dioxide. In other words, if an effective repellent is in the air, the mosquito gets lost on its track to the target.
What are the best repellents? Well, one of the favorites, oil of citronella (a grass of southeast Asia), is not very good, according to Wright. It requires a much higher concentration to be effective than some other organic compounds with horrible names such as diethyl toluamide.
In recent years, a number of products have come out which are touted as being the last word in mosquito repellent. Some, such as massive doses of vitamin B, are ingested and some are applied directly to the skin.
But there are many home remedies which people insist work as well. It would be interesting to gather together a list of favorite remedies and put them together in a single article. If readers of this column would submit their own or Grandma's favorite solution to the problem, I'll put them together for an entire column later in the year.
