Renee Gullo, age 13, of Fountain Valley, Calif., for her question:

IS THERE A MALE BLACK WIDOW SPIDER?

Generally speaking, spiders are helpful to man because they eat lots of harmful insects. There are more than 29,000 known kinds on earth, although scientists say the total is probably closer to 50,000, with many not being classified as yet. Some are smaller than pinheads, with king size honors going to the South American tarantula which measures 10 inches long.

All spiders have fangs, and most have poison glands. The poison is used to kill insects and other small animals and in most cases is not harmful to man. Six spiders, however, are found in North America that have bites harmful to humans. The six are the brown recluse spider, the sack spider, the black widow, the brown widow, the red legged widow and the varied widow.

The ''widow'' spider is given the name because only the female of the species is known to bite man. Also, the female sometimes kills the male shortly after mating.

There is both a male and a female black widow spider, but the female is the one considered to be the most dangerous spider in North America. Its poison can definitely cause severe illness and great pain.

Many people say the black widow spider can kill humans. It is true that deaths from bites have been reported, but usually they are the result of complications and not from the bite itself. Great care should be taken to avoid bites; and if the worst happens, medical aid should be sought quickly. The best method is to simply avoid the spider if you suspect it might be a black widow, even though only a hurt or frightened spider will bite a human.

The female black widow has a shiny black body that is about the size of a large pea. The underside of her abdomen has a red or yellow mark that looks very much like an hourglass. The male is only about a fourth the size of the female and has no colored spot.

Black widow spiders weave shapeless webs in dark nooks. You'll find them usually in corners of sheds, barns or other buildings near homes.

A black widow spider doesn't attack a person without warning. Usually she will try to hide in her web if she is frightened. However, if she accidentally becomes caught in a person's clothing, she may bite in fear.

Black widow spiders can be found in nearly every state in the United States and in every province in

Canada. However, the Southern states is where they are most common. The brown widow, a close relative, is found in Florida.

There are no bones in a black widow or other spiders. A tough outer skin serves the purpose of a skeleton.