Spring 2003

Spiders. Just mention the name and some people get the creeps. They imagine poisonous spiders everywhere. All spiders are poisonous to some degree in that they all have poison glands that produce toxins used to subdue or kill their prey. Most spiders are not only harmless, but play an important role in the balance of nature.

Fortunately, of the thousands of species of spiders, only a few are dangerous to humans. Only two, the brown recluse and the black widow, of the hundreds of species that have been found living in Mississippi are considered dangerous. All others either lack the biting power or the venom to cause much harm. The brown ere are the ones you should avoid at all costs.

The brown recluse is a common spider in Mississippi. It is found throughout Mississippi and in other southern states as well as in the Midwest and West. It is also known as the "fiddle-back spider" because of the characteristic and distinct dark, violin-sharped marking on its "back." A closely related species occurs in Central and South America.

The recluse is a medium-sized spider one-half to one inch in length, and yellow to brown in color. The body is flattened, with six eyes in a strongly curved row, and with long, slender legs.

As its name implies, this spider is seldom seen, although it may be locally quite abundant. It prefers dark, dry places such as barns, woodpiles, abandoned houses, brush piles, and such. It also likes closets, attics, boxes and bookcases in homes. In South America it is known as the "spider of the corners" and "spider behind the pictures," because of its occurrence on walls especially in the corner, behind pictures, in cracks, and sometimes in clothing that has been hung on walls.

Although this spider is reclusive and not aggressive, it may bite when cornered. Most cases of recluse bites in Mississippi occur in homes, while the victims are sleeping or dressing themselves.

A recluse bite may not be noticed at first. But within a few hours, pain or a burning itch begins at the site of the bite, and fever, weakness, vomiting, joint pain, or a rash may occur. An irregular, distinctly outlined, black, dry spot will soon form. Within twenty-four hours, the area around the spot will become red and inflamed, forming a characteristic "volcano lesion." This affected area may range from the size of dime to the span of a man's hand. Within a few days to a week the affected area will slough off leaving an open wound surrounded by the raised edge of healthy tissue.

Treatments vary, but they may be accompanied by the surgical removal of the damaged tissue. Skin grafting is sometimes necessary for large wounds. Symptoms or complications may last for several months, and scarring often occurs.

Although recluse bites are dangerous and painful, they are relatively uncommon. So remember - closets and attics are favorite homes for these spiders. Be sure to inspect or clean all clothes taken out of storage. There are several other common house spiders that are often mistaken for recluses, but only the recluse has a distinct violin-shaped pattern on its back. Be sure to seek immediate treatment if a recluse bite is suspected. Complications are less likely the sooner drug therapy can begin.

Many people have a strong fear of spiders. It is important to remember that although the brown recluse is dangerous, it is not aggressive. A large number of bites attributed to spiders are actually insects such as mosquitos, assassin bugs, and beetles. Most spiders are harmless, and all of them play an important role in nature.

This article was written by Paul Hartfield, an endangered species biologist with the U.S. Fish and Wildlife Service in Jackson, Mississippi.