COLLEGE STATION Spiders may have a place in the great scheme of things helping keep the insect population down and so forth but people don’t want that place to be in their own homes.
Spiders’ reputation as scary beasts is far bigger than their real role in ecology. In the Texas Cooperative Extension publication, “Spiders,” (L-1787), Dr. J. A. Jackman, Extension entomologist, wrote: “Their beneficial role in keeping insect populations in check far outweighs the hazard posed by the few spiders that occasionally bite humans. Very few of the nearly 900 species of spiders in Texas can hurt people.”
However, it’s those “very few” spiders that can harm humans that cause all the confusion and panic.
Although Jackman reassured consumers that tarantulas, jumping spiders and wolf spiders, among others, aren’t particularly dangerous to people, he goes on to warn that recluse spiders and black widow spiders are.
Jackman listed five species of recluse spiders that have been found in Texas: Loxosceles apachae, L. blanda, L. devia, L. reclusa and L. rufescens. The best-known of these, he went on, is the brown recluse spider, L. reclusa. Brown recluse spiders can be identified by their six eyes, in three pairs, which are in a semi-circle on the front of the head. “The violin-shaped marking, often used to identify recluse spiders, is on the first body segment, not the second,” he said, “and it is not always visible.
It (the marking) can be a solid brown color.” The spiders themselves can vary from orange-yellow to dark brown in color, Jackman wrote. “Recluse spiders are frequently found in garages, firewood piles, cluttered cellars and stored board piles,” he wrote. “They often live around human dwellings, in bathrooms, bedrooms and closets, under furniture, behind baseboards and door facings, or in corners and crevices.”
They are shy, however, and don’t necessarily want to have a confrontation with a much- larger human being, but if cornered, they may bite. “People are sometimes bitten while asleep,” Jackman went on, “apparently when rolling over on a spider while in bed. Others are bitten when putting on clothes that have hung undisturbed for a long time and where spiders are hiding.”
Brown recluse spider bites may cause little or no discomfort … or be much worse. It all depends on the bite victim’s sensitivity to the venom and the amount injected, Jackman wrote.
Possible effects include chills, fever, nausea, weakness, restlessness and joint pain, usually felt a day or two after being bitten.
The site of the bite is characterized by a small blister surrounded by a large red, swollen area. The venom can kill the tissue in the bite area, which then sloughs off and makes a larger wound.
Healing can take a long time six to eight weeks is not unusual and often leaves a scar.
The most common species of widow spiders found in Texas are: Latrodectus mactans, L. hesperus, L. variolus and L. geometricus (actually, a brown widow spider), Jackman wrote.
Although the traditional image of a jet black spider with a distinctive red hourglass shape on its underside is accurate, it’s a limited description. Jackman said that these spiders especially males and juveniles might have orange, red and white markings, and might not be jet black. As for the hourglass marking, “Some individuals have irregular or spot-like markings; others have none at all,” he wrote.
These spiders, too, might be found in dark secluded areas of human habitation, including garages and cellars, in and under furniture, in rain spouts or ventilators, in bushes around the house, or even in gas or electric meters, Jackman continued. And like recluse spiders, widows are only likely to bite people when they are cornered, he said.
If bitten, a person might feel something like a pin prick, Jackman wrote, with two red spots in the center of slight red local swelling. Within one to three hours, the pain can become intense and last for as long as two days. Symptoms can include nausea, vomiting, tremors, leg cramps and abdominal pain, elevated blood pressure, heavy sweating and loss of muscle tone.
If that wasn’t bad enough, the effects of this spider’s bite can get worse. “The toxin can also cause breathing difficulties and sometimes unconsciousness,” Jackman wrote. “However, less than 1 percent of people bitten by widow spiders die.”
WHAT TO DO?
For first aid, use ice packs to reduce the swelling and rubbing alcohol to clean the area, and get to a doctor immediately. If at all possible, catch and kill the spider (don’t squash it so bad it can’t be identified), and take it along so the doctor will know exactly what caused the bite.
But to keep these spiders out of the house in the first place, Jackman offered these suggestions:
– Learn which spiders are dangerous and which ones are not. That way, helpful spiders found in the house can be gently caught and put outside, where they belong.
– Keep closets and other dark enclosed areas vacuumed and cleaned. If these areas aren’t quiet and undisturbed, spiders won’t nest in them.
– Use caulk, screening and weather stripping to close up little spider-sized holes and prevent them from entering.
– Tape up or seal boxes that will be put in storage areas, especially those areas already infested with brown recluse spiders. This kind of seal can help keep spiders out of the boxes.
– If possible, hose down the outside of the house, especially under the eaves.
– In general, chemical treatments to remove webs are not justified. Instead, remove them with a broom or stick.
– Consult a professional if the spiders especially brown recluse are difficult to control. Spiders do have a place in the earth’s ecological system. These tips can help insure that place remains … outside.
Copies of this publication are available at county Extension offices.