There are over 35,000 species of spiders worldwide, with about 3,000 occurring in North America. Many species of spiders are household pests. Where ever food is available, spiders are likely to be found. All spiders are predators, feeding on insects and other small arthropods. In the United States only two spider groups are considered dangerous to man, the black widow spiders and brown recluse spiders. Both of these groups are composed of several species.
Spiders are predators, paralyzing or killing their prey with venom. They typically feed by injecting a pre-digestive enzyme fluid into the body of the prey and then return later to suck in the digested liquid food. Spiders can live without food for several weeks to a few months.Most spiders are nocturnal or active at night and will generally scurry away if disturbed unless they are tending to an egg sac or young. During the day, they usually remain hidden and inactive in cracks and crevices or in their webs.
Usually, spiders bite only when provoked such as when squeezing or handling. Bites usually occur when cleaning out neglected places like basements, attics, garages or when putting on seldom-used clothing. Many spiders cannot penetrate human skin with their fangs and the bite of those that do usually result in no more than swelling and inflammation. The primary exceptions are the black widow and brown recluse spiders. Black widows produce a neurotoxin while the brown recluse produces a cytotoxin that will cause an ulcerating sore or lesion. Anti-toxins are available for both. Always consult a physician if a bite is suspected. Try to capture the specimen for positive identification to aid in possible treatment.
Spider control is a 5 step process.
- Inspection: The inspection may have to be made at night due to the nocturnal habits of spiders.
- Identification: This is important for proper control and potential medical treatment.
- Prevention: Making sure that the building is in good physical condition and that it is properly screened and sealed to prevent possible entry. Changing the lighting to off-building locations from mercury to sodium vapor lights or in the case of homes changing the bulbs near entrances to a yellow bulb may be a help in reducing attractiveness. If insects are attracted to your house then so will spiders. Keep shades drawn at night and try to avoid over-watering.
- Sanitation: Keeping the premises clear of debris such as boxes, papers and lumber. It is a wise precaution to wear protective gloves when cleaning areas of this type.
- Mechanical Measure: The key to control is timely removal of spiders, webs and especially egg sacs with a sealed vacuum. Once finished remove and dispose of the bag immediately.