As the name “recluse” suggests, these spiders are usually not aggressive. They prefer dark, undisturbed places near or on the ground for their webs, which are used for nesting, not for trapping prey. In fact, the typical web seen in visible areas such as a wall or eave is most likely not due to a brown recluse, but to other types of spiders that may even pursue the brown recluse as prey. Brown recluse spiders often live in dense clusters. Usually where one is found, there will be more. They are scavengers, prefering dead prey to live.
The nocturnal brown recluse spiders hunt for insects some distance from their webs. Contact with humans usually occurs because they have taken temporary refuge in clothing or bedding. Items left lying undisturbed on the floor, such as supplies, toys, or clothing, are perfect daytime refuges for these spiders. Such objects should be shaken out thoroughly if they have been on the floor or in a closet for any length of time.
Related Species
There are twelve or thirteen recluse spider species in the United States including the infamous Loxosceles reclusa, the brown recluse, which is most common in the midwestern and south-central states, and the Arizona brown spider, or the desert recluse, which is found in the southwestern desert states. The violin-like markings on the desert species are less obvious, but the bite, though not usually life-threatening, should be considered dangerous and can lead to severe tissue damage. Recluse spiders have also been reported in areas outside this range, sometimes hitchhiking in luggage or inadvertently sent in packaging.
Behavior
Like undisturbed places for their webs; hunt primarily at night and will take refuge in clothing and bedding; often found in unused closets and storerooms, behind furniture, and in baseboard cracks and crevices. Outside, they can be found in foundation cracks, cracks in the soil, and window wells. The brown recluse spider prefers food such as firebrats, crickets, cockroaches and other soft bodied creatures. Earning their name well, the brown recluse spider ceases its wanderings at first light.
The brown recluse is a non-aggressive spider and will only bite when disturbed. Usually, the brown recluse spider bite is not felt and the pain sets in from six to eight hours later. A typical bite area may resemble a pimple, pustule or blister formation from six to 12 hours later. The bites are unpleasant, producing an ulcerous wound called a necrotic lesion that turns dark within a day and takes a long time to heal. See Symptoms of Recluse Spider Bite below.
Ways to Control
Vacuuming behind furniture and stored articles, under baseboard heaters, and in closets will help eliminate habitat. Repair torn screens and broken windows, make sure doors shut tightly without gaps. If this spider is common in your area, do not store shoes, clothing, or bedding at ground level where spiders could become entrapped in these articles. Keep beds away from walls as much as possible, and do not use bed skirts that touch the floor. Do not store items under beds. Cut or eliminate long grass growing near foundations. Wear protective clothing when working outside in areas that might harbor spiders and inspect items that you pick up. Always check articles that you bring from outside storage sheds to make sure you don’t bring in spiders or their egg sacs.
Breeding
The female brown recluse spider deposits eggs in off-white silken cases about 1/3 inch in diameter in sheltered, dark areas. Spiderlings emerge in 24-36 days and abandon the egg case. Development is slow, influenced by weather conditions and food availability. They reach maturity in 10 to 12 months and can survive long periods of time without food or water. Immature spiderlings resemble adult brown recluse spiders but have lighter coloration. Spiderlings will molt several times on their journey to adulthood. Brown recluse spider moltings have a stiff appearance - discovery of this type of spider molting can be a useful indication of brown recluse infestation. Adult males and females will vary from light tan to dark brown.
Symptoms of Recluse Spider Bite
The recluse spiders' venom is a necrotoxin, which means it destroys tissue cells. A bite may initially cause a sharp sting or may cause no pain at all. Pain may develop within the first several hours, or even up to 6 to 8 hours after the bite, possibly becoming severe. The victim may experience general feelings of discomfort, malaise, or nausea, and sometimes intense itching.In severe cases there is sloughing off of the skin and formation of a blister, then an ulcer in the area of the bite. There may be a reddish to purplish color in a bullseye pattern to the skin area around bite, with a subsequent sloughing off of the skin, leaving a raw deep area of exposed tissue. These can take weeks to heal in some cases. Chills or fever and sweating may be experienced.
In rare cases:
Blood in urine
Jaundice
Kidney failure
Seizures
Coma
Home Treatment
Apply a cold pack, then seek immediate medical attention.
Before Calling Emergency
Before calling emergency, determine the following:
Patient's age, weight, and condition
Area bitten
Time bitten
Identify the spider, if possible.
The patient should be taken to the emergency room for treatment. The bite may not appear to be very severe and may take some time to progress to a more severe state. However, treatment is important to minimize complications. If possible, bring the spider to the emergency room for identification.
Poison Control, or a local emergency number
You will be instructed on what to do immediately following the bite. The patient should be taken to the emergency room.
For a POISON EMERGENCY call:
1-800-222-1222 ANYWHERE IN THE UNITED STATES.
This national hotline number will let you talk to experts in poisoning. This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
Expectations (prognosis)
Fatalities from brown recluse spider bites are more common in children. With proper medical attention, survival past 48 hours usually indicates that recovery will follow. The ulceration may take up to 6 weeks to heal, with proper care.
Sources:
National Library of Medicine
EPA
"BROWN RECLUSE SPIDER," Michael F. Potter, Urban Entomologist, University of Kentucky College of Agriculture, Department of Entomology, University of Kentucky
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