Brown Recluse Spider
Loxosceles reclusa

What are brown recluse spiders?
The brown recluse spider is one of two dangerously poisonous spiders found in the United States. Although brown-recluses are non-aggressive, disturbing them can cause them to bite and release very potent venom. Fatalities are rare, but are much more common amongst children, the sick, and the elderly.
Throughout the years, the brown recluse has been known by a variety of different names including the violin spider, the fiddleback spider, the recluse spider, and the brown spider.

How do I identify one?
Brown recluse spiders measure approximately ¼” to ½” and have long, delicate grayish to dark brown legs with short, dark hairs. Their leg span is about the size of a half dollar.
There are two major characteristics of brown recluses that make them readily identifiable. The first major characteristic is the presence of six eyes arranged in a semicircle on the forepart of the head. The second major characteristic is a dark violin-shaped marking located immediately behind the eyes. There are many other species of spiders that feature these identifying characteristics but do not otherwise resemble brown recluses. For example, spitting spiders are similar to the recluses in that they have six eyes, but they have many black spots and lines on their bodies that recluses do not have. The woodlouse spider also has six eyes, but has no violin shaped marking. Many tan and gray spiders have dark markings on the head region. These similarities lead to confusion when people are trying to determine the presence of brown recluses. Virtually every spider that is tan or brown has been turned in to entomologists as a possible brown recluse..

Where do they live?
Brown recluses, exactly as their name suggests, are reclusive. They are nocturnal creatures that will spend time hiding out in quiet places during the day such as bathrooms, bedrooms, closets, basements and cellars. They may also take shelter under furniture, appliances, and carpets, behind baseboards and door facings, or in corners and crevices. Some have even been found in stored clothing, old shoes, on the undersides of tables and chairs, and in folded bedding and undisturbed towels stored for long periods of time. It is when people disturb these reclusive spiders that they get bitten.

Can you tell me a bit about their biology?
Brown recluse spiders spin small, loose, and whitish webs with irregular strands. The females lay eggs from May to August in off-white silken cases, or sacs, that measure approximately 1/3” in diameter. Sacs contain 40 or more eggs and are hung in the web, which is guarded by the female. Each female may lay as many as 300 eggs during her lifetime. Spiderlings emerge from the egg case in 24 to 36 days. Their development is influenced by weather conditions and food availability. Spiders can survive long periods of time without food or water and can live anywhere from 2 to 4 years. They are very adaptable and are known to be active in temperatures ranging from 45 to 100 degrees Fahrenheit.

What do I do if I get bit?
As mentioned before, people are usually bitten when they disturb a spider that is being reclusive. This usually happens when unused shoes or clothes are put on. After being bitten, the severity of a person’s reaction depends on the amount of venom injected and the person’s individual sensitivity to it. Effects may be immediate, delayed, or nonexistent. A person may not know they have been bitten until 2 to 8 hours after the event. Others who experience a severe reaction may feel a stinging sensation followed by intense pain. A small white blister usually appears at the bite site and is surrounded by a large, congested, swollen area. After 24 to 36 hours, a systematic reaction begins that is characterized by restlessness, fever, chills, nausea, weakness, and joint pain. The affected area enlarges, becomes inflamed, and the tissue is hard to the touch. The spiders’ venom contain an enzyme that destroys cell membranes in the wound area. Affected tissue gradually sloughs away, exposing underlying tissue. Within 24 hours, the bite site can erupt into a “volcano lesion,” which is a hole in the flesh resulting from damaged, gangrenous tissue.
The open wound can range in size from that of a nickel to the span of a hand. This sunken, ulcerating sore may heal slowly, taking 6 to 8 weeks. Full recovery from a bite may take several months and scarring may remain even after healing. In some cases, plastic surgery or skin grafting is needed.
If you are bitten, try your best to remain calm and if you can, collect the spider that bit you for identification. Get medical advice immediately by contacting either your physician, Poison Information Center, or hospital. Apply antiseptic solution to prevent infection and ice packs to relieve local swelling and pain directly on the bite area.

How do I keep from getting bit?
Since most bites occur when people put on clothes or shoes that have not been used for awhile, it is important to shake out these things before dressing. Do not go barefoot or handle firewood without gloves.
Eliminate clutter in the yard, basement, attic, and any outbuildings. Remove trash, old boxes, piles of lumber, old clothing and other unwanted items from around the house. Dust and vacuum thoroughly and frequently around windows, corners of rooms, under furniture, in storage areas and normally undisturbed places to get rid of spiders, webs, and egg sacs.
Install screens on doors and windows to prevent entry. Seal or caulk cracks and crevices where spiders can enter the house and wash off the outside of the house and under the roof eaves.