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brown recluse spider on floor

AUBURN UNIVERSITY, Ala. – Spiders are beneficial to the environment. Fear of these arachnids is common, but—believe it or not—most spiders cannot hurt humans. However, the brown recluse spider is a dangerous exception.

Identification

The recluse spiders, commonly known as fiddle-back or violin spiders, belong to a variety of spiders in the genus Loxosceles. The most common and most famous species in the United States is the brown recluse spider, Loxosceles reclusa. These arachnids carry this name because of the violin-shaped marking on the dorsal surface of the cephalothorax (i.e., fused head and thorax).

Not every spider that is brown is a recluse. They are identified by their number and pattern of eyes. If you can get close enough, you can determine which species of spider you are observing. The brown recluse has six eyes arranged in three pairs in a semicircular pattern. Sac spiders and funnel weaver (hobo) spiders have eight eyes arranged in two rows of four.

Habitat

The brown recluse spider is typically located throughout Alabama but is more commonly found in the state’s northern half. Preferred habitats are dry areas such as caves, rocks and log piles. However, these spiders can also be prone to moving into your home.

“Brown recluses are attracted to homes not because they are after you, but because they are after your home’s insects,” said Alabama Cooperative Extension System Entomologist Xing Ping Hu. “They can easily get into houses through cracks in foundations, around exterior doors, vents and even under eaves and soffits.”

These arachnids have adapted to living indoors by residing in areas without air conditioning or ventilation. These areas may include a furnace, water heater, bathrooms behind toilets and tubs and basements. They remain active in temperatures ranging from 45 to 110 °F.

Behavior and Life Expectancy

The brown recluse earns its name because of its shy nature. During the daytime, they will remain in hidden, reclusive locations that are typically in dark areas. At night, the spider will wander for prey. They are often found when moving from their retreat because of hunger, pesticide applications, overcrowding or disturbances.

This spider also dislikes conflict. When threatened, they usually flee but are still able to inflict a bite in defense. Brown recluse fangs are tiny, so they are not able to pierce clothing. Humans are usually bitten by one while putting on shoes, rolling onto them while sleeping and moving items that the spider uses as a home.

Unlike most spiders, brown recluses do not construct webs to catch prey. Instead, they build flat webs called retreats consisting of silk strands. Recluses have remarkable survival skills as well. For example, they can live up to 12 months without food and water. The maximum life expectancy for a brown recluse is a maximum of four years.

What to do When Bitten

brown recluse spider bite

Brown recluse bite. (Photo credit: Centers for Disease Control and Prevention).

A bite from a brown recluse is not painful initially; it is the aftereffect that causes issues. Most bites typically heal within three weeks without complication. However, in some cases, it can cause defections of the skin.

The venom from the recluse is a potent cytotoxin that can cause necrotic lesions that could take months to heal. Observe the bite area for a flat or sunken bluish patch with irregular edges.

Initial first aid to a bite should include using an ice pack to prevent or reduce swelling. This will also help the burning sensation after receiving a bite and lessen tissue damage.

Hu says that all brown recluse spider victims should seek medical treatment from licensed doctors. If possible, capture the spider—dead or alive—and bring it to the doctor for species confirmation.

Brown Recluse Control

Recluses can be difficult to control once established in a home. If chemical treatment is preferred, it is recommended that it be conducted by a professional pest control service.

According to Hu, control of these arachnids requires an integrated pest management (IPM) plan. Review the checklist below to create a plan for your home.

  • Sanitation and preparation. Eliminate spider harborages by decluttering closets and storage rooms and areas. Also, eliminate spider food sources by cleaning off dead and alive insects.
  • Inspection. Thorough inspection with a bright flashlight to reveal the location and level of infestation is the first step in effective management. Inspection should focus on likely spider habitats. Indoors, look for spiders, egg sacs and shed spider skins in undisturbed storage areas. These places include closets, crevices behind furniture and beds, behind hanging pictures, clothing, shoes and especially storage containers and boxes. 
  • Monitoring. Sticky spider traps and flat glue boards are excellent non-chemical ways to aid visual inspection. Professional pest control services can also use flushing agents as a monitoring tool to locate breeding areas.
  • Exclusion. Deny the spiders access to homes and hiding places. Seal cracks and crevices in the structure where spiders may gain access to the house.
  • Chemicals. Pesticides labeled for spider control are often required for serious brown recluse infestations. Enlisting the services of a professional pest control operator is an option to be seriously considered when chemicals are to be applied.

More Information

Spiders are not for everyone. However, it is crucial to positively identify venomous species such as the brown recluse. To learn more about spiders as well as other insects you may find around your home, visit the Alabama Extension website at www.aces.edu.

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