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Brown recluse spider

life science Maturity 7-9 Next article →

The brown recluse, known scientifically as Loxosceles reclusa, is a specific type of spider found in North America. It is a member of the Sicariidae family. This spider is famous because it possesses necrotic venom. This means its venom can cause tissue to die. While many people fear them, the brown recluse is not an aggressive hunter. It is one of only two spiders in North America with venom considered dangerous to humans. The other is the black widow.

Brown-recluse-coin-edit
Brown-recluse-coin-edit

Physically, the brown recluse has several unique traits that help experts identify it. Most spiders have eight eyes arranged in four pairs. However, the brown recluse only has six eyes. These eyes are arranged in three pairs, called dyads. One pair is in the middle, and two pairs are on the sides. Another key feature is a dark marking on the cephalothorax, which is the front part of the spider's body. This mark looks like a violin, leading to nicknames like the fiddleback or violin spider. The spider's body color can range from whitish to dark brown or even blackish gray.

Loxosceles reclusa adult male 4
Loxosceles reclusa adult male 4

Understanding how the spider survives requires looking at its biology and behavior. The brown recluse is incredibly resilient. It can survive up to six months of extreme drought or a total lack of food. In one controlled study, a single spider lived for over five seasons without eating anything at all. This toughness helps them live in various habitats. They prefer dry, undisturbed areas like woodpiles, sheds, garages, and closets. They often seek out cardboard because it feels like the rotting tree bark they inhabit in the wild. Unlike many other web-building spiders, they leave their webs at night to hunt.

Life for a brown recluse follows a specific cycle. Adult spiders typically live for one to two years. Between May and July, a female will produce several egg sacs. Each sac contains approximately 50 eggs. These eggs hatch after about one month. The young spiderlings then take about one year to reach adulthood. One interesting way they defend themselves is through a process called autotomy. This is when the spider intentionally drops a leg to escape a predator or to stop venom from spreading. Unlike the huntsman spider, the brown recluse cannot grow a new leg after it is lost. Instead, it simply changes its gait to walk with the remaining legs.

Geography is a major part of the brown recluse's story, and it is often misunderstood. Their documented range is mostly south of a line from southeastern Nebraska through Illinois and Indiana to Ohio. In the south, they are native from central Texas to western Georgia. Many people believe they live in California, but this is a misconception. A large study in California looked at 581 spiders that people thought were brown recluses. Only one of them was actually a brown recluse. Most of the others were harmless spiders from the genus Titiotus. This shows how easy it is for people to misidentify spiders.

When a bite does occur, it can lead to a medical condition called loxoscelism. This happens because the venom contains a substance called sphingomyelinase D. There are two main types of this condition. Cutaneous loxoscelism affects only the skin, causing a necrotizing ulcer where the tissue dies. This wound can grow as large as 25 cm or 10 inches and may take months to heal. The other type is viscerocutaneous loxoscelism, which affects the whole body. This can cause fever, nausea, and vomiting. In very rare cases, it can even cause hemolysis, which is the bursting of red blood cells.

Brown-recluse-coin-edit
Brown-recluse-coin-edit

Most human contact with these spiders happens by accident. They usually bite only when they are pressed against the skin. This often happens when someone reaches into a shoe, a towel, or a piece of clothing that has been sitting undisturbed. Because they are not aggressive, they usually try to flee or even play dead when they feel threatened. By studying their specific habitats and physical markings, scientists and doctors can better distinguish them from other, harmless spiders. This helps prevent the many "false positive" reports that occur when people mistake common household spiders for the brown recluse.

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File:Loxosceles reclusa adult male 4.jpg
Loxosceles reclusa adult male 4.jpg
File:Brown-recluse-coin-edit.jpg
Brown-recluse-coin-edit.jpg
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