One of the 26 spiders on WAnimals

Arachnids · Araneae · Sicariidae

Brown Recluse

Loxosceles reclusa

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

The brown recluse, violin spider or fiddleback spider is a spider belonging to the genus Loxosceles of the family Sicariidae. It is a spider with a powerful necrotic venom and is one of the two spiders of medical importance in North America.

Size

up to 1.2 cm

Lifespan

2 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Nocturnal

Active mainly at night.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Unknown

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Fun facts

  • It has six eyes arranged in three pairs rather than the eight of most spiders: one of the most reliable features for identifying it.
  • It almost always bites by accident, when it gets trapped against the skin while someone is dressing or reaching into a box.
  • Far more recluse bites have been diagnosed than the species' actual distribution allows: a good share of them are in fact bacterial infections.
  • It is identified by a violin-shaped marking on the cephalothorax and, above all, by its eyes: it has six instead of eight, arranged in three pairs, a far more reliable feature than the violin.
  • Its venom contains phospholipases D, formerly known generically as sphingomyelinase D, which destroy cell membranes and cause the characteristic necrosis.
  • But the main problem with this species is overdiagnosis. Outside its real range, in the south-central United States, it is constantly blamed for necrotic lesions that have some other cause, and in states such as California this has reached the status of urban legend.
  • And that mistake has medical consequences: many of those lesions are in fact MRSA infections or other diseases, and treating them as a spider bite delays the correct diagnosis.
  • Most verified bites cause no necrosis: they amount to redness and itching and heal on their own.
  • Surgically excising the bite area to prevent necrosis is contraindicated and usually worsens the outcome.
  • It is retiring and bites only when trapped against the skin, typically while getting dressed or getting into bed.

Life cycle & biology

Skeleton type
Invertebrate - chitin exoskeleton (arachnid)
Habitat & environment
Corners, storerooms, boxes and dry cavities of houses in the central and southern United States

Sources consulted: https://es.wikipedia.org/wiki/Loxosceles_reclusa

Where to watch it

Parks and dive sites where this species has been documented.

Related species

Other species in the catalogue with the most in common with Brown Recluse — same habitat, park, country, tags or family.

Keep exploring

Based on what we already know about brown recluse.

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