One of the 26 spiders on WAnimals
Arachnids · Araneae · Sicariidae
Brown Recluse
Loxosceles reclusa
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
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.
Chilean Recluse
Loxosceles laeta
Great Horned Owl
Bubo virginianus
Eastern Newt
Notophthalmus viridescens
Eastern Tiger Salamander
Ambystoma tigrinum
Southern Black Widow
Latrodectus mactans
American Mink
Neovison vison
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