Brown Recluse Spider, Fiddle-back Spider, Violin Spider
Loxosceles reclusa
Sicariidae (Six-eyed Sicariid Spiders), Order Araneae. Key family characteristics include the unique arrangement of six eyes in three dyads and the presence of venom containing sphingomyelinase D.
Physical Description
The brown recluse has a distinctively uniform, satin-like appearance. Its body is divided into a cephalothorax and abdomen. The cephalothorax features a characteristic dark violin-shaped marking with the neck pointing toward the rear. It lacks strong spines on its legs, appearing rather smooth and delicate.
Size Estimate
Body length typically ranges from 6 to 20 millimeters (0.24 to 0.79 inches), with a leg span up to 25 to 30 millimeters (1 inch). The specimen in the provided blurry jar image is heavily obscured by reflections and refraction, making exact sizing impossible.
Coloration & Markings
Color ranges from light tan to dark brown. The defining marking is the dark violin shape on the dorsal carapace. The abdomen is uniformly colored without prominent patterns, bands, or stripes.
Web Type
Irregular, loose, sticky retreat webs spun in dark, sheltered places such as woodpiles, under rocks, in basements, and closets rather than geometric orb webs.
Eye Arrangement
Six eyes arranged in three distinct pairs (dyads): one pair at the front and one pair on each side, which is a key diagnostic feature separating Sicariidae from most other spiders that possess eight eyes.
Leg Characteristics
Long, slender, and uniformly colored legs lacking prominent spines or distinct color banding. They are held out flat or slightly spread when resting.
Venom & Safety Information
Venom Information
Contains necrotic cytotoxins (specifically sphingomyelinase D) which destroy cell membranes, potentially leading to dermonecrotic lesions, localized pain, and slow-healing wounds.
Medical Significance
Medically significant. While many bites result in mild localized irritation, some cause significant necrotic skin lesions, blistering, and systemic symptoms (loxoscelism) requiring medical evaluation.
Safety Recommendations
Shake out shoes and clothing left on the floor, wear gloves when handling stored items in dark areas, and safely relocate spiders outdoors using a container if found.
Habitat & Behavior
Habitat & Range
Found primarily in the Midwestern and Southern United States, preferring dry, sheltered, undisturbed microhabitats such as under bark, rocks, logs, and indoors in dark corners, attics, and basements.
Behavior & Temperament
Reclusive, nocturnal hunters. They are non-aggressive and typically bite only when trapped against the skin by clothing, shoes, or bedding.
Diet & Prey
Insects including cockroaches, crickets, silverfish, and other small arthropods, captured via active nocturnal hunting around their retreat.
Seasonal Activity
Most active during the warmer spring, summer, and fall months, often moving indoors during winter seeking warmth.
Description
The brown recluse is a notoriously misunderstood inhabitant of dark, undisturbed spaces. While capable of delivering a medically significant necrotic bite, it is inherently shy and prefers to flee rather than fight when encountered.
Key Features
Six eyes arranged in three pairs, a distinct violin-shaped dorsal mark on the cephalothorax, uniform brown legs without banding, and lack of abdominal patterns.
Similar Species
Cellar spiders (Pholcidae), grass spiders (Agelenidae), and wolf spiders (Lycosidae). These can be distinguished by having eight eyes, different body proportions, or distinct abdominal patterns.
Life Cycle
Females produce several egg sacs containing around 50 eggs each during the warm season. Spiderlings undergo multiple molts, reaching adulthood in about a year, and can live for 2 to 4 years.
Ecological Importance
Serves as an effective natural predator of household pests and insects, helping to naturally regulate arthropod populations in its native range.
Conservation Status
Not evaluated by the IUCN, but populations are secure and widespread within their native geographic range.
Interesting Facts
Brown recluses can survive for months without food or water. Despite their reputation, they rarely bite unless directly compressed against human skin.
Photography Tips
Remove the spider from any distorted glass jars, use macro lenses with natural diffused lighting, focus sharply on the eye arrangement and dorsal carapace to capture the violin marking clearly.
Identified: 2026-09-06T06:05:37.781908