Western Black Widow (juvenile/subadult), Hourglass Spider
Latrodectus hesperus (likely), Latrodectus mactans (potential)
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
A globose abdomen that is disproportionately larger than the cephalothorax. The surface is smooth and shiny. In this subadult phase, the abdomen is elongated rather than perfectly round. The cephalothorax is dark and relatively small.
Size Estimate
Body length 8-12mm; leg span approximately 25-35mm. This appears to be a subadult female based on the remaining dorsal patterns and emerging dark coloration.
Coloration & Markings
Jet black base coloration on the legs and cephalothorax. The dorsal (top) of the abdomen features a series of striking red-to-orange spots or chevrons arranged vertically, flanked by white or pale borders. The characteristic red hourglass is on the underside (ventral) and not fully visible here.
Web Type
Tangle web or cobweb. These are irregular, messy-looking structures made of exceptionally strong silk, usually built in dark, recessed areas near the ground.
Eye Arrangement
Eight eyes arranged in two rows of four. The lateral eyes are widely separated from the median eyes, typical of the Theridiidae family.
Leg Characteristics
Long, slender legs with the first and fourth pairs being the longest. Proportionately thin compared to the body. Features a comb-like row of bristles on the hind tarsi used for swathing prey in silk.
Venom & Safety Information
Venom Information
Contains potent neurotoxins (alpha-latrotoxin). The venom affects the nervous system, causing the release of neurotransmitters. Potency is high but volume injected is small.
Medical Significance
Medically significant. Bites can cause latrodectism, characterized by severe muscle pain, abdominal cramps, and sweating. While rarely fatal to healthy adults, medical attention should be sought, especially for children or the elderly.
Safety Recommendations
Wear gloves when moving woodpiles or cleaning garages. If found on furniture, use a glass and paper to relocate the spider to a distant area away from the home. Do not handle with bare hands.
Habitat & Behavior
Habitat & Range
Common across North America; Latrodectus hesperus is dominant in the Western US/Canada. Found in cluttered areas, garages, crawl spaces, woodpiles, and under outdoor furniture.
Behavior & Temperament
Extremely shy, reclusive, and non-aggressive. They prefer to flee or drop from their web when disturbed. They typically only bite when squeezed or pressed against skin.
Diet & Prey
Generalist predators consuming beetles, cockroaches, crickets, and other spiders. They use their strong silk to entangle prey before delivering a paralyzing bite.
Seasonal Activity
Most active during late summer and autumn when females reach maturity and males wander in search of mates. Overwinters as subadults or eggs.
Description
This stunning subadult female represents one of the most famous arachnids in the world. Often feared, she is actually a master of pest control, sitting quietly in a corner while waiting for nuisance insects. Her transitional markings—the red spots along her back—will eventually fade into a solid, glossy black as she matures.
Key Features
Glossy black body, red dorsal spots (in juveniles), long slender legs, and the presence of a red hourglass on the ventral side.
Similar Species
Steatoda grossa (False Black Widow) which lacks red markings; Latrodectus variolus (Northern Black Widow) which has a broken hourglass.
Life Cycle
Females produce tan, papery egg sacs containing up to 400 eggs. Juveniles are much lighter (tan/white) and gradually darken to black through successive molts. Lifespan is typically 1-3 years.
Ecological Importance
Critical for controlling populations of disease-carrying insects like cockroaches and various agricultural pests.
Conservation Status
Stable; not listed as threatened. They thrive in human-altered environments.
Interesting Facts
The silk of a black widow is proportionately stronger than steel. Contrary to popular myth, females do not always eat the males after mating; this behavior is more common in laboratory settings than in the wild.
Photography Tips
Focus on the dorsal markings to confirm age/species. Use a macro lens or 'Portrait' mode from a safe distance (12+ inches) to capture the contrast between the red spots and black body.
Identified: 2026-05-28T22:34:32.516452