Cupboard Spider, False Black Widow, Dark Comb-Footed Spider
Steatoda grossa
Theridiidae (Cobweb Spiders), Order Araneae. Characterized by a comb of serrated bristles on the tarsus of the fourth leg used for throwing silk.
Physical Description
A medium-sized spider with a bulbous, globose abdomen and a smaller cephalothorax. The abdomen is glossy and somewhat leathery in texture. Females are significantly larger and rounder than males, which have more slender bodies and longer legs.
Size Estimate
Body length 6-10 mm for females, 4-6 mm for males. Total leg span can reach 25-30 mm. This specimen appears to be an adult female.
Coloration & Markings
Dark purple-brown to nearly black base color. It features a distinctive pale, crescent-shaped band on the anterior of the abdomen and several light-colored spots or 'dimples' arranged dorsally. Unlike true widows, it lacks a red hourglass.
Web Type
Tangle web or 'cobweb'. A messy, three-dimensional scaffold of sticky silk usually built in dark corners, under furniture, or in cupboards. It often includes a tubular retreat.
Eye Arrangement
8 eyes in two rows of four. The eyes are small and typical of the family Theridiidae, grouped closely on the front of the cephalothorax.
Leg Characteristics
The legs are slender, tapering, and typically darker than or the same color as the cephalothorax. They lack heavy spines. The fourth pair of legs features a tarsal comb for silk manipulation.
Venom & Safety Information
Venom Information
Neurotoxic venom, though significantly less potent than that of the Latrodectus (true widow) genus. It contains alpha-latrotoxins but in much lower concentrations.
Medical Significance
Low to moderate medical significance. Bites can cause localized pain, swelling, and occasionally mild 'latrodectism' symptoms like malaise or nausea, but they are not life-threatening. Symptoms usually subside within 1-5 days.
Safety Recommendations
Use gloves when cleaning out dark areas or moving stored boxes. If bitten, clean the area with soap and water and apply a cold compress. Seek medical attention only if severe systemic symptoms develop.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; found worldwide in temperate regions. Common in and around human dwellings, basements, sheds, and garages. Prefers dark, undisturbed crevices.
Behavior & Temperament
Sedentary and nocturnal. It spends most of its time in its web. Generally shy and non-aggressive; it will usually retreat or play dead (thanatosis) if disturbed. Bites are rare and usually occur when the spider is pressed against skin.
Diet & Prey
Generalist predator of crawling and flying insects. Known to be a significant predator of other spiders, including true black widows and various household pests like woodlice and beetles.
Seasonal Activity
Active year-round in climate-controlled indoor environments. Outdoors, peak activity and mating occur during late summer and autumn.
Description
A common 'cobweb spider' often mistaken for dangerous relatives, the Cupboard Spider is a master of the dark corners of the home. Its glossy, dark abdomen and messy web make it a frequent companion in closets and garages.
Key Features
Glossy bulbous abdomen, crescent mark on the front of the abdomen, lack of red hourglass, and the presence of pale dorsal spots.
Similar Species
Latrodectus mactans (Southern Black Widow) which has a red hourglass; Steatoda nobilis (Noble False Widow) which has more elaborate 'skull' markings on the abdomen.
Life Cycle
Females can live up to 6 years. They produce round, papery, white-to-cream colored egg sacs containing 40-100 eggs. Spiderlings disperse via ballooning. Mating involves complex chemical signaling via pheromones.
Ecological Importance
Acts as an effective natural pest control agent within human structures, consuming large quantities of nuisance insects and other spiders.
Conservation Status
Not evaluated by IUCN, but widespread and common with stable populations throughout its range.
Interesting Facts
Steatoda grossa is a known natural enemy of the Black Widow spider and will actively hunt and displace them. It is one of the longest-lived spiders commonly found in households.
Photography Tips
Focus on the dorsal side of the abdomen to capture the crescent and spots. Use a macro lens and diffused lighting to manage the high reflections from the glossy body surface.
Identified: 2026-07-06T22:08:33.859315