Cupboard Spider, False Black Widow, Dark Comb-Footed Spider
Steatoda grossa
Family Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
The specimen features a bulbous, globose abdomen characteristic of the cobweb spider family. The cephalothorax is smaller and flatter. The texture appears smooth and slightly glossy. In this light, the abdomen shows a distinct pattern of pale, crescent-shaped markings on a darker base.
Size Estimate
Based on the cup and cigarette pack for scale, the body length is approximately 6-10mm with a leg span of about 20-25mm. This appears to be an adult female or a sub-adult.
Coloration & Markings
Deep purplish-brown to black base color. A distinctive pale or white crescent-shaped band is visible on the anterior portion of the abdomen, often followed by triangular or chevron-like spots further back.
Web Type
Tangle web or 'cobweb'. It consists of a messy, multi-dimensional scaffold of sticky silk, usually built in dark corners, under furniture, or in crevices.
Eye Arrangement
Typical Theridiid arrangement: eight eyes in two rows of four. The eyes are generally small and of similar size, though difficult to see without extreme macro photography.
Leg Characteristics
Long, slender legs. The legs are typically darker or equal in tone to the cephalothorax and feature a 'comb' of serrated bristles on the tarsus of the fourth leg for throwing silk over prey.
Venom & Safety Information
Venom Information
Contains latrodectine-like venom, which is neurotoxic but much less potent than that of true black widows (Latrodectus).
Medical Significance
Low to moderate danger. Bites are rare and usually occur when the spider is pressed against skin. Symptoms (steatodism) may include localized pain, swelling, and occasionally mild nausea or malaise, lasting 1-6 hours.
Safety Recommendations
Relocate using the 'cup and paper' method if found indoors. Wear gloves when cleaning out dark sheds or under-sink areas to avoid accidental 'pinch' bites.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; found worldwide. Highly associated with human habitation, preferring cupboards, basements, sheds, and shaded outdoor areas like the porch furniture seen here.
Behavior & Temperament
Sedentary ambush hunter. They are generally timid and prefer to retreat into a crevice when disturbed rather than bite. They are most active at night.
Diet & Prey
Generalist feeder on crawling insects, pillbugs, and other spiders. They use their strong silk to entangle prey much larger than themselves.
Seasonal Activity
Active year-round in temperature-controlled indoor environments; peak activity and mating typically occur in summer and autumn in outdoor settings.
Description
A common 'house spider' often mistaken for its more dangerous widow cousins. This spider is a master of the dark, cluttered corners of human dwellings, providing free pest control by catching ants and roaches.
Key Features
Bulbous abdomen, dark coloration with pale crescent markings, lack of a red hourglass, and the presence of a cobweb.
Similar Species
Latrodectus (Black Widow) - distinguished by the red hourglass; Steatoda nobilis (Noble False Widow) - distinguished by a more 'skull-like' pattern on the abdomen.
Life Cycle
Females produce several round, white/papery egg sacs. Spiderlings disperse via ballooning. Females can live for several years, while males have much shorter lifespans and die shortly after mating.
Ecological Importance
Significant urban predator for pest control. They regulate populations of insects that are often considered nuisances in homes.
Conservation Status
Not evaluated by IUCN; stable and common globally due to its adaptability to human structures.
Interesting Facts
The False Black Widow is known to prey on true Black Widows. They are also being studied for their silk's mechanical properties, which are remarkably strong for their size.
Photography Tips
Focus on the dorsal (top) pattern of the abdomen for identification. Use a soft flash to bring out the subtle purplish hues against the dark body.
Identified: 2026-07-12T21:02:26.258576