False Black Widow, Cupboard Spider, Bitten Spider, Dark Comb-Footed Spider
Steatoda grossa
Theridiidae (Cobweb Spiders), Order Araneae. Key family traits include a 'comb' of serrated bristles on the fourth leg and the construction of messy, three-dimensional tangle webs.
Physical Description
The specimen is a male (indicated by the enlarged, bulbous pedipalps). It features a dark, reddish-brown to blackened cephalothorax and a bulbous, slightly flattened abdomen. The legs are slender, lacking heavy spines, and are somewhat translucent with darker joints.
Size Estimate
Estimated body length of 5-8mm for this male; leg span approximately 20-30mm. Females are significantly larger and more bulbous (6-11mm body length).
Coloration & Markings
Deep purplish-brown to black-brown base. The abdomen features a characteristic pale, crescent-shaped band on the anterior (front) edge and several lighter, teardrop-shaped spots or chevrons along the dorsal midline. Unlike true Black Widows, it lacks a red hourglass.
Web Type
Tangle web or 'cobweb'. A messy, irregular structure of sticky silk often built in corners, cupboards, or under furniture. It lacks the geometric symmetry of an orb web.
Eye Arrangement
8 eyes in two rows. They are typically small and difficult to see without magnification, characteristic of the Theridiidae family which relies more on web vibrations than vision.
Leg Characteristics
Long, spindly legs; the first pair is typically the longest. They appear smooth to the naked eye but possess a comb-like row of bristles on the tarsi of the fourth pair of legs used for swathing prey in silk.
Venom & Safety Information
Venom Information
Neurotoxic venom (alpha-latrotoxin-like), but significantly less potent than true widows. While it can cause systemic symptoms (steatodism), it is rarely a serious health threat to healthy adults.
Medical Significance
Low to moderate medical significance. Bites are rare and usually occur when the spider is pressed against skin. Symptoms include localized pain, redness, and occasionally nausea or lethargy. Treatment is typically symptomatic (ice and pain relievers).
Safety Recommendations
Relocate using the 'cup and paper' method if found indoors. To prevent sightings, reduce clutter in basements and seal cracks in foundations. Wear gloves when cleaning out dark storage areas.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; found worldwide. Highly synanthropic, preferring man-made structures like houses, basements, sheds, and garages. They favor dark, undisturbed corners.
Behavior & Temperament
Extremely timid and non-aggressive. They spend most of their time hanging upside down in their webs. If disturbed, they typically retreat to a crevice or drop to the ground ('play dead') rather than bite.
Diet & Prey
Generalist predators targeting crawling insects like beetles, pillbugs, and ants. They are also known to prey on other spiders, including the medically significant 'true' Black Widow (Latrodectus).
Seasonal Activity
Active year-round in temperature-controlled indoor environments. Males are most visible wandering indoors during the autumn mating season.
Description
A common 'basement spider' often mistaken for dangerous relatives. This male specimen is a prime example of the species' urban adaptability, using its dark, cryptic coloration to blend into shadows while waiting for prey to stumble into its sticky silk traps.
Key Features
Crescent-shaped pale marking on the front of the abdomen; lacks a red hourglass; bulbous pedipalps (in males); dark reddish-brown to purplish-black coloration.
Similar Species
Latrodectus mactans (Black Widow) is distinguished by the red hourglass; Steatoda nobilis (Noble False Widow) has a more distinct 'skull' pattern on the abdomen.
Life Cycle
Females produce round, white to off-white papery egg sacs. Spiderlings emerge after about a month. Males have a shorter lifespan and are often seen wandering in search of females during late summer and autumn.
Ecological Importance
Provides excellent natural pest control within the home environment, consuming nuisance insects like clothes moths, cockroaches, and silverfish.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread due to their success in human-altered habitats.
Interesting Facts
Steatoda grossa is a known predator of true Black Widows. In some regions, they have been nicknames 'Cupboard Spiders' because of their frequency in kitchen storage areas.
Photography Tips
Focus on the dorsal (top) pattern of the abdomen to confirm the crescent marking. Macro shots of the pedipalps can confirm the sex of the spider.
Identified: 2026-07-17T20:35:45.991270