Cupboard Spider, False Black Widow, Dark Comb-Footed Spider
Steatoda grossa
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
A robust, glossy spider with a characteristic bulbous, teardrop-shaped abdomen and a smaller, oval cephalothorax. The surface is smooth and shiny, with a leather-like texture on the abdomen. Females are significantly larger and more spherical, while males are more slender with longer legs.
Size Estimate
Body length typically 6–11 mm for females, 4–6 mm for males. Total leg span can reach 15–25 mm. This specimen appears to be an adult female.
Coloration & Markings
Deep purplish-brown to nearly black base color. It features a pale, crescent-shaped band on the anterior (front) of the abdomen and a series of pale, triangular or chevron-like spots along the dorsal midline. These markings can fade with age, making older females look solid dark brown or black.
Web Type
Tangle web or 'cobweb'. It consists of a messy-looking, three-dimensional scaffold of sticky silk, typically built in corners, under furniture, or in crevices. The spider usually hides in a retreat at the edge of the web.
Eye Arrangement
Eight eyes arranged in two rows. The eyes are small and relatively equal in size, typical of the Theridiidae family, though not easily visible in the provided photo.
Leg Characteristics
Legs are spindly but strong, typically reddish-brown or dark brown. They lack prominent spines but have fine hairs. The fourth pair of legs has a distinct 'comb' of serrated bristles used to wrap prey in silk.
Venom & Safety Information
Venom Information
Contains latrodectism-like toxins (alpha-latrotoxin), but in much lower concentrations and potency than true Black Widows. The venom is designed to immobilize small invertebrates.
Medical Significance
Low to moderate medical significance. Bites are rare and usually occur when the spider is pressed against skin. Symptoms may include localized pain, blistering, or mild malaise lasting 1-2 days. It is not considered dangerous to healthy adults.
Safety Recommendations
Relocate using a jar and a piece of paper if found in high-traffic areas. Wear gloves when cleaning out dark cupboards or woodpiles. If bitten, clean with soap and water and apply a cold compress.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; found worldwide. Highly synanthropic, meaning it prefers living near humans in houses, basements, sheds, and garages. In the wild, it lives under stones or in tree hollows.
Behavior & Temperament
Sedentary and nocturnal. It is a shy, non-aggressive spider that prefers to flee or drop from its web when disturbed. It spends most of its time hanging upside down in its web awaiting prey.
Diet & Prey
Generalist predator of crawling insects, including beetles, woodlice, and ants. Notably, it is known to prey on other spiders, including more venomous species like the Black Widow.
Seasonal Activity
Active year-round in temperature-controlled indoor environments, though sightings often increase in autumn as they reach maturity and males wander in search of mates.
Description
The False Black Widow is a common household resident often mistaken for its more dangerous relatives. With its chocolate-brown, glossy body and messy webs, it serves as an excellent natural pest controller in homes, quietly snagging unwanted insects from dark corners.
Key Features
Glossy rounded abdomen; purplish-brown hue; pale crescent mark on the front of the abdomen; messy tangle web; lack of a red hourglass mark on the underside.
Similar Species
Latrodectus species (True Black Widows), which have a red hourglass; Steatoda nobilis (Noble False Widow), which has a more distinct 'skull' pattern on the abdomen.
Life Cycle
Females produce several white or off-white papery egg sacs throughout the year. Spiderlings emerge and may balloon to new locations. Lifespan can be up to 6 years for females; males live significantly shorter lives.
Ecological Importance
Plays a vital role in urban ecology by controlling indoor pest populations such as cockroaches and flies. It occupies a niche as a top predator among indoor invertebrates.
Conservation Status
Not evaluated by the IUCN; widespread and common with stable populations due to its adaptation to human environments.
Interesting Facts
This species is an effective competitor of the Black Widow and has been known to displace them in urban environments. It is often used as a 'look-alike' in film and television when a 'dangerous' spider is needed on set without the risk.
Photography Tips
Focus on the dorsal (top) pattern of the abdomen for identification. Use a macro lens or high-zoom setting with auxiliary lighting to highlight the glossy texture and subtle markings in dark corners.
Identified: 2026-06-15T01:27:50.436484