False Black Widow, Cupboard Spider, Dark Comb-footed Spider, Bittle Spider
Steatoda grossa
Theridiidae (Cobweb Spiders), Order Araneae. Characterized by a comb-like row of serrated bristles on the tarsi of the fourth leg.
Physical Description
A medium-sized spider with a shiny, bulbous, globose abdomen and a smaller cephalothorax. The body is relatively hairless and smooth to the touch. Females have a larger, more rounded abdomen, while males are thinner with longer legs.
Size Estimate
Body length 6-10mm (females), 4-6mm (males); leg span approximately 15-25mm. This appears to be an adult female specimen.
Coloration & Markings
Dark purple-brown to blackish-brown base. Often features a pale, crescent-shaped band on the anterior of the abdomen and sometimes faint chevrons or spots. Unlike the true Black Widow, it lacks a red hourglass marking on the underside.
Web Type
Tangle web or cobweb. An irregular, three-dimensional scaffold of sticky silk strands often built in corners, under furniture, or in dark crevices.
Eye Arrangement
Eight eyes arranged in two rows of four. The eyes are relatively small and typical of the Theridiidae family, geared more toward sensing vibrations than clear vision.
Leg Characteristics
Slender, dark legs proportional to the body. The fourth pair of legs features a 'comb' of serrated bristles used to wrap prey in silk. Dark brown to black in color, matching the body.
Venom & Safety Information
Venom Information
Contains latrodectine-like toxins but is significantly less potent than true widows. The venom is neurotoxic but generally not life-threatening to healthy humans.
Medical Significance
Low to moderate significance. Bites may cause localized pain, redness, swelling, and occasionally mild nausea or malaise (steatodism). Symptoms typically resolve within 1-2 days without medical intervention.
Safety Recommendations
Wear gloves when reaching into dark corners or moving stored boxes. To relocate, use the 'cup and paper' method. If bitten, clean the area with soap and water and apply a cold compress.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution found worldwide. Highly synanthropic, preferring dark, sheltered areas inside homes, garages, basements, and sheds, or under rocks and bark in the wild.
Behavior & Temperament
Sedentary and non-aggressive. They are nocturnal hunters that wait in their webs for prey. If disturbed, they usually retreat to a corner or drop on a silk line. They only bite when squeezed or pressed against skin.
Diet & Prey
Generalist predator feeding on woodlice, crickets, flies, and other spiders. They can even subdue larger spiders, including true Black Widows, using their strong silk.
Seasonal Activity
Year-round activity in indoor environments; outdoors, they are most visible from late spring through autumn.
Description
The False Black Widow is a common household resident often mistaken for its more dangerous relative. With its glossy, dark abdomen and messy web, it plays a vital role as an indoor pest controller, silently patrolling dark corners for crawling insects.
Key Features
Bulbous dark abdomen, lack of red hourglass, pale crescent-shaped marking on the front of the abdomen, and 'comb-footed' tarsal bristles.
Similar Species
Latrodectus species (True Black Widows - have red hourglass), Steatoda nobilis (Noble False Widow - has 'skull' pattern), Steatoda borealis.
Life Cycle
Females produce several white to cream-colored, papery egg sacs throughout the year. Spiderlings emerge after about a month. Females can live up to 6 years, while males typically live 1-1.5 years.
Ecological Importance
Critical for natural pest control in human structures, consuming common household pests like cockroaches, ants, and beetles.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread; they are considered an introduced/invasive species in some regions.
Interesting Facts
They are known to prey on Black Widows in areas where their ranges overlap. Unlike many spiders, females can survive for months without food if necessary.
Photography Tips
Focus on the top of the abdomen to capture the crescent marking. Use a side profile to show the globose shape. Indirect lighting helps avoid harsh reflections on the shiny cuticle.
Identified: 2026-07-12T20:56:24.408663