Cupboard spiders

Details

Cupboard spiders commonly refer to comb‑footed spiders of the family Theridiidae that live inindoor corners, cupboards, garages and similar sheltered spaces. The best‑known species isSteatoda grossa, one of the so‑called “false widow” spiders. They spin a three‑dimensional tangle web with a small retreatand ambush passing arthropods.

Ecology & Biology

• Activity: mostly crepuscular to nocturnal; by day they hide in a crumpled retreat within the web.

• Diet: insects and other spiders, occasionally larger arthropods, subdued with sticky silk and rapid wrapping.

• Reproduction: females suspend several egg sacs within the tangle; juveniles initially remain near the maternal web before dispersing.

Identification

• Body size: females typically 6–10 mm, males 4–6 mm (excluding legs).

• Colour: generally dark brown to purplish‑brown/blackish with paler abdominal markings; ventral surface may be lighter.

• Form: ovoid to slightly globose abdomen, relatively slender legs; leg IV bears a      tarsal comb used to flick sticky silk.

Range & Habitat

Steatoda grossa is thought to be native to parts of the Old World but is now widespread inEurope, North America, Australia, New Zealand and elsewhere. It favours cupboards, sheds, garages, basements, eaves and fence lineswhere disturbance is low and prey is available.

People & Safety

• Medical relevance: overall low to moderate. Bites may cause local pain, redness and swelling, and in some cases mild systemic symptoms, but are usually      much less severe than true widow (Latrodectus) bites.

• Advice: keep clutter down, clean corners and remove old webs; if spiders must be moved, use a      cup‑and‑card and relocate outdoors. Wash and monitor any suspected bite and seek medical advice if symptoms persist or worsen.

IUCN: Steatoda grossa and related species are currently Not Evaluated (NE).