Comb‑footed platform spiders

IUCN

Scientific Name：Theridiidae (e.g., Parasteatoda, Steatoda)

Basic Information

Scientific classification

name：Comb‑footed platform spiders
Scientific Name：Theridiidae (e.g., Parasteatoda, Steatoda)
Outline：Arthropoda
Family：Theridiidae Parasteatoda

Vital signs

length：Typically 3–10 mm (females larger)
Weight：Small spiders; varies by species
lifetime：About 1–2 years (environment‑dependent)

Feature

Platform tangle with gumfoot lines; leg‑IV tarsal comb flings silk; crepuscular–nocturnal ambush.

Distribution and Habitat

Cosmopolitan; eaves, frames, sheds, fences and shrubs where wind is low and prey is frequent.

Appearance

Ovoid/spherical abdomen; variable colours (brown/grey/black/pale); some with glassy/metallic sheen.

Details

Comb‑footed platform spiders refer to members of the family Theridiidae that build aplatform‑like three‑dimensional tangle fitted with gumfooted lines—sticky vertical threads anchored to the substrate. When insects strike these lines they are snapped up toward the platform, where the spider uses thetarsal comb on leg IV (serrated bristles) to fling adhesive silk and wrap prey. Representative genera includeParasteatoda and Steatoda.

Ecology & Biology

Foraging: platform tangle + gumfoot lines act as a trap‑and‑haul system for surface‑running insects.
Activity: mostly crepuscular–nocturnal; by day they rest in a retreat above the platform.
Reproduction: females place egg sacs within the web and guard briefly; juveniles linger near the maternal web.

Identification

Body size: typically 3–10 mm (females larger).
Key trait: a tarsal comb on the fourth leg used to fling sticky silk; abdomen often ovoid/spherical.
Colours: variable—browns, greys, blacks and pale morphs; some species show a glassy/metallic sheen.

Range & Habitat

Theridiids are cosmopolitan. Platform‑type webs occur around eaves, window frames, sheds, fences and in vegetation where wind is reduced and prey traffic is high.

People & Safety

Medical relevance: as a group‑level entry, most platform‑building theridiids are of low medical importance to people (excluding a few high‑profile exceptions not covered here).
Advice: minimise night lighting that attracts insects and remove old webs; relocate spiders gently with the cup‑and‑card method if needed.

IUCN: many species are unassessed; marked here as Not Evaluated (NE).