comb-footed spider

arachnid

Also known as: Theridiidae, cobweb weaver, tangle-web spider

Written and fact-checked by

Britannica Editors

History

Taxonomy

Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Theridiidae

See also list of spiders.

comb-footed spider, (family Theridiidae), any of more than 2,500 species and around 130 genera of spiders distributed around the world. The webs of comb-footed spiders consist of an irregular network of threads from which the spider often hangs. The common name of the group is derived from a row of bristles on the tarsus, or “foot,” of the hind legs, which are used to throw silken strands over prey to ensnare it.

Major genera are Theridion, which includes the Hawaiian happy face spider (T. grallator); Parasteatoda, which includes the common American house spider (P. tepidariorum); Achaearanea; and Latrodectus, the black widows.

One Propostira species, discovered in 2026 and yet to receive its species epithet, uses a specialized “ballista” to launch Asian weaver ants (O. smaragdina) into its snare. The spider constructs a cone-shaped trap of tightly bundled silk lines attached to an anchor point, and applies a pheromone. When an ant bites through the silken cone, the stored tension launches the ant more than 30 cm (12 inches) into the spider’s web at remarkable speed, where it is ensnared and eaten.