Swift Spiders, genus Nyssus

Swift spiders are in the genus Nyssus in family Corinnidae. Many Corinnidae are mimics of Hymenoptera species, and the common Nyssus species are no exception, being mimics of pompilid or mutillid wasps. There are two very common and widespread Nyssus species, N. coloripes and N. albopunctatus. These active ground spiders are often noticed running on the ground and up and over seats, handrails, logs etc.

Identification

Swift spiders range from 5 mm to 11 mm long. The two common swift spider species are black with a pattern of white or sometimes yellow spots and stripes, and N. coloripes often has yellow to amber front legs.

Swift spiders have eight eyes of similar size grouped in two bowed rows like paired parentheses ‘()’.

Habitat

Swift spiders occur across Australia, particularly in open forests but in habitats ranging from heath and grasslands to rainforest. The two common species are also found in New Zealand, where it is thought they have been introduced. Swift spiders are active hunters, but may have a retreat for shelter, moulting and producing an eggsac.

Distribution

Other behaviours and adaptations

Nyssus coloripes is the most commonly recorded species and occurs throughout Australia. This species is a mimic of pompilid wasps, which move in a characteristic stop-start manner through the leaf litter, their orange antennae waving to search out their prey. The yellow / orange front legs and black and white colour pattern of the spiders look similar, and spiders often pause under a leaf where their true identity is less visible when not in motion. The related species Nyssus albopunctatus is almost as common but lacks yellow front legs. This species is thought to mimic female mutillid wasps.

Danger to humans

These spiders occasionally bite people but effects are usually minor and resolve within a few minutes. They are not considered dangerous.