Robber Spiders

Argyrodes

Classification

Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Theridiidae
Genus: Argyrodes

Pronunciation

How to pronounce Argyrodes: /ˌɑːr.d͡ʒɪˈroʊˌdiːz/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Argyrodes elevatus mâle,bosse clypeale by LOPEZ André. Used under a CC BY-SA 4.0 license.

Bulletin of the Museum of Comparative Zoology at Harvard College (1962) (20497838891) by Internet Archive Book Images. Used under a No restrictions license.

Golden Silk Spider - Nephila clavipes and Argyrodes nephilae or elevatus, Dinner Island Ranch Wildlife Management Area, Florida by Judy Gallagher. Used under a CC BY 2.0 license.

Nephila clavipes and Argyrodes nephilae, Dinner Island Ranch Wildlife Management Area, Hendry County, Florida by Judy Gallagher. Used under a CC BY 2.0 license.

Argyrodes nephilae (Bermuda) by Sam Fraser-Smith. Used under a CC BY 2.0 license.

Summary

Argyrodes, also known as dewdrop spiders, are small, kleptoparasitic comb-footed spiders known for their unique feeding strategies and commensal relationships with larger orb-weaver spiders' webs.

Physical Characteristics

Most species are relatively small, many are black with silvery markings. The body shape is characteristic, often conical or triangular, with a shorter third pair of legs. A. incursus has a body length of 3 to 4.5 millimetres, while A. fissifrons measures about 12 millimetres.

Identification Tips

Look for small spiders residing on the outskirts of webs built by larger orb-weaver spiders, often with silver markings that may attract larger prey.

Habitat

Primarily found in tropical and subtropical environments, often inhabiting the webs of other spiders.

Distribution

Worldwide distribution with a concentration in the tropics. Species are found in the United States, particularly A. elevatus in the southern US, A. nephilae in Florida, and A. pluto from Maryland to Missouri, extending to Mexico and Jamaica.

Diet

Kleptoparasitic, feeding on small prey items caught in the webs of host spiders. Some species also feed on the host spider itself.

Ecosystem Role

Argyrodes spiders play a role in ecosystem dynamics as kleptoparasites, influencing prey dynamics within the host webs, and can also affect host spider populations.

Evolution

The genus was first described by Eugène Louis Simon in 1864 and shows adaptations that enable kleptoparasitic behavior, influencing its evolutionary course.

Misconceptions

A common misconception is that Argyrodes frequently steal significant prey from host spiders; however, research shows they usually restrict themselves to smaller, unwanted prey items.