Diagnostic characters
- Large abdomen relative to the cephalothorax, often ornamented with tubercles or shoulder humps
- Web is a flat vertical spiral on radial supports
- Hangs head-down at the hub of the web
- Three claws on each tarsus, the third used to manipulate silk
- Many species eat and rebuild the capture spiral each night
Habitat and seasonality
Gardens, shrub margins, tall grass, eaves, porch lights, bridge structures, and any site with anchor points and flying insect traffic.
Populations become conspicuous in late summer and autumn as females reach adult size. Most temperate species die after the first hard frost, overwintering as eggs.
Medical significance
Low. Bites require considerable provocation and produce brief local pain with no systemic or necrotic effects.
Web construction
An orb is built in a fixed sequence: a bridge line, a Y-shaped frame, radial spokes, a temporary non-sticky auxiliary spiral laid outward, then the viscid capture spiral laid inward while the auxiliary spiral is removed. A mature female can complete the structure in under an hour.
The capture spiral carries aqueous glue droplets from the aggregate glands. These droplets lose adhesion as they dry and accumulate debris, which is why most araneids consume and rebuild the spiral on a daily cycle, recycling the protein.
Stabilimenta
Several genera, most conspicuously Argiope, add dense zigzag bands of white silk to the hub. The function remains debated: proposed explanations include web advertisement to prevent bird damage, prey attraction through ultraviolet reflectance, camouflage of the spider's outline, and thermoregulation. Evidence supports more than one function depending on species and context.
The Joro spider
Trichonephila clavata, native to East Asia, was first documented in Georgia around 2013 and has since expanded across the southeastern United States. It is a large, conspicuous araneid with a golden three-dimensional web. Current evidence indicates no medical significance and no documented displacement of native orb weavers, though monitoring of its range expansion is ongoing.
Families most often confused with Araneidae
| Family | How to separate it |
|---|---|
| Tetragnathidae | Long-jawed orb weavers have elongated bodies and enormous chelicerae, and build a horizontal or inclined orb |
| Uloboridae | Hackled orb weavers lack venom glands entirely and produce fuzzy cribellate rather than viscid silk |
| Theridiidae | Cobweb weavers build irregular tangles, never a geometric orb |
Profiled species in this family
| Species | Scientific name | Medical significance |
|---|---|---|
| Joro Spider | Trichonephila clavata | none |
| Yellow Garden Spider | Argiope aurantia | none |
| Golden Silk Orb Weaver | Trichonephila clavipes | low |
References
- [1]World Spider Catalog, version 26 - Natural History Museum Bern. Accessed 2026-06-14.
- [2]Spiders of North America: An Identification Manual, 2nd ed. - American Arachnological Society. Accessed 2026-06-14.
- [3]Common Spiders of North America - University of California Press. Accessed 2026-06-14.