Trichonephila clavata

(L. Koch, 1878)

Jorō spider, Joro Spider, Parachute spider

Trichonephila clavata, commonly known as the Jorō spider, is a large orb-weaving spider native to East Asia that has become established as an in the southeastern United States since approximately 2010. First confirmed in Georgia in 2014, it has expanded rapidly across multiple states through a combination of ballooning and human-mediated transport. The is notable for its substantial size, striking coloration, and extensive golden webs, but poses minimal risk to humans due to small fangs and docile . Its physiological adaptations—including higher metabolic rate, faster rate, and greater cold than its Trichonephila clavipes—suggest potential for continued northward range expansion.

Trichonephila clavata by (c) Kumon, some rights reserved (CC BY). Used under a CC-BY license.

Joro Spider - Trichonephila clavata (50564813031) by Christina Butler from Georgia, United States. Used under a CC BY 2.0 license.

Joro Spider Korea by BagInABag. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Trichonephila clavata: /ˌtrɪkoʊˈnɛfɪlə kləˈvɑːtə/

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

Identification

Distinguished from native North American orb-weavers by its exceptionally large size, bright yellow and blue abdominal striping with red markings, and three-layered web structure. Most readily confused with its Trichonephila clavipes (golden silk spider), from which it differs in lacking the hair tufts on the first, second, and fourth leg pairs characteristic of that . T. clavata also shows greater cold and more rapid development than T. clavipes. The marbled orb-weaver (Araneus marmoreus), black and yellow garden spider (Argiope aurantia), and spotted orb-weaver (Neoscona crucifera) are smaller native species with different color patterns and web architectures.

Images

Appearance

females are large-bodied spiders with body lengths of 17–25 mm, while males are considerably smaller at 7–10 mm. The female displays bold longitudinal stripes of yellow and dark blue, with distinctive red markings toward the rear. Both sexes possess large abdomens and long legs with yellow and black banding. The underside of the abdomen features striking red coloration. Webs are substantial structures, often exceeding one meter in diameter, with yellow silk threads that appear gold in sunlight. The web architecture is unusual among orb-weavers, consisting of three layers: a central orb flanked by irregular barrier webs both and .

Habitat

In its native East Asian range, occupies varied including forests, edges, and anthropogenic landscapes. In the introduced North American range, has been documented in secondary forests, suburban areas, urban environments, and along roadsides. Shows notable for human-disturbed habitats, with webs frequently constructed on homes, landscape plants, utility poles, and other structures. A 2024 study confirmed web placement within 5–10 meters of roads and demonstrated that spiders near moderate- to heavy-traffic roads showed slightly reduced prey attack rates (51% vs. 65%) compared to low-traffic sites, but maintained comparable body mass, indicating compensatory foraging ability.

Distribution

Native to East Asia: Japan (except Hokkaidō), Korea, Taiwan, China, and India. First detected in North America in northeast Georgia, USA around 2010, with confirmed establishment by 2014. As of October 2022, confirmed in Georgia, South Carolina, North Carolina, Tennessee, Alabama, Oklahoma, West Virginia, Maryland, and Pennsylvania. By 2024, documented in additional states including Virginia, Kentucky, Ohio, Massachusetts, New York, and Florida. Disjunct occur in the northeastern United States, including confirmed breeding populations in Howard County, Maryland since 2022. The has also been recorded in Jammu and Kashmir, India at 1,557 m elevation, representing a northern range extension in Asia.

Seasonality

Overwinters as within silk egg sacs attached to vegetation. Juveniles emerge and disperse in spring. are present from late summer through autumn, with mating occurring in autumn when smaller males enter female webs. Females deposit egg sacs containing 400–1,500 eggs on trees in autumn, then perish by late autumn or early winter. The is completed more rapidly than that of T. clavipes, enabling exploitation of narrower seasonal windows.

Diet

Captures flying insects and potentially other small animals in its orb web. metabarcoding studies of prey remains from webs in the southeastern United States revealed diverse prey , though specific taxonomic composition requires further resolution. In its native Asian range, has ancient associations with agricultural pests including brown marmorated stink bug (Halyomorpha halys) and spotted lanternfly (Lycorma delicatula). In North America, has been documented capturing brown marmorated stink bugs, which native spiders have not been known to consume.

Life Cycle

with stage. Eggs hatch in spring; juveniles disperse via ballooning on silk threads. Development proceeds through multiple instars, with sexual maturity reached in late summer. Mating occurs in autumn, with males seeking out females in their webs. Females produce a single egg sac containing 400–1,500 eggs attached to tree bark or vegetation. senesce and die with onset of cold weather; no overwintering adult stage.

Behavior

Exhibits pronounced startle response to disturbance, remaining immobile for extended periods (over one hour in experimental conditions following air puff stimulus)—the longest documented freezing response among studied spider . This behavioral trait may facilitate of urban environments by reducing responses to anthropogenic disturbance. When handled, females typically attempt to escape rather than bite, and bites require substantial provocation. Females display nonsexual toward other females, with fights occurring in 40% of same-size pairings and 18% of different-size pairings in laboratory trials; 9% of trials resulted in fatal outcomes. Field observations document kleptoparasitism by northern cardinals, which perch on webs to steal captured prey.

Ecological Role

As a large-bodied orb-weaver, functions as a of flying insects. Potential for of agricultural pests, particularly brown marmorated stink bug and spotted lanternfly, with which it shares evolutionary history. May compete with native large orb-weavers including Argiope aurantia, Araneus marmoreus, and Neoscona crucifera for web-building sites and prey resources; in other regions where established, T. clavata has become the orb-weaver. Serves as prey for birds and reptiles. Webs have been documented supporting perching birds (up to 70 g breaking strength), representing a novel structural role.

Human Relevance

Poses minimal direct risk to humans; fangs are too small to reliably pierce human skin, and bites are rare even with deliberate handling. When bites do occur, effects are comparable to mosquito bites—localized redness and swelling resolving within 24 hours. Frequently generates public concern due to large size, conspicuous web placement on structures, and media sensationalism. Management is typically unnecessary; physical removal with broom or stick is effective if desired. Several labeled spider control products are effective but generally not required. Named after the Jorō-gumo of Japanese folklore—a shapeshifting spider-woman who seduces and devours men. Consumed as food by Ao-Naga people in native range.

Similar Taxa

Trichonephila clavipesGolden silk spider; native to Central and South America, established in southeastern US for over 160 years. Distinguished by hair tufts on legs 1, 2, and 4; lower cold ; restricted to warmer southern states.
Argiope aurantiaBlack and yellow garden spider; native North American orb-weaver with similar warning coloration but smaller size (females to 28 mm but more slender), different web architecture ( present), and distinct zigzag silk patterns.
Araneus marmoreusMarbled orb-weaver; native with rounded, variably colored but lacks bold longitudinal striping and red markings; smaller maximum size; builds more conventional orb webs without three-layer structure.

Misconceptions

Despite media characterizations as 'terrifying' or 'venomous,' the Jorō spider poses negligible medical risk to humans. The 'parachute spider' moniker refers to ballooning of spiderlings on silk threads, not aerial dropping of . Predictions of imminent massive range expansion should be tempered by recognition that establishment in new regions depends on multiple factors including winter survival, competitive interactions, and continued human transport.