Jorō Spider

The Jorō spider is a large, brightly patterned orb-weaving spider native to Japan, Korea, China, and Taiwan, named after a shapeshifting spider figure from Japanese folklore. Females are especially eye-catching, with a yellow, blue-gray, and red-banded abdomen and long, similarly banded legs, and they construct expansive, multi-layered golden-silk webs that can span several feet between trees, power lines, and buildings.

First detected in the state of Georgia in the United States around 2013, the Jorō spider has since spread rapidly across the southeastern U.S. and continues to expand its range, likely aided by accidental transport and its capacity for long-distance ballooning dispersal as spiderlings. Its rapid establishment has drawn significant public and scientific attention, both because of its large size and striking appearance and because of ongoing research into its ecological effects on native spider communities and insect populations.

Despite its size and bold coloring, the Jorō spider is a docile, non-aggressive orb weaver that behaves much like other large Nephila-relative spiders, remaining at the center of its web and reacting to disturbance by retreating or dropping rather than confronting.

• Large, elongated abdomen boldly patterned in yellow, blue-gray, and touches of red, with a distinct yellow-and-black striped pattern
• Long, thin legs banded in yellow and black/dark blue-gray
• Females are dramatically larger than the small, plain brown males
• Builds large, three-dimensional golden-hued orb webs with irregular scaffolding threads in addition to the main orb
• Similar in general form to other large golden orb weavers (Trichonephila/Nephila species), distinguished by its specific color pattern and East Asian to now-southeastern U.S. range

Jorō spiders build their large webs at forest edges, in tall trees, on power lines, between buildings, and in gardens with sufficiently tall anchor points for their expansive webs. Native to Japan, Korea, China, and Taiwan, the species has become established across much of Georgia and is expanding into neighboring southeastern U.S. states. Adults are most conspicuous from late summer through fall as females reach full size and their webs become large and heavily provisioned.

This spider constructs a large, multi-layered golden orb web, often including irregular barrier threads in front of the main capture spiral, and remains at the hub to detect vibrations from trapped prey. Diet includes a wide variety of flying and jumping insects, including some larger prey such as wasps, stink bugs, and even occasional small vertebrates entangled in the web. Jorō spiders are solitary but often build webs in loose aggregations where prey and anchor points are abundant, and they tend to retreat or play dead when disturbed. Young spiderlings disperse over long distances through ballooning, riding silk threads on air currents, which has contributed to the species' rapid range expansion.

Females lay a single large egg sac in fall, typically hidden in a silken mass tucked into bark crevices or structures, containing many hundreds of eggs, and adults die with the onset of cold weather. Eggs overwinter and spiderlings emerge in spring, dispersing widely via ballooning before settling to build their own small webs. Spiders grow through numerous molts over the summer, reaching full adult size and mating by late summer and fall, completing one generation per year.