Fact Sheet FS1386
In Brief…
Trichonephila clavate L. Koch, 1878, also known as the Jorō spider, is a native to Asia, specifically the countries of Japan, India, China, North and South Korea, Taiwan, Indochina, and Nepal. Its name derives from the Japanese legendary folklore creature "jorō-gumo," which translates to "entangling or binding bride." It belongs to the arachnid family Araneidae, the orb-weaving spiders.
Introduced to the United States in 2013, the Jorō spider is believed to have stowed away in a shipping container. It was first detected in Hoschton, a small town in northeast Georgia, and it has since spread to parts of Alabama, Tennessee, North and South Carolina, West Virginia, and Maryland, about 75 miles in all directions from its initial detection point. The Jorō spider migrates at a rate of about ten miles per year and is expected to eventually populate the entire eastern part of the U.S. Human transport may facilitate the migration rate.
In contrast to related species, the Jorō spider can survive colder climates. For example, it lives in the northern part of Honshu, Japan's main island, which typically reaches nighttime temperatures at or below freezing. The reason for the Jorō spider's hardiness may be because it has a metabolism rate that is twice as high, based on oxygen usage, as its related species, and a heart rate that is 77% faster when subjected to cold temperatures. In addition, the Jorō spider's life cycle is shorter than its close relatives. Thus, it is expected that this species will spread farther north in the U.S., particularly in the more temperate areas of the eastern coast, and that it will likely naturalize.
The Jorō spider has been found in various environs, including wooded locales and around natural waterways as well as in urban and residential areas. It prefers outdoor habitats and does not seek to enter residences. A 2024 study revealed that Jorō spiders are tolerant of the vibrations and noise that are a part of the urban landscape. Human-generated vibrations, which indicated the presence of food to spiders, did not interfere with the spider's ability to find sustenance. Though they were slightly less inclined to strike out at prey, their weight remained stable.
Figure 1: Jorō spider, female, dorsal view.
Description
The large and colorful female Jorō spider has a body length of 1.25" and a leg span of up to 4". Viewed from above, her cephalothorax is covered in silver hair, while the oval abdomen is bright yellow with bluish bands. The underside of the female spider reveals a black and yellow-white patterned body with red spots at the posterior end. Her legs are black with yellow bands.
The male Jorō spider is green-brown and often indistinguishable from other spiders. His body is about 0.3". His cephalothorax has longitudinal dark brown stripes, while his abdomen has a central, dark brown stripe and yellowish stripes on either side. His legs are tan and grey-brown banded. This sexual dimorphism, or difference in size between the female and male Jorō spiders, is among the greatest known in the animal kingdom.
There are variants of the Jorō spider with solid black legs and other differences that can be detected when viewed microscopically. These spiders, while members of the same species, have been ascertained to be genetically distinct.
Immature female spiders, or spiderlings, are differently colored than adult females. The female spiderling has a brown cephalothorax, an oval abdomen with a black and yellow pattern, and legs which are black with yellow bands.
Figure 2: Jorō spider, female, ventral view. Photo adapted from Rebekah D. Wallace, UGA, Bugwood.org, CC BY 3.0.
Life Cycle
Mature females spin webs that span 10' or more from strong, sticky yellow or golden silk; it is among the strongest silk in existence. Jorō spider webs are generally located higher than those of other spiders. The support strands for the webs can measure up to 20' and can stretch between treetops, poles, shrubs and other props. It is used by both the female and the male Jorō spider, as the adult male spider does not spin his own web. It is not yet known how the males find their way to the females' webs.
There may be several males in the web, each sparring with the others for his chance to mate with the female. One generation is produced per year, in mid-October into November, with 400 – 500 eggs or more overwintering in a single, white, fluffy silk-covered egg sac deposited on leaves, tree bark, or other flat objects. The eggs, protected in the sac, overwinter. Jorō spiders typically succumb to freezing temperatures in winter.
The eggs hatch in April–May. Once hatched, spiderlings have a method of moving themselves far from the nesting site called ballooning. Spiderlings can free up silk from their spinnerets, which allows them to be carried tens to hundreds of miles via air currents, electromagnetic currents, and storms. Young spiderlings, both male and female, spin webs of clear silk that are largely unremarkable although, rarely, they may create stabilimenta. A stabilimentum is a design that is woven into a web; Jorō spiderlings may add them, though adults never do. As Jorō spiderlings mature, their silk becomes stronger, stickier, and golden in color. The spiderlings pass through at least three instar stages, maturing in August–September. The female spiderling will reach adulthood in 3–5 months, becoming more noticeably colorful as she reaches adulthood, with the male reaching maturity earlier. The entire life cycle of the Joro spider lasts approximately 6–8 months.
Figure 3: Jorō spider male/female pair. Photo adapted from Carly Mirabile, UGA, Bugwood.org, Bugwood.org, CC BY 3.0.
Interactions with the Environment
While the Jorō spider has fangs and kills its prey with venom, it is generally harmless to humans and pets, as its fangs do not easily pierce skin. Experience has shown that they rarely bite, even when their environment is disrupted. It has been reported that, when bites do occur, they result in redness and localized pain, with no medical intervention required. There have not been reports of incidents of allergic reactions to Jorō spider venom. Jorō spiders tend to be shy and, when disturbed, they either flee, or they freeze in place, at times for up to an hour.
Jorō spiders eat arthropods, such as grasshoppers and moths, among both native and invasive species that it catches in its web. It is a predator of invasive brown marmorated stink bugs and spotted lanternflies. It will not consume all insects, though. A 2024 study at the Odom School of Ecology at the University of Georgia demonstrated that 80% of the test subject spiders declined to ingest monarch butterflies, with some of the spiders assisting the monarchs to free themselves of the constraint of the web.
The Jorō spider, in turn, is preyed upon by the mud dauber wasp, which paralyzes the spider, brings it to its nest and uses it as food for its progeny. There have been anecdotal reports of Jorō spiders being consumed by birds.
As this spider is relatively new to the U.S., it is not yet known what the effect will be on the environment. For example, it is unclear whether the Jorō spider will outcompete other orb weavers, such as the golden silk orb-weaver, or other large spiders. There have been observationsof Jorō spider webs near those of other orb weaving spider webs, and, on occasion, the webs have been attached to each other. The spider's effect on the ecological balance of the organisms that it eats, and is eaten by, has yet to be determined.
Figure 4: Trichonephila clavipes, golden silk orb-weaver. Photo adapted from Chris Evans, U. of I., Bugwood.org, CC BY 3.0.
Control
As the Joro spider is new to New Jersey, its status as an invasive or newly arrived, naturalizing species has yet to be determined and therefore, control methods are still undetermined. However, there are two areas where Jorō spider webs should be removed: 1) in the locale of a beehive, and 2) around flower or pollinator gardens. Pollinators continue to struggle, and Jorō spider webs are particularly large and sticky. Destroying the web is not likely to be a long-term solutionas the spider may simply return and rebuild.
Problematic Jorō spiders can be controlled. One method is to relocate the spider to a less populated area, such as a riverbank, a lakeshore, or a forest. Another method is to manually crush them. If the web is high, a broom may prove to be handy in bringing the spider down to an area where it can be handled. If populations in an inhabited location become unmanageable, egg sacs, located in autumn, can be disrupted before the eggs have a chance to hatch.
Fogging and large-area outdoor sprays may have negative consequences for the beneficial insect community, as some of the products used are lethal to many organisms. It has been found that scale insects, which tend to harm vegetable and ornamental plants, increase in population and concomitant plant damage after this type of intervention. Individual treatment of the Jorō spider is likely to be most effective with the least number of negative consequences.
If insecticides are used, read and follow all pesticide label directions, restrictions, and precautionary statements before use. Chemical treatments which have proven effective in controlling the Jorō spider include pyrethroids and synthetic pyrethroid products, such as cypermethrin, lambda-cyhalothrin, and bifenthrin. In external areas, such as under the eaves of a house, aerosols may be the only method of delivery which will reach the web. Remember that insecticides may be harmful to bees foraging in the area, so avoid insecticide applications if blossoms are present or bees are active.
Figure 5: Argiope trifasciata, banded garden spider. Photo Credit: Whitney Cranshaw, CSU, Bugwood.org.
Differentiating Jorō Spiders from Similar Arachnids
There are species of arachnids in the U.S. which, in appearance, are close to the Jorō spider, and which may be mistaken for it. Trichonephila clavipes, the golden silk orb-weaver, is related to the Jorō spider. Also known as the banana spider, it inhabits similar regions in the U.S., from Florida to Virginia, although this spider has moved west into Texas. The female is approximately the same size as the Jorō spider, but it has some distinguishing characteristics. Its first, second, and fourth pairs of legs have bands of black bristles alternating with orange bands; the tips of all legs are black. While the cephalothorax is covered in silver hair, like that of the female Jorō spider, the golden silk orb-weaver's abdomen is burnt orange with columns of paired yellow spots, along with smaller yellow markings along the sides. This spider's web is golden like the Jorō spider's but is significantly smaller, reaching a maximum diameter of 5'.
There are two spiders of the Argiope genus which, though smaller than the Jorō spider, have some similarities. The yellow garden spider, Argiope aurantia, can be found in all states but Alaska, as well as Central America, Mexico, and the southern portions of Canada. The female yellow garden spider body can reach 1" in length; including the leg length, it can reach 2.5". Its cephalothorax is covered in silver hair. The yellow garden spider's abdomen is ovoid shaped, as opposed to the oval shape of the Joro spider. Its dorsal aspect is yellow patterned on the sides with a black swath dotted by three pairs of yellow spots down the center. Its second, third, and fourth leg pairs have tan femurs with black tibias, metatarsi, and tarsi. Its first leg pair has dark grey femurs with black tibias, metatarsi, and tarsi. The web can reach 2' in diameter and typically has a zigzag-patterned stabilimentum.
Argiope trifasciata, the banded garden spider, is roughly the same size as the yellow garden spider. It has a cephalothorax covered in silver hair. Its abdomen is oval shaped, somewhat pointed at the posterior, and the dorsal aspect is colored with silver, black, and yellow bands. It has a faint U-shaped marking, with the rounded portion of the U at the center of the abdomen and ending at the posterior aspect. Its legs are brown with black bands. The web is similar in size to that of the yellow garden spider, often with a stabilimentum which can vary in pattern.
Figure 6: Argiope aurantia, yellow garden spider. Photo credit: R. Carll.
References
February 2026
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