When walking through the woods or even in your own backyard, you may run across a large black and yellow spider, which may be weaving a big orb web or sitting patiently waiting for prey to get caught in the sticky threads. Spiders are in the Class Arachnida and are related to insects, as both are arthropods (arthropods are invertebrates with distinct body segments, jointed legs, and an exoskeleton). In South Carolina, four big yellow and black orbweaver spider species can be found; these are the yellow garden spider, the banded garden spider, the golden silk orb weaver, and the Jorō spider, a relatively new species in SC. These large spiders are docile, not generally considered dangerous, and capture and consume insects, some of which are pests of people, pets, and crops.
Yellow Garden Spider (Argiope aurantia)
The yellow garden spider is found throughout South Carolina. The body’s main color is a bright yellow with a splotch of black in the middle. Females are distinguished by these characteristics, while males are much smaller and more muted in color. Females can have a body length up to 1 inch long, while males are rarely more than ¼ inch long. With their legs splayed out, they may appear twice as long in their webs.
Garden spider webs are often placed near open sunny areas, usually in tall vegetation at about knee length (like a garden, hence the common name). The web is known for its intricate style, having a typical orb shape but sporting a lightning bolt zig-zag pattern vertically through the middle of the web. Sometimes yellow garden spiders are called writing spiders because of the zig-zag pattern in their web. This web decoration is known as a stabilimentum and its purpose is still being debated – it may be to help attract prey, or make the spider appear larger than it is (which would help the spider defend itself), or it may be to increase the visibility of the web, so vertebrates do not walk or fly into it. Sometimes (especially as juveniles), garden spiders will build stabilimenta in a circular platform in the middle of their webs instead of a vertical zigzag pattern.
The round egg sac of the spider is usually shades of white or brown and can be found hanging on the web. When the spiders mature, males will try to find a mate by spinning a web near or within a female’s web. To get her attention, the male will strum the web, alerting her of his presence. The pair will mate, and shortly afterwards the male will die, sometimes serving as a post-coital meal for the female. The female will then lay her eggs and encase them in an egg sac to protect them from the environment.
Adult yellow garden spider on a web. Note the thick, white, zigzag stabilimentum in the middle of the web.
David Coyle, ©2024 Clemson Extension
Yellow garden spider egg sacs are suspended in the web, are white to brown in color, and somewhat teardrop shaped.
Photo by Wikimedia Commons, user Joyous!, licensed under the Creative Commons Attribution-Share Alike 4.0 International, 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license: https://commons.wikimedia.org/wiki/File:Argiope_aurantia_egg_sac.jpg.
Banded Garden Spider (Argiope trifasciata)
The banded garden spider is also found throughout South Carolina. A close relative of the yellow garden spider, the banded garden spider can be distinguished by the yellow, white, and black stripes on its dewdrop-shape abdomen. In fact, its scientific name, “trifasciata”, means three-banded, in reference to the thin, tri-colored horizontal banding. Its eight legs are yellow with black stripes. The patterning on its ventral (belly) side resembles two vertical yellow bands separated by a black patch.
Like other garden spiders in the genus Argiope, the banded garden spider is often found resting with its legs paired in an X-pattern on a web with thick, white zigzags running down the middle in a line. It is also commonly found in garden-like settings, meadows, and old fields, often at knee height, and sits in the middle of its web (also known as the hub) during the day. Like other orbweavers, the banded garden spider is a generalist predator, catching an assortment of invertebrate prey items. Larger prey are wrapped in silk while smaller prey are bitten and carried directly to the hub for consumption.
Both garden spiders have one generation per year. Adult garden spiders are typically observed between July and October. Yellow garden spiders lay up to four egg sacs while the banded garden spider lays a single egg sac, usually between September to October. The eggs overwinter in the egg sac, with spiderlings emerging in the spring, typically between April to May.
Garden spiders like the banded garden spider often rest with their legs paired in an X-pattern.
Photo by iNaturalist user Claudia Fernandez, licensed under the Creative Commons Attribution-Noncommercial 4.0 International Deed: https://www.inaturalist.org/observations/175710084.
Juvenile garden spiders, like this banded garden spider, often have a more elongate abdominal shape that lacks the diagnostic patterning of the adults.
Photo by iNaturalist user dillonmr, licensed under the Creative Commons Attribution-Noncommercial 4.0 International Deed: https://www.inaturalist.org/observations/243776936.
Golden Silk Orbweavers (Trichonephila clavipes)
Golden orbweavers in the spider family Nephilidae are large spiders known for their expansive golden webs. Present around the world, these spiders are often found in areas with dense vegetation and a humid climate. The most common species in South Carolina is the golden silk spider (also called the golden silk orbweaver or banana spider), which was first documented in Charleston, South Carolina in 1863.
Golden silk orbweavers have a trademark white cephalothorax (the body part with the head and where the legs attach), which is used by the spider for heat regulation during hot days. Their abdomen is bright yellow, which is likely why these spiders are also known as “banana spiders”. Golden silk orbweavers have a hairy “bottlebrush” appearance on some of their leg segments, which allows you to distinguish them from other big, yellow orbweavers, including the Joro spider. The size of these spiders is also impressive, with female bodies averaging between 1½ and 2 inches long and males being a little less than 1 inch long in total. With their legs spread wide, these spiders can be larger than a person’s palm! This makes them the largest web-building spider in North America.
What makes spiders in this family distinctive, however, is their web: the silk spun by these spiders is made up of specific chemicals that make it golden in color. Both golden silk orbweavers and Joro spiders have golden webs. The reason for this color is still being studied, though it is thought that the yellow color can be attractive to insects or act as camouflage, as it can be difficult to see in the speckled sunlight of the forest. People have tried to use the silk to make material for clothing, but due to the difficulty of raising these spiders in captivity, this has not been a successful endeavor, yet.
Reproduction in this group involves males seeking out a potential mate carefully, preferably choosing a female who is distracted by feeding. The male will alert the female that he is nearby by strumming the web, and if not met with aggression, will move forward in his advances. If the female shows any sign of aggression, the male will either wait for a different time to approach or flee. Once the male meets the female, the pair mates. Because of her immobility due to feeding (or molting), the male may successfully flee after mating occurs without being eaten by the female. Although not as common in this group, some males are eaten after mating. Multiple males will compete to mate with the same female, and those who mate with the female for a longer period have a better chance of producing offspring.
The female will lay her egg sac within her web in an area with dense covering, such as under leaves. This provides the sac protection from predators. Spiderlings look very different from adults. Rather than being bright like the adults, juvenile Trichonephila spiders resemble other native orbweavers in the southeastern U.S. in appearance, such as the orchard spider (Leucauge sp.), basilica orbweaver (Mecynogea lemniscata), or lined orbweaver (Mangora gibberosa). This is because their legs range from a dark green to yellowish hue depending on the lighting, and the abdomen has a mottled white, yellow, and black patterning. Younger Trichonephila spiderlings also have a similar shape and size to native orbweavers and their webs lack the distinctive golden color of the adult females (mature males do not build webs and instead wander in search of female webs).
Adult golden silk orbweaver. Note that its abdomen lacks silver stripes, which are characteristic of Joro spiders.
David Coyle, ©2024 Clemson Extension.
Male (smaller) and female (larger) golden silk orbweaver. Note the hairy “bottlebrush” appearance on the black leg segments of the female.
Photo by Sturgis McKeever, Georgia Southern University, Bugwood.org.
Jorō Spider (Trichonephila clavata)
The Jorō spider has become a popular name in the media due to its discovery in the Georgia Piedmont in 2014 and subsequent spread to South Carolina and other surrounding states. Of the four spiders described here, it is the only non-native, invasive spider. It is originally from east Asian countries including Japan, Korea, and China, and even received its common name from a Japanese entity known as the jorogumo, a shapeshifting spider spirit. Given the recency of its introduction, one potential concern is whether it will outcompete native orbweavers, which play an important ecosystem regulatory role as predators of many small invertebrates as well as food sources for larger vertebrates like birds, reptiles, amphibians, and fish. For more information on the Jorō spider please see our HGIC 2517, Joro Spiders fact sheet to learn how to tell these species apart.
The Jorō spider is an orb weaver whose colors are vibrant and flashy. Like its relative, the golden silk orbweaver, this arachnid has a white cephalothorax and its abdomen is bright yellow. Adult females also weave brilliantly golden webs. Unlike the golden silk orbweaver, the Jorō spider’s abdomen has horizontal silver stripes and a more distinctive reddish pink patch near the tip of its ventral side.
Its reproductive habits are similar to the golden silk orbweaver. Males are only a fraction of the female’s size, and multiple males can often be observed in a single female web. Although females only lay one egg sac in the fall that hatches in the spring, each egg sac can house between 400-500 eggs. Unlike garden spiders, Jorō spiders do not lay egg sacs within their webs. Instead, females attach their egg sacs underneath tree bark, on the undersides of leaves, or in tight spaces of human-made structures, such as between wooden slats of a deck. The egg sac itself is not a tightly woven structure that completely encases the eggs as seen in the garden spider egg sacs; instead, the eggs are glued together in a flat, oval mass and a looser, more porous silk webbing attaches this mass to their substrate. Initially white in color, the silk and eggs may darken to a brownish color over time.
Jorō spider sitting on its web.
Photo by iNaturalist user xx7trey (Trey Wardlaw), licensed under the Creative Commons Attribution-Noncommercial 4.0 International Deed: https://www.inaturalist.org/photos/240469491.
A Spider’s Role in the Environment
Spiders play an important role in the environment, serving as a natural form of pest control, preying on insects that may be harmful to crops, humans, and pets. Spiders do not, however, differentiate between detrimental and beneficial prey – they are just as likely to capture and eat a harmful crop pest as they are a beneficial native pollinator. The four spider species listed above are not harmful to humans. In fact, these species are quite docile, and if given the option, will run rather than bite. If by chance one does bite, the bite is similar to a bee sting and not known to require medical attention like bites from black or brown widow spiders or brown recluse spiders.
Originally published 08/21
This document was revised by Dr. Angela Chaung and Dr. Dave Coyle on November 20, 2024.
