We don’t usually notice Black-and-yellow Spiders until fall, when they’re all grown up and showing off as the sit majestically in their distinctive webs. When they’re smaller they tend to hide out more, trying to stay safe from predators.
You may know them by another name: Yellow Garden Spider, Golden Garden Spider, Writing Spider, Corn Spider or McKinley Spider. “Orb-weaver”¹ is sometimes attached to the name. Their official Latin name is Argiope aurantia (R-gee-Oh-pee R-ench-uh). Argiope means “silver-face” and aurantia means “gilded.”
The spiders hatched late last fall or this spring, depending on the geographic region. Either way, by fall the females have reached their full size of 0.75 to 1.10 inches long (19-28 mm) and are making a strong statement — not only by their size and pretty appearance, but with their webs, as well.
Large and distinctive, their webs may be up to 2 feet (60 cm) in diameter. In the center of it, the spider lays a dense silk zigzag pattern, known as a stabilimentum. There are at least 77 other species of spiders that do this, too, but it isn’t understood why. Theories abound: That the web decoration helps to camouflage the spiders as they sit in the center; that it makes the web appear larger; that it’s used to regulate excess silk; that it attracts males to females; that it attracts prey; or that its highly visible strands prevent birds from flying through and destroying the web.
Males look much different from females. They pale in comparison, not only by coloration, but by size — only 0.20 to 0.35-inch long (5 to 9 mm). They build their webs near those of females, but they usually go unnoticed. Sometimes they build their webs within a female’s web.
|Black-and-yellow Garden Spiders breed twice a year. Males die soon after mating. The female lays her eggs on a sheet of silk and covers them with a layer of silk topped by another, papery layer of silk. She then rolls them into a roundish ball and often places it near the center of her web. She will produce up to three, rarely four, egg sacs during the summer. She dies in late fall. In areas with cold winters, the eggs hatch in the late summer or fall and the hatchlings stay dormant within their egg sac until the following spring.|
|Hatchlings look like tiny adults. Males disperse and prowl for females. Once they find them they stay near females’ webs, sometimes building a web of their own nearby or even within a female’s web. Males die soon after mating, but in warm climates females may live for several years.|
|Black-and-yellow Garden Spiders are carnivorous. They feed on small flying insects that get caught in their web, including flies, grasshoppers, wasps and bees. If prey comes calling, the spiders might vibrate their webs in hopes of scaring them away. If that fails, they drop to the ground and hide. Predators include birds, lizards, shrews and wasps.|
Black-and-yellow Garden Spiders may look dangerous, but they’re not aggressive and don’t bite unless grabbed. Their venom is no worse than a bee sting to humans and it’s being studied for use in therapeutic medicines.
¹Spiders that construct their nests to have a circular appearance.
More reading: All about spiders