Yellow Garden Spider
The spider species Argiope aurantia is commonly known as the yellow garden spider, black and yellow garden spider, golden garden spider, writing spider, zigzag spider, zipper spider, black and yellow argiope, corn spider, Steeler spider, or McKinley spider. The species was first described by Hippolyte Lucas in 1833. It is common to the contiguous United States, Hawaii, southern Canada, Mexico, and Central America. It has distinctive yellow and black markings on the abdomen and a mostly white cephalothorax. Its scientific Latin name translates to "gilded silver-face" (the genus name Argiope meaning "silver-face", while the specific epithet aurantia means "gilded"). The body length of males range from 5 - 9 mm; females range from 19 - 28 mm. These spiders may bite if disturbed or harassed, but the venom is harmless to non-allergic humans, roughly equivalent to a bumblebee sting in intensity.
This spider is found from Canada to Costa Rica, but less so in the basin and mountain areas of the Rockies.
Argiope spiders are not aggressive. They might bite if grabbed, but other than for defense they do not attack large animals. Their venom often contains a library of polyamine toxins with potential as therapeutic medicinal agents. Notable among these is the argiotoxin ArgTX-636. A bite by Argiope aurantia is comparable to a bee sting with redness and swelling. For a healthy adult, a bite is not considered an issue. Though they are not aggressive spiders, the very young, elderly, and those with compromised immune systems should exercise caution, just as they would around a beehive or a hornet nest.
Yellow garden spiders breed twice a year. The males roam in search of a female, building a small web near or actually in the female's web, then court the females by plucking strands on her web. Often, when the male approaches the female, he has a safety drop line ready, in case she attacks him. The male uses the palpal bulbs on his pedipalps to transfer sperm to the female. After inserting the second palpal bulb, the male dies, and is sometimes then eaten by the female. The female lays her eggs at night on a sheet of silky material, then covers them with another layer of silk, then a protective brownish silk. She then uses her legs to form the sheet into a ball with an upturned neck. Egg sacs range from 5/8" to 1" in diameter. The location of the egg sac varies. She sometimes suspends the egg sac near her web or placed several feet from the web. Each spider produces from one to four sacs with perhaps over a thousand eggs inside each. In the spring, the young spiders exit the sac. They are so tiny that they look like dust gathered inside the silk mesh. Some of the spiderlings remain nearby, but others exude a strand of silk that gets caught by the breeze, carrying the spiderling to a more distant area.
Females of the species are the most commonly seen in gardens. Their webs are usually characterized by a zigzag shaped stabilimentum (an extra thick line of silk) in the middle extending vertically. The spiders spend most of their time in their webs, waiting for prey to become ensnared. When prey becomes caught in the web, the spider may undulate the web back and forth to further trap the insect. When the prey is secure, the spider kills it by injecting its venom and then wraps the prey in a cocoon of silk for later consumption (typically 1–4 hours later). Prey includes small vertebrates, such as geckos and green anoles, as well as insects.