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Argiope aurantia (Black and yellow Argiope)

Mature female	Juvenile spider
© by: Todd A. Blackledge 1997	© by: Todd A. Blackledge 1997
This is a large female Argiope aurantia in an orb web, containing a linear stabilimentum. She has a small, wrapped prey hanging beneath her. Total body length approx. 2.5cm.	This is an immature Argiope aurantia (approx. 1cm body size). While the disc-shaped stabilimentum is quite conspicuous to the human eye, the spider's body is well camouflaged against the silk.

Argiope trifasciata (Banded Argiope)

Argiope aurantia and Argiope trifasciata are common throughout most of the US. They can often be found building webs side by side but A. trifasciata tends to favor slightly drier habitats. A. trifasciata lacks the strong black patches of A. aurantia, although it often has thin black bands on its abdomen. While A. aurantia includes a stabilimentum in almost every single web it builds, A. trifasciata only sometimes builds a stabilimentum. Silk stabilimenta can be a good defense against predators but also cost spiders prey so they have to decide carefully whether or not to include a stabilimentum in each web. Argiope uses its past foraging success to help make this decision. Hungry spiders, which most need to capture prey, are less likely to build stabilimenta.

Argiope argentata

This is largely tropical species of Argiope is found within the US only in the southern most parts of Florida. It builds a different shape of stabilimentum from other US Argiope. A. aurantia and A. trifasciata both build a vertical linear stabilimentum as adults. A. argentata builds a cruciform or x-shaped design. This spider has included only a single arm of the "x". Individual spiders will sometimes include a complete "x" in a web or not built any stabilimentum, but partial decorations are typically most common.

The life of Argiope
You are most likely to see Argiope in the late summer and early autumn. This is when the females mature, becoming very large as they yolk up their eggs. The females will construct one or more egg sacs in autumn. The egg sacs will be attached to vegetation near the website and can contain hundreds of eggs. The young hatch in autumn but remain inside the eggsac over winter. Spiderlings emerge from the eggsacs in the spring and build small webs deep in grass and other vegetation throughout the summer. As the spiders grow in size they tend build larger webs higher in the vegetation and thus more noticeable. Once mature, males stop building webs altogether and instead search for females with which to mate. Females will continue to build webs as adults.

Is Argiope dangerous?
Like almost all spiders, Argiope uses venom to subdue and digest its insect prey. But, they aren't particularly dangerous to people. Most spider bites result in nothing more than a sore, itchy swelling that goes away in a few days. Of course, it is always a good idea to not handle the spiders so that you don't get bitten! If an Argiope builds a web near your home or garden don't worry. They aren't especially aggressive and don't like to leave their webs. Instead take the opportunity to watch these fascinating spiders live their lives!

What are some other spiders that build stabilimenta?

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