Wings Of Science!
Goldy_C: "n this one what the hell is in that yellow thing? I think its ultra-poisonous venom *shivers*: http://www.janfox.com/images/big_spiders/HWspider2.jpg"
Answer: This is an Argiope Aurantia, but most people call them garden spiders, or tomato spiders. Only the females are this big, and you can watch her lay eggs and tend them as the summer wears on. The information available suggests that the venom of this spider is very potent to insects. In fact, at least one commercial concern has studied ways to use Argiope venom as an insecticide. That project was placed on hold, however, because insects would eventually become immune to the venom if it was used extensively for insecticidal purposes, and the consequences to this and other spiders whose venom is similar cannot be predicted with certainty. Apparently, the venom is almost harmless to humans, but this spider is known to bite if it is handled roughly. Bites by spiders of the genus Argiope are not common. Some sources even report that they will not bite humans. Others claim they are not venomous. The truth is they are venomous, and records of humans being bitten by these spiders do exist. Although these spiders are not aggressive, they will bite if handled, especially when treated roughly. Persons who have been bitten report an immediate sharp pain that is felt at the site of the bite, but because the venom is rather weak it typically fails to produce serious corollary swelling or irritation. Minor itching and/or swelling at the bite itself has been observed. Oral administration of diphenydramine hydrochloride (i.e., the common over-the-counter antihistamine Benadryl) is said to relieve the pain. As time passes, and no additional discomfort develops, the anxiety associated with the bite subsides as well.
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!
Further Reading Material:
http://www.lander.edu/rsfox/310argiopeLab.html
Photos:
http://www.floridanature.org/photos/Argiope_aurantia_2,_Tallahassee,_200010.jpg
http://www.floridanature.org/photos/Argiope_aurantia_1a,_Tallahassee,_200009.jpg
http://www.floridanature.org/photos/Argiope_aurantia_1b,_Tallahassee,_200009.jpg
http://www.floridanature.org/photos/Argiope_aurantia_1c,_Tallahassee,_200009.jpg
http://www.floridanature.org/photos/Argiope_aurantia_1d,_Tallahassee,_200009.jpg
Take It Easy,
Wings
