Argiope Aurantia
Halloween Spider Week continues! This Argiope aurantia, or Golden Orb Weaver, lives outside the 2nd story stairwell of a parking garage frequented by reader Andy Roche, who sent in this great photo. Argiope spiders have a very high “creep factor” because they can reach up to 3cm–and remember, that’s not counting legs.
Orb Weavers build the classic spiral spiderwebs, called–you guessed it–orb webs. The radial guy lines are made of dry silk, while the spiraling pieces are made of sticky silk that traps insects. The general theory is that the spider can walk on the dry silk without getting stuck, and this is generally true; the reality is that spiders just understand how silk and webs work, and when they get a leg stuck in their own web they carefully pull it free without thrashing around to get the rest of themselves stuck. The next time they return to the center of their web to rest, they pull the affected leg up to their mouth and carefully chew any residual glue off.
One of the interesting telltales of Argiope webs is the stabilimentum, the fuzzy white sheet at the center of the web, often with zig-zaggy bits above and below. (You can see a very small, single “lightning bolt” zigzag coming down from below the spider’s perch.) Nobody knows why they do this; the best theory is that it provides camouflage against avian predators.
Slowly getting the site back onto an even keel. It's nice to get back into the old posting rhythm.
JVidal-Riggs said,
October 25, 2007 @ 9:56 am
I can’t help but correct you: it’s Argiope aurantia–in ‘Genus species,’ ’species’ is never capitalized.
My one-hundred percent favorite spider is Nephila clavipes–they’ve got the same web design as Argiope.
David Brady said,
October 25, 2007 @ 10:01 am
JVidal-Riggs: Thank you! I didn’t know that. Corrected.
ZWarrior said,
October 25, 2007 @ 10:06 am
All I know is that the picture was tough to take. This was one of four I took and I had to stop traffic on the in between landings while I took these. Very fearsome looking spider who has moved on since the picture was taken.
Thanks for having the site, it has been an inspiration to get back out there with the camera and look for things to take shots of.
Kazriko said,
October 25, 2007 @ 4:21 pm
One thing I’ve heard is that the white bits are an evolutionary thing, not to camouflage from predators, but to keep birds from flying through and destroying the web. I’m not sure which one is more accurate, but the same thing said that a web with that white bit catches 30% less bugs, so it needs to be something useful for them to have started doing it.
JVidal-Riggs said,
October 25, 2007 @ 5:12 pm
The white bit sure doesn’t always work, I can tell you that! I walked straight through a web like that once, wound up with a 3cm spider centered on my sternum. Scared the crap out of me.
David Brady said,
October 25, 2007 @ 9:39 pm
Kazriko: Interesting! I watched a magpie stalk a praying mantis the other day, and birds definitely are the number one predators of spiders, so I can see how the stabilimentum would provide camouflage. Another part of the creep factor of orb weavers is how motionless they remain, even under close scrutiny. It may very well be that holding still on a camouflaged background fools birds just often enough to make up for the food loss from bugs that see the web and steer clear.
David Brady said,
October 25, 2007 @ 9:43 pm
JVidal-Riggs: Hee! I am, for all my arachnophile posturing, rather arachnophobic. I’m okay with seeing any kind of spider, and I can handle touching jumping spiders, but yeah, getting an orb weaver ON ME would cause me to have an energetic reaction. I wouldn’t call myself phobic or anything because I wouldn’t have an insane reaction, but I would definitely be urgent about getting it off me and out where I could keep an eye on it.
Thanks for the great anecdote!
ZWarrior said,
October 26, 2007 @ 6:16 am
Yikes, that would have me doing the whirling heebie jeebies. Spiders are cool to look at, but I really don’t like them on me. This one was actually on the other side of a window about 10 feet out from me, as well as 2 stories up so I didn’t have any problem with it.
On my chest? Yikes!
mollie hughes said,
August 18, 2008 @ 11:16 pm
lol you guys are funny.. i hold my Argiope aurantia all the time and she has never biten me!.. i have a home-made spider habitat in my room that i created out of glass and wood, the bottom has lots of plants and the top has wooden polls for them to make webs on, it stands about 4 feet tall and 3 feet wide on all sides… i collect spiders every year for the winter and since the bug suply isnt that great during snow season i buy crickets at the local pet store for them to eat… my oldest spider is 4 years old and she is my only Argiope aurantia (i did have 2 but she ate my other one haha! girls rule).. i also have a veriety of cobweb spiders and jumping ones but she is my only “cool” spider ^.^