But these are really cool photos, plus some facts about spider anatomy & webs.
The Daily Bucket is a place where we post our observations about what is happening in the natural world. Birds, Blooms, Butterflies & Bugs - each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
September 2013
This Golden Orb-weaver (Nephila clavipes) has been hanging out behind my house the last 2 months. The web stretches around 4 feet from the wall of my outdoor shower to the Magnolia tree. It's also secured to the tree and the wall at other points. I'm impressed by the mechanics of this web that it can be so taut with so few attachment points. If it was me building a web, I'd have every primary web line stuck to a secure object. Think of a wagon wheel with two dozen spokes radiating out to the rim. It's easier than that for spiders but if you have ever whiled away a couple hours watching one build a web, there is more going on than you think. This site has some great drawings that explain how orb-weavers build their web.
I had been waiting thru a few overcast and rainy days hoping to shoot some photos of the webbing as the sunlight shined across it.
At the time I was focused on getting the camera to focus and didn't realize that there was a capture and wrap going on. It wasn't until I looked at the downloaded photos that I learned it was a yellow jacket, and zooming in from the other side I found another surprise.
Find out more below the orange webbing as I attempt a simplified explanation of spider silk.
In this photo you can see the silk emanating from the spider's spinneret at the base of the abdomen. This is probably its dropline. Use only in emergency. There is also a thread attached to the yellow jacket. So it holds and turns the YJ in its jaws while using the other legs to snatch and position the silk. I'm not sure but it looked to be using silk from the center of the web.
I found this list of the types of silk at Wiki and a couple other websites.
Gland & Silk Use
Ampullate (Major) Dragline silk—used for the web’s outer rim and spokes and the lifeline.
Ampullate (Minor) Used for temporary scaffolding during web construction.
Flagelliform Capture-spiral silk—used for the capturing lines of the web.
Tubuliform Egg cocoon silk—used for protective egg sacs.
Aciniform Used to wrap and secure freshly captured prey;
Aggregate A silk glue of sticky globules
Piriform Used to form bonds between separate threads for attachment points
This chart shows the basic structure. 1 is the glands; 2 is a sac to store the liquid; 3 reduces the sac; 4 is a channel that produces the thread and 5 is a valve. Pretty simple huh? Except for all the chemistry going on.
Finally, here is the closeup from the other side of the web. Seeing the flies on the YJ was unexpected, especially as the spider was wrapping up its capture. The flies were moving around so I figured this silk was not sticky. And one more surprise that I did not notice till this morning -- it's a 7-legged spider! And doing quite well, thank you.
Well that's it for this bucket. Another overcast morning in Tallahassee as the temps creep back up into the mid-80s and a "chance of showers." It's been 60s overnight but opening the windows in the morning only raises the indoor humidity. I close the windows at night to keep the cockroaches from sneaking in around the screens. Ah yes - life in the woods. Right now tho I can hear a Pileated Woodpecker working over the big dead Loblolly pine. Every storm that blows thru brings another limb down from the top. Soon I'll be left with a barren 60' stump. A decade from now it might be 30' and someday nothing but lighter.
And The Daily Bucket is now open for your thoughts and observations...
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