Spiders
Andrew Lin sent in these great photos. Usually when someone sends me several pictures, I sift through and pick the best one. Sometimes I’ll run a twofer if I can’t really pick. But Andrew sent in four pictures, and they tell a story. So brace yourselves: today is the first-ever InsectPOD fourfer!
The large spider is a hunting spider, and the small one is a cobweb spider of family Theridiidae. I don’t recall the species or genus, but the two spots on her abdomen seem familiar. In Greek, the word Theridion has several meanings. It can mean “a tiny animal”, which is accurate because she’s probably only 2 or 3mm long. It can mean “a wild beast”. Well, she ain’t exactly a kitten, is she?
Theridion can also mean “fierce”. And to make that point as perfectly clear as possible here: she is in the process of killing and eating that big hunting spider.
The hunting spider stumbled into her netlike web. Now this might surprise you, but not all spiders are at home in a web. All spiders do use silk, but the hunting spider prefers to roam free, and only uses her silk to spin a sleeping bag shelter to sleep in during the day. Our little Theridiidae spider, upon discovering the larger spider blundering through the web, ran down and started slapping wet silk around the area. The hunting spider, already tangled in the cobs, became glued in place. The cobweb spider added more and more glue and waited for the prey to become tired and stop struggling. At that point, the cobweb spider would finally crawl right down to the prey and do what spiders do that scares us: envenomation.
If you look at the first picture above, the cobweb spider is biting the hunting spider. Probably not for the first time; I have seen cobweb spiders actually bite their prey repeatedly, waiting a minute between bites to let the venom work. Or possibly to allow their venom glands to fill back up for another bite.
Satisfied that her prey is dead, the gift-wrapping begins in earnest. She cocoons her prey for ease of transport. Yes, she’s really going to haul that much-larger-than-her spider up into her web before she eats it. In the picture above you can see her legs splayed in “gantry mode” to slap silk around the prey more easily.
And finally, she’s got things pretty much wrapped up. She gets above the prey, attaches a dragline to the cocoon, bites the cocoon free from the cobweb, and drags the cocoon up into the web before eating. For a cobweb spider, the lower net areas are a dangerous area even for the web owner. She’ll pull the prey up near her lair to eat in relative safety.
Thank you, Andrew! It was a great spot for you to see this as it was happening. And thanks for remembering to grab the camera!
Slowly getting the site back onto an even keel. It's nice to get back into the old posting rhythm.
Parkway said,
July 11, 2008 @ 7:06 am
Nice set of pictures -webs are obviously tricky to photograph, they’re supposed to be invisible, after all!
And what’s happened to the Buffer Count?
tceisele said,
July 11, 2008 @ 7:49 am
I saw one of these little cobweb spiders catch and kill a great big stone centipede[1], probably ten times her mass, that had *claws* probably bigger than her. They’ve got no fear of tackling bigger prey, at all. This kind of implies that giant spiders the size of, say, beagles or large cats would be able to take on adult humans in single combat.
[1] The pictures came out impossibly blurry, though. The light was dim, they were thrashing about, and I’d just gotten the camera the day before and wasn’t all that familiar with it. Not that I’m all that good at action shots *now*, mind you, but still.
Kit Watson said,
July 11, 2008 @ 8:01 am
Wow!
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JFargo said,
July 11, 2008 @ 8:13 am
That is absolutely awesome. I’ll take the small web spiders over hunting spiders in my house any day, so it’s good to see one take down the other.
Very awesome, Andrew!
Andrew said,
July 11, 2008 @ 8:40 am
A couple hours after I took the posted pictures, I went back to the web. The hunting spider was pretty much completely deflated, having been sucked dry by the now-extremely-portly cobweb spider. It was like looking at a balloon animal that had all the air let out.
Kenneth McFarlane said,
July 11, 2008 @ 9:02 am
I love theridiidae! I’m currently keeping a Steatoda triangulosa who’s been blessing me with a plethora of little spiderlings (soon to be released into the forgotten corner of the basement I pulled their mother from).
It certainly is amazing the size of prey she’s been going after. Although I have to say I haven’t fed her anything quite so intimidating as a spider four times her size.
David Brady said,
July 11, 2008 @ 10:07 am
@Parkway: Thanks for the reminder! Buffer Count is currently 0. I’m staying about 12 hours ahead right now. My long-term plan is hold on to whatever lead I currently have with about-weekly bursts of increasing the lead. The get-ahead phase is planned for tonight, so hopefully tomorrow’s buffer count should be somewhere between 2 and 5.
I also think posting the BC in the comments isn’t really working. What I need to do is teach the webserver how to calculate the BC, and then just put that number up on the page somewhere.
Scott said,
July 11, 2008 @ 11:14 am
“This kind of implies that giant spiders the size of, say, beagles or large cats”
I don’t even want to THINK about that.
This is a great series of pics.