"Most spiders kill with venom... Their famous webs are simply elegant traps, designed to immobilise prey so that the spider can deliver a fatal bite. But the uloborid spiders have uniquely lost their venom glands and have to subdue their prey through other means......these spiders will wrap their trapped prey in what seems to be an excessive amount of silk. Earlier studies showed that two species of uloborids spent over an hour enveloping their prey, more than a hundred times what other orb-weavers will devote to the task. In doing so, they used up a spectacular 80 metres of silk...
...[the] silken shroud compresses an insect with such force that its legs break and its eyes buckle inward. The spider crushes its prey to death by cocooning it in silk.
To give you a sense of scale, the image [above] shows a wrapped fly next to one of its legs, which Eberhard removed before the spider set to work...
...since uloborids have no venom and don't bite, they slobber all over their cocoons instead. Eberhard thinks that the function of the apparently excessive wrapping is to compress the insect into a small enough volume that it can be spat on effectively.
I do one peculiar thing you perhaps never thought of. I frequently rescue fireflies trapped inside the spiders' web. Almost all of them lives a normal life, a few get limb injuries. Such injuries may result from my own mistakes in extricating them.
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