> The team of scientists discovered that 69,000 Tegenaria domestica, known as the barn funnel weaver, were living with about 42,000 Prinerigone vagans, which inhabit wet places. Usually the barn funnel weavers prey on P. vagans, which are smaller.

> “But in the cave, because it’s dark in there, our hypothesis was that they do not see each other,” Blerina Vrenozi, a biologist, zoologist and ecologist at the University of Tirana in Albania said in an interview. “So they do not attack.”

I thought one of the major purposes of spiderwebs was that the spider can detect the presence of something else in the web without needing to be able to see it.

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acomjean 2 days ago | parent | next [-]

I think you are right. If I remember there were 2 types of silk, and they could use their legs to “listen” to vibrations when something gets caught anywhere in the web. They seem to avoid getting stuck in their own webs.

But they do have 8 eyes, so I’m assuming they make visual confirmation. But these cave spiders are in the dark…

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BirAdam 2 days ago | parent [-]

Depending upon the species, spiders can make more types of silk: strong, soft, sticking, sensing, etc.

Most spiders have terrible eyesight despite having eight eyes. Those with good eyesight are jumping spiders, portia, and a few ground spiders. These species are easily distinguished by having two large front-facing eyes.

Due to bad eyesight, most spiders use touch through their webs and/or hairs. The hirsute species can easily identify pretty much anything that causes a wind current near them, and most all species can easily identify prey by the distinct vibrations they make once caught in the web.

If you watch most spiders, however, they can occasionally be fooled on windy day when a leaf or other detritus hits their webs, and they have to go touch it to find out it isn't prey. Eyesight just isn't a thing most are great with.

	▲	eimrine 2 days ago \| parent [-]
		Most of spiders I tried to fool can't be fooled by a leaf, they usually wait for recurring vibrations. Touching the web by a stick never produces enough good vibration to attract the spider. Baiting to things on the web is mostly about young spiders, the biggest spiders I have seen on their webs usually kind of lazy.

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bulletsvshumans 2 days ago | parent | prev [-]

Maybe the glut of conventional food leaves the prospect of eating their compatriots less appetizing.

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thaumasiotes 2 days ago | parent [-]

Probably not; these aren't closely related spiders. It would be like a human eating a monkey, which is something humans like doing.

But if the smaller spiders can fight back at all, it might well make that battle less appealing.

	▲	eimrine 2 days ago \| parent [-]
		Spider fight is wrestling about who does the one shot one hit, they do not hit or puncture in other in order to make just a mechanical damage.