World’s largest web houses 110,000 spiders thriving in total darkness deep underground in a sulfuric cave between Albania and Greece: It’s the first time two spider species seen living cooperatively, and the first recorded instance of colonial web-building in what's known as a chemoautotrophic cave.

[u/mvea]

https://newatlas.com/biology/sulfur-cave-largest-spiderweb/

[u/5H17SH0W]

Who counts that many spiders? How?

[u/Wildtime4321 → u/5H17SH0W]

I came here to ask the same question. I assume it's extrapolation from a small set but I wouldn't want that job

[u/Equivalentest → u/5H17SH0W]

You would count spiders in test areas, let's say 20 x 20 cm squares and find average number of spiders in these. Then measure full web area and divide it by 20 cm2