This is definitely not recommended viewing for arachnophobes.
Twenty-year old Brazilian web designer Erick Reis got a shock when he left his friend’s house in the town of Santo Antônio da Platina in southern Brazil early in February. Looking up, he saw what seemed like thousands of swarming black dots in the sky, hanging off power lines and cables. Those dots turned out to be spiders, crawling across a mammoth web.
Reis filmed the spiders and uploaded the video to Youtube on Feb. 8 so that the rest of the world too could witness the strange phenomena.
The Brazilian news site, G1, which initially reported on the story, identified the creatures as Anelosimus eximius after consulting with a local biologist, reports the Examiner.
Anelosimus is an incredibly social species of spider, colonies of which generally build large webs that can span two or three meters across. They tend to be found in rain forests across South America, but their hammock-like webs have been known to be picked up and blown to a different location by winds – perhaps explaining Reis’s sighting.
However the appearance and shape of the web indicates that that initial assessment may be wrong, according to Wired. Speaking with Deborah Smith, an entomologist at the University of Kansas who specializes in spiders, Wired explains that the spiders in the video appear to be larger than those attributed to the Anelosimus species.
Both Smith and Arachnologist George Uetz suggest that they could be of the Parawixa bistriata species instead. “This colony is quite large,” says Uetz, “the web is fixed, although it is very fine and mostly invisible.” The giant web could be their means of capturing prey, but worryingly for the locals, it’s still unknown whether these spiders are permanently setting up a home or just using the area as a temporary hunting ground.