This exemplifies how humans are distorting the ecosystem.
As global warming makes more parts of the world hospitable to more creatures, humans are struggling to adjust. Some are having a harder time than others. Take a secondary school in Gloucestershire county of the U.K. that had to close down today due to an infestation of Britain's most venomous spider.
The false widow spider (Steatoda nobilis), as the spider is known, is related to the deadly black widow, but its bites are less dangerous to humans. Reactions generally range from swelling and feverishness to extreme pain—in other words, severe allergic reactions.
Given that, British tabloids may be overdoing the arachnid drama with headlines like "Millions of KILLER spiders on the loose across the U.K." or "False widow spider ATE my leg." Personal accounts abound as well, such as that from a man who collapsed in a Southampton Toys R Us after being bitten 10 times, or of another who was sidelined from his amateur football club due to a bite. (The latter required surgery.) Other bite victims have suffered hospitalization and even amputation.
Aside from their dramatic effect, the spreading spiders exemplify how humans are distorting the ecosystem. Since the spiders first arrived in the south coast of England in the late 1800s on cargo ships from the Canary Islands, shipments of imported bananas have continued to boost their populations. False widows have colonized most of the southern U.K., as well as Ireland. They're basically an invasive species that keeps invading.
That alone doesn't explain why the spider has crept steadily northward—it’s been seen as far north as Norfolk—or why that spread has gathered speed in the last 25 years, as the U.K.'s National History Museum reports. Confirmed false widow bites have risen each year since the first one was recorded, in 1999, as entomologist Stuart Hine explained.
Scientific consensus has it that global warming is probably the cause, as it allows them to breed faster and thrive in areas that were once too cold for it to live in. "It is likely that this spread is at least partly a response to a changing climate," Dr. John Tweddle, an NHM scientist, told the Telegraph. "[A]s such we’re expecting the species to continue to increase its distribution within the UK."
This post originally appeared on Quartz, an Atlantic partner site.