UK Residents Warned: False Widow Spiders on the MoveExperts are urging people across the UK to keep windows shut as the False Widow spider enters peak mating season. Dr. Tom Elwood, arachnologist, explains that August is when males roam indoors through windows, vents, and even drains in search of mates. Though not deadly, their bite causes wasp-like pain, swelling, and fever. Cases of serious reactions have been documented. To stay safe: shut windows, seal cracks, clean frames, trim nearby plants, and use peppermint oil as a deterrent. With climate change extending their activity, preparation is key to avoiding unwanted encounters.