Homes will see an increase in large spiders in coming weeks as males go on the hunt for a mate, experts say.
Fine weather throughout the summer is expected to result in a “good year” for residents to encounter large house spiders.
Spiders remain in their webs - commonly in sheds, gardens and wood piles - until the autumn, when males become nomadic to search for a mate.
This leads to an influx of male spiders indoors between mid-September to mid-October, while females remain in their webs.
Adam Hart , professor of science communication at the University of Gloucestershire, said: “We’ve been running a survey of house spiders for a couple of years and mid-September through to mid-October is the height of ‘spider season’.
“We’ve had another good summer which means we might be in for another good year for large spiders (or a bad year if you aren’t a fan).”
Results of the Royal Society of Biology’s recent house spider survey found there are approximately 660 species of spider in the UK.
The society, along with the University of Gloucestershire, has developed a free mobile app, Spider in da House, to help people differentiate between them.
Users might spot the giant house spider Tegenaria gigantea, one of the largest species of spider in the UK which can have a leg span of up to 7.5cm.
People used to eat the Tegenaria gigantea, along with other types of house spider, to combat fever.
Mr Hart acknowledged that spiders are not popular with all residents but added the creatures are “very important ecologically”.
“They are diverse and common, and as a predator they are crucial in maintaining the biodiversity of our gardens, woodlands, field margins, hedges - in fact pretty much everywhere,” he said.
Residents can also find jumping spiders in their homes, including the zebra jumping spider, which is recognisable by the distinctive black and white stripes on its abdomen.
The app helps users identify whether spiders are male or female. Unlike in most mammals, female spiders are often larger than males.
Both sexes of spider remain in their webs until autumn, when males go to hunt for females who remain in their webs awaiting suitors.
After a male has found a female’s web, he remains there for a number of weeks, mating with her repeatedly.
The female then overwinters with stored sperm, allowing her to produce more than 10 egg sacs - each containing up to 60 eggs - the following spring.