Spiders in house: How to keep arachnids from invading Northern Ireland homes - including False Widow spiders

This time of year is mating season for spiders, leading to increased sightings across the UK as males leave their webs in the search for a breeding partner.

This means that many spiders will potentially make their way into properties and homes through open windows, under doors and through gaps in buildings, says Paul Paul Blackhurst, Head of the Technical Training Academy at Rentokil Pest Control.

“In the UK there are around 650 species of arachnids, yet we can expect to see less than a dozen of these in our homes," he said.

“The most common species found in UK homes are the Lesser House Spider, which can grow to 17–20mm long, and the Giant House Spider, which can reach 25mm once they enter sexual maturity and if they have had access to lots of food. It is important to note that both of these species are extremely reluctant to bite, preferring to escape and hide.”

Mr Blackhurst also gave advice on False widow spiders.

These have been reported in southern parts of the Republic of Ireland and are said to have a bite similar to that of a wasp.

“False widow spiders are a group of species that resemble the notorious black widow spider, and were accidentally imported to the UK about 150 years ago, with increased sightings in recent years as they adapt to our temperate climate," he said.

"These spiders will only bite humans if they are provoked, with bites usually only cause a temporary pain and swelling at a similar intensity to a wasp sting. Rentokil Pest Control offers a False Widow Spider Monitoring Service, providing an accurate identification of the species before control measures are put in place.”

He also gave a five point plan on keeping spiders out of your home this Autumn.

Protect your house by closing doors and windows, and filling in small holes and limit their food source by clearing away any dead flies, or any other small, crawling insects, he says.

Here are Rentokil Pest Control’s five top tips to make your home as unwelcome as possible to spiders:

1. Vacuum regularly – high and low

Make sure that you hoover the sheltered spots too, such as beneath worktops and behind cupboards and sofas.

2. Remove noticeable webs

This should be done on a regular basis, remembering to check the corners of the ceiling, picture frames and mirrors.

3. Fill gaps

Where possible, make sure that you fill in the gaps between walls, pipework and under the doors.

4. Remove sheltering sites

Spiders will look to tuck themselves away in your firewood piles, garden bags and any compost heaps that you have. Try and also store these items away from the house perimeter walls.

5. Deter all insects

As insects are drawn to light, and with flies and moths being ideal spider prey, it is advisable not to leave lights on unnecessarily.