Every year in the Autumn, our 8-legged Arachnid friends that have been living quite happy outdoors all Summer, start to move indoors. It is therefore not surprising that Cleankill (along with most other pest control companies), receive lots of enquiries about spiders at this time of year. In addition to the usual enquiries, there has been a lot of recent interest and concern about False widow spiders, following the concerns raised in newspaper and internet articles.
The False Widow Spiders belong to the group Steatoda, of which there are six species know in the UK. They are not aggressive spiders, but as with most spiders, it is never advisable to directly handle them.The Noble false widow Steatoda nobilis is usually found in walls, fences and under tree bark; where they do no harm but spend their time simply feeding on insects and other spiders, and are best left alone.
False widow spiders are NOT in the same family as the highly venomous Black widow spider (Latrodectus mactans) found in North America. The Black widow female hangs upside-down and usually has a distinctive bright red hour-glass shaped marking on the shiny black underside. The Natural History Museum website states that only 12 out of the 640 UK resident spider species have ever been known to bite humans, and that nobody has ever died of a spider bite.
The Natural History Museum’s Insect Information Service hears of about 10 cases of spider bites each year in the UK. Spiders in the UK will only usually bite when accidentally squashed against the skin. Arachnophobia (the fear of spiders and other Arachnids such as scorpions) is very common and, in many tropical countries, it makes a lot of sense to be wary of spiders, as there are a few critters out there that you would be best advised to avoid. The world’s most venomous spider is the Brazilian Wandering Spider, an aggressive spider that can be found wandering the jungle floor at night, and hiding under logs, rocks and termite mounds during the day.
The simplest way to deal with invading spiders, that will avoid you having to make any direct contact with them, is:
a) To suck up webs and spiders with a vacuum cleaner, and then deposit the offending items in a bin (preferably located outside).
b) For the occasional intruder that most of us experience from time to time, there are also insecticide aerosols that are approved for spider and crawling insect control, that can be purchased from hardware stores.
c) If it all becomes too much, then Cleankill can also offer advice and treatment with insecticidal sprays and Ultra-Low Volume insecticide treatments, to control spiders.
d) In addition, although I can find no record of it being scientifically proven, many people find that conkers (or horse chestnuts) placed around the house, do seem to deter spiders. Apparently they do not like the smell, and conkers with holes in work even better.
Please note that another common invader at this time of year – Crane flies (or Daddy long legs), are flies and not spiders. The larvae of Crane flies feed on grass roots in lawns and gardens, before pupating and then emerging as adults in the Autumn. They seem to have had a particularly good year this year, with lots of adult flies hatching and then flying into houses through open windows. There is unfortunately no simple cure to the flying invasion apart from keeping the windows shut!
The Natural History Museum website archive article entitled “the truth about false widow spiders” from which many of the facts in this article have been sourced, provides an excellent summary of key identification features, biology and the likelihood of being bitten.