Are spiders scared of conkers?
Posted by Jon on Fri 9 Oct 2009Categories: RSC in the media | [4] Comments
As a high-minded learned society and professional body, with the patronage of Her Majesty herself, we are duty- and honour-bound to promote chemistry and make it accessible to the public.
So when flooded with queries from the public and RSC staff regarding the efficacy of conkers as a spider repellent, we shook ourselves dry and led the charge on a public scientific endeavour – to prove or dismiss the old wives’ tale that spiders really do hate conkers. For the best evidence (one way or the other) we’re offering a prize of £300.
We hypothesise that if it works there must be some chemistry in it. So the call went out to the public, through the illustrious pages of the Daily Telegraph, The Times and Daily Mail, various radio stations, and BBC Breakfast – and the public have responded with eyewitness accounts, photos, videos and even scientific experiments!
Let’s start with our own experiments. RSC staffer Will Russell cleared his busy schedule to spend part of his weekend taunting spiders with conkers and a control object (a table-tennis ball). The results were somewhat inconclusive – each spider reacted differently. Some good scientific methodology here: repeat experiments, a “control”, and the will to do a science experiment on the weekend.
Even Will’s rigorous experiments could not compare to those of Years 5 and 6 of Roselyon School in Cornwall, aided by teacher Mr Ferguson. The budding young scientists designed their own experiments with clearly-defined parameters for success, and demonstrated three of them on camera. They concluded that spiders weren’t bothered by conkers for the most part. Their video is below and well worth watching.
As I wade through the hundreds of letters and photos I’ve been sent, I’ll add more to the overall body of evidence. Below is a gallery of some of the more enlightening photos that we’ve been sent.
Mon 12 Oct 2009 at 11:07
Shame on you RSC! You are using an oft-mistaken tree name to advance your new web page, thus spreading, virus-like, this misinterpetation of a perfectly valid ancient building practice. Firstly, it is not the Horse Chestnut (Aesculus hippocastanum) but the Sweet Chestnut (Castanea) that deters spiders. And it is not the fruit of the tree but the wood itself. Which is why builders use it for rafters and roof trusses. And yes, I can provide proof, but you would need to visit some ancient buildings I could show you to witness their freedom from spiders over the ages.
Mon 12 Oct 2009 at 11:18
Malcolm,
Thanks for the note – you clearly feel very strongly about this!
We’re simply highlighting and questioning some supposed wisdom passed down from generation to generation: that conkers, placed around the house, deter spiders. We’re not advocating or dismissing anything, we’re adjudicating the evidence provided by the public.
Any new light to be shed on the subject is most welcome! We’ve had comments from others, especially in France and the US, that cedar or sandalwood are often used in construction to repel insects with their aromatic scent.
And if this blog post were to be spread “virus-like” or, as internet marketeers might say, “virally”, I’d have no problem with that
greater exposure for more evidence to lead to a more sound conclusion!
As it stands, the bulk of documentary evidence we have been sent says this old wives’ tale works. I remain to be utterly convinced by objective evidence, however…
Mon 12 Oct 2009 at 15:10
In 2005, part of my MA Textile Conservation Dissertation concerned the subject of the clothes moth (not spiders) repelling properties of conkers. Some conkers had been found in an old trunk filled with ceremonial furs and costume and had seemingly protected the contents from attack. My research found many interesting anecdotal stories of a past custome to collect and distribute conkers in drawers and cupboards every autumn to protect contents from insect larva damage.
It is hard to summarise in such a short space but-
The brown skin of the conker contains the triterpenoid saponin, which is a natural insect repellent. Horse chestnut extract is often used in products such as shampoo. The chemicals known as terpenes, are also found in essential oils such as lavender, widely used to repell insects.
It was thought that these chemicals can be detected by the adult female moth or carpet beetle(and maybe spider)disrupting the female’s instinct to lay her eggs close to a food souce such as wool. It is only the larvea which feed on clothing.
Since writing my Dissertation, for the past five years I have kept a juicy piece of woollen cloth in a margerine container with eight conkers (replaced every year)in the dark, warm space under a chest of drawers in the bedroom, on a wool carpet. I have never found any damage or even larvea on the wool, only occassionally a dead adult moth.
Today I did my annual clean under all the bedroom furniture and chimney cupboard in my old cottage, replacing old conkers with new. I have not found any evidence of insect larvea and no spiders at ground level! Normally we have to evict the big Harvest spiders at this time of year elswhere in the cottage. However, most spiders seem to prefer to hang out at the top of walls and on ceilings in my place.
I think the glorious horse chestnut tree and its conkers should be greatly valued – it has so many uses!
Cheryl
Tue 13 Oct 2009 at 06:37
For three or four years I have placed small piles of fresh conkers around my house,in corners and behind furniture. They definately deter spiders as I have windows and doors frequently open and there is a perfect environment outside for them. I can usually be free from them for almost the whole year.