Are spiders scared of conkers?
Posted by Jon on Fri 9 Oct 2009Categories: RSC in the media | [23] 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.
Sat 11 Sep 2010 at 20:15
I am very new to this concept. However, I have dutifully collected conkers this week and deposited piles around my flat, especially in the bathroom where most spiders hang out. Result? Initially MORE appeared near where I had put the conkers, but now they seem to have moved on. Inconclusive!
Fri 24 Sep 2010 at 20:54
I was told about this conker thing a few years ago. I bloomin well hate spiders and therefore every year I collect a pile of conkers and deposit them in small piles next to front and back door, on the bedroom windowledge and in various corners around the house. I have to say I genuinely think that I have noticed less spiders, if any really and considering the spotting of such spiders usually enduces a mad incoherent and totally disproportionate screaming fit! I say it works!
Mon 7 Feb 2011 at 21:26
So wait, is it the wood of the conkers that keeps them away like Malcolm said? I’m arachnaphobic and spiders creep me out. If it is actually the wood, how would you incorporate that into an existing structure?
Sat 7 May 2011 at 08:56
We had always had a constant stream of spiders in our bath until I heard about the “Conker Effect”. For the past 3 years I have put a few conkers around the rim of the bath and the numbers have been reduced to almost zero. I notice that as the year passes and the conkers become less fresh, the spiders become a little more numerous. Once I made the mistake of washing the area under the conkers and then they all came rushing back into the bath. I am convinced!
Mon 9 May 2011 at 22:01
Have you heard of or seen “giant house spiders”? I live in BC, Canada and that is the only creature, let alone the only spider, that scares me. My phobia of that one creature is very serious. Would anyone know if horse chestnuts do a good job at keeping giant house spiders away?
Sun 15 May 2011 at 11:50
Great experiments by Roselyon School, but they do not answer the question. If spiders climb across conkers to escape from water, it doesn’t mean they like building their webs near conkers. We don’t lie down for a picnic in the middle of a patch of nettles, but we would run through a patch of nettles to escape from a humgry lion! Also the short term exposure to conkers are perhaps eclipsed by the need to hide, rather than be exposed to the open. Will get my class onto this next autumn
Mon 16 May 2011 at 09:59
Conkers definately get rid of spiders in our utility room and downstairs loo! Nobody seems to have mentioned that you have to pierce the skin of the conker to let out the aroma which seems to be what the spiders are not keen on. My son Matthew counted approximately 70 baby spiders the year we didn’t use conkers, and since we now use them regularly we get none at all! So, yes, conkers do get rid of spiders!!
Mon 30 May 2011 at 12:35
It seems that the documentary evidence implies that the conkers have to have time to take effect and that the spiders then gradually move away. The experiments are not sufficiently controlled to allow for this as the spiders are clearly stressed by the human contact.
I think an experiment in two different spider-infested buildings over a year might be a better way to go. Fill one with conkers and the other with ping-pong balls.
Tue 31 May 2011 at 10:32
[...] Update: After collecting the evidence, the RSC decided to award the £300 to Year 5 and 6 pupils from Roselyon School in Cornwall who had [...]
Tue 9 Aug 2011 at 19:26
So, if conkers don’t work, what does?
I’ve recently moved into a new flat and have, in the 3 months I’ve been here, already seen 3 LARGE spiders, and numerous smaller ones.
The tiny ones I don’t mind, Harvestmen (A.K.A Daddy Long Legs, in some parts of the world), I also don’t mind.
But the big, hairy, house-spiders leave me petrified – I spent a very distressing night sat, unable to move, in my hallway the other night thanks to two of said monsterous beasties, so, if there is anything that will keep them at bay, then I’d REALLY, SERIOUSLY like to know what it is!
Some sources seem to indicate that various essential oils, particularly citrus, will do the trick, but these same sources often also state that conkers will too.
So, is there any evidence that anything is at all effective in repelling spiders, and if so, what?
Sun 4 Sep 2011 at 09:14
I say conkers do work. I haven’t got documented proof, but I suffer bad arachnophobia and over the last year I have had conkers around the house at specific locations and I have seen one, maybe two, spiders in this time.
But all the years before, without conkers, I used to see, on average, 3 in my room a month and more around the rest of the house.
Coincidence? I think not.
Mon 5 Sep 2011 at 00:22
I am sat here in a cold sweat after just witnessing a HUGE Tegenaria gigantea run down my curtain, and head straight towards me. Fortunately (for me, not the spider) its journey was cut short when a shoe ‘fell’ on it several times.
Conker season is almost here so I’m going to give it a go. Would it be more effective to grind/blend the conkers, or is it possible to make a liquid with them to paint onto window sills?
Tue 6 Sep 2011 at 04:05
i know 2 things that work well:-
1. raid! its gr8 stuff and it gets rid of em for good!
2. a rolled up news paper, also gets rid of em for good!
Thu 22 Sep 2011 at 08:29
Hi all
I’ve always hated spiders, especially the big hairy ones, so I will definitely be trying this conker trick. Everyone I know swears by it! I recently had a horrific experience when a spider the size of my palm decided to set up camp in my kitchen sink. I was hysterical. I had to actually call my mum. God love her, she talked me through getting rid of it really calmly (involving covering it with a tea towel and smacking the living daylights out of it with a shoe!)
But I don’t like killing them – they are good for our environment! And conkers can actually be quite aesthetically pleasing, when arranged nicely
I will definitely give it a go! And Marcus is right – Raid nearly vaporises them!!
Thu 22 Sep 2011 at 08:31
Oh, and I love the suggestions/comments by Ivo Weck and Mark Toner. Hit the nail on the head with those two!
Sat 1 Oct 2011 at 20:47
I AM PETRIFIED BY SPIDERS SO WHEN I HEARD ABOUT THE CONKER TRICK,I COLLECTED A GIANT PILE OF THEM ND PUT THEM IN LOADS OF DIFERENT PLACES IN THE HOUSE ND BOUT 20 IN MY ROOM ND I HAV 2 SAY IT HAS WORKED…TRY IT
Tue 4 Oct 2011 at 11:06
Echoing what Malcolm Smith said in 2009 (I have only just found this website) I had also believed that it was Sweet Chestnut (Castanea) that repelled spiders – as it is used internally in buildings in Tuscany for that reason.
Sun 9 Oct 2011 at 23:56
the biggest trouble with the spider/conker myth is that the type of person to fear tiny harmless animals are the polar opposite of the type of person to go to the trouble of conducting a proper scientific test on such a thing. very dodgy.
its all anecdotal. i expect what is really happening is massive dose of ‘confirmation bias’ combined with the improper recording of presence and absence of spiders in rooms before and during a test period. spider phobics are in desperate hope of a repellent working, and might well fall into the trap of attributing any slight difference in arachnid numbers to the conkers. but what they have forgotten is that spider numbers continually fluctuate anyway,for year to year, month to month and day to day. so unless they have recorded gaps in the presence of spiders when conkers were absent, the conclusion that conkers are effective is totally invalid. i expect people are discounting or ignoring when the the idea doesnt really work very well (which is confirmation bias) and also exaggerating how many spiders really were ‘infesting’ their house before littering their house with huge piles of conkers .
im also theoretically critical because its the exact opposite of what we should expect in nature. evolutionarily, it would be a huge disadvantage for plants to develop chemicals to deter the most important group of insect killers in nature from themselves! moreover, as spiders are not vegetarians, they do not require the chemical sensitivity to avoid certain plants, or distinguish between them. in any case, there are thousands of species of spiders. it would be highly unlikely they would all behave the same way to the conker threat!! logically, it would be of far greater benefit for plants to develop chemicals to ATTRACT spiders to their seeds or foliage. there is evidence that plants attacked by caterpillars attract wasps.
incidentally, i put a pile of fresh conkers next to hole where a big house spider is always in residence. it had NO EFFECT. its still there !
i suspect conkers are neutral to spiders; and treated as merely part of the environment.
you’ll never get rid of spiders. the only effective cure for culturally learnt fears like this (effecting women in western world) is to culturally unlearn it. pick up and study closely one of these 300 million year old beauties of evolution, and dont be so silly.
Mon 7 Nov 2011 at 18:01
A method used in South Africa is to mix 30 drops of citronella in 250 ML water and spray lightly on all the walls. Apparently cats don’t like it either…