This is number three of my five favours: I offered to research something.

Cristina commented, asking me to look into whether her 97 year-old aunt was mad. Not generally, but regarding her belief that leaving conkers around the house deters spiders from hanging around and doing, you know, spidery things. My findings (using Google and Yahoo! Answers) are below.

I’d never heard of conkering spiders (ho ho). But it’s apparently something lots of people think is true. And ‘thinking’, opposed to ‘knowing’ seems to be the theme with conkers (The word Conker for example, is “perhaps related to French conque meaning a conch, as the game was originally played using snail shells.”)

Forums around the web are littered with more ‘perhapses’, but also lots of people professing to have had genuine success with the technique. So Cristina’s aunt is not alone.

There seems to be no actual ‘proof’ that conkers deter spiders. However, The Royal Society of chemistry is currently attempting to set the record straight. They are “carrying out experiments” in people’s homes and offering £300 – yes £300! – to anyone that can back the claims with “persuasive evidence that ‘conkerphobia’ really exists.”

John Edwards of the RSC offers this crucial advice:

“Apparently they have to be fairly fresh to have their deterrent effect. But there are claims on the web, pardon the pun, that spiders don’t like them at all.”

A tip that may or may not have been followed by these school children in Cornwall. (Thanks to Friday and Yahoo! Answers for the tip-off)

[I love the idea of a 'spider choice chamber' by the way. Must use that as a metaphor soon]

This was a gallant effort at ‘science’. In the comments on the RSC blog post, though, two more thorough insights are offered up by readers. The first is from a textiles student who had done his own research. He says:

“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.”

This is backed up elsewhere too. Then a second person suggested that it’s actually…

“…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”

Which would explain this: Betterware’s SPIDER STOP, which “contains natural chestnut extracts” to “deter spiders without causing them harm”.

So Cristina, there seems to be some documented proof of chemicals in chestnuts that deter spiders/insects. Perhaps not enough proof to be certain. I can at least say that if your aunt is mad, then so are lots of other people. On the plus-side, if she can get a photo of a spider – preferably in tears – fainting next to a conker (could be dramatic if she gets its reflection in its shiny surface) she could win 300 big ones from the RSC. Something to think about.

Tags: miscellaneous