Snail predation by Rove beetles?

[Happibun]

I was wondering if anyone could help me identify what has been eating my snails

I seem to have an abundant population of them, and each year I ensure that they are well fed by planting out tasty young plants for them to decimate in my garden

Whilst gardening a couple of days ago I noticed a pile of empty brown garden snail shells below my shed's water spout. Each shell had a small, slightly irregular hole in it.

I took some photos.





I was wondering if anyone had seen anything like it before. I looked it up on the internet, and the only thing I could think it could be was Rove beetles, like the Devil's Coach horse, but I'm not certain. I could not find any photos with anything similar at all.

I would be so pleased if I could be sure.

Thank you.

[naturelover]

Hi happybun,a warm welcome to the site,yes i have seen this befor,always thought it was a bird, like a thrush.

[Paul mabbott]

Yes, welcome.
To the best of my knowledge any beetles that eat snails (and I'm not aware of rove beetles doing this) do it from the other end. There was another thread fairly recently about this which might be worth looking at - sorry, I'm just going out!

[aeshna5]

As Paul says predatory beetles eat the fleshy part via the operculum. I know there are some carabid (ground) beetles such as Cychrus caraboides that specialise in snails with long narrow jaws.

Song Thrushes smash the snails on an anvil + don't leave small holes like this. Rodents such as Wood Mice regularly feed on snails, but again the damage is more extensive.

I'm afraid I don't know what is doing this though!

[dragonfly]

looks like the work of a black bird to me however there is a parasitic wasp that does eat snails and other small creatures
it would make a hole to get out not in after eating the snail
did you place them all together or is that how you found them if you found them like this i would say black bird

[Kayleigh]

As aeshna5 said, there would be more damage to the shell if a blackbird or thrush had eaten them..They look like they have been drilled into..

[Action_Man]

Dont other snails have the ability to drill into shells and devour the contents ? ...

[Happibun]

Thank you, all of you for putting your thoughts to this, and thanks ever so for the warm welcome too

When I first found the holes in the shells, my first thought was of the similar holes I had seen in fossils caused by Murex (a predatory sea snail), but those holes were perfectly round, where as the ones from my garden were slightly irregular, and anyway, I had never heard of a land equivalent.

My next thought was if this was a bird, but all bird predation I have seen causes much more trauma to the shell, thrushes for example smash it.

One thing that I do think is important, is that these shells are in a pile below my shed's drainpipe. One shell was sitting just in the end of it, the others most probably had been washed down. That means that the predation is happening either in the pipe, or on my shed roof (which is covered by an extensive mature clematis). It would be difficult for a shell to be washed down off the roof of the shed, because the clematis would prevent it, so it seems most likely that the deed is being done in my guttering or the drainpipe.

The next thing I did was post the pictures to my Flickr account Flickr: Photos from Happibun, as I have a few friends there who are naturalists. We discussed the pictures and collectively scratched our heads.

Next I googled some choice words, and came up with a couple of references to rove beetles. One of which was this:-

Devil's coachman blurb on Flickr - Photo Sharing!

From: The Gardener's Guide to Common-Sense Pest Control
by William Olkowski, Sheila Daar, Helga Olkowski - 1996 - Gardening - 320 pages (Click the link for the pic, I can't paste it directly.)

So amazing as it may seem, the most likely candidate I have is a beetle. I am incredulous too, but that is why I am asking if anyone else has seen anything like it, or knows more.

I am intrigued also. I would love to know more about the mechanism the beetles use, and why go through the shell if you can get at the soft parts anyway? Perhaps they are attacking the shells when the snail is hunkered down and hibernating. Most interesting is why there is so little about this on the internet. Usually you can find all sorts when you start to search, but this brought up almost nothing.

Paul, if you could get round to directing me to the thread you mentioned that would be great. Ta

Jo

[hedgerow]

This is something that I have heard about but never seen evidence of. Never understood why they go through the shell instead of around but its really interesting in concept.
good luck
hedgerowmobile

[Paul mabbott]

http://www.wildaboutbritain.co.uk/fo...il-shells.html