Snail predation by Rove beetles?

[Kayleigh]

Originally Posted by Happibun

Bugbotherer, you are in luck.

I took these photos of the smaller snails too. The only reason I didn't post them last night was that I was processing them to get the most out of them. By the time I had finished, I was too sleepy to post them.

Number 3 is an anomaly, it has a different apex angle, and quite a pronounced shoulder. I don't have a snail identification book, so I can not identify these, but I don't doubt that they are what you say they are. These pictures should help with a positive identification though.

Anyhow, there I was getting increasingly sold on the idea that the predation was due to some carnivorous snails, and it may well be still in part at least, when my eye was drawn to some movement inside one of the smaller shells I was photographing.

This crawled out...

Well blow me! Talk about jammy luck...

OK, so that is way too small to be an adult Devil's coach horse, but it could be a first instar. From what I have found about them, the 3 instars are similar to adult in shape if not size. Certainly it is Rove beetle shaped, and it flicked it's tail up when I poked it, but then I gather other species of Rove beetle do that too. It moved blooming quickly, and I'm afraid that it got away from me after I managed to get a couple of shots. I'm really sorry about the quality of the pictures, but it was small and fast! You can just about make out a powerful set of jaws in the second photo.

So... whatever is eating my snails (and you can bet that there is more than one type of predator noshing one them), may still be a beetle or a carnivorous snail. The evidence for what is making the little holes is still inconclusive.

All this really brings me full circle to my original query, 'What does rove beetle predation look like?', only now I also need to find out what zonitidae predation looks like too, and I need to find out quickly, the children are getting increasingly mutinous. Thankfully DD has not seen the beetle pictures yet, or I'd be banished along with the shells in to the garden

I have tried to appease her with stories of wasps in fridges, and so on, but she has decided that I am mad, that everyone that I talk to is mad too, and that she can sue for child abuse. I may be left with no option but to counter attack with some obscure entomological interest in the fridge myself, though I draw the line at cockroaches (and live fishing maggots - don't they have a habit of escaping? ).

Obviously, I'll let you know if I find anything else.

Jo

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The snails made me do it!

This thread is fascinating although the only thing I know about snails is they eat my Hostas. I'm with the kids on this You should be out in the garden, haven't you got a garage or shed to examine your specimens

Yes! the maggots did escape into the back of MY CAR. He spilt the tub and did't tell me For weeks I had to open the hatch and doors to let the flies out before I could drive anywhere..

[geckoeye]

Hey look at this! You might have got it spot on right from the start (before my possible red herring). Be really interesting to hear what the nhm people come up with

Slug and snail control

Here's the quote to read from the link above:
"Rove Beetles (Ocypus olens) are native to Britain and are natural predators of slugs and snails. They are about 2.5cm in length and have large jaws, predation of snails can be recognised by the jagged hole on the side of an empty snail shell. "

[haematocephalus]

Originally Posted by Happibun

OK, so that is way too small to be an adult Devil's coach horse, but it could be a first instar.

Beetles have larvae (with several instars), then pupae, then adults, which don't grow any more - your photo is of a small adult rove beetle, not Devil's Coach Horse.

Don't know whether this is another potential predator of the snails, or attracted by the rotting flesh, or a predator of the other predators!

Martin


Martin Harvey

[geckoeye]

I know you already posted a quote about rove beetles leaving 3mm holes in snail shells Happibun. The above quote supports this and also describes them as jagged which would seem to fit...I had such high hopes for Zonitidae. Now I think I'm more in the rove beetle camp. Especially after the one you found with the shells

[Happibun]

Originally Posted by haematocephalus

Beetles have larvae (with several instars), then pupae, then adults, which don't grow any more - your photo is of a small adult rove beetle, not Devil's Coach Horse.

Don't know whether this is another potential predator of the snails, or attracted by the rotting flesh, or a predator of the other predators!

Martin


Martin Harvey

Thanks for sorting my confusion out Martin. Aye, well my ignorance is proven, I get well befuddled with things with lotsa legs (and in the case of larvae, no legs at all?)

The little beetle is way too small to make the holes in the brown snail shells. It'll be a carrion opportunist no doubt, cheesed off that I was wobbling it's restaurant around.

It in itself is no proof that the bigger rove beetles are around then.

[Dogghound]

Other possibilities are the Staphylid was over wintering in the snails shell, i agree this is 100% not Staphylinus olens Devils coach horse. They are a very large family with lots of similar small black species. I very much doubt rove beetles are capable of biting a hole in the side of a snail shell then burrowing in, in my experience the attack the snail when it is partly withdrawn from its shell, or through the shell opening. Im sure if you crack a number of shells with holes in and without holes you will find a large amount of other species living in them.

[Dogghound]

Also the rove beetle itself is a member of the sub family Oxytelinae, Likely Anotylus sp or possibly Oxytelus sp .

[Kayleigh]

Originally Posted by geckoeye

Hey look at this! You might have got it spot on right from the start (before my possible red herring). Be really interesting to hear what the nhm people come up with

Slug and snail control

Here's the quote to read from the link above:
"Rove Beetles (Ocypus olens) are native to Britain and are natural predators of slugs and snails. They are about 2.5cm in length and have large jaws, predation of snails can be recognised by the jagged hole on the side of an empty snail shell. "

Looks like I need to set up the right habitat to attract the rove beetles...I already have the right one for the snails..So maybe they are here already..I am a great believer in letting nature take its course..Where there is prey there will be predators. When the weather gets warmer I will go on a snail hunt..

I wonder it there is a water snail predator equivalent equivalent

[Bub-les]

I have no answers but its a fascinating thread
looking forward to some more thoughts, ideas and answers
Barbara