Snail predation by Rove beetles?

[Meta menardi]

Well I am certainly not bored by this, but don't go and sample a load more, you seem to have a consistent result and now it neds to be sorted out.

If you get all the evidence, it could take time to have more created, some of those shells look quite old.

I think the predation by other snails sounds very interesting, you must be building up a load of candidates for this.

[thes3raph1m]

i would take a look inside that drainpipe... remove it if you can, force the snails out by placing it into some water (i dunno if that would work, but if someone tried to drown me in a pipe i was simply holding on to... id move) ID each snail in there... perhaps some of them are this ?nitidula? thing or perhaps some of them are showing signs of damage but are not dead yet...

also set up a time lapse camera... perhaps there is a frenchy in your garden with an irregularly shaped straw??

can anyone say escargoe a la fraiche

[Happibun]

Dearest Daughter has asked me to point out that she does not have a mild phobia of snails, she absolutely detests them. She is now officially on strike from dishwasher duty until I remove the shells from the kitchen.

Littlest said he didn't want to eat his breakfast where he could see them.

Huh!

I will not compromise my scientific integrity, or insatiable curiosity! It could be worse, there could be live ones in the batch, and I did make sure that I shook most of the woodlice and earwigs out of the shells before I brought them in...

I pointed this out to DD this morning, and she ran out of the room squeaking. Honestly! Kids nowadays...

Today I plan on going on another snail hunt, but this time it will be for Zonitidae. I have purchased a little ruler, for the vast sum of 35p to get some scale in to my shots, but I won't go as far as dismantling the Victorian cast iron drainpipe, or uprooting bestrawed Frenchmen in my shrubbery just yet. I might consider manufacturing an elongated bottle brush type thing though, if I really want to count how many gastropods live in the drainpipe high rise. At the very least, it should afford my neighbours some amusement.

Jo

______________________________

The snails made me do it....

[Meta menardi]

Originally Posted by Kayleigh

They will be selling Aegopinella nitidula in garden centres soon along with nematodes..

Sadly Kayleigh, having checked the NBN site for distribution of the species, it is pretty well everywhere in the country, so it is probably there already, just not effective enough to protect Hostas (and I have to say that a god display of Hostas is a delight).

[bugbotherer]

Fascinating thread.
Here's a few of my thoughts for the melting pot. When a snail is overwintering they are firmly stuck to a surface using a modified mucus secretion that may be repelant to predators as well as an attractant to other snails. Once it's stuck down the only way to get at the soft bits would be to either go through the glue or drill through the shell. Another thought is that they may be parasitised and then the only way out for a parasite would be to go through the shell (if it's stuck down). There are a number of dipteran snail parasites (who's life cycle is just tad hazy in this respect) that might be considered along with the beetles.

[geckoeye]

Hey good effort! Good set of new pictures. As you say 1.04 is a bit interesting - the 'snail varnish' looks a bit like its been rasped away all around the hole though other parts of the shell have peeled off also so tricky to tell if its a sign of the entry technique or just weathering. The other shells don't have it quite as pronounced. Is that why you pointed out 1.04?

If you want an expert opinion I'd suggest maybe contacting someone at the natural history museum. I wouldn't want to encourage everyone to bombard them with questions about nature puzzles - they're busy folk - but I have found them really helpful when I've been stuck on difficult ID's in the past and the folk that work on the less cute furry 'n cuddly creatures generally seem pleased that someone should take an interest in their subject. There are some mollusc folk in this list:
Staff directory - Natural History Museum
and email address is usually x.surname@nhm.ac.uk i think (where x is first name initial). Otherwise the BBC Wildlife questions and answers might help but could take a while to get a reply.

Hope we're all put out of our suspense soon!
Happy zonitidae searching,

PS snail shells are good to eat for strengthening growing bones - your kids should be eating them!

[geckoeye]

Hey good effort! Good set of new pictures. In haste....
As you say 1.04 is a bit interesting - the 'snail varnish' looks a bit like its been rasped away all around the hole though other parts of the shell have peeled off also so tricky to tell if its a sign of the entry technique or just weathering. The other shells don't have it quite as pronounced. Is that why you pointed out 1.04?

If you want an expert opinion I'd suggest maybe contacting someone at the natural history museum. I wouldn't want to encourage everyone to bombard them with questions about nature puzzles - they're busy folk - but I have found them really helpful when I've been stuck on difficult ID's in the past and the folk that work on the less cute furry 'n cuddly creatures generally seem pleased that someone should take an interest in their subject. There are some mollusc folk in this list:

Staff directory - Natural History Museum

and email address is usually x.surname@nhm.ac.uk i think (where x is first name initial). Otherwise the BBC Wildlife questions and answers might help but could take a while to get a reply.

Hope we're all put out of our suspense soon!
Happy zonitidae searching,

PS snail shells are good to eat for strengthening growing bones - your kids should be eating them!

[hedgerow]

You've done it know Jo,
everytime I see a snail shell I have a strange compulsion to examine it for holes,
no luck yet and I' not sure what I'll do with one if I find it yet.
I have a niggling thought that there might be something about this on one of Sir David Attenboroughs' programs so am going through my dvd collection to find out (good as excuse as any).

As far as the snail shells on in the kitchen, My wife and now grown up kids often open the fridge to find wasps buzzing around in clear containers while I cool them down to make transfer to different containers and examination easier, especially with the hyperactive ichneumons. So far nobody has tried to cook and eat any of them although the first time it happened there where a few choice shouts. All in the name of science of cause.
If I find anything off the dvd's I will let you know.

Pete

[Kayleigh]

My hubby used to keep maggots in the fridge for fishing. until I made him buy another to keep them in..

[hedgerow]

Found some snail damage at last but totally different to the holes so just for Happibun
Snail shell damage DSCF7564 on Flickr - Photo Sharing!

[Happibun]

Thank you Geckoeye, I've got my Nat History Museum insider on the job. He's doing some research, and has given me contact details of the head entomologist and those of the National mollusc man (er, what I mean is the man who does molluscs not a man who is one. Though 'man who does molluscs' sounds worse in some ways, and even worse if he 'did' them nationally).

To everyone, I'm processing some more pictures for your perusal. We have some very interesting developments here For starters, here's the first pic of some different snails I found.

I sectioned off a 2x2 foot section of flower bed next to the drainpipe and searched it for shells that were not brown snail ones. As you can see, I've got quite a few. There are (I think) 2 species here, but I am not sure yet of the ID. The first 3 rows I'm calling type 2 (as opposed to type 1 which was the brown snail), and the little one on it's own by the ruler is type 3. I'm processing aperture, umbilicus and apex angle shots to demonstrate my sub divisions and to help with ID. It is taking time because my camera is rather basic, the snails are very small, and I've had problems lighting them well.

Thank you for your encouragement, for following this thread, and for your input. I love the idea that there are people out there looking closely at snails now. Keep your observations and comments coming in please Pete (Hedgerow), that shot of rodent / bird predation is excellent, thank you.

Here's an interesting factoid: those brown snails that we are so used to, are the fastest snails (slitherwise) in the world.

Let's face it, Hostas don't stand a chance.

Jo

[Happibun]

More for Geckoeye:

Yes, I pointed out 1.04 because the damage to the 'snail varnish' looked like it had been made by radulation. However, with just the one example showing it, it is impossible to tell if all the holes were made like that, or if scraping with a radula really was the cause. my experience has shown that brown snail shells loose their snail varnish, or periostracum quite soon post mortem, indeed, I have seen live snails with extensive damage to this layer, so the lack of it does not necessarily signify that the shells are all that old.

For those of you who might be interested in the morphology of gastropod shells, the Wikipedia article on it is a good place to start - Gastropod shell - Wikipedia, the free encyclopedia

Jo

[bugbotherer]

Happibun,
For a better chance of id amongst the lurking malacologists on WAB you also need a picture of the shells 'other side'. Often the umbilicus (central 'hole') and aperture have detail that can help quite a bit. For some shells you also need a side shot along the plane of the shell. I'm fairly sure that the set of small snail shells are the very common Discus snails (Discus rotundatus). The big brown ones earlier are Helix aspersa

[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!

[bugbotherer]

Side view and umbilicus view throws out Discus rotundatus for both. From those views I would say that both are candidates for being the Strawberry snail (Trichia striolata)

[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