White worm-like/caterpillar-like creature preying on tadpoles and froglets?

[flyright]

Hello there

I'm new to this forum but really hope there's someone out there who can inform me!

We have a stream-like water feature in our garden (we're in Scotland, by the way - East Lothian) and have been lucky enough to host lots and lots of tadpoles this year. Many of these are at the froglet stage. I was taking a look the other day and noticed that one froglet had a white worm-like or even small caterpillar-like creature attached to its back leg, and was trying to shake it off. The thing obviously had a good grip, because the poor froglet sank down to the bottom of the pond, exhausted. I really couldn't do anything - pulling the creature off would probably have resulted in the froglet losing its back leg, so I let Nature take its course. Then I saw another of these white things chasing the other tadpoles, who had the good sense to swim away double-quick. It seemed to be trying to "nip" them.

Does anyone have any insights into what this thing might be? I'll try and get a photo (not easy - not got a flash camera and the area where these things are is very shaded) - but it's about an inch to an inch-and-a-half in length, all white except for a brown/orange head, with legs a bit like a centipede anda body which is articulated a bit like a caterpillar. I know I can't stop the blackbirds from feasting on the tadpoles (very efficient they are too!) but at least that's a quick death - this looks like a long and painful one and I'm intrigued to know what this thing is.

Sorry for wordy post - hope someone can help! By the way, if even half our tadpoles survive, we'll have a frog-infested garden - great, as this year we have had no midges whatsoever!!

All the best

Susan

[MeadsMan]

Hello,could you see how many legs it had ?There are a couple of things that in there larva stage would likely eat your Tadpoles,I would think it is likely either a Dragonfly nymph,or pehaps Diving beetle larva.Perhaps you can have a look in a book or google it to see if they match what you are seeing.One of those would be my guess,but I am no expert.could you see how many legs it had ?

[flyright]

Thanks for that, Meadsman. I didn't see any legs - to be honest, I cannot remember if it had legs as such. I've done what you suggested, and googled both dragonfly nymphs and diving beetle larva, but the pictures I found of these don't really resemble what I saw. I shall go out again today and see if I can get a closer look!

There certainly are small beetles living in the water feature, which dive and swim about. Not sure if these are diving beetles - they're not very big (perhaps just under a centimetre long, tops).

I shall go out and see if I have anything else to report! Thanks so much for taking the time to reply, though.

Cheers

Susan

[MeadsMan]

The larva and adults of the things I mentioned both are fairly large at both stages.If possable let us know how big it is,and if it has legs.It`s obviously carnivore,I am still thinking it is the larva of something.

[crazylilthing]

Hi Susan,

Was it like this?


http://tbn0.google.com/images?q=tbn:...dpole_crop.jpg

Depending on the light a dragonfly larva could look very pale like this. They are ferocious predators of things about this size and bigger!

Like you, I wouldn't try to save the froglet as it's natural selection.

[flyright]

Hi there

It was a little like that - but kind of "fatter" round the middle. I've been out each day to see if I could see another one, but to no avail! They must know I have my camera....

I'd certainly say this was a ferocious predator. However, if it is a dragonfly larva, I certainly have never seen any dragonflies around our garden. I shall keep looking - today's supposed to be a hot sunny day and there's usually lots of pond and tadpole/froglet activity when the sun shines on the water! Hopefully I might have something to report later...

Thanks, though, for your time!

[Wild-Woman]

Sounds like a species of leech to me.

[crazylilthing]

Originally Posted by flyright

Hi there

However, if it is a dragonfly larva, I certainly have never seen any dragonflies around our garden.

Well, the larval stage can last for several years! A dragonfly could have mated, dropped her eggs on the water and flown off in seconds while you weren't around.

Still sounds like the one to consider unless there's an expert who knows of another powerful carnivorous underwater predator fitting this description

[harasseddad]

One of the water beetle larvae sounds more likely than dragonfly nymph to be honest. For starters dragons hunt by shooting out their mask after stalking their prey; so the actual kill is very fast - either a hit or a miss but in milliseconds. This sounds much more like a bite attack - which would suggest beetle.

[The Woodman]

Have a look at this for any similarity - Dytiscus larva attacking a tadpole.

TrekNature | Attacking Great Diving Beetle Larva Photo