Very Unusual Yellow Caterpillar - Dorset

[dgreves]

Hello. Can anyone ID this large yellow caterpillar for me please? It has baffled every expert I've shown it to so far. It was about 3 inches long on calcareous grassland in Purbeck, Dorset, UK. Spotted in the first week of June this year.





I also shot some video at the same time if this helps:

http://www.vimeo.com/12359960

Any ideas welcome!

[millerd]

My "Observer's Book of Caterpillars" (1979) is not very helpful, but amongst the illustrations, the nearest match is the Goat Moth...

Dave

[dgreves]

Definitely not a Goat Moth I don't think but thanks Dave. Closer to a Swift Moth of some variety but none which I've been able to match.

[Charles Nicol]

possibly Broad-Bordered Yellow Underwing...

http://www.flickr.com/photos/26138378@N03/3521829674/

they seem to have an ant problem !!

Charles

[Trev Sawyer]

Scanning through Porter's "Caterpillars of the British Isles", the closest I can find would be "Large Wainscot" or "White Colon" but I don't think they are right either. It's a real noodle-scratcher, so you may be best to ask Reg Fry on the UKleps.org site.

Trev

[dgreves]

Charles - Broad-bordered Yellow Underwing looks a definite possibility although a lot more speckled than this suspect.

Trev - can't find Large Wainscot or White Colon on ukleps - do they have other names?

I emailed Reg at ukleps but I know he's not keen on ID queries and no reply so far. Can anyone get me an introduction?

[Lee Hurrell]

You could always try Ian at UK Moths (http://www.ukmoths.org.uk) EDIT - I've edited this to the correct address.

Cheers

Lee

[dgreves]

Lee - ukmoths.org appears to have been hijacked by a domain name registrar.

[Lee Hurrell]

Sorry, it should be www.ukmoths.org.uk

Cheers

Lee

[Trev Sawyer]

Large Wainscot is Rhizedra lutosa and White Colon is Sideridis albicolon.

Trev

[dgreves]

Lee - I did take a look at ukmoths.org.uk last week actually but couldn't find an email address to contact Ian. Any idea what it is?

Trev - ukleps doesn't seem to contain either of those species. Anywhere else you've seen the caterpillars pictured? Habitat described on ukmoths doesn't sound like a good match.

[Lee Hurrell]

There is a 'contact me' link on this page:

http://ukmoths.org.uk/email.php

Cheers

Lee

[Trev Sawyer]

I've not seen any photos apart from the ones in the book I mentioned
I don't think they are correct - they just looked as close as any in the book. Then other place to try, may be the Hants Moth site... I got a tricky caterpillar identified via their Moth talk ID page a while back See: http://www.hantsmoths.org.uk/forum/index.php

Trev

[Dave McCormick]

I asked a friend of mine who is an expert on the early stages of butterflies and moths, he suggested a prominent moth of some sort, but this even had him stumped, but I was really surprised it stumped him, he has always surprised me in caterpillar/Egg IDs. I posted a link to this message on UK Leps group to see what they come up with

[dgreves]

Dave - thanks. Would you really describe it as "Green" though? I'm seeing yellow.

[Dave McCormick]

Yeah, I'd say yellowish-green

[Lee Hurrell]

Hmmm, sort of mustard...

[Dave McCormick]

I got a reply on the caterpillar, although its not a 100% ID, but it might be this, Reg Fry from UK Leps suggested it is a powedered quaker cat that is parasited and moved into the open and he said that would explain the caterpillars, but powdered quaker usually conceales itself when pupating and doesn't normally venture into the open.

[dgreves]

Dave - thanks. I'm looking at Powdered Quaker on ukleps and I would never have recognised it - that one appears to have quite distinctive stripes the entire length of its body in all its illustrated variations. But I'm in no position to argue! The body form does look a good match and I bow to Reg's judgement.

When you say it's been parasited you mean the ants may have laid their eggs inside it?

[Dave McCormick]

Parasited, yeah, eggs have been laid in the caterpillar from a parasitic wasp. The caterpillar is unaware of this, it just feeds on after the wasp has done it, the eggs hatch and the grubs eat part of what the caterpillar eats, when the cat is fully grown, it will go to pupate, but instead it will due and the grubs burst out and pupate.