Caterpillar ID, please

Jo Sara · #1 (**permalink**) 29-09-2011, 03:54 PM

Just rescued this caterpillar from my pond. It's about 15mm long. I had a look in my insect book and I thought it might be a Yellow Tail, but looking at other images on the web, it's not quite the same. The Yellow Tail doesn' have the large brown tuft that this one has. The side marking aren't quite the same as a Yellow Tail either. The white markings are only really on the rear half of this one, not all along like the Yellow Tail. And the head is completely black on this one, the Yellow Tail had some markings on it.

Any ideas what this one could be?

Ta in advance.

Jo

P.S. Sorry that the pics are a bit blurred. I was using Macro, I think i got too close because it was so small.

Graham Barker · #2 (**permalink**) 29-09-2011, 09:08 PM

hi
certainly agree that its not like a yellow tail. my guess, hopefully someone will back this up as i dont usually i.d. caterpillars...is light knot grass, Acronicta menyanthidis.
graham

Hedera · #3 (**permalink**) 29-09-2011, 09:15 PM

I agree with you!

JRsbugs · #4 (**permalink**) 30-09-2011, 10:22 AM

Light Knot Grass doesn't have the tufts, look at Knot Grass. One stage matches this well.

Lepidoptera Species by Common Name in Alphabetical Order

Jo Sara · #5 (**permalink**) 01-10-2011, 12:02 PM

Thanks everyone.

I see what you mean, JRsbugs. There is a stage of the Knot Grass that matches my one exactly.

Wow. I had no idea that the caterpillars evolved their patterns as they grew too. That makes it even more difficult to ID them. Good spot.

poschiavanus · #6 (**permalink**) 01-10-2011, 12:08 PM

There's an interesting chapter about this in the "Moths" New Naturalists volume by Michael Majerus (he did his PhD on the genetics of variation of larvae in Angle Shades).

There are a couple of other Acronicta species which change fairly significantly: the Alder moth starts out looking like a bird-dropping, but ends up a dramatic black and yellow.