Grey Dagger caterpillar, but what is it doing?

Miss Caretaker · #1 (**permalink**) 16-08-2010, 05:33 PM

Evening folks!
I spotted this Grey Dagger (I think!) cat. on a rose bush this afternoon and after reading up on UKMoths it says that they overwinter as a pupa. My first thoughts on seeing this was that it was preparing to pupate, but I'm not sure now as I can't imagine anything with any sense chosing the upper side of a leaf to pupate on; surely it would get picked off by a bird. My second thought was parasitisation (sp?) but I really haven't a clue! Any help out there?!

Thanks,
Jo

GuyF · #2 (**permalink**) 17-08-2010, 03:14 PM

Quote:

Originally Posted by Miss Caretaker

Evening folks!
I spotted this Grey Dagger (I think!) cat. on a rose bush this afternoon and after reading up on UKMoths it says that they overwinter as a pupa. My first thoughts on seeing this was that it was preparing to pupate, but I'm not sure now as I can't imagine anything with any sense chosing the upper side of a leaf to pupate on; surely it would get picked off by a bird. My second thought was parasitisation (sp?) but I really haven't a clue! Any help out there?!

Thanks,
Jo

I'd say that your second thought is probably correct. It looks to me like a parasitoid has emerged from within the caterpillar and formed a cocoon which you can see underneath the body. The culprit is probably a species of Ichneumon Wasp.
Guy

p.s. I agree that it's a Grey Dagger!

Miss Caretaker · #3 (**permalink**) 17-08-2010, 05:31 PM

Thanks, the thing that confused me was that the caterpillar still seems to be alive; I always assumed (never assume anything!) that the cat. would be dead by the time the parasite emerged from its host. I had a look just now and it still wiggles if you give it a gentle prod

Thanks for the id confirmation too!
Jo

Harry Eales · #4 (**permalink**) 19-08-2010, 10:05 AM

I agree the white object is a parasites cocoon. Many infected larva they do not always die at the time the parasite emerges, but can linger on for several days. They don't recover though, it will die in time. It's certainly worth keeping the parasites cocoon and pupae, there's still a lot to be learned about which species parasite which moth species.

The parasite could be a fly or a parasitic wasp species.

Harry

Miss Caretaker · #5 (**permalink**) 19-08-2010, 10:22 AM

I could put the leaf it's on in a jar but I think it'd be so tiny when it emerges that I won't be able to get a decent photo. Who would I be able to send it to for ID and who would need the record of what emerged?
Thanks,
Jo

Miss Caretaker · #6 (**permalink**) 20-08-2010, 02:16 PM

Just to update; I have popped it in a container and am awaiting the patter of tiny feet. However the poor caterpillar is still alive

. 4 days on and I can still see it occasionally waving its head about in what looks like an effort to move. I wonder if it feels pain...
Jo

ollyk · #7 (**permalink**) 20-08-2010, 08:22 PM

I actually think it is in a zombified state (it has not been, and still not acting normally) and perhaps kept alive on reserves to act as a decoy for any potential predators???
Best to leave and let nature take it's course.

On second thoughts maybe in some bizarre twist it has to be predated to complete the lifecycle

Miss Caretaker · #8 (**permalink**) 03-09-2010, 07:00 PM

Just a quick update on the caterpillar; it's still alive and yesterday it was moving about so much that I could see that it wasn't actually attached to the pupa. I can't believe it's still alive after going all this time without food

. The pupa has got darker recently but still no sign of it emerging...

Jo