www.ukbutterflies.co.uk

Hi, looking after peacock butterfly species I noticed some strange formations, cocoon lookalike. All caterpillars successfully pupated, only at the bottom of the cage the 'cocoons' remained. I attach a picture. The 'cocoons' remind me of cinnabar moth pupa, only they are smaller and not as ridged. I don't think other species were mixed with peacock caterpillars, we bought them from a vendor.
Just to say we are only hobbyists, we release the butterflies with my toddler once they pupate.

Hi Kat,

The pupae you have discovered are those of a species of parasitic fly and will have emerged as grubs from some of your Peacock caterpillars or pupae just prior to their own pupation. If the former, you will find some dried up husks of deceased caterpillars and if the latter, some of your Peacock pupae will have little holes in them. Either way unfortunately, these ones will never become butterflies. I'm afraid I don't know enough to say which species of fly will eventually emerge from those pupae.

Cheers,

Dave

Thank you Dave. That's quite sad, but it explains actually why we have more empty chrysalis than released butterflies. I will put them in the garden, I don't like flies at all brrr