RHoman's picture

Copper Bottomed Confusion

The "Copper Underwings" have made many an iSpot appearance and will probably pop again in the coming weeks. Until now, the emphasis has been on securing an ID based on the hindwing colours and now this -

linked from


If this is a good feature then some of the iSpot "CU aggs" could be seperated????



DavidHowdon's picture


The upperwing characteristic is known but to my knowledge not reliable. The recent "British and Irish moths: an illustrated guide to selected difficult species" from Butterfly Conservation states "The underside of the hindwing is the most reliable feature" (and goes on the describe the feature well discussed elsewhere on iSpot).

It notes that "Other external characters should only be used as a guide".

This guide also notes that "The hidnwing underside is not totally reliable" noting that in "some berbera the discal area is quite pale" making the copper suffusion hard to see and so recommends dissection in those cases.