On Yellow Flag at Thundry Meadows, Elstead, Surrey. Pairs in cop and singles seen. Some of the females were a metallic BLUE. (Seen in cop with a brown male). Donacia?
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Many thanks. I HAVE a specimen - is it an easy dissection?!
Yes it is in males which are very well endowed, then as I said it really comes down to whether you believe the species are genuinely distinct and you can decide from the characters in the Menzies Cox paper in the British Ent & Nat Hist Soc Journal 1996 available to download here http://www.biodiversitylibrary.org/item/94526#page/419/mode/1up. good luck!
There's a bit more about distinguishing these two species in Mike Cox's "supplementary material" to his Chrysomelidae atlas - the supplementary material can be downloaded from this page (scroll down the page to find it):
Entomologist and biological recorder
Thanks for all your help!
Does the fact that some of them were stuffed into the flowerhead of a Yellow Flag (and they were all on YF) point towards sericea?
Iris isn't a larval foodplant of either species, if they are different species. The adults go to flowers to feed on pollen and aren't too particular about flower species. Sedges are another favourite. However, yellow iris suggests you are in a not too acidic site, which tips the balance slightly towards sericea s. str. A sharp close-up of the pronotum would help, but dissection of a male is the safest way to put a name to it.
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