miketh's picture

Unidentified blue green bug/beetle

Observed: 19th August 2013 By: miketh
Blue green beetle 5mm

Found thousands (probably millions) of these flying beetles or bugs in a corn field near our home. Blue Green body with an orange/brown neck and two antennae at front - about 5mm long. Thought they were cereal leaf beetles which are 'Oulema melanopus' but the internet pictures seem to be different so I now think I agree with rockwolf that it is more likely 'Gastrophysa polygoni' which is also a type of leaf beetle - but is different sub-family of the Chrysomelidae family - cannot find anything else to match it.

Species interactions

No interactions present.

Species with which Leaf beetle (Gastrophysa polygoni) interacts


miketh's picture


Thanks rockwolf. I typed in both my genus and your suggestion and found the following extract from a Canadian paper..'Gastrophysa polygoni can be confused with Oulema melanopus (Linnaeus, 1758) as they occur in the same habitats and are superficially similar. However, G.Polygoni possesses a distinct lateral bead on the pronotum and confused elytral punctures whereas the sides of the pronotum are rounded in O. melanopus and its elytral punctures are arranged in regular rows. Difficult to tell them apart in my photo but I think Gastrophysa is correct.

rockwolf's picture

Have always

found the Gastrophysa has a far more 'rounded' appearance than the Oulema which are slightly slimmer.
The Leaf beetles (Chrysomelidae) aren't the easiest of families! :-)