Phyllobius/Polydrusus weevil, Surrey

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Phyllobius/Polydrusus weevil, Surrey

My first ID query on the new website- truly a milestone in my pan-species career...

Found this broad-headed weevil on birch leaves at Fairmile Common this morning. I had it down as P. pyri, but now I'm not so sure. Polydrusus marginatus is often associated with Betula, but I guess that's a bit of a long shot? 


Hopefully they've uploaded OK... 

EDIT: Eish! They are quite big aren't they? I guess I'll resize them next time. 







The dorsal antennal

The dorsal antennal insertions are the key to Phyllobius - I remember it by the 'o' in the middle of  PhyllObius reminding me of the circular easily visible antennal insertion points, but then I'm odd like that. In Polydrusus, the insertions are lateral and you can only see one not two from any specific angle.


It looks good for Phyll-O-bius pyri to me, but I await shooting down :D

I'd never heard about the

I'd never heard about the antennal differences before. Thanks for that! 


Agree with Jonathan that this is Phyllobius (and love the 'O' mnemonic, will have to remember that), and assuming there is a tooth under each femora (which I think I can just see) then I can't see any reason for this not to be P. pyri. But P. verspertinus is supposed to be very similar (I've never managed to find that).

It is pyri - the clue is the

It is pyri - the clue is the pale scutellum.  Pyri is the only species in which the scutellum is paler than the adjacent elytra and thus stands out visibly.  This is a useful ID trick when you can't put the insect under the microscope to start checking the scales.


Thanks for that Clive, but does it rule out vespertinus? Photos on the web seem to show that with a pale scutellum as well.

I've never seen vespertinus

I've never seen vespertinus either.  Morris says that all morphological differences with pyri are slight, and some authors do not regard it as a good species.  I think further work is needed before I would put a tick against vespertinus.  pyri is in itself quite variable.