Leaf beetle ?

[peterbolson]

I found this floating in the river. 7mm long. For a long time I thought it was dead as in stayed motionless in the position of the first photo but just as I was about to dispose of it it woke up.

[Jason Green]

Evening Peter,

It's a Flea Beetle from the Chrysomelidae sub-family Alticinae.

I trust you still have the specimen? I hope so, as to key it out I need a well-lit shot of the ventral surface - in particular all six coxae, and one each of the middle leg and lower half of the hind, jumping leg to check for a spine.

Whilst these beetles seem easy enough to key-out, ideally you need a pinned specimen under the microscope as it needs frequent rotation between the legs, elytron surface, antennae examination and legs too. These features just won't show in sufficient detail from field-captured photographs. I believe your approach is to collect the specimen home and bring it's temperature down and get it more co-operative. That should enable you to get the shots needed. I hope!

Take care,

Jason

[peterbolson]

Hi Jason
Funnily enough I took this photo when I thought it was dead. It might help but doesn't answer all your queries. I'll have another go tomorrow.

[Matt Smith]

It's not a flea beetle, it is too large and does not have the developed "jumping" hind legs of a flea beetle. This is one of the larger Chrysomelids - Chrysolina banksi

[peterbolson]

Thanks Matt.
I can't find it in Harde's Field Guide - does it have another name ?
I see from bioimages that it grazes on a number of wild plants, ribwort & mint being most relevant to where I found it.
Peter

[Jason Green]

Ah, in the cold light of day compared to your post - yes, the hind femora are too narrow. Sorry Peter! I didn't read the size. I must have been tricked by the rear tarsi and rounded body - I'm working on a mounted one at the moment.

Originally Posted by Matt Smith

This is one of the larger Chrysomelids - Chrysolina banksi

Thanks - out of interest, what is unique about this one, making it banksi?