GardenBanter.co.uk - Beetle(?) ID

On 29/05/17 08:52, Chris Hogg wrote:
On Mon, 29 May 2017 07:44:21 +0100, Jeff Layman
wrote:

Any idea what these are? They were 7 - 8 mm long, and around for about a
month before disappearing last week. I thought that they were beetles of
some sort, but I have always assumed beetles were insectivorous. Nearly
all the plants we have found these on (the one shown here is a purple
Corylus) have small holes in the leaves. But I never saw one in the act
of eating a leaf.

https://postimg.org/image/mnlet237p/

Surely they're beetles, but what sort, I can only guess at, even with
the help of an insect identification book! But making that guess, I'd
go for a member of the Chrysomelidae, which contains 25,000 species,
250 of them in the UK. My book says "They are almost all leaf-feeders
and are commonly called leaf beetles. Most of them are quite small,
and many are brightly coloured, often metallic", which would seem to
fit the general appearance of yours. Possibilities include Agelastica
alni (Alder leaf beetle) http://tinyurl.com/ya3923co and Chrysolina
coerulans (Blue mint beetle) http://tinyurl.com/y7tyj54u Both are
lustrous blue beetles. Some brief descriptions and links on this
rather general page on new and expanding insect species,
http://gwydir.demon.co.uk/insects/WatchList.htm (scroll down about
half way).

Thanks for that. I think you are spot on with Alder leaf beetle. I had a
look at the RHS page (via your demon.co.uk link) and found this:
In 2014 it was re-discovered in southern Hampshire (Southampton) and
is also spreading in that county." I am just outside Southampton, so it
fits well. We've never seen it here before, and it has done a little bit
of damage as the photo shows. But maybe its larvae, which might appear
in the next few weeks, will do a lot more.

I'll get the spray gun primed... :-)

--

Jeff