Hi, today I was working in a garden when the owner & I realised there were beetles falling from the air while mating and crawling all over the grass. They were quite good flyers but in their clusters of 2,3 or 4 they fell. They were mostly centered around a medium sized whitebeam, landing on the leaves, and flying around it in fairly large numbers. They were chunky around a cm long, thick bodied beetles, brown wing cases with bumps at the back, black heads, grey blue underneath. A look through a beetle book suggested elm beetles. I brought two home and did my best to photograph them. If they are elm beetle why are they present in such numbers? I stopped on the way home and looked at some elm sucker hedges but saw no beetles anywhere around.
Alex and Chris,
I presume you are referring to the Elm bark beetles, Scolytus multistriatus and S. scolytus.
Your look verty similar.
There are some other species in that genus in the UK, and I don't have a key to separate them.
But that is immaterial, because your beetles are about twice the size of those.
Considering other members of the Melolonthini tribe:
There is a slight similarity to summer chafer, Amphimallon solstitialis.
But your beetles are about half the size of those.
It may be:
- Hoplia philanthus
It is about the right size: 8-9mm long
I don't think it is:
- Amphimallon fallenii or A. solstitiale
- Omaloplia ruricola
- Serica brunea
So this is a partial reply: your beetles are not elm bark beetles.
I hope somebody else can ID them.
My best guess for now is Hoplia philanthus, the Welsh chafer.
I see you posted while I was writing!
I note re your Phyllopertha horticola:
"A striking and very distinctive species although without experience Hoplia might be mistaken for this in the field."
If you're sure, that's fine with me.
Thank you it is a Welsh chafer, I took alot of photos and comparing them to the articles it is clear, in fact the two I photographed were a male and a female (red and black legs). The text says it is uncommon, at an estimate there were 300 - 500 madly mating in that North Norfolk garden, so we were lucky to see such a lot. The large cock chafer is common here too.Thanks Chris