Rove beetles and a wood borer.

[Gerel]

Hi,

I found dozens of these smallish rove beetles (Stenus sp. ?) sheltering under a piece of corrugated roofing. Anyone know why they congregate in such large numbers?



This little wood-borer (about 3mm) came out of a dead ivy stem. So far I have got nowhere with identifying it.



regards

Steve

[Dogghound]

1. Stenus Either S.clavicornis or S.providus I tend to think the latter is a better option. Although they are very similar, and should have genital examination to be sure.
2. Orchesia undulata

[Rossco]

Nice behavioural photos of the Stenus rove beetles, Steve. I've never seen a group of them like that, but as it's the winter they probably aggregate so that finding each other in the spring when they need to get it on is that much easier.

The O. undulata you found eats fungi.

[Paul mabbott]

These ground hunting beetles such as Stenus will, like other species, concentrate (a) where they're protected and (b) where their prey is. Their prey will collect where they're protected from the environment! Stenus hunt Collembola and other small invertebrates which are abundant under ground cover.
PS: Note the relative size of the eyes of Stenus spp compared to other staphylinids - very large, necessary for visual hunting.

[Gerel]

Thanks for the replies, there were over a hundred of the Stenus, all within an inch or two of one edge of the piece of roofing (which was only a couple of feet long). Quite strange to see so many at once.

I should have known the O. undulata, as I found and ID'd one last year .

A beetle, a bug and a hopper.

It was right inside the stem which is why I was thinking of boring beetles, I suppose it must have followed something elses tunnel.



Steve

[Dogghound]

Originally Posted by Gerel

It was right inside the stem which is why I was thinking of boring beetles, I suppose it must have followed something elses tunnel.



Steve

This is a perfect overwintering site, this will have been what it was doing until you found it.

[Gerel]

Originally Posted by Dogghound

This is a perfect overwintering site, this will have been what it was doing until you found it.

Make me feel guilty why don't you?

[Dogghound]

Originally Posted by Gerel

Make me feel guilty why don't you?

Its likely that you have completely wiped this species out in the local area which could lead to nationwide declines in the species, resulting in various bird species loosing their staple diet causing the whole eco-system to collapse. Hehe. Im sure it will be ok if its frost free.

[Gerel]

Originally Posted by Dogghound

Its likely that you have completely wiped this species out in the local area which could lead to nationwide declines in the species, resulting in various bird species loosing their staple diet causing the whole eco-system to collapse. Hehe. Im sure it will be ok if its frost free.

Oh dear

(Actually the ivy was attached to some firewood I was fetching in, so if it had stayed where it was its chances would have been exceedingly slim )