The Humbling River

Just downhill from here lies Uig Wood, with a block of native 'Celtic Rainforest' woodland heading upstream of the road and a 130 year old planted woodland dominating the downstream side of the same road. The upstream section has a footpath that dead-ends after just a few hundred feet at the remains of a weir (dynamited apart in the 1930s by a person with a grudge to bear, apparently!) Unlike the busy downstream section, this upper section enjoys far fewer visitors. I like it, it gives me the opportunity to act like a complete insect geek in public, all in relative safety and anonymity.

The river has been running high for much of the year thus far, thanks to an extremely extended wet period, but it has now finally subsided somewhat. Subsided to the point that I can safely explore the backwaters and pools for diving beetles without the need for chest waders, a sturdy rope and an emergency whistle.

Now you may call me childish or simple-minded (and honestly I don't mind), but I find it absolutely captivating to quietly watch diving beetles swimming around underwater as though they own the place. Which in their world they clearly do. One genus in particular would appear to be quite common in the river; Oreodytes. These are small diving beetles, closely related to the far larger Dytiscus diving beetles that many folks are familiar with. There are only four members of the genus known to occur in Britain, Oreodytes alpinus, davisii, sanmarkii and septentrionalis. O.alpinus is a curiosity in Britain, known only from the far north eastern corner of Scotland and presumed to be a relict species left over from the last Ice Age. It's also the only member of the genus I've yet to encounter. 

A couple of days back I found myself at the edge of a shallow pool, watching a couple of Oreodytes swimming across the surface of algae-laden stones, I managed to hook one out without too much difficulty. Back indoors I soon had it carded and ready for identification

Pity it has lost an antenna

This is Oreodytes sanmarkii, a species that I've found here before. And here is the other species of Oreodytes that I've found in this river

A very poorly carded specimen, I know this...

I must have been in some sort of a tearing rush when I carded this beetle, it's appalling! I need to find another and set it out properly. This is Oreodytes davisii, which, at 3.8 - 4.5mm, is more elongated and somewhat larger than the commoner Oreodytes sanmarkii (2.9 - 3.3mm). 

Here's a pic of them side by side

My carding technique is definitely improving...

That's a pretty obvious size difference when shown side by side! I've recorded Oreodytes septentrionalis only once before, with Mark Telfer at Loch Garten last year. Mark retained and determined the specimen, hence I'm keen to find and determine my own at some point. Plus I'd really like to get up to that top corner of Scotland and see if I can locate Oreodytes alpinus for myself. 

I haven't listened to this track for a good few months, YouTube tells me it now has something to do with the soundtrack to a Transformers film, which is pretty gutting. Anyway, if you don't know it, this is Puscifer with their sublime track The Humbling River