Monday, September 24, 2018

Whipping out yer bits

It's the thing that those who look at beetles often fail to mention (although I often use it as a line at parties) - the fact that in order to identify many beetle species one has to examine the structure of the genitalia under a microscope.

It's taken me a while to dive in properly but now I've started I have to say that I'm rather enjoying it. And it certainly makes identifying many species just that little bit easier.

Take the staph genus Philonthus. There are about 46 species recorded in the UK and external characters only get you so far, especially if you don't have known reference material for comparison. However, find a male, whip out its bits (or in the case of a beetle, its aedeagus) then bob's yer uncle, much easier. Compare to drawings of known species and play match the nadger.

Each species has an unique key (the aedeagus) that fits the females reproductive tract (the lock). It's this that is one of the methods of speciation for many beetles.

For example, I found this particular individual on strandline material in northern Cumbria. I could only get it so far using the keys but the aedeagus immediately IDs it as P. carbonarius.

Another individual from this genus was collected from cow dung in Cambridgeshire in the early summer. The two red patches on the elytra are fairly distinctive but just be sure the aedaegus identifies this as P. cruentatus.

Another genus of staph Lathrobium. Relatively straightforward to get to that bit but once again the aedeagus confirms this as L. geminum.

And it's not just staphs that this is useful for. I found this Heterocerus mud beetle the same night as the aforementioned P. cruentatus but this individual had been attracted to the light of the moth trap we were running. I only got so far with the key and some of the features weren't that distinctive and I certainly wasn't confident putting a specific name to it. A quick root around and its family jewels confirm it as H. fenestratus a rather common beetle but one that I'm happy that I've identified correctly.......

Sunday, September 2, 2018

Some Spanish wildlife

Back at the end of July we took our family holidays in northern Spain, spending 2 weeks in Asturias.
A great time was had involving lots of rioja, wild swimming and salted pork products.
Butterfly numbers were down a huge amount form last year but there was still plenty to see.

A selection of goodies follows

Saturday, September 1, 2018

A tale of two histerids

Just down the road from me and within spitting distance of the River Cam is some rather uninspiring farmland.

However, it (and some of the vegetation around) hold a couple of rather good beetles, the leaf beetle Chrysomela saliceti and the histerid Saprinus virescens. For the chrysomelid I think it's its only known UK site.

Fellow moth-er and beetler, Bill had found a Saprinus during the week under some knotgrass - where they prey on the associated Gastrophysa polygoni, so I thought I should go and find my own.

I spent a good couple of hours poking about under all the knotgrass I could find but drew a blank. On leaving, I bumped into beetle expert and pan-species lister, Steve Lane who showed me one that he had found up the road in another field edge - untickable and in a pot but still nice to see.

Whilst there he took me through a hedge to the corner of another field where he'd found some good arable plants. All of which were new to me.
Dwarf Spurge Euphorbia exigua
Round-leaved Fluellen Kickxia spuria
Sharp-leaved Fluellen Kickxia elatine
I also saw this, which presumably must be Redshank Persicaria maculosa but doesn't seem 'quite right'.

Steve also mentioned a large manure heap back down the road that was heaving with Lesser Earwigs (cue a guffaw from the clued-up schoolboys) and the staph Astenus pulchellus.

Off I went and got sieving. Both species were easily seen and I also found the rather nice histerid, Atholus bimaculatus, which was a new one for me.

So I did end the day with a new histerid, just not the one I intended.