There are a few beetle groups that have me scratching my head. The genus Cercyon for instance. Apart from C. analis which is rather elongate, the majority that I come across are carded and put away for a rainy day and a time when I can compare to some known specimens, preferably in a museum. That's not going to happen soon is it?
This one came to light this summer. At 2mm it's fairly typical and I just go round the houses with key trying to convince myself that I'm taking the right path through the couplets. The added problem with this genus is that some of the key characteristics are underneath, so how best to keep them?
Cue clumsy segue into a beetle I can actually identify. This time one of the Byturidae. This family has only two UK species. So far I've only ever come across Byturus tomentosus aka the Raspberry Beetle, a notorious pest of gardener's raspberries and other cane fruit.
Looking at a sample this evening I found the other species in the genus, Byturus ochraceus. It's a bit bigger with larger eyes and slightly more hefty looking pronotum.
Which is which?
There's some good comparison pics and info on the old Watford Coleoptera Group site here.
Post title inspiration is the only song I know with raspberry in it!
I'd not come across any bark beetles before this year, but I have now encountered a handful of species. I beat my first, Tomicus piniperda, from Scot's Pine at the start of the year and then several others have all been attracted to light (plus one species to recently cut wood) during the spring and summer.
I tentatively identified another new one today from a tube of samples from a moth trapping visit to Chippenham Fen back in May. I find the best method with this group is to picture match to narrow it to genus before hitting the keys for specifics.
Having struggled with the keys to genus, a couple of quick comparisons to the images online got me to Dryocoetes. There are only 3 species found in the UK with a fourth having been recorded as a non-established introduction.
The first couplet in the key is how deep the sutural striae are. Basically the bits either side of where the elytra join. This was hardly deepened at all leading to this being D. autographus. Looking at images of the species with deeper striae I'm pretty confident I'm correct but as I keep discovering with beetles it's often two steps forward and one step back!!
The post title link comes from a certain Mr D Bowie.
What else is there to do on a dark, wet and cold evening except crack open a tube of light caught beetles from the fridge and identify a few?
I seem to have avoided water beetles by dint of me only ever having stuck a net in water a couple of times. The ones I do see are the ones that come to light but diversity is normally low. However, on the really hot August nights this year there were several news ones turning up that I'd not encountered before.
First up were several of this rather elongated beetle with a slightly reddish coloration. Liopterus haemorrhoidalis. At 7mm it's pretty easily recognisable and goes by the common name The Piles Beetle. I shit ye not! I guess the specific name derives from the beetle's colour but then someone decided to have some fun. Fair play to them, this one's name will forever be ingrained in my memory.
There were also several species of the genus Hygrotus.
Firstly the common H. impressopunctatus. This species is really strongly punctured and the elytra look quite gnarly under the microscope. Length wise it comes in at a respectable 4.8mm.
This next individual was a little larger at 5.1mm and had much more subtle punctures and a slightly more elongated shape. I think this might be H. parallellogrammus which is species often associated with brackish water although there are quite a few records from inland water bodies. One to get checked at some point.
This other species was much more diminutive at 3.7mm and is H. nigrolineatus.
Other new (for me) water beetles included this Ilybius fuliginosus, another really common beetle but not one I'd come across before. You can see the yellow flashes down the side of the elytra that helpp distinguish this species.
Last but not least was a new species of Enochrus, and one that was easy to ID. The black head in contrast to the pale pronotum and elytra make this E. melanocephalus.
I must say that apart from the dreaded Hydroporus genus I'm slowly beginning to warm to water beetles. It's even got to the point where I can feel a possible effort to be made next year on this group, especially now that I have a net sat in the garage not doing much...
After the opening beetle there could only really be one song to accompany this post....
The carabid beetle genus Ophonus is one that I almost exclusively see whilst light trapping. In fact I have only ever found them through other methods a couple of times, usually from looking in the seed heads of wild carrot.
There are 14 species to be found in the UK. One of them, O. ardiosiacus turns up regularly in the garden over the summer months and on the warmer nights can be pretty common.
I find some of these really difficult to key out. Of the species with sharp pronotal hind angles there comes a point in the key where you need to make a judgement on pronotum width and curviness. It's the couplet that separates O. puncticeps.
For puncticeps it says the pronotum is more narrow, less than 1.3 times as wide as long, sides are little contracted or sinuate towards base.
Other species should key the other way as they should have a wider pronotum, more than 1.3 times as wide as long and it's more sinuate laterally.on the width to length ratio of the pronotum, and also the amount that the edge of the pronotum is sinuate (curvy).
So here are a couple of species of Ophonus. One should key one way, the second, the other. But which one is which?
I'll put you out your misery, the species on the right should have a narrower pronotum and a less curvy side. I can convince my self that it's less wide than the species on the left but as to less wavy? Wouldn't have thought so.
Luckily both these individuals are male so I was able to dissect to confirm their identity. Here they are side by side. Can you see a difference in pronotal shape?
I've confusingly swapped them in this image 😂
The aedagus of the right hand beetle (from the top photo) confirms it as O. puncticeps (see below it's not it's in fact rufibarbis). This turned up fairly regularly in the garden over the summer to light, and this year was the second most commonly recorded species.
The left hand beetle is a different species and its aedagus suggests it is O. puncticollis. This species appears to be much scarcer with very few recent records and those mainly in Kent. But once again I suspect the NBN isn't up to date and I imagine this species is a bit more widespread.
To my eye, at least the pronotal differences aren't that obvious. Especially when once factors in that these are encountered at night whilst light trapping. It reinforces the need to have comparative material and to dissect occasional males for confirmation. It would have been quite easy to miss this one.
EDIT: Having looked at this again and examining the inner sclerites of the aedeagus I can see that what I thought was puncticeps above is in fact rufibarbis which explains the problem I have had with the pronotal feature..... You live and learn.
EDIT: also the puncticollis might in fact be melletii so it's safe to say I've really messed this one up!
The new beetles keep on coming. But out of the fridge now that I've put a pause on collecting anything at the moment. I need to finish the back log of IDs and records before I'll allow myself to do some sieving of the compost heaps at the end of the garden.
There are still several tubes left of light trap beetles to deal with. First up this week was Stegobium paniceum, also known as the Drugstore Beetle. This is the only member of its genus. It is found across the world and apparently is one of the most frequently encountered pest species, infesting a very wide range of stored products. First time I've seen it though.
The other new species for me from the last trawl was my second species of Monotoma. On the right you can see the really common Monotoma picipes but on the left is what I think is Monotoma longicollis. It's smaller, shinier and the pronotum is widest at the front.
Another warm August night, light trap beetle had me scratching my head. On first look I thought it was going to be a Cryptophagus. I had planned to dissect and card and put to one side to look at when I have more comparative material. Cryptophagus are what is technically known as a f**king nightmare. Possibly my least favourite genus that I have encountered so far.
But on looking down the microscope I was greeted with the above sight which, whilst similar, was definitely not a Cryptophagus. However, I was fairly clueless after that fact.
Some help on Facebook pointed me at Cryptophilus, an erotylid. The only species listed in the latest Duff is C. propinquus but in the last checklist there is only C. integer. NBN also only has the latter. What's going on?
So it turns out that Cryptophilus propinquus is one of the two species that until recently had been known collectively under the name Cryptophilus integer.
But someone worked out that the beetles identified as Cryptophilus integer were in fact actually two different species! So there had been confusion. I guess this might happen when beetles are a bit boring and not much to look at. The type specimen of Cryptophilus integer was examined to see which of the two species would be assigned the original name, but then it turned out that the type specimen of Cryptophilus integer was actually not a Cryptophilus at all, but a junior synonym of Micrambe abietis.
Yes, I'm confused too.
Anyway these shenanigans resulted in the resurrection of two other species names, to fill the gap for the two species previously known as C. integer.
Cryptophilus propinquus
Cryptophilus angustus (this one after some further drama).
My one is propinquus and was first described in the wild in the UK from a Vane trap in Richmond Park in 2006. It has been expanding rapidly and has been found in piles of rotting vegetation as well as to light.
I've not been up to much natural history for the last couple of weeks as the weather has not been the best and work has been rather frenetic. What snatched moments I've had have been given over to working through the beetle backlog that is currently residing in my fridge.
In mid August, when the moth traps were delivering good numbers of cool beetles I took a few specimens of Anotylus rove beetles. Anotylus rugosus is a really common visitor to light and I see it frequently from spring to late summer. Most of the ones I see are the all-black form but they also come in slightly paler form with redder elytra. I'd not seen or looked at the paler ones so decided to take a couple for a proper look.
The easy way to tell them is that they have a crenulate (wavy) edge to the pronotum and a clypeus (front of the head) that is dull and matt due to microsculpture.
In the picture below you can see both these features in the right hand individual.
2 female Anotylus
A couple of the Anotylus (see left hand beetle in above and below image) didn't have the matt clypeus in fact it was the same shininess as the rest of the head. Going through the key this suggests that these must be A. insecatus. This would be a new species for me. The left hand individual has less extensive striations on the top of the head and slightly smaller eyes which both seem to fit with this ID.
When viewed side by side the presumed insecatus is also more generally shiny
Annoyingly, the two individuals caught were both female so I couldn't check the abdominal sternite feature in the key, although I have to admit to struggling with this on other species. Just need to compare these to paler rugosus females now.....
Numbers in the moth trap were much lower this week but included most of the Autumnal species that one would expect to see in this part of VC29. Bycatch of other species has really dropped off since the last of the warm summer evenings, pretty much limited to craneflies, wasps and the odd ladybird.
A fly in the moth trap this week caught my eye. I have seen this species before but I have never had a proper look at one and more importantly never actually recorded it.
It's a female Sargus bipunctatus, also known Twin-spot Centurion, a species of soldierfly. It's a relatively common autumn species across most of England, but iRecord still sends me an automated email to tell me that my record is outside of the known range. I suspect it does this every time a new 10km square is filled in.
