A Sticky Business

Part of my role as maintenance man is to deploy and regularly inspect various pest control devices. My 'pest control arsenal', amongst many other things, includes some sixty or so sticky traps, cleverly and discretely hidden around the premises. I check these on a weekly basis and write up any relevant findings. And no, I've never seen or trapped a roach here, something everyone but me will doubtless be glad to hear. I'd quite like to add it to my 1K square list...but don't tell the bosses that!

I've been especially looking out for the various tiny beetles that may, if left to themselves, get into the flour bins or amongst the bran and undergo a rapid population explosion. Partly because I'm keen to see the kitchen remain essentially pest free, but mostly because I'd really quite like to see one! I've had a run of 'nice' finds in the sticky traps this autumn, culminating in what may be the first Scottish record for one tiny beetle. 

In case you aren't sure what a sticky trap actually looks like, this is pretty similar to the type I shove behind headboards and beneath beds, I use about twenty five of these.

The wee beasties crawl in, stick to the glued floor inside and I monitor any unwanted 'guests' within

I use more robust traps in the kitchen areas and it's these traps that turn up the goods. But before we get around to the star of the show, here are a small selection of sticky delights to whet your appetite. All of these pics were taken by holding my camera up to the eyepiece of my microscope, clicking and pretty much hoping for the best, hence the poor quality

Ptinus fur - 3mm of loveliness, unfortunately not allowed in the kitchen area

Tegenaria domestica - by far the largest victim of the sticky traps

Lepinotus patruelis - a very small (2mm) indoors barkfly with reduced wings

A member of the Liposcelididae family of barkflies - well beyond my capabilities!

Chilenocaecilius ornatipennis - 2nd Scottish  indoors record of this invading South American barkfly

If nothing else, these traps are great for recording barkflies! But this morning I found a tiny beetle (so tiny I needed a microscope to confirm it was definitely a beetle and not a grain of debris). As soon as I clapped eyes on it, I knew it was something I'd never seen before. 

What the heck is that???

I initially wondered if it was some sort of exotic weevil without geniculate antennae, but soon ditched that thought. I was still in work time, so I couldn't spend too long trying to figure out what I had discovered, but I needed to know if it was a potential pest species. I found it close to where the flour bins are located, was this a dried food pest? Would it get into the flour or bran? What about all the dried fruit and cheeses? Heck, what was this thing?

I limited myself to 15 minutes Googling for inspiration and thought I was onto a firm lead with some of the smaller silvanids of the genus Silvanus that sometimes get into grains. But they weren't quite right, though they led me to a thing called Oryzaephilus surinamensis which looks very cool indeed. I really want to see one of those! 

Just as my time was up I hit lucky and figured it was a latridiid, and a good visual match seemed to be Adistemia, a small genus of just twelve species, only one of which is on the British list. I managed a short video clip before scurrying back out to work again

After work, I used Mike Hackston's brilliant Key to the family Latriididae and ran my beast through without difficulty to Adistemia watsoni, something I'd never even heard of before. It's rather a small beetle, coming in a little under 2mm fully extended. Not precisely a pest species, it scavenges bits of mouldy organic debris for a living. Not that the head chef will appreciate me telling him that, I think I'll maybe neglect to mention anything to him.  

About time I replaced that tape measure...

Unfortunately, due to it being well and truly gummed to the sticky trap, I made a bit of a mess trying to extract it for carding. One elytron came clean off and the back legs were solidly stuck together. I didn't bother trying to set it properly, I just blodged it onto the card as was. Facing left to right, in fact (best I could manage seeing as it was gummed to the forceps and mounting needle as well as glued to the card!) It's fine unless you need to see the hind and middle legs... 

I had a look on the NBN Map and was pleased to discover there are no records north of Wales (usual NBN caveats apply). Whacking the pics onto the Beetles of Britain Facebook Group was a popular move with quite a few folks liking it and one expert confirming the ID. I may have to start checking these sticky traps more often, who knows what will be in them next time!

The one thing that bothers me is that it has black eyes (in keeping with most latriids) but Adistemia watsoni is supposed to have pale eyes. See here! 

So if it isn't watsoni...what is it???

Edit: consensus between the experts seems to be that dry-mounted specimens are prone to losing the blackness of the eyes, maybe the author of the link above has been fooled by this phenomenon. Images of live animals all seem to show dark eyes. 

Incredibly, it would appear that this beetle has not been recorded in Britain this century!!!! Last sightings were in my old stomping ground of Epsom Town in 1999, when John Owen found them in numbers inside accumulated pigeon droppings beneath a nest ledge. I'd heard the story of the 'rare beetle in the Epsom carpark' several times over the years, how incredible that I've blundered into that same species 20 years and 600 miles later - yet when John Owen found it in 1999, I was living within a mile of it. Truly bizarre!