One of the good things about recording beetles is that you can do it at any time of the year, since many beetles overwinter as adults. In summer techniques like sweeping and beating are used to find active insects, but in winter the emphasis shifts to finding insects that have tucked themselves away in various hideouts to await more favourable conditions. Habitats like litter piles, loose bark, crevices and rotholes in trees, and particularly the base of grass tussocks, are all worth exploring.
I had had some success a few days earlier on the River Etherow where flood refuse had piled up along the bank, so had decided to visit to Chester Meadows on the 15th January to see if I could find any more riverside litter. There are several spots on The Meadows where the bank of the River Dee is accessible. Mid-January is not normally a time you would associate with field entomology! It was bright but only about 6C with very little evidence of any activity as I worked my way along the bank, scraping up oddments of litter and sieving them. A few small carabids were pooted; one of the big problems of winter collecting is that most beetles will be inactive, or at least play dead in the tray, so very little is moving and things can be very hard to spot. The solution to this is not to try; good field time is precious so you simply bag up the sievings for later searching, and move on.
If you want to find a lot of different beetles then you need to search a lot of different habitats. There were quite a few opportunities in the area; a decaying log near the river’s edge (prise out a few lumps and crumble them through the sieve); a very old willow (scrape debris behind loose bark into tray, retrieve abandoned bird’s nest from rot-hole). A little further along someone had left a pile of chipped timber so this was sieved thoroughly. I’ve often found woodchip piles to be interesting; they need to be warm and well-drained and should show signs of white fungal growth. In this instance the side exposed to the sun was suitable, and was peppered with fungal hyphae, while the shaded side of the heap was wet and black and rather nasty. You rarely find anything in this material.
The final technique I wanted to try – which I actually hadn’t used much previously – was ‘tussocking’, where you cut a grass tussock off at its base, and shake it over a sieve to extract the insects hibernating there. The tool of choice is a small pruning saw, preferably a folding one. You don’t want a tussock that’s too big because you need to saw it off quickly. Having found a suitable tussock, you gently ease the grass up to expose the base, then saw it off. Ideally you should not go deeply into the soil (although I’m sure there’s interesting stuff there too) but the insects will be fairly deep so you don’t want just the open grass top either. A little practice is needed to cut it at just the right spot, then quickly drop it into the sieve, get your fingers into it and open it up thoroughly so nothing can hide.
This was much more successful and I found Bembidion, Agonum, Oxypselaphus etc. in large numbers along with hundreds of small Staphs and some hibernating ladybirds. All topped off with a generous helping of Alder Leaf Beetles of course. Different tussocks had different character, those growing near isolated trees being particularly rich in occupants. But by this point my feet were freezing so I fairly quickly worked about a dozen tussocks, bagged the result, around a kilo of material, and made a run for the car. The day’s ‘takings’ were about 20 species in the pooter and a couple of kilos of fine sievings.
On getting home you can dump the sievings into a tray and wait for things to start moving, and you will find quite a lot that way. A good headband magnifier is a great help for this. But many beetles are very small and easily missed, so a much better method is to let the beetles do the work by using an extractor (Figure 3). This is just a coarse sieve basket held over a bucket; the litter is filled into the basket and the insects drop thorough into the bucket due to their own activity.
Some will climb to the top of the basket where they can be easily retrieved. After half an hour and a cup of tea, the basket can be carefully lifted out, and the first crop of invertebrates tipped from the bucket into a deep petri dish where they can be sorted under a low power stereo microscope. The bucket can be checked every few hours and will continue to yield a stream of insects. After a day it helps to give it a stir; I also add some shredded paper to open it up a bit. The insects are captured and sorted live, so anything unwanted can be released.
Although they may seem similar, an extractor works on different principles to the well-known Tullgren or Berlese funnels, which force insects into a collection jar by gradually drying the material from above with a heat source. The extractor needs no heat source; a large fraction of insects will fall through within 24 hours, and at this time the material will be little drier than when it started.
So what were the final results? Even I was a little surprised at the final tally of 114 species for a 2-hour field session in January. If you bear in mind that I’d only pooted about 20 species, and perhaps could have pushed that to 40 if I’d searched the tray in the field, then you can see how invaluable the technique is. You do, of course, have to have the time to deal with all this material when you get home! The full list of captures is at the end of the article, but as many of these will be unfamiliar, here are a few highlights:
Encephalus complicans (Figure 1) is a small Staphylinid, not particularly rare but previously I’ve only found singles, however in this case the extractor yielded around a dozen. It’s fascinating to watch as it can curl its hind-body upwards, completely and tightly around it’s shortened elytra, almost like a pill woodlouse, and then looks like a tiny ball as it runs about!
Isochnus foliorum (Notable A) (Figure 2) is one of the Rhamphini, the jumping weevils, whose hind femora are enlarged to allow it to jump, a bit like Alticine leaf beetles. As far as I know the only other Cheshire record for this species comes from Wybunbury.
Sepedophilus bipunctatus (Notable B) (Figure 4) is predominantly a southern species in rotting timber. Ralph Atherton and Don Stenhouse reported it new to Cheshire in 2010 and since then I’ve found it four times so it must be doing well.
Tropiphorus terricola (Notable B) (Figure 5), a large weevil which I previously found at Chester Meadows a few years ago, this is its only Cheshire locality as far as I know.
Rhinocyllus conicus (Notable A) (Figure 6) is a weevil that feeds on thistles. Formerly rare, it’s expanded its range in recent years and is spreading from the south. I’d heard records from Staffordshire and was hoping to see it in Cheshire soon. It nearly escaped me as I found it making an exit along the edge of my desk!
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