Devil’s-bit Scabious Jewel Beetle Trachys troglodytes
While Trachys troglodytes may not be quite as jewel-like as some of its larger relatives in family Buprestidae, it is still a little gem. I’ve only started finding it in the last couple of years while surveying calcareous grasslands with a suction-sampler.
Devil's-bit Scabious Jewel Beetle Trachys troglodytes
The best way to record this species, as Keith Alexander has described (Alexander, 1989), is to look for the larval leaf-mines in the host plant: Devil’s-bit Scabious Succisa pratensis. Late summer into early autumn is a good season to be looking, when the Devil’s-bit is in flower. But if you are confident at recognising Devil’s-bit from just the leaves, the leaf-mines can be found from at least 7th June (my earliest record).
Trachys troglodytes mine
Trachys troglodytes is not the only species to mine the leaves of Devil’s-bit but the shiny black spot is diagnostic; it marks the spot at which the egg was laid and thus marks the point from which the larva starts feeding to produce its full-depth blotch mine.
Until Keith sussed out the leaf-mines and published his note, Trachys troglodytes was regarded as quite a rarity. The current map shows it is widespread in southern Britain, though not nearly as widespread as the distribution of its host-plant!
Reference
Alexander, K.N.A. (1989). Trachys troglodytes Gyllenhal (Coleoptera: Buprestidae) widespread in the Cotswold limestone grasslands of Gloucestershire. British journal of entomology and natural history, 2: 91 – 92. [Browse this article online here].
Pat-a-cake, pat-a-cake, beetling man …
This is Peter Hammond at Langley Park demonstrating his Pat-a-Cake method with fine sievings from red-rotten heartwood.
Here’s a technique for finding the sort of tiny beetles that are so small or well camouflaged that you can’t see them until they move. Try it next summer:
- Tip the sievings onto a sheet in full sun, preferably on a hot surface such as sun-baked tarmac.
- Pat the sievings down into a very thin layer.
- Lay aside your pipe.
- Take up your pooter.
- Get comfy.
- Wait for rare beetles to break cover as the heat starts to bother them.
We were looking for the tiny pselaphine Plectophloeus nitidus, which we didn’t find. But we did see the very distinctive larvae of Scraptia (Scraptiidae) with their bulbous tails that they autotomise (self-amputate) under duress.
5th British site for Dactylosternum abdominale: the back garden
Tony Allen discovered this hydrophilid beetle new to Britain from a silage clamp at Wimborne St. Giles, Dorset in 2003. It didn’t persist in Dorset but next turned up in Colin Welch’s plastic compost bins in his garden at Hemington, Northamptonshire on 2nd October 2005 where it persisted for several years but hasn’t been seen since Colin used his compost in 2010.
Tony had kindly given me one of his specimens so I knew what it looked like and had hoped I might find it in our compost bins one day. So when I lifted the lid on Wednesday 12th October and saw the back end of a hydrophilid heading down into the goo, I had no hesitation in thrusting my hand in to catch it! And Dactylosternum abdominale it was! I soon learnt of two other recent records. Martin Collier and Andrew Duff found it in a rotten hollow poplar log in a plantation near Mundford, West Norfolk, on 29th September, and James McGill found half a dozen on a well-rotted bracket fungus in Swell Wood, South Somerset on 2nd October. It sounds like it is getting established this year, especially as it is being found in more natural microhabitats. I have since found more in my compost bin.
Hawthorn Jewel Beetle Agrilus sinuatus
Hawthorn Jewel Beetle. One of Philip Harwood's specimens photographed at Oxford University Museum of Natural History.
I have never actually seen a live Hawthorn Jewel Beetle Agrilus sinuatus though I have recorded the species on a dozen occasions. It can be found over a wide area of southern England (map here) by looking at mature hawthorns where the D-shaped exit-holes are a tell-tale sign. The D-shape matches the cross-section of the adult jewel beetle: flattened on top and convex below. The holes are best looked for on lower branches that are dying back but can also be found on the trunk and major boughs.
D-shaped exit hole characteristic of Agrilus.
To be extra sure you have found Agrilus sinuatus exit-holes, you can whittle away the bark to reveal the vacated larval borings which seem to always have quite a regular snaky, zig-zag pattern. The larval borings are also illustrated in a note by Keith Alexander (1990) who pioneered the recording of jewel beetles in this way: available online here. I would like to think that the ‘sinuatus’ of the name (given by Olivier in 1790) refers to the sinuate pattern of the larval borings.
Snaky borings of Agrilus sinuatus in a hawthorn branch.
Finding adults in the field must require some luck. They may be very short-lived, they may spend their lives out of reach around the crowns of hawthorns, or they may be too flighty to simply tap them out onto a beating tray. Agrilus sinuatus was regarded as ‘very rare’ by Fowler in 1890, as Vulnerable (RDB2) in 1987, and was downgraded to Nationally Scarce (Na) in 1992 and although still officially Na today we can probably safely call it common, largely thanks to a better understanding of how to spot the signs.
The best way to see adults would presumably be to rear them out of a suitable hawthorn branch. Under natural conditions, adults are active from mid-June to late September so collecting a branch any time up to mid-June ought to do it. The trick would be to find a branch that doesn’t yet have any D-shaped holes in it but looks like it will do soon!
Reference
Alexander, K.N.A. (1990). Agrilus sinuatus (Olivier) (Coleoptera: Buprestidae) widespread in Gloucestershire, and at a Herefordshire locality. British journal of entomology and natural history, 3: 31 – 32. [Browse this article online here].
Rosemary Rainbows: Chrysolina americana
When we moved into this house and planted up the garden with insect-friendly plants, we put in loads of Lavender and Rosemary, hoping one day to attract the Rosemary Leaf-beetle Chrysolina americana. Today I saw the first one in the garden … on Lemon Balm! This is an alien beetle which despite the ‘americana‘ name is a native of southern Europe. It is such a looker that I am happy to welcome it in, in any case it has now become well established since it was first recorded in Britain (at RHS Wisley in 1994): see map here.
Rosemary Leaf-beetle Chrysolina americana
It is best to look for it on Rosemary and Lavender but it can also breed on Thyme and Sage. See the Royal Horticultural Society’s Rosemary Beetle Survey webpage for more info and to submit sightings.
The only similar beetle in Britain is the very rare Rainbow Leaf-beetle Chrysolina cerealis which feeds on thyme on the slopes of Snowdon and in Cwm Idwal. I have been up and looked for it but without success. I hope to see it one day but meanwhile it is great to have americana in the garden.
Carabid twitching
Yesterday I went to look for a rare carabid Pogonus luridipennis at a site near Skegness where it was discovered earlier this year. The site was visited again on 10th September when at least 6 were seen under a piece of discarded carpet within the first 5 minutes, followed by four hours of fruitless searching. On 17th September I also found a piece of carpet within the first 5 minutes but there were only Pogonus chalceus, Dicheirotrichus gustavi and D. obsoletus under it. Two hours of hard graft later and it was looking like yet another wasted journey. And then I found another piece of discarded carpet with dozens of carabids under it including 5 Pogonus luridipennis!
Pogonus luridipennis from Skegness
Published habitat information for this species in Britain includes “on clayish seashores, mostly in marshes under seaweed” and “coastal habitats, particularly saltmarshes”. The reality for this and several other ‘saltmarsh’ carabids is that they prefer the margins of lagoons which are only rarely inundated by seawater. Pogonus luridipennis seems to be particularly fussy and after a long run of records from Salthouse, Norfolk in the 80s and 90s, it was last seen there in 2001 (and has been repeatedly looked for since without success). The last Norfolk record was from Titchwell in 2005 (Dave Gibbs). It has not been recorded from the Severn Estuary for a few decades now. It still persists on the Dorset coast with a recent record from Eype.
Hopefully, now that we have a reliable site for P. luridipennis, research by John Walters under the Biodiversity Action Plan will be able to answer a few questions about when, where and how to find it, and ultimately how to conserve it.
At Skegness, it looks as though it would be extremely difficult to find if it wasn’t for a few pieces of old carpet that someone has thrown away on the edge of the lagoon. Before I got into beetles, I thought all litter should be collected and disposed of properly. Now I usually regard pieces of litter as valuable refuges for invertebrates and I put them back carefully after looking underneath!
Litter or valuable refuge? The Pogonus luridipennis carpet.
Flushed with success, I thought I’d check out a site near Lincoln where Alan Lazenby discovered Amara nitida on 8th July 1990. Having started my interest in carabids in the Brecks, a hotspot for Amara species, I still regard Amara as the most interesting genus of all. Amara nitida is easily misidentified and is probably not as common as the distribution map suggests. My efforts to see it in Britain have concentrated on sites with definite records. I’ve been to the heathy clearing in Swanton Novers Wood, Norfolk where Bryan Sage discovered one on 11th June 2006. I’ve worked flood debris at Pontrilas, Herefordshire where C.E. Tottenham found it on 29th November 1929 and I’ve looked for it at Lyme Regis, Dorset and Ports Down Hill, Hampshire. It’s always felt like a wild goose chase and I’ve never seriously believed I would ever see this beetle. And now I have! Alan’s site looked unremarkable and I was deeply pessimistic of my chances. But it came up trumps! In a fairly quick look I found one female so there’s probably quite a good population there.
Amara nitida
Can this be the right place? The seemingly unremarkable spot where I found Amara nitida at the base of Meadowsweet and willowherb stems along a tiny stream.
Twitching rare beetles usually requires patience, doggedness and immense reserves of optimism. Saturday was a truly exceptional day. Maybe I should go and look for the real holy grail next?
Have you seen a Hazelnut Weevil Curculio nucum hole?
This is a species I have never seen though the distinctive holes it leaves in hazelnuts were a familiar sight in my childhood in Gwent when gathering nuts in the autumn. I know other coleopterists have encountered this species rarely or not at all and there is a general belief that it has declined severely. Presumably Grey Squirrels are to blame as they have increased in recent decades and most hazelnuts are now eaten by squirrels before they’ve ripened.
Curculio nucum exit holes
Has it declined? Was it ever common? Fowler (1891) referred to it as “local; generally distributed in the London district and the South of England …”, and Joy (1932) gave it as local. Roger Booth investigated this in 2003 by surveying some of the early beetle collections at the Natural History Museum. It is not always easy to interpret such sources but, for example, C.E. Tottenham recorded adults on 9 occasions in a 38-year period (1911 – 1949) totalling only 10 specimens. Roger concluded that the weevil never was very abundant.
Adult Curculio nucum © Roger Key
Nevertheless, it does look as though C. nucum is rarer now. It now seems to be a species that an active coleopterist will encounter about once in every 20 years (or less often than that in my case!).
So, I was really pleased to see lots of hazelnuts with holes in on the Isle of Wight on Monday (12th September). I picked up 141 hazelnuts of which 14 had C. nucum exit holes. The island is still free of Grey Squirrels and maybe the local Red Squirrels are less voracious in their appetite for hazelnuts?
We could get a much better idea of the current status of C. nucum by recording exit-holes in hazelnuts rather than looking for the adults on hazel bushes in May and June. I’m going to start keeping more of an eye out and I’d be interested to hear what others find.
The hole is made by the fully-grown larva as it exits the nut before overwintering in the ground where it will pupate in the following spring. I’ve brought some nuts home from the Isle of Wight in the slender hope that there may be some larvae still to emerge, and in the even more slender hope that I’ll be able to rear them through to adulthood in 2012.
Ophonus: the arable weeds of the beetle world
This is a great time of year for finding species of Ophonus ground-beetles by checking the seed-heads of Wild Carrot Daucus carota. As the seeds ripen, the heads change from a flat-topped umbel into a more or less spherical shape with all the seeds on the inside. Ophonus like to sit inside the middle of carrot seed-heads, spending their days munching seeds. It’s quite easy to prise open the seed-heads and check for beetles.
Pair of Ophonus ardosiacus in a carrot head. Officially Nationally Scarce (Nb), this beetle has become quite common in recent years probably at least partly thanks to arable margin schemes.
Ophonus ardosiacus eating a ripening carrot seed
At least some species of Ophonus will also fly to light. O. ardosiacus is quite frequent in moth traps. One of the rarer species, O. melletii, has only been recorded seven times in the last decade but two of the records are from light traps.
It would be great to get more records of Ophonus, especially from moth-trappers. I would be happy to receive Ophonus specimens for identification from anyone and everyone. Details on posting live specimens here.
Of the 14 British species, only three could be described as at all common (rufibarbis, puncticeps and ardosiacus) and the rest are at least scarce and in some cases extremely rare. Many have clearly declined dramatically during the 20th century, in the same way that many once-common arable weeds such as Corncockle and Corn Buttercup have declined. Losses of the beetles are probably also related to agricultural intensification and the loss of areas of disturbed ground that have a diverse range of weeds, producing lots of seeds, year-in year-out.
I have a passion for these ground beetles. I have attempted to see all the British species, visiting last-known sites, often repeatedly over many years. But there are still five species I have never managed to find. At least four of those species I believe should still be findable in Britain if only I could work out exactly where, when and how. The other one (O. subsinuatus) has not been recorded since 1886 (Portland) and it would be an amazing discovery if it was ever found again in Britain. Four species of Ophonus are currently on the Biodiversity Action Plan list but several others are of equal concern.
I have just had a week’s holiday, and dedicated a few days to searching for Ophonus. It was great to see Ophonus melletii (two males) at long last, by visiting the best known area for the species at Cheam on Monday. As far as I know it was last seen here in 2004 by Martin Luff. I also found one O. schaubergerianus (previously recorded here by David Copestake in 1993), three O. ardosiacus and one O. puncticeps.
Ophonus melletii from Cheam
Ophonus schaubergerianus from Cheam
On Wednesday, I targeted one of the more recent (1988) localities for O. puncticollis near Hurley, Berkshire but the habitat seems completely unsuitable now. Later in the day I explored some field edges around Lodge Hill in the Chilterns near Princes Risborough and came up trumps with a new site for O. laticollis, a species which seems to be having a mini-resurgence on arable margins thanks to the ESA scheme and similar subsidies.
Ophonus laticollis at Lodge Hill (found dead). 3rd record for Bucks.
On Saturday, Jo and I day-tripped the Isle of Wight and worked the soft-rock Red Cliff, east from Yaverland out to the start of the chalk Culver Cliff. I was targeting O. cordatus again, a species last seen in Britain on Salisbury Plain in 1996. It was recorded from “Sandown, Culver Cliff” by W. Holland in 1903 and from “Red Cliff” by Howard Mendel in 1988. We found dozens of O. ardosiacus, several O. puncticeps, a few O. azureus and one O. rupicola (only the second I have found): O. cordatus must still be there but as so often in the quest to find rare beetles, doggedness is going to be the key to success.
Red Cliff, looking east towards the chalk of Culver Cliff. Ophonus azureus was found on the ground beneath the Wild Carrot plants in the foreground.
Ophonus rupicola in the grip
Amazingly, despite seeing seven species of Ophonus in a week, I didn’t see any of the commonest of them all: O. rufibarbis!
Blind beetles
To me there is something thrilling and exotic about blind beetles. They’re the sort of things I expect to exist in guano-filled bat caves in the tropics, or deep underground in the limestone districts of the Mediterranean. But I’ve been finding one species in my back garden recently when lifting the spuds: the tiny bothriderid Anommatus duodecimstriatus. To be found by carefully inspecting the remains of the seed potatoes. The potatoes have many eyes but the beetles have none!
Anommatus duodecimstriatus
Although most likely to be encountered in old seed potatoes, it has apparently also been recorded ‘under elm wood’, under bark and from ivy. It is Nationally Scarce (Na) but I tend to think that anything that occurs in our perfectly ordinary garden must be common, even if it isn’t seen very often. There is another, even rarer (RDBK) species in the genus, Anommatus diecki, which is associated with subterranean dead wood.
Parabathyscia wollastoni
Parabathyscia wollastoni (Leiodidae) is another splendidly-named blind beetle that I saw for the first time this year by suction-sampling in grassland surrounding Sutton Bingham Reservoir, Somerset. It has no conservation status – in other words, it is common – so maybe I just haven’t been looking properly for the last twenty years. Joy describes it as having a ‘very small eye’ but I can‘t see one. Like A. duodecimstriatus, it can sometimes be found in old seed potatoes. There is another blind leiodid on the British list, a species I have yet to see, Leptinus testaceus (on the left in this photo). It can be found in or near the nests of mice and bumblebees and is probably an ectoparasite on mice.
The weirdest blind beetle I have seen in Britain is Claviger testaceus, a pselaphine that inhabits ants’ nests. My sole encounter with this species was on the extremely steep, loose, chalk rubble of Culver Cliff on the south coast of the Isle of Wight in a Lasius ?niger? nest. I’d love to see more of them and also to see the really rare (RDB1) Claviger longicornis but given that I must have looked at hundreds of ants’ nests under rocks and only once found a Claviger, I suspect it could be a long time before I see another.
Claviger longicornis with its rudimentary head
With the help of Steve Bolchover, Roger Booth, Michael Darby, Tony Drane and David Murray I think there are six other blind beetles on the British list, in addition to the six already mentioned above, though there may be more. The subterranean weevil Ferreria marqueti (Raymondionymidae) was added to the British list from Kew Gardens by Alex Williams in 1968. More recently John Owen has established that a good way to find it is by setting subterranean traps at the roots of exotic conifers in suburban gardens in SW London. Owen’s study recorded 193 individuals, with records from 10 out of 12 gardens studied. The same study found 162 specimens of the blind subterranean colydiid beetle Langelandia anophthalma, from four of the gardens. Langelandia is a Rare (RDB3) species, associated with a range of decaying underground plant material: it has been found around decaying tree roots but also in old seed potatoes. There are also three species of Ptinella (Ptiliidae) that can occur in either blind or eyed forms: P. errabunda, P. aptera and P. taylorae.I’ve seen errabunda and aptera on several occasions, either under bark or (aptera) in a woodchip pile. Finally, there is the peculiar salpingid Aglenus brunneus which I have only found once, by sieving straw on the floor of a barn. This seems to be its typical habitat, especially where there is mouldy corn mixed in with the debris.
We may one day get another if the beaver reintroductions bring Beaver Beetle Platypsyllus castoris (another leiodid) with them. But the beavers have been combed before release into the wild, and so far, no Beaver Beetles. Shame! Bizarre-looking things (on the right in this photo).
Although they lack eyes it is probably not fair to describe these beetles as blind – they probably have enough photosensitivity to be able to shy away from the light and burrow into the dark.
Thanks once again to Oxford University Museum of Natural History for use of the digital photo-montage kit.
Lundy invertebrates: Britain’s little Galapagos
Lundy has been described as Britain’s Galapagos in miniature. Lundy Cabbage Coincya wrightii has evolved here in isolation to become one of Britain’s few endemic plants. Lundy Cabbage in turn supports the endemic Bronze Lundy Cabbage Flea-beetle Psylliodes luridipennis and two other beetles of uncertain taxonomic status: Lundy Cabbage Weevil, a pale-legged form (form pallipes) of the weevil Ceutorhynchus contractus, and Blue Lundy Cabbage Flea-beetle, a flightless variety of Psylliodes napi (Compton, Key and Key, 2002).
Lundy and its Cabbage
Before leaving Lundy on the afternoon sailing of the MS Oldenburg on 7th May, I spent a few hours searching for invertebrates in Millcombe Valley. I concentrated on the beetles associated with Lundy Cabbage, mostly by tapping plants over a tray. The Lundy Cabbage Weevil was abundant with several in every tap-sample. Flea-beetles were a different story and it took over half an hour to find the first one. I eventually found a total of 6 flea-beetles and although at the time I thought, disappointingly, they were all Blue LCFb’s, there were actually three of each. In the field the two Flea-beetles are very similar but Bronze LCFb has a more bronze-green and less shining appearance, with paler antennae. A bit worrying to find so few Bronze LCFb’s but all three individuals were teneral so it is likely that the beetles will be more numerous later in the season.
Lundy Cabbage Weevil
Lundy has one other speciality beetle that I was keen to see: Melanophthalma distinguenda. Despite the ‘distinguenda’ name it is anything but distinguished – this is yet another little brown job from the Latridiidae family, associated with moulds and detritus. It has been known from Lundy since before 1931 and in 1995, A.J. Parsons discovered it further up the Bristol Channel on Steep Holm by examining loose gravel on a path. It is not known from anywhere else in Britain and its world range otherwise includes France, Germany, Austria, Switzerland, Hungary and Italy. I didn’t hold out much hope of finding it, and hadn’t expected it to be associated with the Lundy Cabbage. But I found 6 by tapping Lundy Cabbage plants and by sieving litter from around their roots. It doesn’t appear to have been recorded from Lundy for more than 40 years!
A single Rose Chafer Cetonia aurata was nice to see and a short walk north along the coastal path revealed a few Green Tiger-beetles Cicindela campestris, including a mating pair.
Rose Chafer
mating Tigers
Compton, S.G., Key, R.S. and Key, R.J.D. (2002). Conserving our little Galapagos – Lundy, Lundy Cabbage and its beetles. British Wildlife, 13, 184 – 190.
