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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!

Rosencrantz and Guildenstern and a Jersey Tiger are dead

male Jersey Tiger

This male Jersey Tiger was fatally attracted to the bright lights of London’s West End. I found it last night, dead, in the foyer of the Theatre Royal, Haymarket. Although it was appropriate to the existentialist theme of the night’s performance, it seemed an unlikely place to find one. It is a new 10-km square according to the Atlas but, as this map shows, it’s not far for a moth to fly from the extensive green space of St. James’ Park/ Green Park/ Buckingham Palace Gardens.

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.