In previous years I’ve reported on the 6 mistletoe insects we have in Britain – and how we know very little about them. Indeed 2 of the 6 were only discovered here in the years since 2000 and the distribution and biology of all 6 are hardly known. But all are definitely tied to mistletoe, as they eat nothing else (except the Anthocoris bug, which eats the others).
The six are: a moth Celypha woodiana (the Mistletoe Marble Moth), a beetle Ixapion variegatum (the Mistletoe Weevil), three sap-sucking bugs Hypseloecus visci, Pinalitus viscicola and Cacopsylla visci and the predatory bug Anthocoris visci
The weevil lays its eggs inside mistletoe stems and the larva develops inside, only emerging as an adult weevil and leaving a distinctive exit hole. Affected shoots often show die-back of the terminal bud. And that’s about all that is known about it. A simple life-cycle, no complications. Or none known.
However, a recent paper by Ian Thompson and Godfrey Blunt in Field Studies journal recording studies of invertebrate communities in Shropshire orchards makes an intriguing observation. The authors made a special effort to record mistletoe insects within the orchards they visited, including collecting some mistletoe shoots with bud die-back to see if weevils emerged. Some weevils did indeed emerge from some of the samples. But from others a tiny parasitic wasp emerged instead of the weevil. It was from a genus of wasps, Triaspis, that specialises in parasitising the eggs and larvae of beetles.
The obvious inference is that this wasp was parasitising the Mistletoe Weevil larvae. The wasp proved impossible to identify to species – and so may, itself, be newly discovered and might, perhaps, be a dedicated specialist only parasitising the Mistletoe Weevil. Which only eats mistletoe, itself a parasite.
So we could have a new species and a new parasite – of an insect that eats a parasite.
Almost November, so time to look at how mistletoe is looking for Christmas this year. And, again (this is several years in a row now) it’s looking fairly good. The female plants I’ve looked at are festooned with berries and it would seem we have yet another ‘bumper crop’.
Of course it’s not a crop, not in the conventional sense of something grown for harvest, as most simply grows where it wants to and isn’t actively encouraged. But in areas and habitats where it grows well – primarily the SW midlands in mature (often over-mature) apple orchards – it can seem like a crop, and certainly can be harvested like one.
One unusual aspect this season is that many of the berries are whitening up already – whereas they normally stay green well into November. Why, I don’t know, but it does seem consistent with many other berries and fruits ripening earlier than usual this year. So far it’s only whitening from green, the later change from opaque white to translucent white usually only happens in December/January, so it will be interesting to see if that is early this year too.
First wholesale auctions of apple orchard mistletoe are at the end of November – I’ll report then on how the plants have matured, and what prices are like.
Berkeley Power Station, the UK’s first commercial nuclear power plant, sits on the edge of the River Severn in Gloucestershire. Opened in 1962 and closed in 1989 it still dominates the area, though it is now in advanced stages of decommission. And it is surrounded by mistletoe, as this is the nucleus (geddit??) of UK mistletoe country.
Its sister Oldbury (operating 1967-2012, famous for featuring in Blake’s 7 and Doctor Who episodes) is visible a little further down river. Hinckley Point A (1965-2000) & B (1976 to date) are well over the horizon to the south, as is the controversial part-built Hinckley Point C (20??- )
Berkeley Castle, just up the road, is at the opposite extreme of modernity, lived in by the same family since the 12th Century.
But back to the mistletoe – this is the Severn Vale, home of most of Gloucestershire’s mistletoe, growing in old orchards, parkland lime trees and riverside poplars – as well as lots of other habitats and hosts. And, last Saturday, we took advantage of a sunny day (merging effortlessly into grey rain later) to walk a circuit from Bevington, just south of Berkeley town, along the high ridge of Whitcliff Deer Park, into Berkeley town, out onto the riverside at the Power Station and along the floodwall before turning back inland.
At first, not much mistletoe –the southern end of Whitcliff Park is planted with Beech and Oak, neither particularly good for mistletoe. But further north there is the inevitable line of Lime trees, typical of English Parkland and festooned with mistletoe. Further on, in the vale itself there is a glorious excess of mistletoe on many of the road and streamside (aka drainage ditch-side) Poplars with yet more out by the Power Station site. It makes for some interesting landscapes. Nothing to do with the Power Station, obviously, but did berries glow in the winter sun more than usual?
Some pictures, some with captions, below…
Lastly, some mistletoe links – for general mistletoe info visit the Mistletoe Pages website.
Spring is just about here, which means it’s almost the end of mistletoe berrying – cutting berries for propagation projects and for the mistletoe grow-kit business – for this season. Which is always something of a relief, after 6 months of life dominated by mistletoe queries, projects and talking, cutting, gathering, planting etc. Though I expect, after many years experience, that this will, as usual, make for a disconcertingly directionless few weeks at the start of April.
But for the next 2 weeks the season goes on mainly, at this late stage, simply servicing the grow-kit demand, cutting berries to send out to wannabe mistletoe growers around the country. I say cutting, not picking, as we find that picked berries become, through being picked, damaged, with broken skin and oozing berry contents. And those deteriorate quickly, as well as just becoming a glutinous mess if posted en masse. So every berry is actually cut, using those tiny scissors made for florists, to retain a little bit of stalk, thereby keeping the berry intact.
This is done with bunches of mistletoe cut from the tree, so it can be done in relative comfort indoors. But it does create an interesting new ‘leaning forward’ neck-ache, to add to the ‘craning-upwards’ neck-ache already prevalent after spending hours staring upwards and stretching to cut the mistletoe from the tree with an extending pruning pole.
The seeds in the berries are, by now, itching to germinate, with the hypocotyl primordia showing as a small but prominent bulge on the seed. Within a few weeks any not planted will simply germinate within the berry, still on the parent plant – in a defiant final , but in their case pointless, effort to survive. By May any berries left on the parent will contain these tragic might-have-been mistletoes, their hypocotyls hopelessly extended and seeking a host branch yet doomed through being stuck, literally, within their own berry.
But this isn’t the fate of the seeds from the berries in the grow-kits – they’re the lucky ones, being sent out to be formally introduced to their new hosts…
Christmas may be the time we admire mistletoe and its white berries, but February and March are when mistletoe berries are properly ripe. The Christmas tradition is two months early – NOW is the time to have a look at those berries and their lovely sticky green seeds.
Which is precisely what we’re doing here at Mistletoe Matters, combining some mistletoe management work with some mistletoe propagation work – every berried branch that’s cut at this time of year has the potential to create many more mistletoe plants.
In the long-term. Those berries and their seeds may be ripe just now, but the germinating seeds will take several years to produce a decent-sized mistletoe plant. First and second year growths are so tiny that they are easily overlooked.
I regularly get enquiries from people who planted mistletoe seeds a couple of years ago and assume they’ve failed, as they don’t have a ‘big’ mistletoe bush yet. And emails from people who have suddenly noticed mistletoe growing in their tree, the one they planted seeds on 4 or more years previously. What a coincidence they say! Er, no, that’s entirely to be expected, I reply.
The next few weeks really are the second phase of the mistletoe season for mistletoe enthusiasts, after a (well-earned) break in January. I’ll be posting more soon…