Tuesday, 29 October 2013

Boddington Meadow and Listerine

Corizus hyoscyami, found at Boddington Meadow
29 October, 2013
A blustery day but, with plenty of sunshine to enjoy, I took myself to Boddington Meadow. The first hour produced little of great interest but then my attention was caught by a brightly coloured bug on a dock leaf. I suspected it was Corizus hyoscyami, and consulting my books once home, this was confirmed.

For many years this insect was more or less confined to sandy coasts in the south-west of England and Wales.Then, a decade or so ago, it begin to steadily spread north and east across Britain. The cause of this is unclear; the usual suggestion is climate warming, and this may be true, but it seems likely that more subtle factors have played a part. I recorded it about 3-4 years ago from Byfield Pocket Park, but today's finding was still of interest. Rather surprisingly it does not yet appear to have acquired a common name. Hyoscyamus is the Latin name for Henbane, an extremely poisonous plant akin to Deadly Nightshade. In the time of Martin Lister, who first recorded this bug in Britain, it was generally found in association with Henbane, but nowadays a considerable number of plants also act as host. Martin Lister (1639-1712) was a Fellow of the Royal Society, physician to Queen Anne and the M.P for Brackley. He is still remembered via Listerine mouthwash. (What is the connection between Brackley and Listerine? - now there's a good pub-quiz question!)

Flies basking in autumn sunshine
Boddington Meadow. 29 October, 2013
As the afternoon wore on the temperature began to drop. However, tree trunks on the northern edge of the reserve were still bathed in sunshine, with dozens of flies taking advantage. Among these were several Noon Flies, Mesembrina meridiana, and my photograph shows three of these. All were females, recognisable as such because their eyes are separated (the eyes of males are almost touching). Other species present included Polietes lardarius, Calliphora vicina and Calliphora vomitoria.
Noon Flies basking in sunshine.
Boddington Meadow, 29 October, 2013

Wednesday, 23 October 2013

Star Jelly and Ramshorns

In a friend's garden earlier today, I saw something glistening in a very damp lawn and was pleased to see that it was a slime mould; to be more precise it was Nostoc commune. This is not a rare species (and can be a problem for anyone wanting a bowling-green for a lawn) but, with its green-brown coloration, it is easily overlooked.
Nostoc commune in a lawn at Aston le Walls,
Northamptonshire. 23 October, 2013

In Northamptonshire it was once known as "Star Jelly" from the belief that it grew where a shooting star had hit the earth. A great deal of folk lore is attached to this strange organism. It is technically a cyanobacterium and I have no intention of going into details of its peculiar life; anyone thirsting for details can easily find these from a plethora of web-sites.

The first British reference to it apparently dates the 15th century, when it was recorded from Cornwall. It was referred to as "sterre-slyme" (star-slime) so, even then, a belief prevailed that it was associated with shooting stars. In dry conditions it takes on the appearance if a small piece of dry seaweed, but with the coming of rain it can swell quite rapidly.

Earlier in the day I was pleased to spot a Ramshorn Gall on an oak tree in Byfield Pocket Park. Whereas the Star Jelly has been known since 1440, this gall it has only been known in Britain since 1997. It too is easily overlooked, especially when it has become dry - as was the case with my specimen. Like many galls on oak trees, it was caused by a cynipid wasp, in this case Andricus aries. Since being first found near Maidenhead it has spread at remarkable speed through Britain and by 2010 had been found as far north as Perthshire, Scotland.

Ramshorn Gall caused by the wasp
Andricus aries. Byfield Pocket Park 23 October, 2013
A number of gall wasps are spreading north and west across Europe and many are finding their way into Britain so we may expect more 'invasions' like this in the future.

Thursday, 17 October 2013

The Angle Shades Moth

Angle Shades Moth at Harlestone Heath
Garden Centre, nerar Northampton
Strolling through a garden centre earlier today I was pleased to see a fine specimen of the Angle Shades Moth, Phlogophora meticulosa, on some bedding plants. The staff would be advised to get rid of the moth (although I wasn't going to tell them) because, although the adults are not a pest, the caterpillars certainly can be, nibbling away at unopened flower buds and so on. They feed on a wide range of plant leaves including dock, bramble, chickweed, birch and oak but seem to have a particular liking for potted Pelargoniums. These caterpillars are usually bright green with vague yellow markings and a darker green head. 

This handsome moth is quite variable in colour although the basic pattern does not vary. Thus there are specimens with a considerable amount of green in their wing colours whilst others have lovely lilac or pink shades. The example I saw was very obvious against the green foliage but with a background of dead or withered leaves it would be very well camouflaged indeed. 

Research suggests that there may be two species involved, more or less identical to each other in general appearance. One is resident in Britain with the second species being a summer migrant, coming to this country in considerable numbers. (Don't tell the Daily Mail!)

Robin's Pincushion

Most country dwellers will be familiar with this structure, found on various species of wild rose. In many books it is referred to as the rose bedeguar gall. Whatever one chooses to call it, it is a most remarkable structure and has been the subject of much research. 

Robin's Pin Cushion. Byfield Pocket Park
16 October, 2013
The gall is induced by a tiny (3-4 mm long) cynipid wasp, Diplolepis rosae, and it begins to develop when the wasp lays its eggs in the tissues of a rose leaf bud. Up to 100 eggs may be deposited and, as the eggs develop, the rose is somehow stimulated to produce the extra tissues to form the gall. Just how the rose is induced to produce these tissues remains something of a mystery. Inside the gall the wasp larvae begin to develop, taking their nourishment from the surrounding plant cells. Sometime in the autumn, usually around late October, the larvae are full-grown. They have stored up considerable reserves of fat, and these will sustain the banana-shaped grubs through the winter. They spend the winter in a form of hibernation known as a diapause. Round about the beginning of May the grub goes through a final moult and a few days later the wasp - now an adult - chews its way to the outside world. 
A closer view of the same gall.

Extraordinary though all this is, the story of the gall now becomes far more complex. As it develops more insects, mostly other species of wasp, begin to move in. Some will feed on the plant tissues but others, known as parasitoids, will begin to feed on the original wasp grubs. Eventually an exceedingly complex community develops and so far 14 different species have been identified from these galls, with even more from the galls on the continental mainland. The precise way in which all these "inquiline" species interact is still far from clear and to explain even a little of what is going on would make this a mega-blog. I would commend a fascinating article by Simon Randolph in British Wildlife Vol 24, No 1.  Members of the British Plant Gall Society are helping to take research further

Thursday, 3 October 2013

The Sore-bottomed Shieldbug

This isn't its recognised name of course; I am referring to the Hawthorn Shieldbug, with its curious Latin name of Acanthosoma haemorrhoidale. The genus name is straightforward, for 'acanthosoma' simply means 'spiny bodied'. It is the species name which is puzzling - until, that is, the rear end of the bug is examined. It is a bright pink, leading Linnaeus - who must have had a sense of humour - to conclude that the unfortunate creature was suffering from piles!

As one would expect, this bug is common on hawthorn bushes although observations made in Surrey ("Shieldbugs of Surrey" by Roger Hawkins) show that it can be particularly abundant on some species of Cotoneaster, especially Cotoneaster x watereri. I saw it in Byfield Pocket Park earlier today on Bramble and it kindly sat still while I photographed it.

Hawthorn Shieldbug, Acanthosoma haemorroidale
Byfield Pocket Park.  3.October, 2013

September is the best month to see this bug. Odd specimens turn up at other times of the year but adults are most numerous in early autumn. They then go into hibernation in late October. This is quite a large bug, but its chestnut-red and green body matches the berries and leaves of hawthorn and it can quite easily be overlooked. As with most of its relatives, any attempt to handle it will leave a pungent smell on the fingers - the same smell that deters would-be predators

Hawthorn Shieldbug, showing its "sore bottom"
It is necessary to turn the bug over to see the red patch at the base to the abdomen. (Bug-lovers will be pleased to know that, having had its nether regions photographed, the plucky creature recovered and I was able to set it free.)