Knapweed ichneumon wasp

I recently caught this ichneumon wasp laying eggs into larvae concealed inside the flower stems and upper stalks of knapweed, Centaurea nigra, in Emthree. 

The wasp draws its ovipositor from its sheath (the black sting-like projection to the rear of its abdomen) then curls it under its body to pierce the plant tissue with great delicacy and skill.  Somehow, of course, it is able to detect the presence of the larvae in which its own larvae will live, probably in this case picture-winged flies (Tephritidae).

Identifying an ichneumon such as this is difficult without catching it, and not easy even if one does.  What I will try to do in this instance is to collect some of the flower heads and stalks and see if I can breed out both parasitoid and hosts.

A new harvestman

I found the harvestman Leiobunum rotundum perched halfway up the stem of the white marsh thistle in Emthree the other day.

Quite a widespread species in Britain but possibly declining.  I have seen it once before in our garden (1997).

Great white thistle

One of the several marsh thistles (Cirsium palustre) in Emthree has grown to nearly three metres tall and has white rather than purple flowers.  There certainly seems to be no lack of fertility in the soil, though unless it is in the rainfall, I do not understand where it comes from.

Meter on BBC TV's The One Show

Recently the TV cameras descended on the Square Meter to film a short piece on the project for The One Show.

It was broadcast on Monday, 24 June and is available on iPlayer here:

http://www.bbc.co.uk/iplayer/episode/b03665cr/The_One_Show_24_06_2013/

The Metre piece starts 10 minutes into the show.

Steinkellner's flat-body

Yesterday I found a small moth resting on the trunk of the larger birch tree in the Metre itself.  It turned out to be the Oecophorid Semioscopis steinkellneriana, Steinkellner's flat-body.

This species has larvae that feed on blackthorn and rowan (neither of which grow in the Square Metre), so its choice of a birch trunk seems purely fortuitous.  It is not very well camouflaged either.

On the sallow next to the birch I spotted a small, black sawfly caterpillar feeding alone.

It does not look like the widespread Nematus pavidus as this seems much paler and feeds gregariously on sallow.  I will just have to see if it survives long enough to get a picture of the full grown larva.  It seems quite aggressive, raising its rear half angrily when disturbed and it feeds quite openly, often a mark of distastefulness.

Bugle time

Bugle flowers are now coming up to their peak all over Emthree as ‘blue steeples' (an Austrian term for the plant) and it is, as Geoffrey Grigson says in his Englishman’s Flora “A most lovable and inexhaustible little plant.”

These days it seems to feature only rarely in books about herbs and forageables but in the past it had quite a reputation for helping to heal wounds and cure whitlows etc. As Gerard wrote “The decoction of Prunell made with wine and water doth join together and make whole and sound all wounds, both inward and outward, even as Bugle doth. To be short, it serveth for the same that the Bugle serveth and in the world there are not two better wound herbs as hath been often proved.”

By ‘Prunell’ he means self-heal (Prunella vulgaris).

Bugle also does not seem to welcome many invertebrates. Although the flowers are popular with carder bees and some hover flies, rather few species choose to eat it. Those that do include the larvae of the yellow and black sawfly (Athalia cordata), one micro moth, the aphid Myzus ajugae and the Eriophyid mite Aceria ajugae. I have found all these except the mite in Emthree over the years.

The ash and the ants

A colony of wrinkled ants, Myrmica ruginodis, has appeared under the Lyon Stone.  Much later than usual and normally by this time of year there are several large colonies.

This evening I spotted two individuals that had climbed to the top of the ash tree, now just over a metre tall, and were browsing eagerly on the tiny glandular hairs that cover the new leaf stalks and petioles.

Such attractions are known as 'extra-floral nectaries' (EFNs) as they are not associated with flowers and they occur on quite a wide range of plants (including narrow-leaved vetch in the Square Metre).

The hairs produce a sweet material containing various sugars and other substances and are clearly both tasty and nourishing as far as the ants are concerned.  What advantage the plant gains is not clear, but is has been suggested that the ants discourage other insects and herbivores both of which might damage the plant (I find that unconvincing).

Like others with ash trees I am scrutinising our Metre plant regularly for ash die back disease, but it seems fine so far.  However, as spores of the die back fungus are dispersed from fallen leaf stalks of the tree, ants might well unwittingly transport them from the ground to the most vulnerable parts of the plants.

Note the ant on the left of the above picture of the terminal shoot of our tree.

Where have all the insects gone?

Another example of natural biodiversity.  The south west slope of The Waste, in the penumbra of the Square Metre, I counted 26 different plant species all self-sown and growing happily together.

There is a yellow meadow ant's nest at the top of the picture and the plastic half bottle in the centre is to try and draw the ants up to ensure they have not deserted.

Insects still seem very scarce and I have not yet found any ants' nests.  Yesterday the first butterfly settled in Emthree - a speckled wood  Today a green longhorn moth, Adela reaumurella, came to rest on a leaf of red campion, its long antennae blowing about in the chilly May wind.

Yesterday I heard a buzzard mewing its way over Churchland Wood to the east.  Eventually it appeared wheeling over our garden and I had a clear sight of it directly above the large birch tree.  Unless one actually comes and settles in Emthree, this is the nearest I reckon I will come to a buzzard record.

Twenty eight plants but no ants

Mice & Red, the more northerly of the two grasslands in the Square Metre proper, looks rough and untidy after the long winter.  Many fallen leaves and pallid dead grass stalks still lie on its surface.  The birds have been pulling up moss and scraping at the surface layer in pursuit of invertebrates.  They also scatter bits of wood from North Wall on the right of the picture below.

Nevertheless, many plants are developing and this afternoon I counted 28 species (there are probably a few I overlooked).  Although there were several species of grass, these are no longer dominant as they were in the early years of the project.

This is the list: Ash; Bird’s foot trefoil; Bramble; Broad buckler-fern; Bugle; Creeping bent; False brome grass; Figwort; Forget-me-not; Goosegrass; Hawthorn; Heath speedwell; Herb-robert; Hogweed; Ivy; Marsh thistle; Narrow-leaved vetch; Ragwort; Rough meadow-grass; Self-heal; Smooth tare; Sorrel; Spindle; Sweet vernal grass; Trailing tormentil; White clover; Wild rose; Wood dock.

However, many old friends were not visible - mouse-ear chickweed, for example, and other plants are present only as singletons or in very small numbers.  Insects are also very scarce and I have seen few beetles or spiders and no ants at all though they were once abundant from mid-March.  I wonder if whatever it is that is afflicting bees is also having and effect on ants (also social insects of the Hymenoptera, Aculeata) and other groups.

Is it a rowan?

Spotted a small seedling in the south western corner of the project area near the chestnut log seat.  I thought it was hawthorn, but the narrow divided leaf at the rear indicates in might be a rowan, Sorbus aucuparia.  If it is, this will be a first for the project.

Professor Zavřel's midges

A few days ago Sammy made me a small emergence trap for insects out of a plastic food box with some nylon tights material tied over the top.  This balances happily on Midsummer Pond, the principle being that insects emerging from the mud and water will fly up into the roof of the trap from where they can be collected for identification.

I made my first emergence trap over fifty years ago when I floated a wooden, gauze-covered contraption out onto a Wealden pond at Robertsbridge and, within a few weeks, garnered an impressive number of non-biting midge species and other insects that had spent their early stages in the pond.

Today my new emergence trap contained two species: a dark-haired biting midge Forcipomyia sp. (Diptera: Ceratopogonidae) and the non-biting midge Zavrelimyia barbatipes (Diptera: Chironomidae).  The Zavrelimyia has carnivorous larvae whose prey is very small organisms in the water.  I have found adults several times in our area, usually associated with stagnant ponds.  However, other records are from streams and cold lakes.  This raises the possibility that there are two or more very similar species with the Z. barbatipes name - only DNA could tell.

The adult midges are pretty little insects with dark-banded wings and, in the males, translucent bodies marked the black and brown.

The genus Zavrelimyia is named after Jan Zavřel who was born in Třebíč, now in the Czech Republic, and who as a university professor did much research work on the Chironomidae and many other things.

April 12-22 2013

With the cold weather receding a little it is getting much busier in Emthree, though flora and fauna still seems to be behind.

22 April.  Made a positive identification of a small plant of broad buckler-fern Dryopteris dilatata with one frond unfurling just behind the log across the middle of Emthree.

Interesting that the spore cases, the small pale green dots, are already well-formed.

21 April.  More creatures are now appearing underneath the New Gingerbread Refuge.  Today there were several pseudoscorpions (walking backwards as usual).

And a small black mite, a very common species in habitats like this, with a springtail next to it.

I have decided to make an exclosure in the open area between the Square Metre and Medlar Wood.  The ground here is trampled by various animals and still brown and ungrateful look after a long winter.  It will be interesting to see what grazing protection delivers.

16 April 2013.  When I was about to leave Emthree I noticed what I though was a small piece of black stick protruding from the ground near the tall birch.  It is clearly a Xylaria fungus, with a stalk and a long, narrow spore bearing body (on the left).  It most nearly resembles the American Xylaria scopiformis: more work to be done on this one.

15 April 2013.  There are many tiny non-biting midges now swarming every evening in the lee of Bramble Hedge.  They are Limnophyes minimus and I suspect they breed in the mud of Midsummer Pond and other wet places in the vicinity.

Underneath New Gingerbread Refuge a pair of pill millipedes has appeared looking very affectionate.  They are long lived invertebrates: I wonder if they mate for life.  The mollusc on the left is a discus snail.

The season gets going

Today was a mixed April showers sort of day, but it continues to get warm after a long winter.  In the trees and bushes round about Emthree the birds were celebrating with a cheerful ensemble of piping and seeping.

In the Square Metre itself the bugle leaves are growing quite quickly and look like small lettuces with red-veined leaves, while over towards Medlar Wood the rather sinister sinuous coils of black bryony, Tamus communis, are emerging from the soil.

Underneath the new Gingerbread Refuge I found a fine centipede, Lithobius variegatus.  If you look along its its right hand side (from our perspective) you will see a small woodlouse (the common pygmy woodlouse, Trichoniscus pusillus I think) against the 5th body segment.

Quite a hazardous resting place as Lithobius are fierce predators.  Still, this woodlouse is said to be the commonest terrestrial isopod in Britain, so they must be pretty good survivors.

Where the sun has warmed the now discarded plastic seat, Egle flies have been gathering in the last few days when it is sunny.  Dipterist friends agree that this is due to the seat being warmer and, according to Alan Stubbs, acting as a distinctive marker indicating a good place for the flies to congregate.  Egle (there are several species) appear at the same time as the sallow blossom in which, after they have fallen, the larvae develop.

Common pouchwort

5 March 2013.  This was a brimstone day (I saw a male butterfly of this species in our lane) with the temperature reaching 13.3 C. 

I am continually surprised at what goes unnoticed, by me at least.  In the afternoon, as it was sunny, I sat on my wooden seat and scoured the surface of Emthree with close focus binoculars and noticed what was obviously a small liverwort growing on the damp eastern face of of the rock at the southern end of Henry's grave (Henry was our Jack Russell terrier who died almost exactly 11 years ago).

The plant turned out to be common pouchwort Calypogeia fissa a common and widespread bryophyte, but one I had not recorded in Emthree before.

Early March

1 March 2013 I was struck today by a comment in Grimaldi & Engel (2007) Why Descriptive Science Still Matters. Bioscience 57 (8) : “Even the most prosaic description is actually a highly selective account of features that are found to be significant in comparison with related things. As a result, there is no such thing as a perfectly complete description or a perfectly complete classification or organization system; as descriptions become more refined and thorough, so do the systems of organization.”

It seems I still have a long way to go with Emthree.

2 March 2013 I have set out two half watermelon skins on the north west and south west sides of the Green Sanctuary to see what happens to them. If full of water they will, of course, act like water bowl traps for insects. That might be quite interesting as they will, of course, retain some of the esters and other aromatic chemicals of the fruit.

The pendulous sedge Carex pendula in Medlar Wood has been eaten down by at least 50% by rabbits, but I am sure it will recover.

3 March 2013 The newly arrived chestnut round was scattered with tiny dark brown objects like spiky moles. Close examination showed these to be dead scales from the Lawson’s cypress hedge behind the metre.

The tiny heart-shaped dead and empty seed ponds of heath speedwell Veronica officinalis are a distinctive feature of the dry grass and the plant, as the Online Atlas of the British and Irish Flora points out, “grows on well-drained, often moderately acidic or leached soils, and in some grasslands is confined to raised ground or anthills”. Our plants do best on raised ground and anthills.

 

4 March 2013 I photographed to small holly discovered yesterday behind Midsummer Pond. It is decidedly yellowish green rather than the dark racing green of normal holly, so I shall have to watch it closely. A wire rabbit guard is called for.

It was a fine sunny day, the first I think with spring in the air. The birds were singing loudly and the grass had a flattened, dull, post-winter cast.

The leaf bud on a wild rose was swelling with joy above the winter thorns.

Early spring at last?

After the long cold and wet of the winter, the thermometer suddenly rose today reaching 11.9 C at the warmest.  The sun shone more often than it didn't and bird song was picking up.

The land is still saturated with water and there was much standing in Emthree, with the ponds and pools full and a long puddle on the path around The Waste.

The brightest thing visually was the bark of the birch tree, peeling in orange flakes to reveal the steely white beneath, small horizontal lenticils like subcutaneous worms circumnavigating the trunk and complex 3D black flecks and patterns.

Just behind the old log at the back of Midsummer Pond I noticed a line of some 13 ivy seedlings.

There must be some reason why they are disposed in such an orderly row, but I cannot think what it is.

A bit further away the pendulous sedge (Carex pendula) is starting to grow away after a strong assault by hungry rabbits, while the stinging nettles, despite the cold, have already started into growth.

January feather

A small, pure white downy feather on the grass by the eastern edge of The Square Metre. Such a delicate, out of place thing, unsullied by the muddy wet of winter. Wild rose leaves stay green all through the colder months. The blackbirds are singing loudly. Tiny midges float across my gaze, little disturbances in the atmosphere, little flying pieces of smoke.

I have spotted a plant of wood avens or herb Bennet, Geum urbanum, in Medlar Wood, a new record for Emthree and the first new record for 2013. As the name implies, this is characteristically a woodland species, but comes up very frequently in gardens. The roots have a clove like taste and can be used to flavour food and drink.

Two bricks and a stone

Quite cold but beautifully sunny for most of the day making it feel almost like early spring. I kept to my promises to myself and took a second brick down to Emthree and have installed it , frog up, next to yesterday’s frog down example. I filled the sky-reflecting frog with local water and was quite surprised by the amount it held.

I think it is worthy of the Tate Gallery.

I also uncovered the Glen Lyon Stone. The lichen has gone, but otherwise in is, unsurprisingly, not visibly changed since its arrival in 2004.

The top picture shows how it was yesterday.  The second picture how it was today.  And the third picture how it was in July 2004.

 

New refugia & thistles

It has been a mild opening to the year, but is now turning colder – only 6.8 C on my midday visit. I have installed a pale orange chunk of split sweet chestnut (from the wood at the end of the garden) to where the first piece of wood, now long decayed, once lay. It was called ‘Gingerbread Refuge’ and I shall continue to use this name.

Just outside the north west corner of Emthree I have replaced an old, black plastic plant tray with a reddish house brick, its frog (the indentation on one face), lain downwards. I might add another brick, face up, so that the frog acts as a tiny shallow scrape, though I will have to keep it topped up with water.

I noticed two kinds of thistle rosette. One, growing almost vertically on North Wall, has very weakly serrated leaves quite different from the marsh thistle towards the south east corner of Emthree whose leaves are deeply serrated and very prickly. Both will need watching as the season advances.