Buddleias

Buddleja alternifolia at Northcourt Gardens,
Isle of Wight. 24 June, 2013

Strictly speaking the title for this blog should be "Buddlejas" since Buddleja is the correct spelling for the genus but, like Aubretia (which should be Aubrieta), I am sticking to the familiar spelling. 

When on the Isle of Wight recently I visited the lovely private gardens at Northcourt, in the village of Shorwell. Buddleja alternifolia was growing particularly well, making a waterfall of lilac bloom on a steep slope.




The shrub has more delicate foliage than the coarser leaves of the common Buddleja davidii giving a more graceful overall effect.

Buddleja alternifolia in greater detail.

Structurally the individual flowers are very similar and also attract a wide range of insects. I have it in my garden but it is not well positioned and is slightly over- whelmed by more robust plants. 

Buddleja globosa, Niton, Isle of Wight.
24 June, 2013

Superficially quite different is Buddleja globosa, sometimes called the Orange Ball Tree. Again, a close examination of the flowers shows a clear similarity to B. davidii but this shrub, native to the Andes (in Chile the leaves are made into a tea), is far more robust and requires plenty of space. My photograph was taken, curiously enough, only a few metres from a pub called the Buddle Inn, in the village of Niton. Adam Buddle (1662-1715) after whom the genus is named, was a botanist from Essex, but whether there is any connection between the inn and the botanist I have no idea. 

Buddleja davidii of course also commemorates the Basque explorer, missionary and naturalist, Father Armand David, known as Pere David, who first recorded it from China. This extraordinary man collected and described an enormous number of plants and animals and he seems to have been the first European to see a Giant Panda. To zoologists he is best remembered through Pere David's deer, which he helped to save from extinction. Botanically he lives on through the lovely shrub Rhododendron davidii and the Pocket Handkerchief Tree, Davidia involucrata, just two of many species named after him.

A dark form of Buddleja davidii
Byfield, 30 July, 2013

The Butterfly Bush, as B. davidii is often known, is now available in a range of colours from deep purple to almost a pure white. (The white form has a yellow centre, making the individual flowers look like tiny fried eggs.) Its original colour is a pale lilac and where the plant has escaped - as it has done on an enormous scale - seedlings soon revert to this shade. I was intrigued to notice, on a recent journey, that the sides of a road cutting near Newbury are covered with buddleia to the exclusion of almost anything else. Indeed, in some parts of the world it has been declared a noxious weed. All the three species mentioned occur with some regularity on waste ground but B. davidii is obviously the garden escapee par excellence.

The classification of the Buddleja genus, with about a hundred species, is confusing. For a long time they were placed, together with a few other genera, in their own family, the Buddlejaceae, but many botanists found this situation unsatisfactory and placed them in the Loganiaceae. However they are now generally regarded as belonging to the Scrophulariaceae. Surprisingly few of the species seem to be in general cultivation.

Galls

Gall on willow caused by the sawfly Pontania proxima.
Byfield Pocket Park. 23 July, 2013

I like galls - so if you are prepared to be bored, read on.

Galls come in a variety of forms. A swelling on the leaf is perhaps the commonest type with some trees such as oak and willow being afflicted with a great variety, both in form and in the type of organism responsible. Sawflies are may be involved, as shown on the first picture. In fact sawflies are a very tricky group to identify and it is often easier to name them through the galls they form rather than trying to dissect the actual insect.

  

Gall on leaf of Lime tree formed by the mite
Eriophyes exilis.  Byfield playing fields.
20.July, 2013

Among the commonest of gall-forming organisms are mites.  These are a challenging  group of organisms and specialists (acarologists) are few and far between. For the layman noting the position of the gall is often crucial. The next photograph shows the gall of a mite, Eriophyes exilis, on a lime tree; in this instance the fact that the gall is located at the junction of veins is key to the identification. 

A related mite is responsible for the example shown next. It affects leaves of the blackthorn and again the position of the galls is diagnostic. In this case the the gall's positioning on the leaf margin allows it to be identified as Eriophyes similis. 

Eriophyes similis galling blackthorn.
Byfield Pocket Park. 26 July, 2013

Peach Leaf Curl. An example from the gardens at
Northcourt, Isle of Wight. 24 June, 2013 

Many gardeners will be familiar with peach leaf curl. Here the problem is caused by a fungus, Taphrina deformans and, as my picture shows, the distorted, thickened leaves can be quite grotesque. Few plants seem to avoid attacks by fungi, although the consequence is not necessarily as dramatic as in this example, photographed on the Isle of Wight.

Mites, sawflies, fungi - many organisms may cause galls, but among the commonest are diptera. i.e. two-winged flies. The galls may be simple swellings on leaves or stems, but may be more complex and even not obviously gall-like at all. Bunched leaves at the tips of hawthorn branches indicate that Dasineura crataegi has been at work. The result is known as the Hawthorn Button-top Gall. Dasineura species are members of a family of flies called the Cecidomyiidae (Greek: kekis - a gall, and myia - a fly) and attack a wide range of plants. 

Hawthorn Button-top Gall. Byfield Pocket Park
26 July, 2013

The study of galls, known as cecidology, has become increasingly popular in recent years, not only because the curious form of galls gives them interest but many of them such as Gooseberry "big bud" and Peach Leaf Curl do considerable damage to commercially important plants.

Royal Baby: No News

Brown-lipped Snails on parade in Byfield Pocket Park
23, July, 2013

Heavy rain last night brought welcome relief for all. Certainly in the Pocket Park the snails sallied forth in droves to graze on, er, whatever snails graze on. Brown-lipped snails were present in abundance - and in a variety of colours. These colour forms, known as morphs, have been of interest to biologists for well over a century. It is suspected that certain morphs have an advantage in particular habitats, but no firm conclusions have been drawn as far as I know. Also known as the Banded Snail this species, Cepaea nemoralis, has a very close relative, Cepaea hortensis. This is slightly smaller than the Brown-lipped Snail and is generally known as the White-lipped Snail, the 'lip' being the band at the edge of the shell where the animal emerges. It too has a range of morphs.

The leaves of Teasels, Dipsacus fullonum, grow in pairs and a little reservoir of water can accumulate at the point where they meet. A few days ago there was no water to be seen in these cups:

                       By the hot relentless sun
                       E'en the dew is parched up
                       From the Teasel's jointed cup:
                       Oh poor birds, where must ye fly,
                       Now your water pots are dry?

                                                    John Clare, Noon, 1820

(I apologise for repeating this snatch of Clare's work; I first quoted it in a blog on 3rd December - but I couldn't resist it.)

Teasels, showing water in the jointed cups.
Byfield Pocket Park. 23 July, 2013

As my photograph shows, the rain has worked its magic and in a few days these reservoirs are likely to be teeming with microscopic life. Incidentally teasels are very thistle-like in appearance but are placed in a different family, the Dipsaceae, whereas thistles are in the Daisy Family, Asteraceae.
                       

Another Pocket Park Miscellany

Loose smut Ustilago nuda on barley.
Byfield, 20.July, 2003

I took a trip to the Byfield Pocket Park today - my first visit for a fortnight or so. I approached via the margins of a field, where a barley crop was looking very well. A few of the ears were affected by Loose Smut, Ustilago nuda. This is an easily controlled fungus problem in Britain but in Northern India, where farmers lack the resources for its control, it can be devastating, wiping out whole crops. Fungal infections such as this are very widespread. A little further on a huge branch from a poplar had fallen, blocking the footpath. It gave me an excellent opportunity to examine the foliage and I found that many of the leaf blades had quite large, upward bulges on the upper surface, while the lower surface had the matching concavity covered with a crust of bright yellow fungus. This was Taphrina populina, a common and widespread organism which appears to cause little or no harm to the tree.

Poplar leaf with Taphrina populina
Byfield Pocket Park. 20 July, 2013

Poplar leaf (lower surface) with Taphrina populi.
Byfield Pocket Park.  20 July, 2013

Ragwort, Senecio jacobaea.
Byfield, 20 July, 2013

Nearby was a robust Ragwort plant. This species has, understandably, received a great deal of adverse publicity over recent years on account of deaths to livestock. Horses are particularly susceptible but tests suggest that a healthy horse would need to eat a quantity of Ragwort equivalent to 7% of its body weight for a lethal dose! From an entomological point of view it is excellent, attracting a considerable range of insects. Today I noted three species of hoverfly calling in for refuelling with nectar and pollen.

A little further along the same hedgerow Hogweed Bonking Beetles, were involved in the activity which has given them their semi-official name. The species, Rhagonycha fulva, is one of the soldier beetles, and it uses the broad umbels of hogweed as a trysting place. Its amorous activities have led to its status as one of Britain's commonest beetles. The dark tips to its hard outer wings (the elytra) make it easily recognisable.

Rhagonycha fulva mating on the umbels of Hogweed.
Byfield, 20 July, 2013

Calves Close Spinney

The proposed HS2 rail link will pass through western Northamptonshire, with inevitable damage to important wildlife sites. Calves Close Spinney, a mile or so from Chipping Warden, is likely to be completely destroyed so, with this in mind, I made a couple of visits to check the flies - plus anything else that caught my attention.

During World War 2 the area had been occupied by an air base, R.A.F Chipping Warden. As I wandered through the spinney I saw, all about me, the remains of installations: concrete flooring, an enigmatic flight of steps going nowhere and several more or less complete buildings. A couple of hundred trees occupied the site, with 90% being youngish sycamores; these appeared to have become established following the abandonment of the base soon after the ending of the war. However, here and there were some very fine oaks of considerable age which clearly pre-dated the military requisitioning of the land.

The leaves of the sycamores were shiny with honeydew, produced by vast numbers of aphids. In their fascinating book, "Aphids on deciduous trees", Dixon and Theme write: "The 116,000 leaves of a 20-m sycamore tree can be infested with as many as 2.25 million aphids..." No significant rain has fallen for a couple of weeks so the honeydew, which might have been washed away, has simply built up on the leaf surfaces. Worryingly there were no ladybirds to be seen. These might have helped in aphid control but hardly anyone I've spoken to has seen a ladybird this year. (Later in the day I saw my first 7-spot ladybird of 2013.)

The leaf-mine of the Brown Oak Slender Moth.
Calves Close Spinney, 12 July, 2013

The oaks would have repaid further attention but, having photographed the blotch on a leaf caused by a moth, the Brown Oak Slender (Acrocercops brongniardella), I moved on. In terms of wildlife interest the area was disappointing; lifting logs and stones in the hope of unusual ground beetles revealed only Pterostichus madidus and P. melanarius - both exceedingly common throughout England.



The colourful millipede, Ommantoiulus sabulosus, was present, playing dead for a minute or so before legging it - nothing can leg it better than a millipede.

The millipede Ommantoiulus sabulosus at
Calves Close Spinney. 12 July, 2013

This too is a very widespread species but seems to have a liking for sandy soil. The two orange stripes running along the flanks make it instantly recognisable. Lifting one large slab revealed a deep pit, occupied by the rather large spider, Metellina merianae; I had harboured the hope that it might be the rarer - and larger - Meta menardi. Now that would have been something!

I should mention that I recorded the strange looking fly, Megamerina dolium. It is not rare and is not even a new record for Northants, but I took a pair in cop (i.e.in the act of mating). The species looks vaguely like an ichneumon wasp - but of course has two wings rather than four.

Calves Close Spinney is of considerable interest to WWII historians but it has to be admitted that, in terms of wildlife it appears to be very limited. Given the opportunity I intend to re-visit the site. Something may crop up to make me revise my view.

A Burying Beetle

Walking down Banbury Lane earlier today I saw the corpse of a thrush on the footpath. Not wishing to handle it, yet wanting to check if the bird had been ringed, I turned it over with my foot and was surprised to see a beetle come lumbering out. Fortunately I had a collecting tube with me and was able to catch it. (I also had with me a 'pooter' - a device for sucking up insects, working like a flexible drinking straw - but I was not prepared to use it for an insect that had been in contact with carrion.)

The beetle proved to be Thanatophilus rugosus. It does not appear to have a common name but is a member of the Silphidae, generally known as Burying Beetles.

T.rugosus is not the prettiest if beetles although some of its close relatives have striking red and black coloration. However, pretty or not, these beetles - the sextons of their world - do an important job of clearing up corpses. They work with great determination and a few years ago, on the shore of Pitsford Reservoir, I found a pair of Burying Beetles making a good job of burying the body of quite a large gull. 

Today's beetle would have been frustrated had it attempted to bury the thrush as it was on tarmac. A crow or magpie may feed on it instead; nothing goes to waste in nature.

Ash Tree Problems

Ash leaflet distorted by a Prociphilus aphid.
Boddington Road, Byfield 4 July, 2013

With much talk of Chalara (the fungus Chalara fraxinea) I have been keeping an eye on local ash trees for signs of disease. Ash (Fraxinus excelsior) can be afflicted with various problems but few appear to have serious effects. Along the Boddington Road the leaflets of one tree were badly distorted by the activities of an aphid belonging to the genus Prociphilus. It could be Prociphilus bumeliae or P. fraxini but, although I suspect the former I cannot yet be sure.

Two views of the gall caused by Dasineura fraxini.
Boddington Road, Byfield. 4.July, 2013

Only a few metres away an ash tree was exhibiting a different affliction. The pouch-like galls on the leaflets are the work of a fly, Dasineura fraxini. As with the Prociphilus aphids the tree seems to suffer no ill-effects.

Another fly with a confusingly similar name was also at work, causing yellowing of the leaf and forming tiny pimple-like galls. This was caused by Dasineura fraxinea. Being inconspicuous, these galls are easily overlooked.

Ash leaf attacked by the fly, Dasineura fraxinea
Boddington Road, Byfield  4 July, 2013

But so far, I am pleased to report, I have not seen Chalara locally.

Coincidences?

Case 1.

1. A few years ago the Harlequin Ladybird, Harmonia axyridis, arrived in Britain, raising grave concerns; it was known to be a predator on the larvae of other ladybird species.

2.  Two years ago my observations suggested that it was the commonest ladybird in the Byfield area.

3. This year, to date, I have seen no 7-spot or 2-spot Ladybirds (usually very common).

4.  My garden roses are currently plagued with aphids - insects upon which ladybirds feed voraciously.

Case 2.

1. My garden pond normally supports a strong population of Dolichopod flies (commonly referred to by entomologists as 'dollies').

2. Last year the pond was occupied by three sizable Common Frogs. No dollies were noted.

3. No frogs are present in the pond this year.

4. Dollies are abundant to the extent that when I paused by the pond earlier today my clothing and arms were quickly occupied by these harmless insects. (Particularly prominent were the males of Peocilobothrus nobilitatus; with their white-tipped wings, constantly being waved to attract females, these are perhaps the most distinctive of all dollies.)

The dolichopodid fly Poecilobothrus nobilitatus
beside my garden pond. Byfield, 4 July, 2013

These two cases may be just what the title suggests - coincidences. Our recent weather has been very odd and this may be a crucial factor, but...

I am entitled to ponder.

Ditto, posing on a Hosta leaf

Pocket Park Miscellany

Rarely do I return from Byfield Pocket Park without noting something of interest. It is unlikely to be a rarity but may be an easily overlooked plant or animal or simply something that is photogenic. Palloptera saltuum is an example of the former - not particularly uncommon but easily overlooked, and or that reason distribution maps probably fail to reflect its true status. It is rather small too, and with my simple camera something of a challenge. It is given to wing waving, thus recalling certain Sepsid flies. My specimen, a female, was on a hogweed umbel.

Palloptera saltuum from Byfield Pocket Park.
29 June, 2013

Hogweed, Heracleum sphondylium, is one of our commonest umbellifers and is a magnet for many insects. Entomologists anticipate its flowering with considerable interest for, as well as attracting a range of commonplace insects there is always the chance of something unusual putting in an appearance - but not today. On a nearby umbel posed a very familiar hoverfly, Myathropa florea. Common it may be, but this wasp mimic (or is it a bee mimic?) is always eye-catching.

A hoverfly, Myathropa florea, on hogweed.
Byfield Pocket Park, 29 July,2013

Equally common on hogweed is the beetle, Oedemera nobilis, although today the example I found (a female) was on a buttercup. The bright green coloration and slender shape make it easily recognisable. It is commonly known as the Thick-legged Flower Beetle, but this is a little confusing as only males have the remarkably swollen femora on the back legs. 

Oedemera nobilis on buttercup. Byfield Pocket Park
29 July, 2013

On the leaves of a plant just a short distance away a pair of Woundwort Bugs, Eysarcoris venustissima, ( Eysarcoris fabricii in older books) were mating. The plant in question was indeed Hedge Woundwort, the principal food-plant of this common and charming little insect.

Woundwort Bug. Byfield Pocket Park.
29 July, 2013

 


I returned to the Pocket Park and found another specimen Of Palloptera saltuum. My photograph is a marginal improvement on the first.