Wednesday, December 26, 2007

A Nematode Worm

I am an amateur naturalist trying to learn a little about everything living in my garden.

When I started my blog a year ago, in order that I might avoid "species-count overload" (something that raised some comment and debate at the time) I made the rule that I'd confine my attentions to creatures of a 'sensible size' (a few mm upwards). This remains my broad intention. Since, however, a) rules are made to be broken, and b) Santa has recently been kind enough to deliver me a copy of Life In The Soil (James Nardi, The University of Chicago Press) which contains instructions for making a soil-sampling device known as the Baermann funnel, I can't resist devoting a posting to one of the smaller denizens of my garden.

So, what is a Baermann funnel? As the book says, it is a device whose extreme simplicity belies it's enormous effectiveness in extracting creatures from soil samples. My version is shown in photo 1. To make one, simply cut the end off a plastic fizzy-drinks bottle, fill with an inch of water, stuff a handful of soil inside a muslim bag or stocking (anything with holes small enough to retain the soil but allow small critters to wriggle through), place inside the section of bottle and then stand, cap down, inside a pot so as to position the the lower part of the soil in darkness. Finally stand the whole thing under a source of light (e.g. a desk lamp). Critters in the soil, eager to escape the bright light and heat from the lamp will wriggle down through the soil, through the holes in the stocking and out into the water. After a couple of hours you can unscrew the bottle cap, let the water out into a saucer and look to see who's now swimming around in it....

...and unless you happen to have taken a soil sample from Mars or somesuch, the answer will be: Nematode Worms.

Why? Because, quite simply, nematodes are the most numerous (multicelled) animal on the earth. A square metre of soil may contain a million of them. They are found everywhere (p176 onwards of this book) from the rainforests, to Antarctica, to the mud in the bottom of the ocean, to the soil in my vegetable patch. The much cited quote is from Nathan Cobb, "the father of nematology in the U.S.", who gave the following powerful description of their ubiquity:

"[...] if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes, and oceans represented by a film of nematodes. The location of towns would be decipherable, since for every massing of human beings there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable, and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites."

Togther with some nice animations pertaining to the body parts of nematodes, The Virtual Nematode site even has a computer-generated movie of the nematode-remains of an earth-blown-apart!

So, what did I find in my Baermann funnel. Answer, within an hour I'd collected more than twenty worms from a single handful of soil. Photo 2 shows one of them (40x magnification, click on photo to enlarge).

Now, those of you who follow my postings will know I generally make some effort to try to establish the specific species of creature I've come across. In the case of my nematode however, I feel I may have met my match. According to the book above some 15,000 species of nematode are known. If this weren't daunting enough however, it's estimated this may represent only about 3% (!) of the number of species awaiting discovering. It's probable that new species are appearing, and sadly that human activity is extinguishing others, all the time. If you want your name associated with the discovery of a new species of animal, you could do worse than to make a Baermann funnel!

I've not tried to work out the species of my nematode. It could be that I am making too much of the difficulty of identifying nematodes however (?). Certainly the UNL Nematology Lab has an online interactive key which looks a good way to get started. It seems you can make some headway by looking to see whether the mouthparts of your worm are those of a herbivore suited to piercing plant roots, those of a bacterivore suited to hoovering-up bacteria, or 'other' (fungivore, fellow nematode predator etc.). If you're an amateur brave enough to be cataloguing the nematode fauna of your back yard do please leave a comment.

Monday, December 24, 2007

European Holly Ilex aquifolium

I am an amateur naturalist trying to discover a little about everything living in my garden.

Today's posting is something of a milestone for me as it marks not only my 'species count' reaching fifty, but also one year (give or take a few weeks) since I started blogging the life in my garden. Looking through my window, I find my perception of my garden has been entirely transformed over the course of past year. Previously my garden was a place where 'some plants and stuff grew'. When I look at it now, it seems to be positively vibrating with life; I now know it's a place where snails stab each other with daggers in the name of love; native plants rub shoulders with exotic immigrants; spiderlings enagage in matricide; earwig mothers lovingly tend their eggs; female moles fight aggressive underground battles; ants ferry primrose seeds to and fro; fungal threads push their way through the soil and little lichens eek out quiet lives on exposed stone ledges. To name but a little of the activity going on all around me.

In the year since I started my blog I've had 2859 visits from 851 cities acround the world. At least a few of you have come back more than once, so I guess my postings must provide some small entertainment value. The purpose of my writing has always been to help fix in my own mind a little of the natural history of my garden. If in the process, I'm able to provide a few minutes diversion for some of you out there, I'm very happy.

Enough of the self-referential ramblings! On to the star of today's show, and what could be more appropriate to this festive season than photo 1 (click to enlarge), European Holly (Ilex aquifolium).

According to my copy of The Collins Tree Guide (Johnson and More), the holly (Ilex) genus contains some 400 species (together with numerous garden-centre cultivars). Only one is native to Europe, though as the book says, European Holly (Ilex aquifolium) 'has some claim to be the most ornamental of all' - a sentiment with which I'm in full agreement.

In common with nettles, Holly is mostly dioecious (Greek 'two houses') meaning that individual plants are either male or female and cross-pollination is required to produce a 'berry'. Male flowers can be identified by the presence of four, yellow anthers. Females have a single style.

Holly berries are toxic. According to this site as few as three berries are sufficient to bring on unpleasant side effects.

Strictly, as pointed out in my copy of The Field Guide to Trees (Mitchell, Collins) holly berries are not in fact berries at all. Instead, they are what botanists term drupes. As this site explains, berries have seeds directly surrounded by soft fleshy fruit (grape pips being an example), whilst drupes have their seeds surrounded by a woody 'shell' ('endocarp') (as peaches do).

Holly is a popular food with the caterpillars of the Holly Blue butterfly (Celastrina argiolus), the Double-Striped Pug moth (Gymnoscelis rufifasciata) and the Holly leaf miner (the larvae of a fly, Phytomyza Ilicis). According to a paper by T.R.E. Southwood from 1961 however, of all the common species of British tree, holly has the lowest number of predatory insects - a mere seven species. I find this amazing. There are simply so many (tens of thousands at least) of insect species in Britain, and they are so good at finding ways to eat things, that for one of our commonest woodland trees to be 'immune' to the advances of all but seven really surprises me. Unfortunately reading the full paper above would require me to pay a subscription (see here for my grumble about this) so I've not been able to learn more about the details (if anyone can give me a simple explanation of why so few insects predate holly, do please leave a comment).

Photo 2 shows a close up of the trunk of my holly tree (which is growing at (1.6,1.7) - see here). Holly wood is pale and has been traditionally used to make the white pieces in chess sets. On the odd occasion when I've found the need to prune my tree I've found the branches to be tough and flexible. Pure speculation on my part, but I can imagine hunter-gatherers in Britain a couple of thousand years ago finding a use for the strong bendable branches of holly as lashings.

A more certain past use of holly wood has been for the manufacture of bird lime (a sticky glue used to coat twigs for the purpose of catching song birds alive). I haven't come across a definitive recipe (not that I'd want to make said glue in any case!) but I understand it involves boiling and fermenting the wood and bark in water.

As most people know, holly has a strong symbolism in Christianity, the spiky leaves being associated with Christ's crown of thorns, and the red berries with drops of His blood, hence the line from the famous Christmas carol The Holly and The Ivy

Of all the trees that are in the wood
the holly bears the crown

I read that the religious symbolism of holly stretches much further back into the past, to pre-Christian times. I find so many supposed 'factual' accounts of pagan rituals, Druids etc. on the web to be such a mix of fable and wishful thinking however, that I struggle to know which to believe. I'll defer further comment therefore (if anyone can point me to an historical account from some reputable source do please leave a comment). Instead, I'll leave a final, upbeat word to who else but Willie Shakespeare:

Then heigh ho! the holly!
This life in most jolly!

Happy Christmas all!

Saturday, December 22, 2007

Intermediate screw moss Syntrichia (syn. Tortula) intermedia

I am an amateur naturalist trying to learn something about everything living in my garden.

Photo 1 (click to enlarge) shows a patch of moss growing on top of a large stone in my garden, closeby my kitchen door (at (0.9,1.5) - see here).

In fact there are a number of mosses present in photo 1. Though I've not taken the time to examine it in detail, from its appearance I believe the flat feathery one below the coin in the centre of photo 1 to be our old friend Silky Wall Feather moss (Bracythecium rutablum).

The moss that's the focus of today's posting however is that directly left of the coin with leaves arranged in little 'rosettes'.

Photo 2 shows a close up (100x magnification, 1 small graticule division = 10um) of one of the leaves. Things to notice include the tiny spines on the translucent hair emerging from the end of the leaf; the rounded leaf end; the fact that towards the mid-point along its length, the leaf narrows a little and simultaneously 'recurves' (folds over at the edge). Another microscopic feature, most easily seen in the 400x image of photo 3, are the circular cells in the mid leaf, becoming oblong at the edges. Finally, a feature of my moss shown in photo 4 (I've 'tweaked' the colour and contrast on this photo to show things up a little better) are its brown, cylindrical setae (spore capsules). Taken all together, and referring to my battered copy of British Mosses and Liverworts (E.V.Watson, Cambridge Univ. Press 1955), everything points to my moss being Tortula intermedia (Intermediate Wall Screw moss). The site of the British Bryological society has a lovely close-up photo under the alternative name Syntrichia intermedia.

Ubiquitous and persisting through the winter, mosses are inherently 'good value' for the amateur nature lover (a remark I've made previously and heard reiterated on a radio documentary I enjoyed listening to recently via the BBC website). My blog has been my introduction to the mosses and I've thoroughly enjoyed discovering that life forms I'd previously regarded as 'undifferentiated lumps of green stuff' possess, in fact, a minute individuality and beauty all of their own. This is my second Tortula moss but once you've accustomed yourself to notice the difference there's no mistaking the green rosettes of our moss above from the the frosty-white pincushions of Tortula muralis I photographed a year ago. Hooray for the beautiful bryophytes!

Wednesday, December 19, 2007

Two fungi on apples - Venturia inaequalis and a Mucoraceae species.

I am an amateur naturalist trying to discover everything living in my garden.

I have a cooking-apple tree growing in my garden (more on which in a future posting). It produces far more apples than I can cook and winter finds my lawn carpeted with a layer of rotting windfalls. At the time of writing, a flock of songbirds (blackbirds, thrushes, redwings, starlings, fieldfares and others) are visiting my garden daily to eat their fill. Birds are not the only things devouring my apples however...

Photo 1 (click to enlarge) shows an apple clearly afflicted with an outbreak of brown scabs. Recently I acquired a second hand copy of Garden Pests and Diseases (Brooks and Halstead, publ. Simon and Schuster) and from this, and some follow-up searches on the internet, I understand the cause to be a fungus called Venturia inaequalis.

V.inaequalis infects both the leaves and fruit of apple trees and is a member of the enormously numerous division of fungi, the ascomycota = those fungi that "ripen" their spores inside tiny, sausage-shaped tubes called asci (see here for my photo of some asci and here for some more description from me).

In the case of V. inaequalis the spore-containing acsi are, in-turn, packed inside a body known as a psuedoperithecium (a "spore salt-shaker"). I made a little effort myself to try to obtain a microscope photo of one of these, but the strength of my resolve was weakened when I found the matchless images on Tom Volk's website (in any case, I believe I'm unlikely to find a 'fruiting' scab as I've read the pseudoperithecia tend to occur in Spring and are more common on the leaves).

In terms of edibility, brown scabs on apples are entirely harmless (no doubt the same can't be said of the fungicides commerical growers spray on apples to prevent scabs appearing!). Indeed, I've even heard it suggested that amongst the reasons for an increased incidence of cancers in the Western population is our unwillingness to imbibe a healthy population of micro-fungi on our vegetables. I can't vouch for the scientific validity of this theory. I do know you'd need to be very hungry to eat the apple in photo 2!

Looking closely at photo 2 you might notice the small white patches of mould upper left and centre. Viewed under the microscope (approx 40x magnification) a strange and delicately beautiful structure is revealed (photo 3).
On the basis of looks alone (always dangerous when dealing with fungi) and the excellent photo's on this site, I'm identifying this as a member of order the mucoraceae, the 'pin-head' moulds. The 'pin-heads' are technically known as sporangia and are filled with spores. They turn black as the spores mature (as some have in the photo).

To attempt to pin down my mould to one of the three-hundred-or-so mucoraceae species is really the domain of experts. Increasingly DNA analysis is emerging as the only sure-fire method for the identification for micro- (and indeed some macro-) fungi. Taking a shot-in-the-dark however I'll go with Rhizopus stolonifer and invite the experts out there to correct me.

V.ineaqualis and and R.stolonifer are far from the only fungi to attack apples (see here), I'm quite sure more searching would turn up more (a project for a future posting perhaps). For now I'm happy to chalk-up two more species on my garden checklist.

Finally, I mentioned the birds above feeding on the apples on my lawn. Watching them it seems they actively seek out the more rotten apples. I wonder whether they get some health benefit from this (the consumption of pencillin moulds perhaps?), or is it simply that the mouldy ones are the softest and best-tasting. A case of Stilton cheese at Christmas!

Monday, December 17, 2007

Red Underwing Moth Catocala nupta

I am an amateur naturalist trying to find out what lives in my garden.

Photo 1 (click to enlarge) shows a large moth that I found powerfully fluttering its way around my garden one afternoon, late last summer. From R. Lewington's truly beautiful illustrations in my newly acquired copy of the Concise Guide to Moths of Great Britain and Ireland (Townsend, Waring, British Wildlife Publishing ) I'm confident to identify he (or she - can anyone comment?) as a Red Underwing (Catocala nupta).

The book lists eight species of Catocala moth, a number of which (the Red, French Red, Rosy, Light Crimson and Dark Crimson Underwing) are superficially rather similar.

The caterpillars of the Red Underwing feed on willow and poplar.

In Greek 'kato' means 'below' and 'kalos' 'beautiful' (see here for a detailed discussion) - hence Catocala - a genus of moths with 'beautiful hind wings'.

The species name nupta means 'a bride' and was coined by the father of modern taxonomy Carl Linnaeus. Linnaeus was apparently fond of giving this name to moths with bright underwings and in my copy of the fascinating Moths (Michael Majerus, New Naturalist series) A.M. Emmet is quoted as wondering whether brides in eighteenth-century Sweden were in the habit of wearing brightly coloured underwear!

The red underwings serve as a defense against predators. In his book Michael Majerus suggests two mechanisms: firstly, the flash of red and black from the underwings may serve to remind birds of unpleasant tasting insects such as wasps or ladybirds. Secondly, a predator with its mind focused on chasing a flying moth "with red wings" may lose track of its prey when the moth lands, closes its wings (photo 2), and instantly becomes a dull cryptic grey/brown well camouflaged against a tree branch.

Another interesting fact I discover from the book above is that Catocala nupta has been recorded as showing full industrial melanic polymorphism - or, in layman's terms, the advent of heavy industrialisation has caused the evolution of a subspecies of Red Underwing with darker wings designed to give the moth better camouflage against grimy, polluted surfaces (soot-stained tree trunks etc.). Strictly, I'm taking some licence in my explanation: in point-of-fact the book merely states that a melanic form of C. nupta exists without giving any details of its camouflage strategy. (The famous example of a melanic moth is the Peppared moth which has provided a vehicle for extensive studies of Darwin's theory of evolution - Majerus' devotes a an entire chapter to a fascinating account of these studies). I've searched the internet in vain for an image of a melanic Red Underwing (anyone?), although Townsend and Waring's book does contain a picture of a form ("f.") of the Red Underwing Catocala nupta f. brunnescens, which has dirty brown underwings. Can anyone tell me whether this is one-and-the-same as a melanic C.nupta?

Sunday, December 16, 2007

Orb web Spider Tetragnatha extensa

I am an amateur U.K. naturalist trying to discover all the things living in my garden.

Further to the wealth of excitement my first spider posting provoked amongst my legions of readers (hem,hem), photo 1 (click to enlarge) shows another spider I found hanging in the centre of his web in an overgrown corner of my back garden (at (0,2) - see here).

You'll note I refer to my spider as a 'he': Using a hand lens I was able to confirm the presence of palps ending in swollen bulbs.

Back in late-April, when the photo was taken, working with my copy of Spiders (Michael Roberts, Collins Field Guide) I felt I came to a reasonably confident identification of my spider as Tetragnatha extensa. Looking now at my modest-resolution photo, I don't claim to unreservedly stand by this (T. montata might be a alternative (?) for example), but in the absence of better evidence it'll have to stand.

Eight species of the Tetragnatha spider genus are found in Northern Europe. All spin orb webs. Shortly after completeing the web, they take a few seconds to bite a hole out at the centre, there to take up residence waiting for lunch to arrive.

Gnath in biology refers to the jaws, hence Tetra'gnatha "four jaws", a reference to the fieresome mouthparts of these spiders. Photo 2 is my (untrained amateur's) attempt to sketch what would very likely be your terminal sight were you unfortunate enough to find yourself a small fly trapped in an extensa's orb web! The long 'mouthparts' on which the fangs are hinged are known as chelicerae. The chelicerae are used in mating, with the male and female locking theirs together. Atop the chelicerae sits the spider's turret-shaped head with its eight eyes.

T. extensa is one of the commonest Tetragnatha species in Britain and apparently tends to favour a residence close to open water (a slight puzzle in this case since, aside from an open water-butt, that corner of my garden doesn't have any). My copy of The Biology of Spiders (Foelix Rainer, Oxford Uni. Press) refers to a Tetragnatha spider being able to walk on water at 15-20cm/sec (the book doesn't state the species, but from the description I take it to be extensa).

Finally, in case you're wondering about the curious black cylindrical object on the left of photo 1: This is a handy design I got from Dr. Robert's book above for an insect (/spider) viewer. Very simply it comprises two concentric cylinders (in this case the plastic lids from two antiperspirant sprays). The larger has a hole cut in the top. The idea is to pop the insect between the two, and cover the hole with cling-film ('plastic wrap' to those of you reading in the US). By sliding the smaller tube up like a plunger, the insect becomes trapped, immobile against the film and hence easy to examine with a hand lens. Provided you don't keep it there too long, the critter need suffer no ill effects and can be set free afterwards. Neat heh!

Saturday, December 15, 2007

Yellow Corydalis Pseudofumaria (corydalis) lutea

I am an amateur naturalist trying to discover everything living in my garden.

Growing wild under the hedge at rear of my garden (at (0.8,2.0) - see here) are a number of patches of the yellow-flowered plant seen in photo 1 (taken back in early summer) . Photo 2 (click on photo's to enlarge) shows a close up of the pretty, trumpet-shaped flowers.

A short time spent with my copy of the excellent Wildflower Key (Francis Rose, Warne 2006) and I'm confident in identifying my plant as Yellow Corydalis (Psudeofumaria (Corydalis) lutea).

From the book above I learn that the plant family the Fumariaceae (the Fumitories) are related to the poppies (see here). The book lists eleven British species. From Wikipedia's entry however, it seems there is some debate amongst botanists as to whether the the Fumariaceae truely constitute a plant family.

The book describes Yellow Corydalis as introduced to Britain from E.Europe, though "possibly native in Kent". I can say that having learnt to recognise it, I've found it to be quite common, growing wild in Oxfordshire.

Confusingly, the official Latin name for Yellow Corydalis has changed from Corydalis to Pseudofumaria, to reflect that fact that the members of the former plant genus have simple stems whilst the latter have branched stems.

Turning to the internet I can find almost no information specific to my Yellow Fumitory (if anyone can point me to some do please leave a comment). I have come across a range of descriptions of its cousin pink-flowered cousin, Common Fumitory (Fumaria officinalis) however. Common Fumitory is distinguished by having a single seeded fruit (achene) whilst the other fumitories (including Yellow Corydalis) all produce capsules containing multiple seeds.

My copy of The Englishman's Flora (Geoffrey Grigson, Paladin) has no entry on Yellow Corydalis, but once again does discuss Common Fumitory. It seems there is some debate as to whether the name 'fumitory' refers to the pungent, eye-watering smoke that the plant supposedly emits when burnt, whether it is a reference to the 'smokey' colour of the foliage or whether it is a reference to the 'nitric-acid-fumes' smell of the roots. Referring to the second possibility, Grigson quotes William Coles' description of the foliage in his book Adam in Eden (1657) as

"a whitish blew colour as smoak is"

He also gives a rather nice quote from a Stockholm medical manuscript (c.1400)

"Fumiter is erbe, I say,
That springyth in April and in May
In feld, in town, in yerd and gate
There land is fat and good in state"

The poetry prize has to go to Jon Clare who (as I discovered from this site) writes:

"And Fumitory too, a name
Which superstition holds to fame,
Whose red and purple mottled flowers
Are dropped by maids in weeding hours,
To boil in water, milk, and whey,
For washes on a holiday,
To make their beauty fair and sleek,
And scare the tan from summer’s cheek"
(John Clare, quoted by Ann Pratt, ‘Wild Flowers’ (1857)

Can any maids out there report having tried this?!

Wednesday, November 14, 2007

Common Nettle Capsid Liocoris tripustulatis

I am an amateur naturalist trying to identify everything that lives in my garden

In my previous posting I described some of my garden's nettles, and it was on such that I discovered the little bug seen in the centre of photo 1 (click to enlarge). If you look closely you'll see a second individual a little lower down the nettle stem.

Photo 2 shows a magnified (40x) image of my bug. I can only speculate over what purpose it serves the bug to wear the rather smart, yellow, arrow-symbol on its back.
I had expected to struggle, and quite possibly fail, to identify my little insect, but the internet is an amazing thing! Ten minutes of searching against 'bug', 'nettle' and suchlike and I'm reasonably confident to pronounce my insect The Common Nettle Capsid Liocoris tripustulatis.

L. tripustulatis is a member of the insect family the miridae. From my copy of Insects of Britain and Northern Europe (M. Chinery, Collins) I learn that the miridea family is, in turn, part of the insect order hemiptera or the so-called true bugs. The true bugs have piercing mouthparts for sucking the juices of plants and can be distinguished from the beetles, by beetles having hardened wing cases ('elytra') that meet at a line along their backs without overlapping (see a previous posting here).

There are about 6000 true bugs in the family meridae. About 200 are found in Britain.

The true bugs are equipped with a drinking straw' (rostrum) for tapping the stems of plants and sucking out the juices. This is carried horizontally below the body and can be clearly seem in the 40x magnified image of photo 3 (click to enlarge).

Although I've come across various general discussions on the true bugs, I've been able to discover almost nothing on the specific habits of L.tripustulatis; A search of Google books turned up The Biology of the Plant Bugs (Wheeler and Southwood, Cornell University Press). The publishers have made a selection of pages available online and from a single sentence I learn that, along with their association with nettles, L.tripustulatis is known to need on nectar from buttercups. In addition, from a single sentence in my copy of Insects on Nettles (B.N.K. Davis, Richmond Publishing) it seems L.tripustulatis undergoes at least five larval instar phases. Aside from these facts however, the habits of my little bug remain a mystery to me. I'd love to know a little more. As I learnt from my readings on hoverflies, there are simply so many insects that often even the basic behaviours of many are completely unrecorded. My failure to find any substantial information on the natural history of L.tripustulatis perhaps indicates a good project for a keen amateur out there. On the other hand, perhaps much is already known and I've simply not looked in the right places. If anyone out there can help I'd be pleased to discover more about my handsome little capsid.

Monday, November 12, 2007

Stinging nettle Urtica dioica

I am an amateur naturalist trying to learn a little about all the life in my garden.
In a quiet corner of my garden (at (1.8,2.0) - see here) I have been carefully cultivating (hem, hem) a patch of stinging nettles Urtica dioica (photo's 1 and 2 - click to enlarge).

I have two books in my possession that have enabled me to learn something about this ubiquitous British weed: my trusty copy of The Englishman's Flora (Geoffrey Grigson, Paladin) and secondly a recently acquired copy of Insects on Nettles (B.N.K. Davis, Richmond Publishing).

From Geoffrey Grigson's book I learn alternative names for the stinging nettle include The Devil's Leaf in Somerset and Naughty Man's Plaything (!) in Sussex. Secondly that nettles were unintentionally imported into the States by the settlers, with John Josselyn recording in 1672

"[nettles] have sprung up since the English planted and kept cattle in New England"

and thirdly that the Scots poet Thomas Campbell (1777-1844) wrote about sleeping in sheets made from the fibres of nettle stems (I would love to think there is someone out there reading this blog who still has a set of nettle bedsheets. If you're that slumberer do please leave a comment!)

From Dr.Davis' book I am learn that the botanical name dioica is derived from the Greek di-oikos -"two houses" - a reference to the fact that nettles have separate male and female plants which can be differentiated by the flowers: bright yellow on male plants and "silvery, furry" on females. Nettles clearly have a dubious reputation as a weed; Seen under the microscope however I have to say I find the flowers really rather beautiful. Photo 3 shows my 40x closeup of what I assume to be a female plant.

Nettle leaves are edible after suitable cooking (blanching in boiling water for example) and I can report that I myself have eaten nettle risotto from my garden's crop: my memory is of it tasting vaguely like a cross between watercress and spinach.

Of course, the unpleasantly familiar attribute of nettles is their sting. Photo 4 shows my (100x) image of one of the vicious hypodermic syringes responsible. It seems there is some dispute over exactly what chemical is to blame for the painful sting with hystamines, formic acid and oxalic acids all being variously implicated. Hope is at hand however: From Dr. Davis' fascinating book above I learn that one nettle variant (var. subinermis) common in Cambridgeshire lacks stinging hairs.

Nettles get a mention by Shakespeare no fewer than nine times, my favourite being

"the strawberry grows best underneath the nettle,
and wholesome berries thrive and ripen best
Neighboured by fruit of baser quality" (Henry V, Act 1)

Does anyone know if there is any truth in this suggestion that strawberries grow well in the proximity of nettles?

And finally, for all of us who've suffered the stings of nettles. I learn that things could be much worse: from Wikipedia's entry on nettles I learn that Urtica ferox, a dioica relative native to New Zealand, has a sting powerful enough to kill a horse! Can anyone out there report living to tell the tale of having been stung by this terrible triffid?

Saturday, October 6, 2007

Rhubarb Rheum rhabarbarum

I am an amateur naturalist trying to learn something about everything living in my garden.

Situated in my garden border (at (0.6,1.0) - see here) is a patch of rhubarb I grew from seed some years ago. Frustratingly for the purposes of this blog, I have since lost the seed packet and can't remember the exact variety - there are dozens - though it may be Hawkes Champagne (is anyone out there expert enough to tell me from the photo's alone?).

Photo 2, which I took back at the start of May, shows a closeup of my rhubarb's flower stalk. For some reason I'd expected the flowers to smell unpleasant, but in fact they give off a sweet, heavy perfume and are very popular with pollinating insects.

Photo 3 shows the same flower heads some weeks after photo 2 was taken, now 'dripping' with red seed capsules.

I enjoy my rhubarb mainly for its architectural value in the flower bed, though I do occasionally cook some of the stalks. As everyone knows, rhubarb leaves are poisonous. They contain quantities of nasty chemical oxalates and (laxative) anthraquinone glycosides, and although (as I read here) you might need to eat a few kilogrammes to seriously risk death, eating far less would be enough to bring on some pretty unpleasant consequences.

By now, in my quest to discovery something about everything in my garden, I've learnt to expect everything I come across will have a long and remarkable history. Rhubarb certainly lives up to expectations! This site has answers to every rhubarb-related question I could imagine asking (and some I couldn't) and amongst other things I learn that rhubarb gets mentioned in Chinese herbals from 2700BC; that a general in the Ming Dynasty tried to commit suicide by overdosing on rhubarb medicine; and that the famous Marco Polo writes at length on rhubarb in his accounts of his travels. Rhubarb was being grown in Banbury, Oxfordshire (about 15miles from my house) "by Hayward" in 1777 for its herbal value. According to this site, the first English culinary recipe appeared in 1783 in John Farley's book 'The London Art of Cookery', and from the site of the Royal Horticultural Society I learn that in its heyday in the Victorian era, Yorkshire in the North of England was producing 5,000 tons annually. Rhubarb was imported into Maine in the US in the 1790's.

The UK's national collection is today held in the gardens at Harlow Carr. Now, I have nothing but respect for the botanical value of such collections, but I have to confess that the schoolboy in me can't restrain a titter when I bring to mind Python-esque phrases such as "The nation's rhubarb heritage".

Botanically, rhubarb is a member of the polygonaceae family of plants, comprising about a thousand species including sorrel and knotgrass.

Returning to the subject of my rhubarb's flowers, photo 4 shows a close up of a single flower (40x magnification). Rhubarb flowers have nine tiny white petals. In the centre of photo 4 you can see the threefold 'feathery' stigma, which sits atop the pistil - the female part of the plant. A grooved, waxy pollen-containing anther - part of the plant's male 'apparatus' - can be seen bottom, right-of-centre. Photo 5 is my photo of some rhubarb pollen. This site gives a detailed botanical description of the polygonaceae and contains a link to labelled botanical drawings of rhubarb flowers.

And finally, in preparing for this posting I was delighted to discover that Ulm, Montana hosts a rhubarb festival . My imagination runs wild! If you're reading this and have attended, please leave a comment to let me just what it is that goes on at a festival of rhubarb!

Monday, October 1, 2007

A Lichen Xanthoria parietina

I am an amateur naturalist trying to discover a little about everything living in my garden.
Quietly minding its own business on an exterior concrete windowsill of my house is the lichen shown in photo 1 (click on photos to enlarge). It also grows on the branches of the apple tree in my garden.

My knowledge of the 1854 species of British lichen is extremely limited, but this one, Xanthoria parietina is so common in the UK that it is one I do happen to know.

So what is a lichen? As I discovered recently from reading Lichens (Oliver Gilbert, Collins New Naturalist) this was a question that caused much heated debate amongst 19th century naturalists, with some claiming lichens were plants and others fungi. It turns out that both parties were right: lichen comprise a fungus working "in harmony" with algae (or, in about 10% of cases, with cyanobacteria). The fungus makes up most of the lichen body and is the "stuff" you see when you look at a one. The fungus also takes care of a lot of the tasks associated with water and food storage. The algae (or cynaobacteria) perform photosynthesis i.e. turn sunlight into food. A quote attributed to one Trevor Goward, I came across on this site sums things up nicely:

"Lichens are fungi that have discovered agriculture"

Under the microscope, a cross sectional slice (acquired after no small amount of effort fiddling around with a razor blade at my kitchen table) of my lichen shows things up clearly. Photo 2 (400x, click to enlarge) shows the layer of green algal cells (which I read are algae of the genus Trebouxia in the case of X.parientina) sandwiched between layers of fungus (the various layers, taken from top to bottom, being termed the upper cortex; medulla; and the lower cortex).

So, how does one set about identifying a lichen? Firstly, it's important to know that lichen fall into three main categories: crustose these being the lichens that form patches of negligible thickness like patches of gum on a city pavement; foliose, lichens composed of more visible "flakes" (like the X.parietina in photo 1); and fruticose - little hairy/fibrous "clumpy" lichens that mostly frequent trees.

Next, many lichen are selective about the surface on which they will grow: In particular, some require an acidic surface others alkaline. Putting a drop of lemon juice (=an acid) onto a surface and examining it through a hand lens, if the surface is alkaline small bubbles will be seen forming in the droplet.

A next trick widely used by lichenologists to aid identification makes use of chemical colour tests. Applying certain chemicals (such as household bleach and potassium hydroxide solution) to certain lichens results in powerful colour changes. X. parietina turns bright scarlet in response to 10% KOH-solution for example. As I learn from Dr. Gilbert's book, the complex colouring of lichens results from the presence of acidic crystals that lichens secrete within their body. It seems no one really knows the purpose of these compounds, but over 400 types have been discovered.

Finally, for the experts, examining a lichen under a microscope can be a strong aid to identification. Assuming some are present, a particularly revealing part of a lichen to examine is an apothecium. Apothecia are the little circular cup-shaped fruiting bodies visible in photo 1. Photo 3 shows a 1000x magnified view of a small section of one of them and reveals it as comprised of numerous asci - little tubes full of spores. The asci eventually burst open, liberating the spores and so ensuring reproduction. It turns out that in response to certain iodine-based solutions (I've used Melzers agent in photo 3) the tips of the asci of different lichen species stain in characteristically different ways (clearly, staining blue in photo 3). The classic book to turn to for details is Lichens:An Illustrated Guide to the British and Irish Species (F.S.Dobson).

This discussion barely scrapes the surface of the fascinating natural history of lichens: there is their extraordinarily slow growth and the great age some attain; the fact that sporulation is only one amongst a variety of ways that lichen have of reproducing; the extreme sensitivity of certain species to air bourne pollution; and the relationships lichens have with other plants and animals. Sadly, space means a discussion of any of these will have to wait for a future posting. Instead, I'll leave you with a quote from Dr. Gilbert's book attributed to A.C.Benson 1904

"Beauty, beauty? What is it? Is it only a trick of old stone and lichen in sunlight?"

I'll have a look at my windowsill and let you know!

Thursday, September 27, 2007

European mole Talpa europeae

I am an amateur naturalist trying to identify everything living in my garden.

Typical isn't it, you wait thirty-seven blog postings for a garden mammal, and then two come along at once. After my triumph of badger photography, ladies and gentlemen I present photo 1: the European mole (Talpa europeae). As may be obvious from the photo, though mole hills have periodically appeared in my garden for a number of years, I (in common with most people) have never actually seen a live example of this elusive little creature that lives almost its entire life underground hunting for worms and insects.

To learn something about moles I have been reading The Mole (Kenneth Mellane, Collins New Naturalist). Having been written over thirty years ago (1971) I expected the information in the book to have dated somewhat, and indeed the extensive treatment of the methods employed by mole exterminators and the suggested method of tracking moles by fitting rings of radioactive Cobalt-60 (!) to their tails might less readily find their way into a textbook aimed at amateur naturalists today. Interestingly however, though my searches have been far from exhaustive, turning to the internet I've yet to come across any very detailed site describing the ecology of this most secretive of British mammals (can anyone point me to one?).

From Dr Mellane's book I learn that the average male mole comes in at 14.3cm, 110g with females marginally smaller. European moles are not entirely blind, though their eyes are tiny and mostly hidden by their fur (which, I learn, has no particular 'lie' i.e. it responds equally to being stroked in either direction, unlike the fur of, say, cats as pet owners will know). Moles have a highly developed sense of touch - their snout being covered with thousands of tiny, sensitive 'pimples' known as Eimer's organs. I have to confess at first reading I was highly sceptical of the suggestion in the book that:

"it is tempting to think that moles have other and more unusual senses...[finding] its way in its burrows by some sort of "radar" using some radiation we do not experience"

Subsequently however I've come across the NSF Digimorph site, where I read:

"some authors have suggested that the nose of Talpa may be sensitive to electrical or magnetic signals"

Can anyone comment more concretely on whether moles do or don't have senses of this nature?

Apart from a short time spent mating, moles are, as Dr Mellane puts it:

"aggressive, quarrelsome and solitary"

The Arkive site explains that female moles are the only mammals to contain vestigial testes ('Ovotestes'). These produce large amounts of testosterone and it seems this may account for the tendency of female moles to be just as aggressively territorial as males.

Gestation in moles lasts four weeks. Birth is in late April in the South of England, and the young start to leave the nest (one of the few times they may travel above ground) after about a month to establish territories of their own.

Of course, the most widely recognised feature of moles is their hills. They've certainly made quite a mess of my normally immaculate (hem, hem) lawn as photo 2 shows (does anyone know of a humane way of getting rid of moles incidentally?). Moles are extremely skillful tunnelers: burrows may be on multiple levels and in experiments in which whole sections of burrows where removed, Dr Mellane found that they will even pack together balls of clay to reconstruct a tunnel arch. Moles work and sleep in 3 hour shifts (3 awake, 3 asleep etc.) and Dr Mellane likens the effort a mole makes in pushing up the soil in a molehill to a human miner moving 12 tons of soil in an hour.

Occasionally moles may construct giant mole-hills known as 'fortresses' comprising hundreds of kilos of soil. The suggestion seems to be that fortresses are built to raise a brood chamber above the water-level in flood-prone areas. Dr Mellane disputes this however, and asserts that their real purpose remains a mystery.

Finally, I warned last time of the perils of listening to badgers! The lesson from King William III of England's death is that moles can be just as bad for your health. In 1702, William was thrown from his horse when it tripped over a mole hill. William broke his collarbone and subsequently died from complications. I shall be watching where I tread when I next time mow the lawn!

Thursday, September 20, 2007

The European Badger Meles meles

I am an amateur naturalist trying to identify everything that lives in my garden.

Photograph 1 may not be about to win too many wildlife photography competitions (!) - but after more than thirty postings describing the creatures that visit my garden, I am pleased to announce my first mammal: the European Badger (Meles meles).

I must confess that strictly I have not actually seen said badger(s) in my garden, but on the basis that: i) I do not know what else, besides a badger digging for worms, could have left the holes in my lawn in shown in photos 1 and 2 ii) it's not uncommon to see dead badgers on the roads within a mile of my house iii) lying in bed at night I'm fairly certain I've heard the 'wailing' of badgers (very helpfully, the good people of the Department of Zoology at Oxford University have placed a detailed series of badger-call audio files on their site) and iv) my neighbour has seen badgers in his garden - I'm reasonably confident to assert their presence.

Being one of the UK's few, large, wild mammals so much has been written about badgers (not least with regard to the UK government's controversial policy of culling them on the basis of their supposed ( but strongly-contested) link to the spread of tuberculosis in cattle) that it seems almost pointless for me to add more. Since my own purpose in penning my blog is to fix in my own mind some knowledge of my garden's natural history however, I'll press on:

To learn something about badgers I have been reading The Badger (E. Neal, The New Naturalist Monographs, Collins, 3rd ed.). With the greatest respect to the author, having been written in the 1940's, I did find some of the anecdotes just a little dated, but nevertheless came away with a much improved knowledge of this most secretive of mammals.

The European badger is spread across Europe and Asia from Britain to Japan. It is part of the Mustelidae family of mammals which includes weasels, otters and wolverines (none of the latter in the UK). An old, common name for the badger is Brock and in the UK it's not uncommon to find towns and villages with names like Brockhampton and Brockenhurst.

Badgers have the dentition of carnivores - large canines and extremely powerful articulated jaws - but their diet is basically omnivorous. In his book Dr Neal describes his studies into the stomach contents of badgers and reports finding, amongst other things: rabbit bones and fur; grass; beech nuts; shoots of Dog's Mercury (Mercurialis perennis); 45 beetles of the genus Geotrupes; large numbers of earthworms; four hedgehogs (but only 3 spines swallowed); and a stomach full of wasp larvae and comb.

Badgers are communal, and live in underground dens called sets. Set tunnels can extend for more than a hundred metres into hillsides. In Dr Neal's book he describes his studies of the badger population in a 45-acre wood: Conigre Wood near Rendcomb (UK). Despite the many changes to the British countryside since the 1940's I was delighted to find the 2007 picture of Conigre Wood on Google Earth is essentially identical to the black and white photo in Dr Neal's book (Conigre Wood is the large slanted " j" - minus the top dot - in the centre of photo 3) (as here, I understand it's o.k. for me to use Google Earth images). In the book Dr Neal reports there being five badger sets in the wood of which two were large and regularly used. In all, the woodland supported 11 badgers in 1945. I wonder how many are there today?

One of the more remarkable facts I discovered from reading Dr Neal's books is that for badgers there is a very considerable delay between conception (i.e. the act of mating and a female badger egg becoming fertilized) and "pregnancy-proper" (my phrase) when the fertilized egg becomes implanted in the uterine wall. For three months or more following fertilization, the egg simply 'floats around' inside the female as a so-called blastocyst. Only once the blastocyst becomes implanted in the uterine wall does the embryo start "serious" development, with birth occurring 7-8weeks later. The result of this delay is that although a male and female may mate in Spring, birth does not normally occur until December or January. Badger cubs are weaned after 12weeks and will normally leave the parental set within a year.

Finally, for those of you tempted to listen out for the calls of badgers, you may want to take steps to ensure there are no owls in your neighbourhood! According to a manuscript from 1800 quoted in Dr. Neal's book:

Should one hear a badger call
And then an ullot [owl] cry,
Make thy peace with God, good soul,
For shortly thu shalt die.

Ear-plugs in bed from now on ?!

Saturday, September 15, 2007

An Ichneumonoid Wasp Netelia testacea

I am an amateur naturalist trying to identify everything living in my garden.

Photo 1: "I vant to drink your blood!"

Actually, that's not true at all! If you're unfortunate enough to be a caterpillar however, he (/she?) wants to do something even worse to you! Read on:

On the same evening as I met the Brimstone moth in my previous posting, the red wasp in the photo was also fluttering around my night light. Photo 2 (click on photo's to enlarge) shows my wasp's beautifully slender waist and photo 3 (shot from below) his/her long antennnae.

Using the colour plates in Michael Chinery's excellent "Field Guide to Insects of Britain and Northern Europe" (Collins, 3rd Ed.) I've been able to identify my wasp as a member of the Ichneumonidae family of wasps. The Ichneumonidae are parasitic wasps in the grizzly business of laying their eggs on, or inside, caterpillars. In the latter case, when the eggs hatch the unfortunate caterpillar, often still alive, is eaten from the inside out. For those with strong stomachs, this site has lots of quality images of unfortunate caterpillars being variously parasitised.

As I repeatedly discover for the creatures on this site, it seems that a certain Charles Darwin has beaten me to comment. He was so struck by the grizzly business above that in an obscure little book (!) entitled 'On the Origin of Species' (you can find the complete, searchable text on the excellent Darwin online site incidentally) he wrote:

"to my imagination it is far more satisfactory to look at ...the larvae of ichneumonidae feeding within the live bodies of caterpillars,- not as specifically endowed or created, but as small consequences of one general law...namely, multiply, vary, let the strongest live and the weakest die."

If he keeps up his hobby, who knows, one day his natural-history writings may be as famous as mine (hem, hem!).

As every amateur naturalist knows, a bewildering array of insects can be found in the average garden. The question arises therefore, how do you know when you've found a Ichneumon wasp? Common features are long antennae and the long slender ovipositor, as with hoverflies however, ultimately identification rests on an analysis of the venation of the wings. Photo 4 (you'll need to click to enlarge) highlights the wing vein that, as I learn from Micheal Chinery's book above, indicates my wasp is indeed a member of the family Ichneumonidae.

Incidentally, I in no way harmed the wasp in photo's 2 and 3. He/she was released back into my garden after I'd taken my snaps. I can only ask that you take me on trust when I explain that by complete coincidence, 24 hours later, I found a superficially identical dead wasp on the upstairs carpet in my house. It was he/she who contributed the wing to photo 4.

When it comes to an identification of a particular species of Ichneumon wasp, as with beetles, things are much more tricky. There are some 3200 British and Irish species species (and more than 12000 worldwide). Gavin Broad has added an online checklist to the Biological Records Centre database. Based on the colour plate in the book above and its description as:

"one of our commonest ichneumons...Adults often come to lighted windows"

I'm going with the identity of my wasp being Netelia testacea. Unfortunately, as the book adds however:

"Ophion species are superficially very similar, but their venation is slightly different"

and indeed, googling Ophion yields pictures of wasps very similar to mine. Sadly the book gives no further details on separating Netalia from Ophion species. Gavin Broads has helpfully added a pdf key to Ichneumons to the BRC database, but, as he admits in the introduction,

"Identifying ichneumonids can be a daunting process...".

As an amateur I feel I'm lacking in the time (and very likely the skill) needed to work through the several dozen pages of microscopal details in the key. If anyone can confirm or deny my guess at Netalia testacea based on the face- and wing-images above therefore I'd be grateful.

Finally, a word on antennae! Insect antennae fascinate me. Using these tiny flexible rods, I read accounts of insects' ability to detect mating partners and food, sometimes from miles away. For no more reason than simple fascination value therefore, photo 5: a closeup (x100) of the tip of my wasp's antenna. Another of mother nature's tiny miracles.

Saturday, September 8, 2007

Brimstone moth Opisthograptis luteolata

I am an amateur naturalist trying to discover what lives in garden.

As part of my mission to blog all my garden's life , I have so far covered a number of insects. So far however, all have been found during the hours of daylight. The rules of my mission are that I should identify all lifeforms however, so recently I left an outside light on after dusk and was delighted to come back an hour later to find the moth seen in photo one (click to enlarge).

From the characteristic lemon-yellow colouring and patches of brown on the costa (the leading edges of the wing), and using my copy of 'Butterflies and Moths of Britain and Europe' (Collins), I'm confident in my identifying my moth as the Brimstone Moth.

My moth's Latin name is Opisothograptis luteolata, which, by piecing together snippets of information from various sources, I believe translates as Opistho =backwards , graptis=graphics/writing , luteolata= yellowish : "the yellow-with-backward-facing-graphical-symbols moth" though I'm happy to be corrected.

In an effort to learn more about moths I have been reading the excellent and scholarly 'Moths' (Michael Majerus, The New Naturalist series). There are so many fascinating facts contained in this book that I'm sure I'll be referencing it many times in the future. Specifically on the subject of the Brimstone it mentions that it, together with a two other British moths (the Scalloped Hazel and the Peppered) was the subject of an extensive study in the 1890's showing that the caterpillars of these moths vary in colour according to the colour of the plant on which they feed, so as to afford the best camouflage protection. This site has pictures of the brown and green form of Brimstone larvae. Amongst various other shrubs, Brimstone caterpillars feed on apple, birch, rowan and hawthorn.

Those who read my blog will know I don't like to cause harm to any of the creatures in my postings. Sadly however, rather than finding my moth fluttering around my outside light, when I found it it was lying dead on the ground. I suppose it could be that the wall light itself somehow caused my moth's death (by e.g. causing my moth to collide with the wall). Equally, perhaps my moth was simply at the end of its lifespan - an old moth that used the last of its energies in a flight "towards the light!". I have read that some adult moths are doomed to a pitifully short lifespan by a lack mouth parts with which to feed (the purpose of the adult being simply to mate, lay eggs and die, feeding being unnecessary). This led me into a minor quest to try to ascertain whether adult Brimstone moths can feed and if so, on what. My moth was equipped with a proboscis and from Ian Kimbers moth site I learn that adult Brimstones can produce a number of broods across the season from early May to mid-August. Both thse facts suggest an extended lifespan. With the exception of a few vague reference to adult Brimstone moths feeding 'on plants' however, I've been unable to find any detailed description of what they eat. Can anyone comment?

Brimstone moths overwinter as pupae. Naively perhaps, of the options open to a moth - egg, larva, pupa and adult ('imago') - the rather 'dormant' pupal state seemed a natural overwintering choice to me. The Brismtone is a member of the Geometridae family of moths however, and from Michael Majerus' book I was fascinated to learn that of 288 British species of Geometridae, although 152 do indeed opt to overwinter as pupae, 41 do so as eggs, 88 as larva, and surprisingly (to me anyhow) 7 as adults. I imagine that uncovering the ecological factors that influence these choices presents a wealth of opportunities for scientific study.
And finally, partly in response to a recent comment received on this blog, and partly since I simply enjoy them: some microscope picture (click to enlarge) of the wingscales of my moth (400x magnification).

Friday, August 10, 2007

The Butterfly Bush Buddleja davidii

I am an amateur naturalist trying to learn a little about all the life in my garden.

Growing in my garden (at (1.5,0.5) -see here) is a Butterfly Bush (Buddleja davidii). You can see the bush itself in photo 2 (click to enlarge) and a closeup of one of the beautiful flower 'spikes' (my description - the professionals appear to favour the catchy 'a paniculate cyme') in photo 1. The flowers smell as wonderful as they look.

You can find numerous buddleja cultivars in garden centres. The Royal Horticultural Society site has a picture of seventeen of them. As far as I'm aware mine is not an artificial cultivar (can anyone confirm this from the photo?). Paignton Zoo holds the UK's national collection.

The buddleja in my garden grows vigorously and I regularly need to prune it back. True to its common name, it is a magnet for butterflies and other insects - an example being the peacock butterflies I photographed recently feeding there.

Amongst the many pleasant consequences of my self imposed mission to blog my garden is the discovery of so many excellent web resources. In preparing for this posting for example, I came across the excellent UK Biological Records Centre, a database of 15million entries on 12,000 UK species. Amongst the resources, the centre offers a downloadable database providing information on all the alien species of plant and animal to have invaded the British Isles. From the database I learn that Buddleja davidii was first grown in the UK at the famous the Kew Gardens in 1896, and it was not until 1922 that the first wild 'escapee' was recorded (at Harlech in Wales - how seed travelled the several hundred miles from Kew to Harlech I can only imagine!). The latter date surprised me - if I'd been asked to guess, I think I'd have imagined buddleja to have been imported by some intrepid seventeenth century plant hunter. These days you'll see Buddleja davidii on almost any patch of rough, stony ground in the UK and I've been told that it was extremely common on bomb-sites at the end of the second world war; To have spread so widely since only the 1920's is a testament to its hardiness (mine has survived having being ripped out of the ground by the bulldozers of the builders who did some work on my house a few years ago for example!).

The species name daviddii refers to one Father Armand David, a French Catholic missionary and keen naturalist. The first Westerner to discover it, Father David found Buddleja davidii growing on gravel river beds in China in 1876 (or 1869, depending on which web site I look at - does anyone know which is correct?). Father Armand had a prodigious talent for discovering plants and animals: over a thousand new species (including the giant panda - none of those in my garden as far as I'm aware!).

The genus name Buddleja is a reference to the Reverend Adam Buddle (1662-1715) an Essex botanist whose collection of moss, grasses, seaweeds and lichens is today housed in London's Natural History Museum. Mark Lawley's site includes a biographical essay. The name Buddleja was coined by Linneaus in honour of the Rev. B - the Reverend himself never actually encountered the plant. 'Buddleja' is Linneaus's spelling, although it's common to see the alternative 'Buddleia'.

The Buddleja genus contains some 100 species, widely spread across the globe. Buddleja davidii is classed as a problem weed in the US.

And finally, a little microscopy? But of course! For no more reason than its intrinsic fascination value, some buddleja pollen (photo 3, 400x magnification, click to enlarge).

Sunday, August 5, 2007

Common Field Grasshopper (Chorthippus brunneus)

I am an amateur trying to learn something about everything living in my garden.

Sunning itself on (appropriately enough !), my garden sunlounger I found the grasshopper seen in photo 1 (click to enlarge).

I am used to hearing the chirp of grasshoppers on warm days when I go for country walks hereabouts. I do not tend to hear them in my garden however. The grasshopper in the photo is one of only two I can recall having seen there.

Prior to this posting I knew essentially nothing about grasshoppers. Thanks to reading the short but scholarly Grasshoppers and Bush-crickets (Andrew Mahon, publ. Shire Natural History) however, I am now a little better informed.

For the amateur, learning to identify all the British grasshoppers is a realistic proposition (arguably unlike mastering the beetles !) as there are only eleven species, together with ten species of bush cricket. (Amateurs from 'the rest of the world' be warned however, elsewhere a further eleven thousand species are there to be encountered!).

Bush-crickets can be distinguished from grasshoppers, in part, by their longer antennae (typically, longer than their bodies).

Grasshoppers are vegetarians (some bush-crickets are carnivorous). They overwinter as eggs, typically laid into soil or at the base of vegetation, and, following hatching and a period spent as a grub-like larva, grow to adult-hood through a series of nymph-stages (instars), moulting their exo-skeleton between each stage.
Using the key in the book above and working from my photographs, I was able to make some progress towards identifying my grasshopper. Based on my grasshopper not having antennae swollen at the ends into clubs, I understand that he (or she) can be neither a Rufous nor a Mottled grasshopper. Furthermore, viewed from above (photo 2 , click to enlarge) you can also make out the raised "shoulder blades" ('the keels of the protonum'). The fact that these are curved, rather than straight, also means we can dismiss the possibilty of my grasshopper being a Lesser Marsh.

Unfortunalty, some other features (such as the wing veination) that would have clinched the identity of my grasshopper, I wasn't able to get from my photos. Luckily however, the photo on the front cover of Dr. Mahon's book seems a very close match for my grasshopper - so on that basis I'm going with the Common Field. I say 'luckily' as the Common Field shows considerable variation in patterning and coloration as the photo's here prove. Without the picture on the front of Dr. Mahon's book I might have struggled for longer...always assuming of course I'm now correct! If you know for certain please do leave a comment.