A macrochelidae mite

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

On a whim, I recently got out my trusty Baermann funnel (which sounds far more technical than it actually is, namely, a sieve for sieving tiny critters out of soil) and was pleased to discover a host of new-for-my-blog creatures in a handful of old grass clippings. One, a mite, is shown in Photo 1 (click on photo's to enlarge)

Readers of my blog will know I make some effort to research the species of any creature I find in my garden. In the case of my mite however, this turned out to be no small challenge. Before this posting I knew nothing about mites. As I discovered, there are at least three factors mitigating against the amateur seeking to identify one to species level.

Firstly, there is the obvious minute size of mites' physical features. Identification to species can depend on close examination of some minute gland on the body or joint in the jaw-parts ('chelicerae'). With only one specimen and the type of microscope equipment typically available to the amateur, such features can be a challenge to view. The professional may perhaps turn to an extensive university collection of carefully dissected and permanently mounted specimens or examine their find by electron microscope. Sadly however, I don't have a electron microscope in my garden shed (I'm open to donations!).

A second challenge is the sheer number of mite species. More than 45,000 (here) have been recorded and some sources estimate this may be only 5% of the number awaiting discovery. To make matters worse there seems to be a dearth of elementary texts or online keys in the area. A number of advanced texts are available (at suitably advanced cost!) but there seems to be little along the lines of a field guide aimed at the amateur (I'd be pleased to be corrected on this matter).

Attempting to work through academic journal papers and keys brings one to a third difficulty, namely the dense jargon that accompanies the study of mites (acarology). The amateur must wrestle with references to such arcane structures as pretarsal condylophores, filiform corniculae and Claperede's organs. To complicate matters still further, acaralogists refer to the hairs (setae) that decorate mites' bodies in code ('h1', 'pg3' etc.) and not only does there seem to be no simple online explanation of how this code works (anyone?) but there is more than one system in use amongst the professionals.

Thankfully however, there are some notable exceptions to the comments above. On his excellent web site David Walter Evans has put together a Glossary of Acarine Terms, indispensable for making sense of the jargon of acarology. For discussion of some current research topics in acarology and some superb images see Macromite's blog. My searches turned up very few online keys but notable exceptions are the one on David Evans' site above and the interactive key here on the site of the North American Bee-Associated Mites project.

It was the latter that enabled me to make some progress with my mite. I spent some time inputting various features into the key with limited success, but then noticed my mite had 'brush like arthropodrial processes on the chelicerae' (in English: a fringe of hairs on its pincer-like mouthparts). You can see these in photo 2. In the key above this immediately narrows things down from my mite being in any of 36 possible families, to it being in the single family macrochelidae. (As always my identifications come with a health warning - I'm happy for them to be corrected)

Unfortunately that is as far as the key takes me and from the webpages of Dr G.W. Krantz I learn there are still well over a hundred individual species in the macrochelidae family. The book to consult would appear to be A Review of the Macrochelidae of the British Isles by Hyatt and Emberson, but this is out of print and seems generally unavailable.

In the course of my searches I pleased to discover that I am not the only UK amateur taking an interest in the fauna beneath our feet. Over at Alan Hadly's splendid site he too is busy studying macrochelidae mites (together with a host of other critters).

I must end this posting here. My intention in writing my blog is to learn something of the natural history of the creatures I encounter. It may not have escaped the attention of the observant reader however, that in this article I have largely failed to say anything about the natural history of mites. I feel relaxed! With 44,999+ species potentially still at large in my garden, I suspect this will not be the last time I have an opportunity to study these tiny creatures...

Dasineura urticae galls on a nettle leaf

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

I've previously blogged the nettles (Dioica urticae) growing in my garden (indeed, I guess some of you reading this may even now be tucked up in your nettle bed sheets!) and also described some of the capsid bugs (Liocoris tripustulatis) I found living on them.

Recently I've noticed evidence of a second lifeform feeding off my nettles, namely the galls in photo 1.

I am fortunate enough to be in possession of a set of a dozen-or-so volumes of Field Studies, a journal that was at one time published by the Field Studies Council. This admirable UK charity runs a wide range of residential study courses aimed at the amateur naturalist. The Field Studies journal is no longer printed which is a pity as it commonly used to feature keys for the amateur wanting to identify some of the trickier plants and animal in our fields and gardens, including (for present purposes) a key to British Plant Galls by Redfern, Shirley and Bloxham in the October 2002 issue. Fortunately, for those of you without old copies of the journal to hand, this key has been reprinted. You can purchase a copy along with various other gall guides from the British Plant Gall society here.

Redfern, Shirely and Bloxham list five arthropods and one fungal rust capable of causing galls on British nettles. The pouch-like swellings with slit-like grooves in their surfaces on the leaf in photo 1 indicate these are galls caused by the small fly, Dasineura urticae. Had I cut open some of the galls (I didn't) I might have been lucky enough to find some of the white grubs of this fly. Indeed, as I learnt from the very nice 'A Nature Observer's Scrapbook' site, I might even have found some predatory grubs from another species, laid there to eat the Dasineura urticae grubs.

I'm very far from being an expert in diptera (flies). From the Bioimages site however it seems there are several dozen British species in the fly genus Dasineura. This site has pictures of the grubs and galls of some of them.

I have only found one description of an adult D.urticae fly: My copy of Insects on Nettles (Davis, Richmond Publishing) describes a "very small fly with long antenna. Under a microscope an antenna looks like a string of beads...". Unfortunately I haven't been able to find a photograph on the web, although the Bioimages site does carry a photo of another Dasineura species (D. sisymbrii) which I guess may be rather similar since it too has bead-like antenna.

Sadly, that is as much as I have managed to learn about my mysterious fly. How and when the adults mate, how a female locates a host patch of nettles, whether she lays eggs or live grubs, how long the grubs remain inside their gall... I can only guess at the answers to these and a host of other questions. Another garden study-project to add to my burgeoning list!

A Blood-Vein Moth (Timandra comae)

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

What with photography, microscopy and literature searching, my self-imposed mission to catalogue my garden's life places lots of demands on my free-time. When I've a chance however I'm still making an effort to set out my home-made moth trap at night. I did so recently (on the 22nd August for the record) and it yielded a good haul of new species to add to my garden list, amongst them the attractive moth in photo 1.

My moth's common name is The Blood-Vein, for reasons that I imagine are obvious. It is a member of the large (several hundred species in the UK) geometridae family of moths, so called because of the caterpillars of these moths walk with a measuring (=hence 'geometer'), 'inch-worm'-like, gait.

From my copy of Moths of Great Britain and Ireland (Townsend and Lewington) I understand Blood Vein caterpillars feed on dock, sorrel, knotgrass and common orache. I've not been able to find a picture of one on the web (anyone?). Price, Goldstein and Smith studied the suitability of the Blood Vein for introduction into the States as a biological control agent against 'Mile a Minute' Weed (their paper is available here). (They found it was unsuitable)

Adult Blood Vein's are fairly common in Mid- and Southern Britain, but get rarer in the North.

The Blood Vein gets but a single mention in my copy of the excellent Moths (Michael Majerus). One might expect that such small and fragile creatures as moths might tend not to fly about in severe weather such as during heavy downpours. Surprisingly this seems not to be the case however: Majerus reports setting up a moth trap during a severe thunderstorm and trapping several hundred moths, undaunted by the driving rain, within hours. A dozen or so Blood Veins were among them.

The Blood Vein's scientific name is Timandra comae. There seems to be some confusion over the the relationship between this moth and the closely similar Timandra griseata. At various times the two have been lumped together as a single species, and at other times split out as two. Current work suggests they are indeed two separate species.

In Greek mythology Timandra was one of the daughters of the Spartan King Tyndareus and his wife Leda (she of swan-fame). Timandra's sister was Helen of Troy. King Tyndareus managed to upset the goddess Aphrodite and was punished with a curse that all his daughters would be adulteresses. Daughter Timandra duly obliged, eventually marrying one King Echemus only to later desert him for King Phyleus.

Now, whether in fact my moth has a particularly adulteress streak to its nature I really can't say. Indeed, aside from the snippets of information above, I've been failed to find any significant written accounts of the biology and behaviour of The Blood Vein. Whether this is because I've not looked in the right places, or whether it is that The Blood Vein, in common with so many other insect species, has simply not been studied in detail, I do not know. I'd be delighted to find out a little more about this pretty moth however, so do leave a comment if you can help.

A microscopic Peritrichia Cillate (Vorticella?)

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

Readers of my blog may recall that some time ago I decided to investigate the microscopic inhabitants of some rainwater that had collected in my garden. I was delighted at the time to discover some mobile little Haematoccus algae. Spurred on by this success I recently decided to revisit a similar puddle.

This time the water was in shade and contained quantities of decaying leaf-matter. Placing a few drops under my micro- scope I saw nothing at first, but then began to notice numerous small, semi-transparent, stalked objects, such as those above the number '3' in the microscope photo 1 (click to enlarge). My first guess was that these were some sort of fungal spores. Then one moved!

Zooming in (Photo 2) revealed an ovoid creature with a fringe of hairlike cilia at the front end. You can just about make out one poking out above '2.7' on the scale bar. These cilia were in constant motion and set up eddy currents in the water, drawing in small food particles as I watched.

The move- ments made by my creature were highly charac- teristic. Any small distur- bance (such as a tapping the micro- scope slide) caused the stalk supporting the 'head' to rapidly contract, jerking the head backwards in the blink of an eye and at the same time changing the head-shape from ovoid to compact and spherical. Gradually over a period of perhaps half-a-minute the stalk would re-extend and the head return to its original shape.

My creature had one further surprise in store: I was amusing myself tapping the slide and watching the response, when, as if grown tried of my irritating presence, one of my little creatures suddenly detached itself from it's stalk and swam away!

I'm in possession of a nice introductory, colour Guide to Microlife (Rainis and Russell, Grolier Publishing) and I was relatively quickly able to identify my lifeform as a ciliate, the cilophora being a large collection ('phylum') of microscopic animals belonging to the even larger collection of microscopic animals, the protists (to get an idea of just how large you might like to peruse the 81,000 (!) images on the Protist database.)

Fortunately, the structure and habits of my creature allowed for some further progress: the presence of a contractile stalk, the cilia around the mouth and the fact that my little critter was able to swim free of its stalk all point to it being a member of the smaller (though still sizeable) subclass of organisms the peritrichia (which I read is from the Greek, peri=near, trichia=hair).

Now, had I observed any 'stalks' with more than one 'head', that might have narrowed things down to my creature being in the genus Epistylis. I didn't (though of course absence of evidence isn't evidence of absence), which finally brings me to the (somewhat tentative) conclusion that my little creature is a member of the genus Vorticella. Unfortunatly that's as far as I've got. There are a more than a dozen species in this genus and which mine is I can't tell. I'll be happy if anyone out there can tell me.

Naturally, I'm not the first microscopist to observe Vorticella and a little web browsing led me to two very nice articles (here and here) for the amateur. The latter includes some excellent photos including some of Vorticella reproducing by asexual budding. From these and other sites I also learn that a free swimming Vorticella 'head' is termed a telotroch and the stalk is able to contract by virtue of a contractile bundle of threads within termed a moneme. A paper by Sotelo and Trujillo-Cenoz (available to download here) has some ultra-high magnification electron-microscope photos of this and also reveals that the moneme is responsible for the shape-change the head suffers when the stalk contracts.

On the subject of cilia a quick web search turned up numerous papers and articles. My intention was talk about some here, but since I've already gone on for some length in this posting, and since I'm certain to have another opportunity to discuss cilia in the future (so many microscopic creature have them), I'll leave the topic for now.

Instead I'll end with a photo of a free-swimming little animal I encoun- tered in the same sample of water. The ident- ification of this one defeated me. Am I looking at a free swimming Vorticella or is this something else? If you know do please leave a comment.

Couch Grass (Elymus elegans) and Perennial Ryegrass (Lobium perenne)

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

Success in discovering the identity of some plant or animal is all about the careful and methodical observation of details. I've written this before, and had I only paid attention to my own dictum, I might avoided wasting half a morning recently getting thoroughly confused over the species of some grass growing in a corner of my garden!

Intrigued by a comment in a booklet Practical Microscopy (Eric Marson, Northern Biological Supplies) - a superb guide I cannot recommend too highly to any amateur interested in preparing their own high quality microscope slides - I had set out to examine some blades of grass under my microscope.

Venturing into my garden I came across the grass in photo 1. The long, seed bearing structure is technically termed a 'spike'. I picked a little and came back inside but before putting it under the microscope I decided to try identifying the species using my copy of Grasses (Fitter et.al. publ. Collins). Having only a few inches of specimen, it wasn't long before I was stuck however. I went back outside therefore, found my clump of grass and picked a little more. Embassingly foolish as it seems now, this went on for nearly an hour, with me traipsing back and forth, collecting a little more grass each time and returning inside only to find myself more confused than ever.

Finally, in exas- peration, I threw away my growing collection of tattered grass cuttings and started a fresh, and this time, methodical study. The result was the arrangement in photo 2 and the belated realisation I'd been collecting bits of two different grasses!

The two in question are Couch grass (Elymus repens) (photo 2, upper) and Perennial Ryegress (Lolium perenne). Laid out neatly in photo 2 the differences are obvious. I can say that it underlines the lesson that one cannot trust that causal glance at that seemingly undifferentiated clump of 'spike bearing' grass swaying in the breeze!

One difference between the two grasses in photo 2 is leaf size. In fact however, this is not an overly useful guide to species identification, as the size of the leaf baldes can vary with their position on the 'stalk' (culm) and other factors (soil quality etc.). Instead, amongst the most useful guides to a grass's species is the shape and size of the ligule, a small vestigial leaf-like structure the nestles between the culm and a leaf. Photo 3 shows the ligule of Perennial Ryegrass. By contrast, Couch grass lacks a ligule (though just to confuse the unwary, the leaves wrap around the culm via two little sheath-like flaps know as auricles - see photo 4).

Returning to the spikes of my two grasses, photo 5 shows a closeup of both. These bear the grasses' minute flowers (the source of all that hayfever-inducing pollen in summer). As I learnt in my previous study of the Cultivated Oat (Avena sativa), the structure of grass flowers comes with a lot of botanical jargon. I'll not repeat it here, but for completeness I've labelled up photo's 6 and 7.

And what of that micro scope image I originally set out to acquire? Well, as everyone knows you can get a painful cut from the edge of a blade of grass. Putting one under the micro scope (photo 8) shows just why: a margin decorated with a row of tiny saw-toothed daggers. Another of nature's tiny miracles.

Common Wasp Vespula vulgaris

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

Not everyone's favourite insect it must be admitted, photo 1 shows two wasps feeding on a rotten apple on my lawn (a habit shared with the mucor moulds I blogged previously).

The species here is the Common Wasp (Yellowjacket to those of you reading in the States) Vespula vulgaris, one of eight British species in the Vespidae family of social wasps. The hornet I blogged previously is another.

A number of the British social wasps are superficially rather similar and it can pay to take a close look at the face (photo 2) to be confident of the species. Were my wasp to be the not-uncommon German Wasp (Vespula germanica), for example, then it would have three little black dots in the centre of its face (mine doesn't). You can find a nice set of photos of the various British Vespidae species here.

Photo 2 also reveals my wasp is female: Her antennae have 12 segments (males have 13).

Wasps have been very common in my garden in recent summers and this is no doubt partly explained by the impressive abandoned nest (photo 3) I found in attic last winter.

Wasps have two pairs of wings, with each pair comprising a larger- and smaller wing. A pair gets 'zipped' together when the wasp lands so that it appears to be only a single wing. You can see this in photo 1. Taking one of the smaller wings and putting it under the microscope reveals that the analogy to a zip is well chosen: a row of hooks lines the edge of the smaller wing, allowing it to hook tightly onto the larger. Personally I never tire of looking at structures like this under the microscope. Any engineer will tell you how enormously demanding it is to machine mechanical devices to micron accuracy, yet mother nature is routinely able to grow fantastically intricate structures out of such unpromising materials as chitin or cellulose.

My efforts to learn something about Common Wasps led me back to the subject of 'worker policing', which you may recall I touched on in my posting on hornets. Briefly, it turns out that female workers in the colonies of many types of social wasp, bee and ant permit only eggs from the queen to hatch. Eggs laid by female workers are removed from the colony by other workers before they hatch. To the evolutionary biologist, this begs the simple question 'why?'. What advantage does the colony gain by only tolerating the eggs of a single individual (the queen)? Many learned papers have been written on this subject and I wouldn't presume a detailed understanding of all the technicalities but in brief, I understand the reason relates to so called 'kin selection'. It turns out that as a female worker, you are more likely to be closely genetically related to a grub hatching from a queen's egg than you are to one from the egg of fellow worker. Maximising all individuals' relatedness to each other is therefore achieved by preferentially rearing the queen's eggs.

Now, all of the above is as I explained it in my hornet posting. Whilst I didn't doubt the explanation, what I'd struggled to do there was to understand for myself in simple terms precisely why workers relate more closely to the queen's egg than to those of their sisters. In preparing this posting however, I came across the commendably readable More Than Kin and Less Than Kind by Douglas W. Mock. The key information I'd been missing concerns the way in which genes are passed down the generations in these many insects. Firstly it turns out what whilst female wasps each carry two sets of chromosomes (making them 'diploid' - just like us), males carry only a single set (they're haploid). Secondly it transpires that queens in insect colonies that practise worker policing, typically mate with multiple males. The sperm from all the queen's male partners is mixed together and stored in a vessel inside her body known as the spermatheca until needed to fertilise an egg. Which male's sperm fertilises which egg is then random. Taking these two facts together (the haploid/dipoloid male/female divide and the queen's 'random polygamy'), and working through some relatively simple genetics (anyone who remembers Mendel's sweet peas from school biology lessons should follow it), its not too hard to follow the chain of logic that shows that as a female worker born to a queen, you'll have a closer genetic resemblance to eggs from your mother than you will to eggs from your sisters.

And finally, I learn from a paper by Landolt et.al. that a good way to attract Vespula vulgaris wasps is to fill a vessel with acetic acid and isobutanol... of course, alternatively you might simply try eating a sandwich in your garden in August!

Gatekeeper Pyronia tithonus

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

Photo 1, taken on a sunny day in recent July shows a butterfly I found resting on a post in my garden. A few minutes with a butterfly guide and there's no mistaking it as The Gatekeeper (Pyronia tithonus).

My Gatekeeper was very obliging and gave me oodles of time to fetch my camera and take photo's. I might have thought nothing of this, but then I came across a nice online study by Christopher Young of 516 butterflies visiting a UK garden over three seasons. P.tithonus 'stuck around' for the longest of all. Whether this is simple coincidence or whether it points to a behavioural trait of the Gatekeeper I've no idea (an unrecognised butterfly habit awaiting study?).

A second common name for the Gatekeeper is the Hedge Brown. For some reason I prefer the first, though I can't imagine how it originated (anyone?).

The Gatekeeper in photo 1 is a male as confirmed by the dusky patches towards the centre of the forewings. In preparing this posting I came across a number of websites declaring that these are a source of pheromones. I haven't managed to locate an authoritative account to confirm this however (anyone?).

The Gatekeeper is a member of the Nymphalidae family of butterflies that includes some 25 UK resident species, amongst them my previously blogged Peacock . An obvious feature of both are the 'eye' spots. My quotation marks are carefully chosen having come across an interesting article by Stevens et.al. As I learnt in researching my Peacock butterfly posting, many studies have shown that the conspicuous wing spots of certain butterflies have a valuable effect as anti-predator devices, acting to startle small birds about the seize the insect. It has been widely assumed that the reason for this is that, to the birds, the wingspots resemble the eyes of larger predators (hawks, owls etc.). The paper by Stevens et.al. casts doubt on this however since their ingenious test experiments imply that the most effective patterns are not necessarily those that most closely resemble the eyes of predators.

Caterpillars of the Gatekeeper eat grasses. You can find an image of one here.

Sadly, that is as much as I have managed to learn about the Gatekeeper. I should like to have read a 2001 paper by Conradt et.al. that my web searching tuned up. From the abstract, I understand the authors' studies to have shown that P.tithonus can detect and orient itself by landmarks up to 150m away (an impressive distance sensing range for a small insect I'm sure you'll agree). Sadly however, like so much internet information about the natural world, the details are viewable only by making a payment to a private publishing house. Not something I, as am amateur, am inclined to do. Alas therefore, my curiosity and yours, dear reader, must go unsatisfied!