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!

Common Toad Bufo bufo

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

Weeding out my shrubbery recently, I was pleased and surprised to come across a second example of a UK amphibian to add to the first (a common frog) I wrote about last year: specifically a rather large toad. Sadly, by the time I had raced to my house and returned with my camera my toad had disappeared. My luck was in however as a few minutes spent hunting through the undergrowth turned up a second: the little fellow in photo 1.

Britain has only two species of toad. One, the Natterjack (Epidalea calamita), is a rare and protected species. I have never knowingly seen one myself. Our second is the Common Toad. There are various ways to tell the two apart but the most useful from the point of view of photo 1 is the paratoid gland which I've marked with a 'p' in photo 1 (click to enlarge). The fact that this is rather regular and pronounced indicates that mine is a Common Toad (Bufo bufo).

What I've learnt about the Common Toad has been mostly through reading The British Amphibians and Reptiles (Malcolm Smith, Collins New Naturalist). With regard to diet, the book contains the amusing quote (attributed to Newman 1869) "[the food of the toad] seems to consist of all living things that are susceptible to being swallowed". Bees, ants, whole snails, moths and young snakes have all been recorded in the diet of the Common. In the case of some larger South American and African toad species even full grown live mice are taken.

It seems possible the first, larger toad I saw and the second smaller one were a female and male respectively. Male Common toads average 60-65mm. Females are typically 10-15mm longer.

Common toads can live a surprisingly long time. Forty years has been recorded in captivity. They hibernate on land in burrows from around mid-October until mid-March when they emerge to spawn. Spawning continues until around the end of April. As is well known, toad spawn forms long 'necklaces' in the water as opposed to the more amorphous blobs formed by frogspawn.

Finally, a word about the predators of the Common Toad. Crows, magpies, rats and snakes are all known to eat toads (some of the former tending to eat the innards, leaving behind the unpleasant tasting skin). Prize for most gruesome predator has to go to the greenbottle fly Lucilia bufonivora however. Having located a victim an adult bufonivora lays up to 100 eggs on its unfortunate victim's back or thighs. Some time later the eggs hatch and the emergent maggots immediately make their way up the toad's back and into its eyes and from there into the nasal cavity. Within a few days the toad is dead. The maggots devour the corpse before dropping off to pupate in the soil and emerge a week or so later as adults ready to repeat the cycle. For those with a strong stomach you can see a photo of an infected toad here.

The Collared Parachute mushroom Marasmius rotula

I am an amateur naturalist trying to catalogue all the life in my garden.

No, despite appearances to the contrary, I have not gone away! My camera has been kept busy over summer snapping pictures of a host of interesting creatures in my garden and it's high time I resumed the task of writing about them.

Some weeks ago I was clearing away a patch of weeds bordering my vegetable patch and I came across a troop of the lovely little mushrooms seen in photo 1 (click to enlarge). They seemed to be growing on a lump of decaying wood.

A quick look in my mushroom guide and I'm fairly confident my mushroom is a Collared Parachute Marasmius rotula.

I say 'fairly confident' as Marasmius bulliardii is similar in appearance though I read it is typically somewhat smaller than rotula and grows on leaves . You can find pictures of both, plus various other species, on the splendid Bioimages site and a key to some 60+ Marasmius species on Michael Kuo's site.

Had I gone to the trouble of taking a spore print (see my previous posting here), and assuming my mushroom is indeed M.rotula, I'd have found the spore colour was white. Under the microscope the spores are 7-10um x 3-4um in size and elliptical.

Turning to my copy of the excellent Fungi (Spooner and Roberts, publ. Collins) a nice thing to learn about Marasmius mushrooms is that one of them is amongst the world's oldest toadstools. A Marasimus-like mushroom ('Archeomarasiumus liggetti') was found, trapped in a 90 million year old piece of amber, in New Jersey by one David Hibbett, a Harvard mycologist. The American Museum of Natural History webpage carries a photo and Hibbett's webpage includes a link to his 1997 paper on the discovery ('Fossil mushrooms from the Cretaceous and Miocene ambers and the evolution of homobasidiomycetes' ).

And finally, the exceptionally sharp eyed of you may have spotted a second life form in photo 1, namely the little reddish insect clinging to the cap in the centre. Photo 2 shows a close up of the little critter. Some remarkably complex relationships exists between fungi and insects. The grubs of certain woodwasps for example, though partial to chomping holes in trees, are only able to ingest wood that has been first rotted by a fungus. Adult woodwasps therefore carefully transport this fungus in special grooves on their body and introduce it the same hole as their offspring. My little insect in photo 2 has a superficially wasp-like look about him or her, but his or her true identity and whether he or she has any sort of relationship with my mushroom, or simply happened to be passing through when I took the photo, I have no idea. If anyone of the experts out there can offer any information do please leave a comment.

Hebrew Character ( Orthosia gothica) and Common Quaker (Orthosia munda)

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

Photo 1 shows two more moths I caught (for the record, on 26th March) in my recently- constructed moth trap.

I didn't know the species of either at first but from my copy of Moths (Waring, Townsend and Lewington, British Wildlife Publishing) it's clear I've found (left) a Common Quaker (Orthosia cerasi) and (right) a Hebrew Character (Orthosia gothica).

I should easily identify them in future: the two, kidney-shaped wing spots of the Common Quaker and the black shapes on the wings of the Hebrew Character are very characteristic.

The Hebrew Character gets its name from the resemblance of its black wing markings to the letters (characters) of the Hebrew alphabet.

I was puzzled by the origin of the name 'Common Quaker' but then came across an article from the Times newspaper 2003, describing an interview with the naturalist Peter Marran. It seems that many of the common names for British moths were made up by members of the The Aurelian Society - one of world's first entomological societies, established in London in the 1760's. According to the article, Quaker's of the time wore (quotes) "subfusc attire" (i.e. dusky or drab clothes). This inspired the naming of not one but three British moths: The Powdered -, The Twin Spot- and (our moth here) The Common Quaker.

Adult of both the Hebrew Character and the Common Quaker feed on the nectar from sallow catkins whilst their caterpillars will eat a range of plants including Oak, Birch and Hawthorn.

An interesting feature of the Hebrew Character I learnt from reading Michael Majerus' book Moths (The New Naturalist Library) is that it displays high latitude melanism; In Northern Scotland, a form of the Hebrew Character - specifically Orthosia gothica f. gothicina - is found that lacks the black colour to the 'Hebrew letters' on its wings. Some other moths, notably the Scalloped Hazel and the Ingrailed Clay, also shows a distinct form at high latitudes. Why? Because, high latitudes impose some unique selective pressures on the moths that live there: firstly there may be issues of thermal regulation (having dark or pale wings will effect how easily a moth heats up or cools down); secondly the low angle of the sun creates softer lighting conditions that may mean birds can more easily pick out camouflage patterns that might work well elsewhere; thirdly, at high latitude in summer the sun does not set - a challenge for the camouflage of normally night flying moths. Low latitude moths that want to 'make the transition' to high latitudes are therefore faced with the need to adapt their colourings or suffer the consequences. A wonderful example of evolutionary change.

Bee Fly Bombylius major

I am an amateur naturalist trying to identify everything that lives in my garden.
Photos 1 and 2 (click to enlarge) show what must be the most dramatic 'nose' of any British fly.

A quick look through my copy of Michael Chinery's book Insects (Collins) and it appears that I've come upon a Bee Fly (Bombylius major). There are ten British species. B. major is the most commonly observed.

Bee Flies use their 'nose' (proboscis) to probe flowers for nectar. The length arises from their preference for hovering above, rather than actually landing on, flower heads. They do this presumably to avoid being ambushed by predators such as Crab Spiders that sometimes lurk behind flower petals.

Apparantly Bee Fly's are superb ariel acrobats. I didn't get a chance to observe this however since the one in the photo remained stubbornly perched on the branch of my garden apple tree. We'd had a few warm Spring days here in Oxforshire. On the day the photo was taken however it had turned cold and my Bee Fly was very sluggish (he/she was still on the same spot half an hour later).

I've not found a specialist UK site devoted to Bee Flies, but you can find a key to those of Canada here.

The best general description of Bee Fly natural history I've come across on the internet is that of Louise Kulzer. They have a complex life cycle. As above, adults feed on nectar. Their grubs are parasitic on solitary bees and wasps however. An adult Bee Fly lays it eggs near the burrow of a (true) bee and the grubs, once hatched, find their way into the nest and consume the food intended for the (true) bee larvae. Later, the Bee Fly grub undergoes a 'shape change' (hypermetamorphosis) into a carnivorous grub, and eats the (true) bee larvae.

That at least is a general description. Ideally I'd have liked to have found some more specific details about my species Bombylius major (What types of bee/wasp species it parasitises; How the Bee Flies tracks down a host-bee's nest etc.) but sadly there seem few descriptions on the web. I did find one other site that references a paper by one T.A. Chapman, specifically on the life history of B. major ...from 1878! (I haven't been able to find a copy)

My searches were not entirely in vain. I did come across the studies of Catherine Toft who has written about the ecology of Bee Flies in the Californian Desert, in particular observations on the foraging behaviour of two species. My amateur understandingof her work is as follows:

Back in the late 1960's, one T.W. Shoener argued that, other things being equal, females in nature should seek to maximise the time they spend feeding (on the assumption that taking in more energy through feeding translates into being able to produce more offspring). Males on the other hand should be 'time maximisers' i.e. beyond basic dietary needs, time spent feeding is in some sense 'wasted time' away from looking for, and breeding with, females. Dr Toft noted that two species of Bee Fly (Lorodotus pulchrissimus and L. miscellus) lent themselves very well to a study of this since the two species of fly live in an essentially identical environment, sharing the same desert habitat and even feeding on the same plant.

As it turned out, L.misecellus matched the Shoener prediction: females spent more of their days foraging than males. Males of L. pulchrissimus bucked the trend however. They spent exactly the same amount of time foraging as females. This is apparantly a feature they share with male moose! Although Dr.Toft offers some tentative explanations as to why this might be. The ultimate answer appears to await a deeper study however.

All of which suggests to me, that should you be an amateur naturalist reading this and searching for an amusing but scientifically useful 'project' to undertake in your neighbourhood this summer, you could do worse than to sit in a deckchair with a cold drink and a stop-watch, and time the foraging patterns of that little-known bug in your backgarden!

Candlesnuff fungus Xylaria hypoxylon

I am an amateur naturalist trying to discover everything that lives in my garden.
Chomping its way through a fallen twig, photo 1 shows a collection of the 'candle wick-like' fruiting bodies of the Candlesnuff fugus Xylaria hypoxylon.

This fungus is very common here in the UK. Scan piles of logs or fallen branches and you're likely to spot it on almost any country walk.

In common with the holly leaf fungus I blogged recently, and the morel before that, X.hypoxylon is a member of the ascomycetae - a huge collection (phylum) of fungi that 'grow' their spores inside microscopic tubes called asci.

In the case of X. hypoxylon a couple of hunded asci are, in turn, packaged into a structure called a perithecium - basically a small 'pimple' with a hole in the top through which spores, once liberated from an ascus, escape. There's an excellent cross sectional microscope photograph of a perithecium of one on the mycolog site (it's a big webpage - the photo's about half way down).

To the eye, the perithecia of X.hypoxylon appear as tiny black pimples on the surface of the white 'candle wicks'. You can see some in photo 2. (Perithecia are common features of lichens also (see my post here).) Over time, the surface tends to become increasingly covered with these pimples (compare Photo 1 with Photo 3 taken about two weeks later) until finally the 'wick' ('compound ascoma') appears quite black. The resulting 'charred' look gives the name pyrenomycetes (from the Greek 'pyr' = fire) to the class of mushrooms of which X.hypoxylon is a member.

The definitive web site on the pyrenomycota is that of by J.D. Rodgers.

In fact the life cycle of X.hypoxylon is a little complex. The spores liberated by the pimply black perithecia are the result of sexual reproduction. X. hypoxylon is also able to reproduce asexually via so-called 'condiospores' however. These conidiospores give the fungus its white powdery appearance in photo 1.

Seen under the microscope, the sexual spores of different species of mushroom show characterisitic differences in size and shape (a helpful aid when trying to identify a mushroom - see my previous posting). I read on Michael Kuo's site however, that conidiospores from different fungi all look basically the same. Why nature has chosen to distinguish sexual and asexual spores in this fashion I can't imagine. Can anyone comment?

A black lichen Placynthium nigrum

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

Spring is well and truly springing here in Oxfordshire. Soon animals and plants will be appearing in my garden faster than I can photograph them, let alone write about them. Whilst things are still moderately calm therefore, I'm seizing the moment to press on with my task of cataloguing my garden's lichens.

Quietly going about its business, photo 1 (click on photos to enlage) shows a black crustose lichen (for the uninitiated, see my explanation here) that decorates my garden wall in places. Photo 2 is a closeup (I've slightly digitally sharpened this image using software).

I'm no expert, and happy to be corrected, but from what I can tell from leafing through my copy of Lichens (Frank Doson), although there are numerous lichens with black fruiting bodies ('apothecia') on otherwise coloured 'backgrounds' ('thalli'), there are only a handful of mostly- or wholly-black crustose lichens to be found in Britain. A number are marine. Verrucaria maura, for example, is common on rocky shorelines where it is somtimes mistaken for oil pollution.

Of the mostly black, 'land-locked', lichens, I spent some time looking at the photos of Verrucaria nigrescens on the excellent 'UK Lichens' site. Looking closely however, this seems to have a more chocolate-brown thallus, albeit one peppered with many black 'perithecia' (see my definition here).

On balance therefore I'm tentatively identifying my lichen as Placynthium nigrum which my copy of Dobson describes as being "Very common, mainly on hard calcareous substrates throughout Britain. Often found on flat tombstones and cement".

A slight puzzle is that the photo in Dobson shows a more powdery ('coralloid') surface than is evident in my photo 2, although the book adds this lichen may be "sometimes smooth and cracked especially in polluted areas". Where I live is rural and I don't believe especially polluted. That said, some lichens are extraordinarily sensitive to even minute amounts of air pollution - whole books have been written on this topic. Anyhow this variability in texture gives me some added confidence in my identification.

Turning to my copy of Lichens (Oliver Gilbert, New Naturalist Library) a nice thing to discover was some growth-rate data for Placynthium nigrum. I learn that young patches expand their radius at 1.66mm/year and mature patches at 0.08mm/year. Lichenometry is the technique of dating old structures (churches, stone circles etc.) by studying their lichen populations - you can find an article here. Applying the data above to the approximately circular, 10mm-radius, patch in photo 2 ages my lichen at between 6- and 125-years old! Not the most exact figure I grant you, but fun to know.

As I commented in a recent posting, I am puzzled by the colours lichens adopt. Over the millenia animals have been driven to evolve their numerously-coloured fur coats, feathers and exoskeletons so as to optimally attract mates, hide from predators, advertise their venomous stings etc. Similarly my amateur's understanding is that plants are mostly green by virtue of the need to pack their leaves and stems with chlorophyll. Even various of the larger mushrooms have evolved specific colours, presumably to alert browsers to their poisonous nature or advertise their presence to 'pollinating' (botanists may wish to turn away at this point!) insects. Some even glow in the dark for this very purpose. But how it is that some lichens on my garden stonework gain advanatage by being coloured matt black, whilst others 'prefer' greyish/white and still others, bright yellow, I struggle to guess. Can anyone help?

Today's posting brings my garden lichen species-count to eight. I feels that I may be approaching completion with regard to this particular lifeform. Until, that is, I find another dozen species through more careful inspection of my garden's rocks and trees. Stood outside earlier today for example, when acquiring the photos above I was aware only of our black friend and of the grey-white patches which (though I haven't checked in detail) I'm assuming is our old friend Verrucaria. Sitting now at my computer screen however, staring at an enlarged version of the photo 1, I'm suddenly noticing the array of tiny orange blobs towards the centre of the image. Time to go back outside methinks!