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Monday, 31 December 2012

2012 on the Spot

It's that time of year - the dribbly brained devotees of Mayan stonework-paranoia were wrong and we're still here on New Year's Eve, which means it's time for a run-down of some of my favourite Ecology Spot posts of the last twelve months.

January included a series of four posts about my pet Macleays's Spectre stick insects - I'm not sure I have a favourite as such, though part 2 (the males) does include a shot of one of the boys taking off which was seriously tricky to capture, plus one of my wife's head while she was being used as a launchpad for their aeronautical adventures.

February shifted from tropical-terrestrial to polar-marine with a look at gigantism in Antarctic sea-spiders, inspired by a visit to the Oxford Uni Museum of Natural History.

March was unusually warm and this got me out in the field (well, a churchyard) looking at the bees of a grassy bank, and very pleasant it was too.

In April, more fieldwork led to an unusual aphid/gall find and needed consultation with an aphid specialist to work out - quality collaboration!

May included a variety of invertebrates, including more collaboration, this time in order to identify a tricky pseudoscorpion specimen - a group I've never looked at before.

June saw a rare example of my use of video, looking at the leaf-mining fly larvae in Solomon's-seal.

Into July, and despite the horribly wet summer, I continued to record bee species in our garden (despite the weather, a range of bee-friendly features still attracted them), and reached the grand total of twenty species and counting.

As the summer finally dried out a bit in August, I shifted briefly away from British invertebrates and looked at a poison-arrow frog - you'll see why when you get to the end...

September saw me get a bit speculative (or odd, depending on your point of view) as I looked at why Smurfs are like slipper limpets. Yes, really...

In October, normal service was resumed and I wrote a series of three posts about tarantula anatomy, the third of which looked at their various appendanges (e.g. feet and fangs) - not one for arachnophobes!

November was a busy month - not only did I go on holiday and come back full of ideas realting to things I'd seen during an unseasonally warm week in Devon, but my key to leaf beetles of the British Isles was also published, oh yes :)

And finally onto December where a rather unusual Christmas-party gift led to some unexpected microscope work and a specimen from an unexpected kingdom...

That's all from me for 2012 - back after the New Year celebrations which should involve a ridiculous hat of some sort...

Yup, that's me in a splendid hat with a gun of rum...

Thursday, 27 December 2012

The tricky world of bee ID

It's that time of year and I thought about posting about something festive (reindeer, mistletoe...) but having just seen a bumblebee fly past, I decided to stick to my favourite topic - invertebrates. Despite the sogginess of the summer, I've been recording bee species in our garden, and aside from their wondrous diversity and interesting life histories have noticed that it seems to be a surprisingly difficult group to get to grips with identification-wise. There's no inherent reason for this - after all, most invertebrate groups require a close look at small features to enable species-level identification (i.e. most bee species can't be distinguished in the field, but that's true of the majority of groups), and there aren't that many species in the UK (about 260 - similar to the hoverflies and flea beetles for example). So, although they are more numerous and a little more difficult than, say, butterflies, the main problem is a lack of modern literature, in particular species-level identification guides, at least in the UK (which is my focus here, though I imagine the same problem exists elsewhere).

An interesting little bee, but how to identify it?
The last comprehensive account of British bees was published in the late 19th century (!) (Saunders 1896) and can now be downloaded from here (click 'view book' on the right then choose the format, the pdf is about 20MB) - including the fine colour plates which are still useful. Then in the early 20th century the British Hymenoptera were covered (well, though not comprehensively) as part of the excellent 'Wayside & Woodland' series (Step 1932), but despite changes to taxonomy, distribution and our knowledge of ecology, there were few publications outside of journal articles until a key the genera in the 1980s (Willmer 1985) and to higher taxonomic levels, including genera in some cases, of the wider Aculeata (Bees, Ants and Wasps) (Yarrow 1986). However, even with readily available keys to genera in place, a single species-level identification guide to UK bees has not been forthcoming and although old does not mean wrong, taxonomic changes, extinctions, new discoveries and so on, do gradually render more venerable works out-of-date. Instead, becoming familar with UK bees as a whole has meant (and still does) accumulating keys covering various genera from a variety of sources such as the leaf-cutter bees (Else 1999), the bumblebees (Edwards & Jenner 2009) and the test keys to Coelioxys and Hylaeus available to download here. These can be supplemented with a range of more general works on Hymenoptera; for example I have recently acquired Bellmann (2010) which covers a selection of Central European Aculeate species (in German), including a wealth of interesting information and some nifty little line drawings to aid identification e.g. of wing cells/venation. It will also lead to an improvement in my ability to read German...

So, there has been progress - some genera are covered (though the test keys are exactly that and need to be used with caution) - and the lack of a current UK guide is well known, being noted in another excellent publication (Baldock 2008) which includes useful photos and a key to bee genera. I use this a lot and its relevance is broader than the title suggests as Surrey supports a large proportion of the national bee fauna. Of course, I haven't yet covered online resources or societies and the one that really stands out here is BWARS (the Bees, Wasps & Ants Recording Society) which includes a variety of resources (inlcuding the test keys mentioned above) such as a more comprehensive bibliography (with more opportunities to improve my German) and an excellent photo gallery. All told, practise is essential and I have learned a lot about bee ID over the last few years, though there are still some gaps I want to fill (when aren't there?). There's also a tantalising hint of a work-in-progress in the form of a 'Handbook of the Bees of the British Isles and the Channel Islands' to be published by the Ray Society, though no date is yet known. I may have to put some money aside for that one...

Happy bee-hunting!

Hmmm, nice clear wing venation, now where's that key...?


References

Baldock, D.W. (2008). Bees of Surrey. Surrey Wildlife Trust, Woking.
Bellmann, H. (2010). Bienen, Wespen, Ameisen. Kosmos, Stuttgart. [In German]
Edwards, M. & Jenner, M. (2009). Field Guide to the Bumblebees of Great Britain & Ireland (rev. ed.). Ocelli, Eastbourne
Else, G.R. (1999). Identification. Leaf-cutter bees. British Wildlife10(6): 388-393.
Saunders, E. (1896). The Hymenoptera Aculeata of the British Isles. Reeve, London.
Step, E. (1932). Bees, Wasps, Ants and Allied Insects of the British Isles. Warne, London.
Willmer, P. (1985). Bees, Ants and wasps. A Key to Genera of the British Aculeates. Field Studies Council, Taunton.
Yarrow, I.H.H. (1986). Key to the Aculeata (ants, bees and wasps). In: Betts, C. (ed.). The Hymenopterist's Handbook (2nd ed.). AES, Hanworth. pp. 168-172.

Monday, 17 December 2012

Into the Tomb of Zootoca

The title of a lost H.P. Lovecraft tale? Nope, though it isn't every Christmas party that you get handed a box containing a mummified corpse...

A mummified common lizard, Zootoca vivipara
Actually, this isn't as odd as it sounds - the lizard was found by friends while taking up an old carpet, and might be a casualty of one of their cats that subsequently dried out. As you'll see later, it isn't perfectly preserved... Anyhow, the first thing I did was measure it - at approximately 40mm in length including tail, it was newly born as the common (or viviparous) lizard (Zootoca vivipara, previously Lacerta) is 37-44mm long at birth with the tail no more than about half the overall length (Beebee & Griffiths 2000, Inns 2009). Then, as ever, I took a closer look...

Dorsal view of the Z. vivipara specimen
As you can see, the skin/scales of the head is largely intact and the scale pattern remains clearly visible, a feature that can be useful for identification, especially in areas (unlike the UK) with a wide range of superficially similar species. As is typical for young common lizards, the colour is dark, though this could be an artefact of death and drying, and zooming in on the abdominal scales gives a hint of the colour that develops after a few weeks. The dense, overlapping arrangement of dorsal scales (with 'keels') is typical of lacertids.

Dorsal abdominal scales of young Z. vivipara - dark but with a hint of the metallic greenish-brown-bronze colour (including some gold flecks) that typically develops after a few weeks (Beebee & Griffiths 2000)
Turning the specimen over, further structures can be seen. As well as skeletal features such as the ribs, some of the ventral scales (or 'plates') are intact (though not the collar area beneath the neck, nor the femoral pores beneath the thigh), and show the development of an iridescent greenish colour. The scales are not simple plates of keratin like the 'scutes' of crocodilians, but are outfoldings of the skin itself that are each covered in a tough waterproof layer and contain both an osteoderm (internal bony plate) for structural integrity and a layer of chromatophores - cells that produce colour - just below the outer epidermis.

Ventral view of young Z. vivipara
Ventral scales/plates of young Z. vivipara
Turning the specimen on its side then allows the skull to be investigated as the skin is missing. You can immediately see the teeth (more below on this) - as is usual for lizards, they are conical and all approximately the same size - and show that the young common lizard is well equipped to begin feeding (on anything small enough to catch, including aphids!) as soon as it is born. It's also worth taking note of the overall structure as lizard skulls are rarely represented in books on animal signs (unlike mammal skulls, a range of which tend to be illustrated) or other resources such as guides to the contents of owl pellets (presumably owls rarely if ever eat them).

Side view of the head of young Z. vivipara.
However, I did notice something towards the rear of the skull - you can just see it in the photo above as a pair of little white dots in the left-most of the three main cavities. Time to switch to a higher magnification...

Small Fungi growing on the head of Z. vivipara

...and another kingdom of organisms as these are clearly Fungi. These structures are around 0.5mm long, with the white 'blob' around 0.1mm in diameter. I can't begin to describe how fiddly it was removing these to make a slide, but I did (tiny tweezers) and decided to see if I could identify the fungus.

Fungus from Z. vivipara (the arrows indicate the length of one of the stalk cells)
This is clearly a spore-mass on a stalk (one cell thick, cell walls indicated by arrows). The white colour of the spore-mass in the first photo is an artefect of lighting and my camera; it is actually a pale yellowish-brown - darker in the second photo where it has been compressed. Consulting Ellis & Ellis (1998) it soon became clear this wasn't a specialised 'bone-eating' fungus but was more likely to be one of the moulds (Ascomycetes) that can be found on a wide range of organic matter. Given the overall form/size and the more-or-less round and transparent spores (some of which appear slightly warty), this is probably Eurotium and/or Aspergillus, although the faint equatorial groove of Eurotium isn't visible in the photos. 'And/or'? you may ask... well...

Cleistothecium (spore mass) of Eurotium /Aspergillus
Warty spores of Eurotium/Aspergillus indicated by arrows. Others are not in focus.

The taxonomy of some fungal groups is complex because different (asexual 'anamorph' and sexual 'teleomorph') stages have been given different names, and in some cases there are several anamorphs, all with separate names. This is case here with Eurotium being the teleomorph and Aspergillus the anamorph - both of which may be found together, and often are. I could expand on this, but fortunately don't need to - as of January 1st 2013, any one fungus will have a single name covering all stages/'morphs', and details of how this will work are given in Hawksworth (2011). As far as this specimen is concerned, taxonomic considerations aside, it does mean that it is mouldy and therefore not perfectly mummified. I have it in a dry container so it may surrvive, or I might find it turns into a clean skeleton. Certainly this eruption from the scales shows it's still active.

'Tuft' of Eurotium/Aspergillus growing from the skin of Z. vivipara
Now, back to the lizard... following a reader's comment, I returned to the specimen and had a better look at the teeth. I also Googled and was surprised to find few images showing lizard teeth in detail - presumably they exist, but not on my bookshelves. As mentioned above, the structure is fairly uniform (unlike us mammals with canines, incisors, molars with varying numbers of cusps and so on), but that is a slight oversimplification.

Cheek teeth of juvenile Z. vivipara
Front teeth of juvenile Z. vivipara
Ignoring the fungal structures this time, the cheek teeth are clearly more-or-less cylindrical with a conical point; they are also transparent showing what I presume is the pulp cavity as a whitish central mass. However, the front teeth are curved backwards and more 'fang-like' as might be expected in order to catch and hold prey. Although showing little obvious differentiation, a search of the literature online indicates (and I'm way out of my comfort zone here!) that lacertid teeth can be categorised as premaxillary (apparently of taxonomic and palaeontological importance with 7 in Zootoca), maxillary and dentary according to their position and associated jawbones (Arribas 1998). This is where I'll stop on dentition, but if any reader would like to expand on this in the comments (e.g. whether the different tooth groups differ structurally), please feel free!

Lastly, I can't finish this post without mentioning reptile conservation in the UK. The common lizard is widespread but has declined, especially in the south, due largely to development pressure and the loss of brownfield sites. Because of this it is now a UK BAP (Biodiversity Action Plan) species. It seems clear that habitat loss needs to be tackled (although with a government that seems to want to relax, rather than tighten, planning laws it is unclear how this will happen), but there is good advice in Gent & Gibson (2003) and Edgar et al. (2010). Rather than repeating what they have said, or putting my campaigning hat on, I'd just like to highlight the importance of collecting (and sending in to Biological Records Centres) reptile species records, especially as part of systematic surveys though ad hoc records are valuable too, and undertaking practical conservation work to improve habitat quality.


References

Arribas, O.J. (1998). Osteology of the Pyrenean Mountain Lizards and comparison with other species
of the collective genus Archaeolacerta Mertens, 1921 s. l. from Europe and Asia Minor (Squamata: Sauna: Lacertidae). Herpetozoa 11(1/2): 47-70.
Beebee, T. & Griffiths, R. (2000). Amphibians & Reptiles. HarperCollins, London.
Edgar, P., Foster, J. & Baker, J. (eds.) (2010). Reptile Habitat Management Handbook. ARC, Bournemouth.
Ellis, M.B. & Ellis, J.P. (1998). Microfungi on Miscellaneous Substrates (2nd ed.). Richmond, Slough.
Gent, T. & Gibson, S. (eds.) (2003). Herpetofauna Workers' Manual (revised reprint). JNCC, Peterborough.
Hawksworth, D. (2011). A new dawn for the naming of fungi: impacts of decisions made in Melbourne in July 2011 on the future publication and regulation of fungal names. Mycokeys 1: 7-20.
Inns, H. (2009). Britain's Reptiles and Amphibians. WildGuides, Old Basing.

Tuesday, 11 December 2012

Sometimes, life is just a blur

No, despite the title, I'm not talking about being far too busy to fit everything in (though that's often true), or having hazy recollections of evenings past due to the influence of rum... Instead, I want to give a little insight into the nature of some enquiries I receive from non-entomologists regarding the identification of invertebrates.

First of all I have to say that I like receiving such requests - I may not always have much time to devote to them, but I do try, and am always pleased that someone has put in the effort, and been interested enough, to photograph an invertebrate and then (often after having tried a general insect book and the web) bothered to find someone - me - to contact. Much better than squashing the unknown!

So, when my mother-in-law got in touch a few days ago saying that a guy (Scott, if you're reading this) doing hedge-trimming had found (and I paraphrase here) 'a big insect like a dragonfly with a stinger' on his leg, it was good to know that it had been put on a leaf and photographed. My initial thought was 'ichneumon' because dragonflies are pretty straightforward to recognise as a group (including the damselflies) and Britain doesn't have many other long, thin, large insects with anything resembling a 'stinger'. I wasn't sure how far I'd get with identification - with around 3,300 species in the UK alone, many of which are very similar, and no single guide to them, it isn't an easy task even with a specimen - from a photo, species-level ID is usually impossible. Still, I was curious and asked for the photos to be emailed to me, and this is one of the set I received...

The mystery ichneumon
Well, the first thing is it is certainly an ichneumon (a type of parasitic wasp, although they are sometimes called 'ichneumon-flies' despite definitely not being flies), and quite a large one going by the ivy leaf and Scott's thumb for scale. However, beyond that it is a little more difficult. It is black with orange legs, a common combination for ichneumons, and has a long ovipositor. This is the 'stinger' but in reality isn't a sting; although some ichneumons (such as the orange-yellow ophions that turn up in moth traps) do sometimes give human fingers a bit of a jab, they are essentially harmless to us. The structure is actually an egg-laying tube and is long because it is used to probe into wood where the host insect larva lives. An egg is laid in (or on, with the young ichneumon larva burrowing inside once hatched) the host and the rest is, well, parasitic - suffice to say the host does not survive having an ichneumon growing inside it. Hosts include beetles, moths, flies and so on, varying by ichneumon species. So, is there anything else I can tell from the photos?

Side view of the mystery ichneumon
You will have noticed that the photos are a bit blurry (hence the title) - cameraphones and compacts often seem to decide the background is more interesting than the real subject - and often this would mean I couldn't use them. However, in this case it makes little difference as ichneumon ID by photo is often uncertain at best in any case. Here I can see the overall size and colour - for example there are no white spots or bands on the abdomen, which means it isn't our largest ichneumon, the sabre wasp Rhyssa  persuasoria. The size rules out most species, and the long ovipositor means it isn't a species of Pimpla (see below). Instead it is likely to be either Lissonota or the more localised Ephilates. Being late in the year, it is possible this individual was avoiding cold conditions and is simply active later than expected - certainly it dropped to the ground and was lost in pant material rather than flying away.

Whichever it is, the specimen is certainly impressive. I find this group of insects intriguing and am slowly  learning to identify them - it's a long process - and the species-level names are often indicative of their parasitic reproductive strategy and habit of hunting openly and actively for hosts; instigator, punctator, divinator, fornicator, consortana, dissoluta, inquisitor, insertana and so on. If you are interested, Broad (2006) provides a useful test key to subfamilies here. Beyond that, it's a matter of accumulating useful webpages, books and articles, and finding hymenopterists to help you - Fitton et al. (1988) shouldn't be too hard to find and covers the subfamily Pimplinae, members of which are quite readily encountered, such as the one below which took shelter in our bedroom while we were on holiday last month...

A pimpline ichneumon, possibly genus Pimpla.
References

Broad, G. (2006). Identification key to the subfamilies of Ichneumonidae (Hymenoptera). Available online here.
Fitton, M.G., Shaw, M.R. & Gauld, I.D. (1988). Pimpline Ichneumon-flies. Hymenoptera, Ichneumonidae (Pimplinae). Handbooks for the Identification of British Insects 7(1): 1-110.

Friday, 30 November 2012

A load of old Balanus

We're all familiar with barnacles, at least in broad terms - we see them on rocks, ships, whales etc, they turn up in A-level college biology projects, and if we slip on them, they are sharp and they hurt. However, how often do we really look at them?

A typical view of a barnacle-encrusted rocky shore (Start Point, south Devon, England)
They are of course crustaceans (of the class Cirripedia, order Thoracica) and come in three main forms, the suborders Lepadomorpha (the stalked 'goose' barnacles), Verruomorpha (like 'typical' barnacles but with only two opercular plates - I'll get on to that later), and Balanomorpha (the 'typical' barnacles'). I'm only going to focus on the latter, though I can't let the opportunity pass by without mentioning the existence of the order Rhizocephala. These are evolutionarily derived relatives of the barnacles and parasitise decapod crustaceans (such as crabs), their free-swimming juveniles settling on their hosts and developing into an 'interna' of root-like growths and an 'externa' which is a sac of reproductive parts. They lack as body as such, and their name means 'root head', and as with many internal parasites, they redirect their hosts' physiology and behaviour to their own ends. If I find any, I'll definitely write about them, but until then, here's a fine little 4-minute video introducing their life cycle through the medium of hand-drawn cut-out animation.

Anyhow, back to barnacles as we know them... The rocky shore above was well encrusted with barnacles of several species. There were many of the small limpet-shaped ones (such as Chthamalus stellatus in the family Chthamalidae), but what grabbed my attention were some larger, less flattened specimens typical of the the family Balanidae.
A barnacle of the family Balanidae.
As you can see, this barnacle is fairly tall (rather than being a low flat cone). Although the joins are rather obscured in this mature specimen, there are six plates forming the outer wall. It isn't clear from the photo, but the base forms a calcareous layer on the underlying rock (rather than a membranous layer) and hence this is in the genus Balanus. Identification past this point is a little tricky because the colours are so variable and corrode to a greyish mishmash in old specimens, but the obscure sutures, sharp 'beak' (tergum) and ribbed outer surface suggest either B. perforatus or B. balanus.

The scutum (seen here as a 'keel' beneath the sharply beaked tergum) is slightly saw-edged, and the smaller barnacles (which I assume are the same species) below the large one have yellowish rims with brown banding below/around them. Also, the opening in the large specimen isn't especially small. These features combine to suggest that this is B. balanus - a common species although south Devon is at the very SW extent of its range as it is absent from Cornwall, but is a place where this species has been regularly recorded. A closer look should also help clarify a couple of the features mentioned here.
The operculum, tergum and scutum of Balanus balanus
Aside from the smaller barnacles that are using it as a substrate, the beaked tergum is clearly visible as is the rough, serrated edge of the scutum. Both these structures are paired (you can see the join at the top of the tergum), forming four internal plates (collectively the 'operculum') that can move and open to allow the feeding structures (feathery 'cirri') to waft in the water and catch food particles.


So, a closer-than-usual look at a familiar organism - and a relatively rare (for me) foray into marine and littoral/intertidal habitats. Maybe I'll have to do more on this as it was the habitat that first grabbed my attention in terms of the invertebrate fauna...

Monday, 26 November 2012

What's in a wall?

As you might imagine, I don't mean bricks and mortar - instead I am more interested in the species that can be found growing on walls, particularly old rough stone walls in areas with low levels of air pollution such as might be found in the village of Slapton in south Devon. Yup, where I was one holiday a couple of weeks ago... Old walls are well known to be important for wildlife - for instance, lizards can often be seen basking on them - but for those of us living or working in cities, especially with relatively new and smooth-surfaced buildings (and more air pollution), the opportunities to see such species can be limited.

Some are so strongly associated with this type of habitat that their common names reflect it, such as the wall pennywort Umbilicus rupestris (the generic name reflects its other common name, 'navelwort'). Like many wall-dwelling species, they are also found on natural rocks, but man-made rocky surfaces can be just as good.

The round leaves of wall pennywort Umbilicus rupestris.
You can see pale green lichenous growth here, but a closer look around this wall revealed a somewhat more impressive display - the little trumpet-like fruiting bodies of the lichen Cladonia (one of several similar species).
A cluster of Cladonia
There were also larger growths of non-lichenous fungi among the damp, mossy hollows. One was the branched and spindly Grey Coral Clavulina cinerea. This is a common species but being associated with the ground in woodlands, might not seem a likely wall-colonist. However, the crevices were full of moss and soil, and roots were present from the woody plants on top of the bank the wall retains. So, from the fungus' point of view, just like home! Another was an attractive orange-red waxcap Hygrocybe sp., possibly H. helobia which was only described scientifically in 1974 and is more often associated with grassy woodland clearing or heaths (but again, conditions are suitable in this wall). However, without closer examination (beyond what I'm likely to do on holiday), the species-level ID remains tentative.
Grey Coral fungus Clavulina cinerea

Waxcap Hygrocybe sp.
Moving through the major taxonomic groups, there are also ferns associated with walls. One of these is the rustyback Asplenium ceterach which I initially thought I had found; however, closer examination (yes, sometimes even on holiday, though it took iSpot to confirm it as I don't ID ferns very often...) showed it to be A. adiantum-nigrum, though both are common in SW England. Another (which I can also find growing from crevices in the walls of the church near where I live) is the maidenhair spleenwort A trichomanes.
Asplenium adiantum-nigrum (upper surface of fronds)

Asplenium adiantum-nigrum (lower surface of frond showing red-brown sori)

Maidenhair spleenwort Adiantum trichomanes
Lastly I want to return to the flowering plants, this time a non-native garden escape Nerine bowdenii, also known as the Guernsey Lily. This southern African species is a popular plant in the village of Slapton and can be seen along the narrow lanes outside many of the cottages. However, coming from mountainous areas, it too can adapt to 'mural' life and at least one had managed to escape through a garden fence and grow on top of the old stone wall featured here. I could continue - after all, with all these plants, fungi and lichens, there are of course many invertebrates (my usual topic!) - however, as I promised my wife I would not spend the week rummaging around with collecting pots, these will remain mysterious for now and I'll simply leave you with the big pink lily which, although appearing delicate, was clearly capable of surviving repeated buffeting by passing vehicles...
Guernsey Lily Nerine bowdenii.

Tuesday, 20 November 2012

No seeds, no fruit, no fungi - November!

It's been an odd year in the UK (and elsewhere) - an unusually warm early spring, then a cold, wet early spring and summer and a very variable autumn with frosts and warm periods. Unsurprisingly, this has seriously impacted some of the UK's wildlife negatively. For example, the Big Butterfly Count found declines in many common species, with 11 of the 21 target species decreasing in abundance by more than a third since 2011. There are a number of reasons - low temperatures clearly affect cold-blooded groups such as insects, which in turn reduces the food available for insectivores such as birds and bats. Plant growth is also affected by cold and water-logging, so less sugar is produced, fruit growth is reduced (and what does grow may be affected by moulds and blights and fall early or rot on the plant), leading to less seed production - bad for plant reproduction and seed-feeders such as many winter birds. This is already having visible effects as more unusual species appear in gardens - so, it is even more important to keep bird-feeders full. Poor fruit/seed growth in Scandinavia has already meant that at least a couple of thousand waxwings have flow across the North Sea to NE Britain. There are also less obvious effects. For example, the reduced sugar production means that ectomycorrhizal (externally root-associated) fungi grow poorly despite the damp conditions.

However, not all is doom and gloom. Some species have taken advantage of warm late summer and autumn temperatures to grow and breed - I have certainly seen late bird-nesting activity, and while in south Devon last week (the SW is the warmest part of the country), while some trees were losing their leaves, others were budding as seen here.

Hazel coming into bud in mid-November in south Devon
Late flowering has provided at least some extended nectar availability (apart from ivy which is always a winter source) as seen here where a small Panurgus calcaratus bee is feeding on a yellow composite flower, again in mid-November. Found in a band across SE England it is also known all round the SW coast as you can see on the map here; clearly a species needing warm temperatures as it is absent further north.

Panurgus calcaratus feeding on a yellow composite flower in warm sunny mid-November conditions in south Devon
Warm damp autumn weather has meant that some fungi have done well eventually, such as those living on damp deadwood and leaf-litter, while in our new garden pond, the pond-skaters have bred very successfully and are highly active. Slugs and snails have also had an excellent year, though this is not popular with gardeners and allotment-holders, not to mention those of us with old houses that have little holes where slugs can gain access in the middkle of the night...

Overall, there are sadly probably more wildlife losers than winners, but what does the future hold? Well, nothing is certain, but an important study by Overland et al. (2012) does give some indications. Firstly, as many people have suggested, it isn't just 2012 when the summer has been cold and wet - this is a pattern that seems to have begun in 2007 when there was what appears to be a sustained shift in early summer Arctic winds. This change is linked to increased North American atmospheric blocking which ultimately leads to the southward movement of the jet stream that has been mentioned in TV weather forecasts. The study also looked at why this has happened and has unsurprisingly concluded that climate change is a likely candidate - in particular the melting of Arctic ice (particularly around Greenland, remembering that Greenland is politically European but geographically North American) which highlights the potential connectivity between Arctic climate and mid-latitude weather i.e. the Arctic heats up, the UK gets bad summers.

This is of course an ongoing story - research is undoubtedly ongoing to finesse some of the findings and explanations. As an academic, I find this fascinating but as someone interested in wildlife and environmental issues, I also find it deeply troubling, especially when the UK government seems to be trying to pull back from its low-carbon committments. However, I'll stop there lest the Ecology Spot becomes my political ranting zone!

Reference

Overland, J. E., Francis, J. A., Hanna, E. & Wang, M. (2012). The recent shift in early summer Arctic atmospheric circulation, Geophysical Research Letters 39, L19804 (6pp.)

Tuesday, 6 November 2012

Cocoons of woolly doom

Back in the day, wardrobes and blanket-boxes smelled of mothballs (largely naphthalene though it was flammable, and camphor is a less toxic alternative) placed to keep fabric-eating moths of the family Tineidae away. Now, they are less common as the moth larvae do not eat synthetic materials, and on the whole houses are cleaner and more hygeinic. However, in forgotten cupboards, they still nibble their way through wool and other animal materials such as furs. The adults tend to be rather drab, but as I found out while clearing a cupboard of woollen items in the attic, the larvae of one species, Tinea pellionella, the case-bearing clothes moth can produce something rather colourful (if also annoying) - their cases or cocoons.

A larval case of Tinea pellionella
The larval case above is clearly made of fibres spun from differently coloured wools (the ones with the holes in...) and in its own way is quite a beautiful thing. It is dorso-ventrally flattened, and the ends are open; thus the larva's front end can protrude to allow feeding and faeces can be ejected (the rear is bottom-right and shows small dark faecal pellets). The moth pupates in the case which is fixed some distance from where it feeds and then emerges, leaving the empty skin protruding. The group as a whole can be difficult to identify, often requiring dissection of adults.

A case of T. pellionella with protruding skin after emergence
Having found (and squashed, sorry) quite a number of these, I hope that I won't need to sew up any more holes - fortunately I'd noticed a few adults flying around and realised that the larvae needed to be found; so, with  a bit of luck the infestation will remain minor, and I'll be off to buy some cedarwood repellent, though the number of dried husks also indicated that our house-spiders were doing a useful job!

A smaller, brighter case of T. pellionella.


Further reading

Heath, J. & Emmet, A.M. (1985). The Moths and Butterflies of Great Britain and Ireland. Volume 2: Cossidae - Heliodinidae. Harley, Colchester. [Part of the impressive (but sometimes expensive) MBGBI series covering all Lepidoptera of the British Isles in considerable detail, including dissection of genitalia]
Palmer, R.M., Porter, J. & Collins, G.A. (2012). Smaller Moths of Surrey. Surrey Wildlife Trust, Woking. [Distribution maps for the county of Surrey, but much information which is more widely applicable]
Stirling, P., Parsons, M. & Lewington, R. (2012). Field Guide to the Micromoths of Great Britain and Ireland. BWP, Gillingham. [excellent affordable guide]

Monday, 5 November 2012

Leaf beetle key - write, edit, plug

If you are a regular here, you'll know that I have a considerable interest in invertebrates and that they form a large proportion of the topics I write about (a glance at the 'tag cloud' in the right margin will confirm that). However, you might not know that I specialise a little more than that and that one of my areas of specialism is in the Chrysomelidae - the 'leaf beetles', which include the 'seed', 'reed', 'flea' and 'tortoise' beetles - and the two small closely related families, the Orsodacnidae and Megalopodidae. You may be familiar with these groups having a slightly different taxonomic arrangement, such as the Bruchinae being accorded full family status, but recent cladistic work (e.g. Reid, 1995) suggests otherwise.

A few years ago I became interested in this group as a voluntary species recorder for the UK's Biological Records Centre (BRC), and later as organiser of the related UK Recording Scheme. I soon found that, even with the excellent Atlas to British and Irish species having been published (Cox, 2007), I needed to collect a large number of individual journal articles in order to be able to reliably identify adults of the British chrysomelid fauna and that even then there were gaps. The last key covering all species was Joy (1932) which, although excellent, was unavoidably out of date (and hard to find affordably until the CD-ROM version appeared), while the update (Hodge & Jones 1995) was out of print. Grr. Although the BRC were extremely helpful, sending me copies of the articles I needed if they had access to them, it became clear that a lack of readily available user-friendly identification literature was a major barrier to expanding interest in this beetle group. Such a barrier needed to be overcome, especially as the Chrysomelidae includes many charismatic (shiny, colourful and metallic such as the green dock-beetle Gastrophysa viridula) species as well as a number of considerable economic importance (horticultural and agricultural pests) such as the unpopular Lily Beetle (Lilioceris lilii) and the notorious potato pest, the Colorado Beetle (Leptinotarsa decemlineata) although the latter is currently unable to colonise Britain due to low winter temperatures. There is also a conservation component as accurate identification is needed to provide useful distribution and monitoring data. For example, there are a number Biodiversity Action Plan (BAP) and Red Data Book (RDB) species, such as the Pashford Pot Beetle Cryptocephalus exiguus which provides an (unfortunately) excellent case study of ineffective landscape-scale conservation, while the flea beetle Psylliodes luridipennis is a UK endemic known only from Lundy Island where it is threatened by over-grazing and invasive rhododendron.

Consequently, I made the decision that 'the book' would only appear if I wrote it, and so I began, aiming for an intermediate audience as I wanted to cover all British and Irish species, and many require dissection under a low-power microscope - not something for beginners maybe... I won't go into too much detail other than to say it was difficult - really, really difficult. The initial draft wasn't too bad to write, but - as expected - had many errors and omissions which were discovered during testing. However, many testers provided excellent tips and suggested changes - some extensive - which greatly improved the final version. The difficulty came where species were not covered reliably by existing literature, and this happened a lot while trying to write keys for the notoriously tricky flea beetle genera such as Longitarsus. I was aided in many cases by the excellent images (including genitalia) on the European Chrysomelidae website, but in the end there is no substitute for going to a museum or other institution, and consulting specimens in their reference collections such as those held in Winchester (Hampshire County Council), Oxford (Oxford Uni Museum of Natural History) and at the BENHS HQ near Reading. This is what sampling and collecting is for - it ain't decoration or 'train-spotting'!

A tray of beetles from the Oxford Uni MNH collections
So, after editing, re-editing, adding a few species that had been newly found in Britain, and making changes following taxonomic updates, the final version - complete with cover photo - went off to the publisher and then the printer. I was expecting it to be ready in mid to late November, but - much excitement - a courier delivered a box of my author's copies this morning - whoop! I think they are great (obviously) and a bargain at only £8.50 - available here - enjoy! All the many many hours of beetle-scrutiny was worth it - now, I seem to remember there's no general textbook covering this family...

Woo hoo! A box of brand new copies of my key to British and Irish leaf beetles.

References



Cox, M.L. (2007). Atlas of the Seed and Leaf Beetles of Britain and Ireland. Pisces, Newbury.

Hodge, P.J. & Jones, R.A. (1995). New British Beetles: Species not in Joy's Practical Handbook. BENHS, Reading.

Joy, N.H. (1932). A Practical Handbook of British Beetles (2 vols., 1976 reprint). Classey, Faringdon.

Reid, C.A.M. (1995). A cladistic analysis of subfamilial relationships in the Chrysomelidae sensu lato (Chrysomeloidea). In: J. Pakaluk & S.A. Ślipiński (eds.) Biology, Phylogeny, and Classification of Coleoptera: Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum i Instytut Zoologii PAN, Warsaw, pp. 559-631.