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...

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.

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.

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.