Collecting invertebrates - some more reassurance

Volucella zonaria. CC image by Martin Cooper.

Last night at home we were looking at some photos, and one of them was of the strange creature above. It was in August and we'd found it sunning itself on a trellis. At first sight it looked like a massive wasp or hornet, but closer inspection proved it had two wings (not four) and no thin waspy waist - it was actually a type of fly.

I've got an excellent book on hoverflies (these wasp mimics are often hoverflies, i.e. in the Syrphidae family) - it's by Stuart Ball and Roger Morris and called 'Britain's Hoverflies'. And because this animal is so distinctive I was able to identify it with the time-honoured practice of page-flicking. But the book is excellent and the keys are easy to use - you'd probably not have too much problem with less obvious species. However, hoverfly season's doubtless pretty much over, so maybe save your money for next year.

However, I read some very useful advice which applies to other invertebrates too. It's reassuring if you're experiencing squeamishness about killing specimens for your collection. If you take what you're doing seriously, your collecting can be for the greater good.

Ball and Morris say: "Many naturalists frown upon the collection of specimens. The prevailing ethos is 'leave nothing but footprints, take nothing but photographs.' [But] this approach does not work for a large proportion of Diptera, or indeed for many other invertebrates. It is often necessary to examine a dead specimen rather closely in order to ensure an accurate identification.

"So is there a potential conflict between collection and conservation? The authors of the book have both spent most of their working lives employed by conservation organisations and do not consider there to be a conflict. Whilst we recognise that a few rare species have such restricted breeding sites that collecting could be damaging, we believe that insect faunas are at far greater risk through not knowing which sites are important and how they should be managed.

"The collection of a few voucher specimens is extremely unlikely to be damaging to hoverfly populations and, in our view, responsible collecting that adds to our knowledge of the distribution and biology of hoverflies, should be encouraged. However, we would stress that if an animal has died to generate an identification then use should be made of the resulting record! It should be lodged with the Recording Scheme and subsequently made available to conservation organisations and researchers. Although not a good reason to condone collecting, it is worth bearing in mind that you will kill many more hoverflies on the front of your car driving to and from a site than you are ever likely to collect."

Another use for dead flies. CC image by James F Carter

At the risk of quoting half their book, they also offer these thoughts on 'Why keep a collection?"

"Vouchers: You can prove to yourself and others that you got the identification correct. This is especially important when you are starting off. The best way to learn is to try naming some specimens and then to get them checked by an expert. Nevertheless, however expert you may become, it remains important to keep vouchers for difficult and uncertain identifications.

Comparison: The identification process often involves comparative judgements (e.g. bigger than...; eye hairs darker than...). In these cases, it is very useful to have material you have previously identified to hand so that you can remind yourself what the various options look like."

They also link to an updated version of the Code of Conduct for Collecting Insects and Other Invertebrates (2002).

You might also like the discussion on why collecting specimens is still relevant and useful (and will remain so) here on ResearchGate.

Fish scales

I previously mentioned that the scale count along the lateral lines of some fish is often diagnostic of the species. But I then read something about the diagnostic value of the shape of the scales themselves - they are often similar within a family or genus, but vary between families and genera.

Gudgeon, Perch and Pike scales

The scales also show growth rings or 'annulae'; and rather like the rings inside a tree, they can be used to determine the age of the fish. The Delaware Division of Fish and Wildlife have a little document about this.  The obvious rings are formed during the winter when the fish (and its scales) grow much more slowly.

The scales above are from bony fish, but cartilaginous fish like sharks have scales that evolved separately. The latter are structurally like our teeth with a pulp cavity and a layer of dentine. And they completely appeal to my love of repeating patterns:

Lemon shark CC image by Pascal Deynat

Shark scales feel rough but apparently the vortices the shapes produce in the water actually cut hydrodynamic drag (ahem, or maybe I've got the wrong end of the stick and they're a bit like winglets on a plane - whichever way, the point is the fish moves more efficiently).

It strikes me that this subject could be something to include in passing in your monograph, especially if you have specimens that represent the different groups (and of course some fish have no scales at all).

Wikipedia  does have a very good overview and there's some more information on a page from Earthlife too.

If you wanted to look at your scales under a microscope that would certainly be possible. And if you got really interested then pursuading my colleague with his elecron microscope to get involved might not be out of the question. And to think that until yesterday I had barely given fish scales a second thought.

Freshwater fish (or: is nothing simple)

Roach (top) and Roach-Bream hybrid (below). CC image by Jam123

People who choose fish for their collection tend to have vastly more knowledge than I do about the subject (my knowledge of fishing could be written on the back of a stamp). I admit that my only brush with fish identification (bar helping with the Environmental Health exams) is my experience of revamping and relabelling the Fish In Jars collection in the field centre. The ones from the estuary and the sea weren't too bad to identify. But when I came to specimens a previous student had collected from fresh water, things got trickier. Especially as they were all looking a bit pickled and faded.

The reason for this confusion is that some species have a habit of hybridising with others. This is apparently not uncommon, but you wouldn't know that from the identification books. They completely ignore the phenomenon, which probably says something about the psychology of people (that they prefer things to be in neat boxes, and freaky things which are neither one thing nor another become almost invisible. Oh the Fortean Times would have a field day). It was once thought that the hybrids were sterile but it now seems that some do breed (so you can have for example, Roach/Bream and Bream hybrids)... things could get out of hand when you just want to put a name to your fish.

I noticed that the Natural History Museum's name checklist doesn't flinch from the topic. But it's no use in helping you identify them.

I expect if you've got fishing experience you'll have an inkling that your specimen Isn't Quite Right, which should help.

Angling Ireland's site  has descriptions of Roach/Bream, Roach/Rudd and Rudd/Bream hybrids.

Idler's Quest also has a discussion and photos of Roach, Bream and Rudd hybrids.

There's some information on hybrid Chub here.

And so-called 'F1 Carp' are a cross between Common and Crucian carp, a deliberate and popular choice for commercial fishing lakes. There's some information on distinguishing them and other carp hybrids on the Crucian Website.

There are probably many other websites that might help, or you could add the opinions of an experienced angler into the mix too.

Failing DNA tests the ways to distinguish between ordinary species and hybrids tend to include looking at the size and shape of fins, their position, and the number of rays they contain; also the number of scales along the lateral line.

Also, they may not be present throughout the whole country - you can try looking at maps on the NBN gateway.

I can only wish you the best of luck - you might get really into this (record all your thought processes in your notebook) or if it drives you mad, you might want to include only straightforward and clear specimens in your collection.

Ancient mosaic of another hybrid - the half fish, half horse Hippocampus. You're probably unlikely to catch this though you might get an ordinary seahorse. CC image from Carole Raddato.

Strange seaweed

I really like Mr Adams' book on snails, as I rather think we have the same sense of humour. I enjoy seeing what he's got to say about his subjects, even if he was saying it 120 years ago and there are much easier books to learn from now (and importantly, which use current taxonomy).

So I enjoy surfing to see what else was written in those times. Today I spotted the seriously antique 'Seaweed Collector's Guide' of 1853. My eye was caught by the following piece of advice:

"I must now caution young beginners to keep apart from other plants all the different varieties of the genus Desmarestia, for they posess the peculiar property of changing the colour of, and very soon decomposing, all other plants, especially those of the finer species, with which they may come in contact.

 "Notwithstanding what has been alleged to the contrary, most of the Desmarestiae, if kept out of sea-water, even for a very inconsiderable time, soon become flaccid, and rapidly advance towards decay."

He says that specimens must always be transported in seawater, as they get irreversibly ruined if you put them in fresh water. He sounds a bit peeved that he's made this observation and somebody is questioning whether it's his imagination or not (Notwithstanding...).

Desmarestia aculeata: public domain image from a Victorian seaweed herbarium in France.

I couldn't help wondering what all this was about. It turns out to be rather interesting, as you can read on the Friday Harbor Laboratories' webpages. The Desmarestia stores sulphuric acid inside its vacuoles - resulting in an internal pH of 0.8 to 1.8 (really very low, like stomach or battery acid). So when the vacuoles burst, it's no wonder your specimens get ruined.

Researchers have shown that grazing sea-urchins are, unsurprisingly, put off from grazing Desmarestia and any other species that it's growing with. The acid erodes their 'teeth' and I imagine it wouldn't feel very nice elsewhere either. It seems that the sulphuric acid vacuoles have evolved as an anti-herbivore measure.

Snail trouble (and a database of photos)

The two snails I identified yesterday were easy to key out. But the one I picked up next was small. So is it a juvenile snail? Or is it an adult of a small species? If it's a juvenile its measurements won't fit the ones in the keys, so I'll immediately be barking up the wrong tree.

What we ideally need is someone who knows. This is a good tip for any type of creature or plant you're interested in. Sadly I don't know anyone and Mr Adams is long dead. I could join a local group of snail fanatics or take a course. But in the meantime I have sought some information from books and the internet...

Cameron says that adults of many species have a lip (or teeth) to their shell. But sadly many do not, so that's not altogether helpful.

However, the British Conchological Society key says on this page that if the maximum shell breadth is less than 8mm and the number of whorls is less than 3 and a half, you probably have a juvenile (with the implication it's worth looking for another specimen if you actually want to have a chance of identifying anything). But if your snail has 4 or more whorls, even if it's less than 8mm, then you probably have an adult.

You count the whorls by running an imaginary line from the centre of the spiral, out so it forms a semi-circle with the first part. You count from the end of that semi-circle: each time you return to the line, it's a whorl. It can be difficult to tell where to start counting the whorls because they're so tiny in the centre (the 'protoconch').
 

 

Here's my little snail, it's just over 8mm wide. You can borrow some vernier callipers from me if you want to measure your snails - they are easier than using a ruler. You can see this one has about 4 whorls, so I'm going to assume it's an adult.

Here's its underside - you can see it's got an 'umbilicus' - a hole where the whorls don't totally close up on themselves.

This is not the world's best photo, but it's to try to show the flatness of the shell - this doesn't look like your average conical garden snail.

Using the pictoral key in Cameron's book, it's easy to pick out the right section - it's >7mm wide, and it's  flattened, glossy or waxy with no lip and no patterns or bands (it's quite shiny). This puts it in the 'Zonitidae',  or Glass Snails.

But now another problem - the key brings us to a pair of statements which seem very difficult to decide between. It even says, omniously, to 'take special care as the distinction can be hard to make'. But the accompanying drawings of rapidly vs. slowly expanding whorls look exactly the same to me.

This is no time to be loyal to one key, so I leapt to try Daw and Ivison's Bristol key - this brought me out at a similar dilemma - I'm left to choose between a number of Aegopinella, Oxychilus and Zonitoides species, all of which seemingly have similar characteristics with their flattened spires, colours, and sizes. It doesn't help that my specimen is empty and it would be useful to have information about its one-time occupant's body. Perhaps this shows there's something to be said for collecting live specimens.

I'm going to draw myself a little table and try to work this one out. Cameron soothingly says 'Do not expect to identify every shell you find.' But I'm going to persist for a while longer.

The tortuous workings of the mind of an extreme amateur snail identifier

After much agonising I have decided on Aegopinella nitidula, commonly known as the 'Smooth Glass Snail'. The size, number of whorls and 'opaque milky flush round the umbilicus' swung it. I might be wrong yet, through sheer lack of experience. I need to keep this one and compare it with similar-looking specimens in the future.

I've found lots of photos on AnimalBase,  which is run by a university in Germany, and the photos were contributed by European malacologists so you can be confident in their identification. Their search page is here.

Names have changed since Mr Adams' day, but it's comforting to hear him say that "this interesting genus often gives more trouble to the novice than all the rest of the British land and freshwater shells put together, except the vexatious Pisidia." Those vexatious little Pisidias eh. He also advises that "the animals should be studied and compared", meaning that their bodies differ in appearance, not just their shells.

And speaking of names and terminology, you may like Mr Adams' Snail Glossary as much as I do: it gives the English translation of Latin names like 'splendens' (shining) and 'punctata' (marked with minute spots) - but also of the names of parts of snails and shells which you may come across (eg umbo and operculum). Pisidium by the way means 'like a pea' - it's the group of tiny freshwater clams.

Some snails on campus

I'm always telling students of the ponds 'don't fall in' so it was disappointing that I got an entire shoeful of water this lunchtime. All in the name of furthering my snail-related knowledge. I found this specimen amongst the brooklime (memorably named Veronica beccabunga) creeping around the edge of the pond. It's come out quite easily with Daw and Ivison's Bristol key.

So it seems convincingly to be Succinea putris,  the Amber Snail. My Victorian snail-fancier Mr Adams says they "inhabit moist places by water. Though amphibious it is seldom seen in the water except in spring when on its way from its winter quarters in the mud."

CC image by James K Lindsay

Naturally things are never entirely simple and Cameron's land snails book describes other Succineids that look extremely similar when the snail's not in residence. But I think we can discount them (one is rarely over 12mm and is commoner in the north, and the other is restricted to East Anglia). A hundred years ago I think taxonomists were making it yet more complicated, as Mr Adams says "the varieties seem to graduate into each other, and into the type in a most perplexing manner, and I advise the tyro [beginner] to leave them severely alone."  Severely alone. 

Succinea putris means 'amber' and 'stinking'. Amber is the colour of the shell and I'd like to think 'stinking' refers to where it lives rather than how it smells itself.  Here's the snail I got the wet stinking sock for:

CC image by BJShoenmakers

So this one (since it's freshwater it needs a different key.. I used Collins) is a Great Ramshorn Snail, Planorbarius corneus (I wrote vorneus above as there's a misprint in Collins, helpfully). It's massive and looks like a ram's horn so I guess it's well named. 'Planorb..' means flat coiled, and 'corneus' means horn-like. These Latin names aren't just random you see.

Planorbids have various methods of obtaining oxygen while they're underwater. They have a lunglike cavity which they can fill with air (they are pulmonate snails like those on land, but they've returned to an aquatic habitat). They also use part of their mantle as a gill by extending it into the water. And they've independently evolved haemoglobin so they can keep hold of their oxygen effectively (their bodies do look noticeably red). The sediments they crawl across at the bottom of ponds can be pretty anoxic places so all these methods are useful.

Mushroom season is upon us

A keen fungi forager brought some mushrooms in to be freeze dried this morning. Naturally, being British, the weather featured in our conversation. But in this case it wasn't small talk, it was a recognition that hideously dark and wet autumn weather is the Harbinger of Mushrooms. Now is the time to be seeking them.

Waxcaps CC image by Andreas Kunze

Inspired by his lovely collection of Hygrocybe (waxcaps) I sought some information on the internet, and I found a website you may find useful - The Mushroom Diary.

It's written by John Harris and features fungi from this country. The website zooms about a bit in a rather annoying way (perhaps I'm just oldfashioned) but the photos are good, there's usually some useful description and id tips, and as it's a blog you can tell when he found what. It's quite nice to browse through (in the hope that the species will spark some recognition when you see them in the flesh).


I also like his general identification guide which highlights the features you need to scrutinise your mushroom for.

Relaxing moths, and mould

I happened across this document this morning: How to make and use spreading boards for insects, by Alice Gray.

It's pretty ancient, but moth pinning isn't really one of those hi-tech 21st century things, so I think you might still find parts of it useful.

I've heard a couple of people bemoan their moths going mouldy - she uses some toxic-sounding chemical which was probably considered fine in the 1940s. But I think you might benefit from taking her advice about relaxing the moths - that only 24 hours in the relaxing chamber "should bring the driest specimen to a working condition." Prevention would be better than cure - so try to keep the humidity high for the minimum time, and then keep them dry after pinning.

That isn't tackling the mould issue if it already exists - but I've been trying to read up about it to find something that will work without gassing you in the process. I've read about using cloves / clove oil, so that might be something to try. 

She gives very detailed advice about pinning (you might even find it too detailed) but I did notice a few little insider tips such as:

"With the tweezers remove a specimen from the relaxing box, holding it firmly by the thorax. Blow on it gently from behind. If the wings flutter slightly, the specimen is soft enough to spread."

also that,  "When filled, the spreading board should be stored in a warm airy place while the specimens dry. If the specimens have been previously dried, and relaxed, this will require from two days to a week, depending upon temperature, humidity, and the size of the insects. If fresh specimens are being mounted, they will take about three weeks, skippers and large moths not less than four weeks. In extremely damp climates forced drying in a slow oven may sometimes be necessary. It is never advisable to remove specimens from the board on a rainy day."

Mmm liverworts

I'm part way through an MSc (this one in Biological Recording at MMU) and this year I have to devise and carry out some fieldwork for a dissertation. I'm veering towards mosses and liverworts as I do like them very much (and they have the advantage of being present whatever the season). So whilst on one of our regular Drawing Tours with my sister we stopped at a potential survey site this weekend, a spring at Doulting (near Shepton Mallet in Somerset).

St Aldhelm's Well (CC image by Kerryn)

The water was fantastically clear and cold where it came out of the hillside (the photo above). Then the water ran mellifluously into and out of a stone trough, and down through a grating to run under the road. The stones and walls were smothered in mosses and liverworts. I took some samples which  I will try to identify (when I have a minute, and I'll try to show you how I'm doing it). Some of the liverworts were huge and thallose - I'm sure anyone would have been enamoured with them. They looked rather like this, branching across the surfaces:

CC image by Jason Holinger

Incidentally I had an extremely interesting morning yesterday as I accompanied some students on a tour of Bristol Botanic Garden (the glasshouses there had their fair share of liverworts too). I urge you to go as it's actually free if you're a student, and it's fascinating as it's laid out along the latest phylogenetic understanding of the plant world (this is very unusual as Botanic Gardens are usually venerable institutions and switching things round is a pain, but they moved site relatively recently and were able to take advantage of it).

Anyway it was interesting to take a route along the course of plant evolution, and discover how bryophytes and other groups developed in a much warmer wetter era of Earth's history. Plants only evolved seeds when the climate became drier, when reproduction using swimming sperm (for liverworts do have swimming sperm) became more difficult. That was the change from the Carboniferous to the Permian. I could go on... But I won't, I'll just recommend a trip to the Garden.

A useful spider website (ignore the pun)

I'm trying to warm to spiders. I'm feeling more sympathetic to them now Tegenaria season seems to be over (quote from a student: I thought it was a mouse running across the floor).

I was thinking about one I saw the other day as I sat on a wall in the sun - the much friendlier Salticus scenicus or Zebra Spider. They have big eyes and you can see them moving their head about to get a good view.

Zebra spider CC image by Fotonfanger

The species is also called a Jumping Spider - it's got a very distinctive jerky way of moving and it can leap surprisingly big distances. There are some videos on Wildscreen Arkive.

Whilst trying to find some information I chanced upon this page, part of Ed Neuwenheuy's 'Spiders of North-West Europe' site.

It's a 'spider location chart' which can help you recognise the family from the environment you find the spider in.

Under the chart, there is a panel of all the different spider families, from which you can find photos and an overview of the variety found in this part of the world. (He also has a thumbnail chart of these).

I think it looks very good - it should help you develop a feel for the characteristics of the different families. But you still can't avoid using the books with the keys of course :)

It strikes me how colourful spiders seem to be and how important it will be to record their colours and patterns before these potentially disappear (after death and in the preservation fluid) - or you'll be making the process of identifying them that much more difficult. Time to get your paintbox out perhaps. Or the camera on your phone I suppose.

16th October
This morning as I stumbled around the house in my early morning daze, it struck me that there are a lot of Pholcus phalangioides spiders around (we have low doorways and I came face to face with one).

CC image by Sven Siegmund

They're quite large but delicate looking. I was struck by its knees. They have a rather distinctive long pale body. If you actually get round to some housework to dislodge them they do a mad shaking manoevre (which you can see on this youtube video). However they're pretty hard and I've even heard tell that they despatch a Tegenaria. If this is true then they're welcome lodgers.

It's possible they're not native to this country, but they can survive its cold winters by living in nice warm houses - and they've made their way all over the world.

Distribution maps and the NBN Gateway

You might find it interesting to see a distribution map of your species for this country - which you'll be able to find at the NBN Gateway.

This is a hub for biological records - they've amassed over 100 million of them from diverse sources. Pop your species name in the search box at the top right, and you'll be given its map and a link to download it.

The result might not be very enlightening if you've got a species that's very common and is found across the whole country (i.e., a swathe of coloured dots). But if you have one that's geographically restricted like my Pomatias elegans snail, it might reassure you that you've made the right decision against a similar-looking species which is found elsewhere..

from the NBN Gateway - Pomatias elegans distribution

Of course there are issues with this sort of thing - if you're looking at the map of an obscure fly, it might look rare even if it isn't - there's unlikely to be so many records (because not so many people are looking for them;  they might be hard to identify correctly; and because the records only reflect where people have looked - probably where they live and where they go on holiday, rather than reflecting an equal effort in each square). But there we are.

It might still be something you'd like to add to your notebook as supporting material and for interest.

~I see from the 1st April 2017 the NBN Gateway will get replaced by NBN Atlas UK, and it will be much easier to access records (other than those for 'sensitive' and rare species). To begin with the BSBI will only be transferring Scottish plant records, but hopefully English and Welsh records will follow.

Moths in Dartmoor

This season's First Year field trip to Dartmoor featured unprecedented Moth Enthusiasm. I was still staring down the microscopes with keen students at gone eleven pm (beers were at hand, mind).

I found this guide to the features of the different families (drawn up for the Garden Moth Scheme) to be supremely useful in narrowing down our specimens to the right area of the book. I can print one out for you in colour if you ask nicely.

It enabled us to easily spot the group that this species was in, because of its unusually pointy 'nose' - it's a Snout, Hypena proboscidalis. The nose is actually a pair of palps that are held forward.

CC image by Donald Hobern

We also saw the lovely Autographa gamma or 'Silver Y' with its extremely distinctive tufts of hair on its back:

CC image by Donald Hobern

These might look like Just Brown Moths to you, but under the dissecting microscopes they were fascinating in their furriness and the pattern of their scales. It was nice to see their faceted eyes as well.

Whilst using the GMS guide, it also struck me that it's quite important to make a stab at naming them while the moths are still alive and in their natural poses - these help a lot in identification. You can see that the Snout rests with its wings in a flat triangular formation, whereas the Silver Y angles them together like a roof. That's why I think it's such a shame that traditional pinning dictates you spread the wings - the creatures end up looking nothing like their live counterparts. But there we are.

Snail updates

CC image by Africa Gomez

Of all the groups I've made pages for, the creatures I perhaps feel least able to identify are terrestrial molluscs [*in retrospect this is a lie, my experience of spiders is minimal also]. so I'm slightly worried I might have sold them short to you as a choice.

But today I offer some encouragement for those who might pick them. As I snatched some lunch in the autumn sunshine I glanced down and saw an empty shell of the snail above. I put it through the BRERC key and it rapidly and easily came out as Hygromia cinctella, the girdled snail. To be fair it has a very obvious keeled shape with a white band. But I was pleased at the painlessness of the experience.

This Mediterranean species has only been in Britain for the last 60 or so years, and was seemingly confined to the south-east until the seventies. For some reason it's spread rapidly since and has now made it as far as Scotland - apparently aided by being transported around in potplants through garden centres. It doesn't seem to be causing any problems (unlike some more nefarious introduced molluscs around the world).

Judging by the key's descriptions, it's worth noting that a lot of species are very small as adults. Some are absurdly small (there is a life-size picture of each species in the key, and some are only a millimetre high). So although you don't want to be examining a 'baby snail' thinking it's an adult, you don't want to be overlooking tiny snails just because they're small. Much careful searching is going to be necessary I think, and examination under a microscope. Do bring in your snails. I am going to keep an eye out for them too if I can.

5th October. Another snail.
I have to sort out something for my dissertation this year, so went searching for moss at the weekend. As I was clambering about, a shell caught my eye. So this is my own notebook; my own attempt to key it out:

As you can see, it was quite easy to identify. (I probably should have included some measurements of the shell). I used the BRERC snail key which is for the Bristol area, but the edge of the Salisbury Plain is not far away, and luckily this species is quite distinctive. I've run it through the FSC key and that seems to require closer attention, but it does still come out quickly.

I might also include a photo of the species and maybe an OS map clipping. Here's Pomatias elegans in an alive state:

CC image by Hectonichus

There's a distribution map for the species on the National Biodiversity Network - you can see it's certainly in the area I found it (which is encouraging). So a distribution map might be another thing for your notebook, and you can search for all sorts of things on the NBN Gateway.