Book review: Britain's Spiders - a field guide

From British Spider's cover

Britain’s Spiders – A field guide by Lawrence Bee, Geoff Oxford and Helen Smith is a new book from the excellent WILDGuides stable, published in association with the British Arachnological Society. This book will likely fuel a revolution in spider identification in the UK that I believe is already underway. In this blog I will review the new book, but more than that I want to describe what it offers within the context of how people are learning spider identification and recording skills today.

Britain's Spiders - coverLike many before me, I started to learn spider identification by attending a couple of Field Studies Council courses back in 2006. They were excellent courses and really kick-started the development of my spider ID skills. In common with most spider identification courses running at that time, we dived straight into microscopic identification and our field visits concentrated on collecting adult spiders for preservation and identification back at the ‘lab’; we hardly did any field ID.

A few years later I was confident that I could identify the vast majority of specimens that came my way with the aid of my microscope and the excellent literature available (mainly the three volume Spiders of Great Britain and Ireland by Michael Roberts). But while helping out at a couple of BioBlitzes, I became painfully aware of a considerable gap in my identification skills; some species whose genitalia I knew intimately remained a mystery to me in the field! It was a real barrier to illustrating the diversity of form, biology and ecology of living animals and inspiring budding spider enthusiasts.

I felt sure that I should be able to go progress further with identification in the field and that even where spiders couldn’t be identified to species – as I knew would most often be the case – it should nearly always be possible to identify them to family level and frequently to genus too.

British Spider Identification Facebook GroupI addressed the gap in my knowledge by making a deliberate effort to go as far with ID in the field as I could and reinforced this by looking at lots of images, particularly on iSpot and the Facebook group now known as the British Spider Identification Group created by Jenni Louise Cox. I obtained a copy of the out-of-print Country Life guide to spiders of Britain and northern Europe by Dick Jones and read it from cover to cover. The latter gave really useful ID tips for living spiders, but the really transformative feature of all of these resources was the photography.

I’m a big fan of artwork in field-guides, e.g. for groups like birds, moths and dragonflies, where I think well-executed paintings frequently capture the essence of the living animals and encompass a degree of natural variation that is harder to illustrate with photographs. But the superb spider illustrations by Roberts never attempted to capture the essence of a living spider – indeed they deliberately illustrate preserved specimens since they were designed to facilitate identification of such – and for my money photographs of spiders are a much better tool for illustrating these animals as they appear in the field.

Learn to Love SpidersToday I manage the Field Studies Council’s Tomorrow’s Biodiversity Project and one of our ‘exemplar projects’ within this involves working with Nigel Cane-Honeysett of the Shropshire Spider Group to develop a suite of integrated spider ID courses that cater for different levels and requirements. We differentiate four different types of training:

  • Engagement (we badge these day courses as ‘Learn to Love Spiders’) where we concentrate on discovering the wonder of spiders and try to avoid too much technical talk and ID per se.
  • Field ID of Spiders (and harvestmen) where we tackle ID in earnest but strictly with living spiders both in the field (using spi-pots and hand lenses) and in the classroom (using digital microscopes and captured live spiders).  Upcoming course: Aug 9th, Bishops Wood, Worcs
  • Spider ID with Microscopes which is more like the ‘traditional’ ID course where we work with preserved specimens in the classroom and introduce the idea of definitive ID by examination of reproductive organs and other microscopic features.  Upcoming course: Sept 6th, Preston Montford, Shropshire
  • A variety of events/courses for ‘experts’.

These courses link together well and, for those that want it, they provide a path to progress ID skills from zero to the highest level at their own pace. But equally we recognise that different people like to take their learning in different directions – whilst some want to develop the skills to be able to identify any preserved specimen, others prefer to go as far as they can with the living animals only.

In our experience, more and more people count themselves in the latter category and our field ID courses are amongst our most popular. I believe that this is fuelled by a number of factors including:

  • Incredible advances in the quality and accessibility of digital macro photography equipment.
  • The popularity of social media platforms that have helped leverage the power of digital photography as an ID tool.
  • A growing recognition amongst the established natural history and recording community that quality macro photography is opening up some taxa to reliable field ID where previously microscopic examination of preserved specimens was the norm.
  • A growing trend to record across several taxonomic groups in the field.
  • A cultural shift resulting in fewer new naturalists being willing to collect specimens for ID.

Bob Kemp Photographing a mating pair of Evarcha falcata watched by Shropshire Spider Recorder Nigel Cane-Honeysett, top rightSome worry that this change may represent a threat to the ongoing development of a vital pool of people with skills in microscopic ID and the collection and curation of spiders. I don’t see it that way; I believe that in the past many people were alienated from spider recording and ID because even introductory courses started at the level of collection, curation and microscopic ID. With a more structured development path and opportunities to make a valuable contribution to spider recording at different levels, including field ID only, we stand to retain more of that early interest. Some of those who start with the intention of only recording spiders in the field may become sufficiently absorbed to move on to collection, curation and microscopic ID. Those who don’t can continue to make a valuable contribution with field ID alone.

All of which brings me to the new WILDGuide – Britain’s Spiders. For a couple of years at our field ID courses Nigel and I have introduced participants to the available literature including Roberts’ Collins field guide, the FSC fold-out chart and Dick Jones’ Country Life guide, but we’ve always concluded by whetting everyone’s appetite for the upcoming WILDGuide! We’ve waited for several years with such great anticipation that it would have been easy for the final product to fall short of our expectations, but I can happily report that it does the opposite!

Britain's Spiders - first page of guide to familiesFirst impressions are those of size and quality. It is a surprisingly large book, but it just about manages to stay small enough to be convenient for a keen learner to take into the field. It is not a hardback, but neither is it a ‘flimsy’ paperback – the cover is something in-between with folded edges (both front and back) that can be used to mark pages if required. The binding is that of a high-quality hardcover (case bound), which makes it surprisingly easy to open any page in this thick book (480 pages) and have it lay pretty flat. The production values scream quality and it is a real credit to the WILDGuides series and attention to detail by the authors and whole publishing team.

There are excellent introductory sections on anatomy, biology & ecology, spiders & people, finding spiders – all well worth careful reading. An excellent section called a ‘Guide to spider families based on appearance’ does what it says on the tin. This is a really useful section for teaching field ID to beginners since a newcomer really feels that they have started to make progress when they can start to recognise broad groups of spiders (i.e. families) based on some features of their appearance and other clues like web structure and behaviour. (Though identification based on web structure is largely covered in separate sections in the book – see below.)

Next there are a couple of really useful sections - a ‘Guide to webs’ and a ‘Guide to egg-sacs’. When one really starts to look at spiders in the field, their webs and egg sacs become central to your observations. During both our engagement and field ID courses, we talk a lot about silk and, in particular, webs (or absence thereof); not only as useful identification features but also for what they tell us about the fascinating biology and ecology of the different groups. So I was really pleased to see these dedicated sections.

A minor criticism is that I feel the excellent information on web ‘taxonomy’ is unnecessarily split between a sub-section of spider biology (‘Webs’) and the ‘Guide to webs’ section. I think I understand why this has been done – webs can hardly be ignored in the ‘Spider biology’ section but they also deserve a section of their own. However I would prefer to see a much more cursory treatment in the ‘Spider biology’ section with a reference to an enhanced ‘Guide to webs’ section with all the important information in one place. The real problem is that both these sections (well-separated in the book) include a taxonomy of web types, but they are not entirely consistent. The ‘Webs’ sub-section (of the ‘Spider biology’ section) states that ‘webs can be classified approximately into eight broad types’ but only describes six plus ‘other web types’. The ‘Guide to webs’ section covers nine types. Regardless of these criticisms, the two sections are excellently produced with first class information and illustrations.

Britains spiders - first page of introduction to species accountsThe central piece of the book is, of course, the species accounts. They are first class and the attention to detail is amazing. Somehow squeezed into each account, yet without appearing cramped, is information on scientific name, common name, observation tips, habitat, size, appearance, similar species, distribution, phenology, status and ease of identification. Furthermore each family, and within that each genus, is introduced separately with useful identification features (covering appearance, behaviour, webs etc). The species accounts (and the rest of the book) are superbly illustrated with hundreds of high-quality images, contributed for the most part by hundreds of amateur photographers, which are intelligently and attractively laid out.

There is a very clear double-page spread explaining how to use and interpret the information accounts. This is compulsory reading – no one should expect to be able to interpret the species accounts correctly without reading this first (and probably continually referring to it until it all becomes second-nature). For example, following the phenology chart for each sex of each species is a coloured dot which indicates the number of records from which the information is drawn (and hence it’s reliability), but unless the reader has referred to the explanation of the species accounts, it will mean nothing. It is this very careful planning and thoughtful layout of the species accounts that has enabled so much information to be presented so succinctly. Given the importance of information on interpreting the species accounts and the frequency with which it will need to be referred to by new users of the book, it would benefit from some way of making it easier to find, for example reproducing it on the front or back endpapers.

One of the most eagerly anticipated features of the book is the information on how far it is possible to identify a species (or genus) in the field. Three symbols are consistently used throughout the book: an eye – meaning the spider ‘can be identified in the field (with experience), usually without capture’; a hand lens – meaning the spider ‘can be identified in the field but needs careful, close examination requiring temporary capture, usually a spi-pot and hand lens’; and a microscope – meaning the spider ‘requires examination and high magnification in good light of features that are beyond the scope of this book’.

Traditionally, the British Arachnological Society’s (BAS) Spider Recording Scheme (SRS) has been rather conservative, only routinely accepting records for twenty or so species identified in the field. This conservatism is an effective defence against too many poorly determined records, not backed up with sufficient evidence, finding their way into the SRS, but it has also been a barrier for participation in spider recording for many people.

Britain's spiders - key to ID difficulty symbolsThe so called ‘Chinery Effect’ – whereby users of field guides merely picture-match specimens against illustrations in the book and submit records of the best match without critical regard to whether or not there are similar species which cannot be determined by eye – was a real danger with the spider field ID resources we’ve had at our disposal to date. But this new WILDGuide, when used correctly, allows the diligent user to avoid the Chinery Effect – effectively informing them just how far, with experience, they can go with reliable identification without collecting and preserving a specimen. I hope that this might now encourage the SRS to open up for more species that can be recorded with care in the field. (An online recording sheet could require recorders to indicate how they determined the spider and discounted similar species. This information could be used for verification purposes.)

Which of the three levels (eye, lens, microscope) to assign to each species was a critical task for the authors: being too conservative risked disappointing recorders who know that it is possible to securely identify more species in the field than has been openly acknowledged to date, but being too permissive risked encouraging recording of species without sufficiently critical determination. I think that the authors got the balance right. If anything, they have erred on the conservative side; for example it is possible to determine male Metellina spp. in the field with lens and spi-pot (using palps and hairs on tarsus/metatarsus I), but the book indicates that the three Metellina species require microscopic examination (irrespective of sex). In truth space considerations probably prevented the inclusion of these kinds of finer points of field identification and given this, it was right to err on the conservative side.

Britain's Spiders - AgelenidaeAll-told, the book indicates that 34 species are identifiable in the field, with practice, without capture and a further 92 are identifiable in the field, with practice, if captured and examined carefully in a spi-pot. I stress the words ‘with practice’ since, just like bird or moth ID, beginners should not expect to be able to identify all of these as soon as they start; it may take years of practice to sharpen the eye and appreciate the subtle, but very real, differences between some species.

Where the hand-lens symbol is used, it would be useful to have an explicit indication of what should be looked for with the lens. I suspect that it may currently often be used to indicate that more caution and circumspection is required when looking at all the morphological features described, but this should be made clear.

The book keeps on giving! After the species accounts come additional useful sections on working in the field, recording spiders, legislation & conservation, further reading and the BAS. There is a large table listing all British species (including the small money spiders – Linyphiids – which aren’t included in the species accounts), with full details on common and scientific name (including the ‘authority’ and synonyms), the ID difficulty symbol, conservation status, relevant legislation and the percentage of 10 km squares in Britain where the species has been recorded. There is also a page reference to the species account where applicable. It’s handy to have this information together in a single reference table.

The WILDGuide, Britains Spiders – a field guide, is a masterful example of a modern field guide for an invertebrate group. It is set to become a central resource for our field ID courses in Shropshire; I have already purchased three classroom copies for the Tomorrow’s Biodiversity/Shropshire Spider Group courses as well as the Kindle version for a laptop which we intend to use by projection in the classroom. This book will equip spider recorders to learn both the possibilities and the limitations of identifying British spiders in the field. It stands to enrich the way we learn about spider identification and provide a useful staging point for those that want to move on to the identification of preserved specimens. I commend this book to all those interested in recording British spiders in the field.