Photo Keys and a life spent paddling! Guest blog by Adrian Chalkley

Female Dytiscus marginalis.  Photo: A ChalkleyIf you can't identify and therefore record what lives in an place then understanding the ecology of that site and protecting or enhancing its biodiversity is surely impossible. But identification is much easier for some groups of creatures than others. Drop into any high street bookshop and you'll find a plethora of books on birds or wild flowers, but look for the same detail for invertebrates and you'll usually only find the most general of guides. Thus people are often unaware of the number of species in an invert taxa and make mistakes, leading to frustration and giving up.

The book that started it allThat's why I'm grateful to TomBio for hosting two of the keys I've produced on their ID Signpost. Both keys rely on photos of real specimens and need nothing more than a homemade net and a hand lens. Being in pdf form they can be downloaded onto a smart phone or tablet for use in the field. Best of all for encouraging new recorders, they deal with small groups of invertebrates and list all the known species, not just the most common, and they are free!  The keys are to Great Diving Beetles and to The Larger Aquatic Bugs. In this blog I will try to explain why I've written these keys; how modern technology has changed my identification and recording and how I came to be involved in Freshwater Biological recording in the first place.

When I was 10 I got the Observers Book of Pond Life for Christmas; this led to Danson Park lake in South London, within a short walk of home, being thoroughly explored with a homemade net and a jam jar on a string. Of course growing up in the 1960s my friends and I could wander freely from breakfast time until tea, so the local rivers and ponds of North Kent were explored for the next few years by foot and push bike. The arrival of A-levels, University and Teacher Training slowed down biological excursions of course. Then a job teaching in a junior school, especially before the rigidity of the National Curriculum, meant that the natural enthusiasm of my pupils for all wildlife only increased my own.

Bullhead. An old photo in the class aquarium.Soon my classroom always had a four foot aquarium with a pump to mimic the local Suffolk streams where we now lived. This would be set up, step by step, in September with a kick sample full of mayfly nymphs, beetles, caddis etc. and after the pupils spent some time studying these some local fish would be introduced after half term. These fish would always be 'borrowed' from the wild then returned, rather larger from my pupils regular feeding, from whence they came after Easter. In this way we managed to get Stickleback, Stone Loach and Bullhead to breed in the classroom. One year I even managed to contrive a sizeable triangular pond in the corner of my room! This rather alarmed both the caretaker and the teacher in the room below! It’s true that the tadpoles which somehow evaded being returned to the outside pond before they could metamorphose did cause some chaos. But personally I felt that the odd escapee beetle, hatched caddis or mayfly merely provided a great teaching opportunity!

Adult Caddis fly Limnephilus lunatus that used to hatch out from the classroom pond & fly around!  Photo: A ChalkleyAs with everything, the more you know the more you realise there is still to know, and despite the pressures of teaching it wasn't long before the general handbooks like the Observers book, which I still have, or the others that came later were not enough. So the bookshelf grew with keys specific to one genera after another. By 1984 when we moved into Suffolk I'd started spending school holidays doing surveys of various nearby streams and ponds identifying everything I could from water fleas to aquatic beetles. Putting my records onto a database, firstly on a Sinclair Spectrum, soon led to becoming County Recorder for freshwater invertebrates. There were many recorders for the more usual taxa and interests but freshwater seemed to be a bit of a minority taste, and so school holidays became busier!

backswimmer Notonecta viridis (they swim upside down but fly the right way up!) Photo: A ChalkleyHaving taken voluntary redundancy from teaching several years ago now, the shelf of keys and reference books has now grown to well over a hundred. As well as running standardised surveys in Suffolk and elsewhere I've now been running freshwater Identification courses for the Field Studies Council at Flatford Mill for the last 12 years. Which also brings me to my involvement with TomBio.

My county database, now re-written by myself in Access, is currently approaching 40,000 records and as well as an ever growing voucher specimen collection I take macro photos of any new species I find. All of these and the shelf full of keys come into their own when teaching at Flatford Mill. However one thing I learnt from attending courses during my teaching career is that it is too easy to lose impetus if you can't get started straight away on what you've learned. But to expect people to rush out after a course and immediately spend a small fortune on a full set of books is pretty unreasonable. Therefore from the start of teaching for the FSC I have produced keys of my own for people to take away. These started off with drawings and limited to species common in Suffolk but have progressed to covering national species lists and mostly using my own photos.

Saucer Bug from one of the Suffolk Broads.  Photo: A ChalkleyFor the last couple of years I have also been a verifier on iRecord and in many ways I find myself going full circle. Amateur naturalists post records on iRecord but may base this on a general guide showing a single species, usually the most common. All I can then do is query the record because, unless they state other morphological details and the key used, it cannot be verified. So I've put a couple of my course keys onto my local naturalists society website and TomBio have also put them onto the ID Signpost.

The beetle key as it appears.  A ChalkleyA Photo Key to Great Diving Beetles

Most pond life books will show Dytiscus marginalis as 'The Great Diving Beetle', but fail to mention that there are five other species as well, nor how to tell all of them from the Great Silver Water Beetle.

My key is aimed at allowing the user to identify all six species of Great Diving Beetles found in the UK, and it also describes the other two large water beetles which may be confused with them. Actual photos show the key features which you need to look for, and the correct terminology to quote on iRecord. Whilst these large beetles are not dangerous and can be held in the hand to identify, this can also be done with the beetle in a pond net or whilst captive in a transparent container.

 A Photo Key to Large Aquatic Bugs

The bugs key as it appears.  A ChalkleyThis covers the larger aquatic bugs likely to be found in Britain, including Water Scorpions and Stick Insects, Saucer and River Bugs as well as Backswimmers. It also includes one unusual Saucer Bug newly arrived from the continent and one Backswimmer which may arrive in the future. 

Again, all you need in order to identify the larger bugs is this key and a magnifying glass, but thick gloves are recommended for Backswimmers as their beak-like rostrum can puncture human skin easily and painfully as I have found! 

I hope as time allows to carry on to produce more keys of this sort.  Though, I have to admit that finding every species in order to ensure the key is comprehensive, and photographing them from all necessary angles, are both very slow parts of the process!  Freshwater Molluscs and Water Fleas are two projects in the pipeline at present. 

Prototype versions of all keys are tested and modified first by giving them out to people on my identification courses at the Field Studies Centre at Flatford Mill, which for 2017 runs from 30th May to 2nd June. Good luck to you if you try out my keys, and please post your records on iRecord or send to your local Biological Records Centre.

Adrian Chalkley is the Suffolk County Recorder for freshwater Invertebrates, an FSC Associate Tutor and also runs Boxvalley Aquasurveys.  Find him on Twitter @Box_Valley