top of page

Making a Reference Collection


The concept of a reference collection is a simple one: to provide material, usually in the form of specimens, that can be used to compare with unidentified specimens and so help decide whether they belong to that species or not. Reference specimens can also be used to appreciate characters that might not be immediately obvious from descriptions e.g. the crossed elytral epipleural margins in most Pterostichus or the difference between coarse and fine punctures in species of Longitarsus. Another very important function of reference collections, at least for fanatical and very ‘nerdy’ coleopterists, is the pleasure to be gained from looking at them, either  to appreciate the beauty of individual  specimens under the microscope or to admire a well  arranged and labelled drawer or box of

beetles. This last aspect is often overlooked when considering the value of such collections but it is very important and should not be underestimated, the impetus to collect is ostensibly to pander to the scientific value of the results but there is no doubt that coleopterists, as well as naturalists in general, are driven to study their subject by some congenital psychological trait; maybe this was fostered by others, maybe during the formative years or at university, but the ability to be fascinated by and to love the subject is part of the individual, and the coleopterist, at whatever level, would be well-advised to occasionally get a few specimens out and simply admire them. I compare this to listening to a piece of complex music, like a Beethoven string quartet, the real and absolute genius can ultimately only be appreciated from the staves but the bewildering psychological beauty belongs to the music itself, detached from the perfection seen in the notes. As a specimen is examined in ever more detail the more perfect it becomes but the real beauty is seen in its entirety, or more so when it is alive and active. But such things are not immortal and to end up in a reference collection is, for many reasons, not such a bad thing, in just the same way that preserving a work of art will allow the talent of the artist or composer or author to become immortal, in human terms, and bring pleasure to millions.

The importance of this is seen in countless reference collections where some species might be difficult to justify for inclusion e.g. it is difficult to imagine the need for Crioceris asparagi in the sense that it is never going to be confused with any other species and the likelihood of it being needed to verify a specimen is remote to say the least. But collections tend to include everything, usually for the sake of completeness i.e. to satisfy the need to build a comprehensive collection rather than for any scientific purpose and this might seem the same as stamp collecting but it adds to the pleasure and sense of personal achievement to obtain specimens of complete family lists, and this is why collectors travel the country to visit sites where rare or very local species are known to occur, the records are useless because they simply duplicate what is already known, and often the specimens are not needed for reference material because they are so distinctive anyway. But new species occur regularly in the UK, their locations get published and collectors very quickly travel the country to obtain their series, this is collecting for the sake of making a collection and nothing else. Any collection not including the Silver Diving Beetle or Prionus would feel somewhat incomplete, however whether such species add to the scientific value is questionable. But what fun!


Killing Beetles

In order to begin a reference collection we must accept that we need to kill beetles. Taking photographs of beetles, or other insects, is becoming increasingly popular, thanks mostly to the availability of affordable digital equipment and sites like facebook where specimens can be displayed for  people to offer opinions about their identity. This is a very valuable resource for many reasons not least of which is that it often produces surprising records of rare species, and it has also developed and made accessible a great beetling community where members at all levels can produce useful results and enjoy the fruits of their labours e.g. people can now become familiar with beetles and research them once they know for certain what they are, and species lists from local societies and nature reserves have expanded greatly in this way. Such is the power of sharing knowledge; very few people will spend the hundreds of hours it takes to become familiar with our fauna beyond the most obvious species but via facebook a great deal of knowledge can be gleaned simply by posting pictures. And as if to facilitate this, modern digital cameras are now well-up to the task of getting decent close-up pictures by day or by night, and one can only imagine the frustration of the pre-digital era of using film and having to wait for it to be developed in order to see the results (which were mostly rubbish anyway) and then having to obtain a name for the subject. Now of course we can mess around with easily obtained digital images; expand or sharpen them, lighten or darken them or mess about with the contrast etc. until we get a result that will allow an identification. But what everybody involved with beetles at whatever level knows for certain is that not everything can be identified from pictures, however good they are and however competent the photographer and identifier. And many very seasoned coleopterists simply cannot get on with identifying pictures of beetles taken in the wild. Nonetheless photography remains a very valuable tool with respect to popularising insects and introducing people to the technicalities of the subject. A poignant demonstration of this can be had from looking at some of the early Royal Entomological Society Handbooks, these provided keys and a few line-drawings for various groups, and I am thinking now particularly of scolytids, longhorns and dytiscids, and from these it was possible, at least in theory although not always, to arrive at an identification, but having done so there were usually no pictures available to verify the results and in any case the usual verification was from Joy’s Handbook which rather defeated the object anyway. I am sure that many people posting pictures and getting good advice from Facebook would be baffled if referred to these early works; they were for people already sufficiently expert to know what they were up to. In those early days-going back only thirty or forty years-the best that could be hoped for was a personal reference collection, and this usually meant punting specimens around museums or getting expert opinions etc.  So back to killing. It seems that many naturalists nowadays- including many of those very people who refer photographs of specimens for opinions-object to the killing of insects for ‘scientific’ purposes-i.e. to allow experts to become familiar with the species and to keep our UK fauna constantly updated-and will frown upon any defence of having to kill insects for such purposes. But we need to get used to the idea that in order to study insects in any but the most superficial detail we must have access to reference material, and this means at some point either killing them or having access to specimens killed by someone else. If this feels a little disturbing, or if it seems to go against the modern trend for nature conservation, then a consideration of the wider world, beyond that of entomology, might help to ease the conscience.


An example of the prevalence of readily available pesticides.

But before such considerations I would like to make the general comment that there is no sensible argument to be made against the selective killing of specimens for scientific purposes, even if the main reason for collecting specimens is for the personal pleasure of making a collection. Among the majority of people and the environmentally-unaware there is no doubt that insects have a bad reputation, people might or might not appreciate a butterfly on a flower but they will generally not tolerate a moth or beetle or cockroach in the house. This is due to a lack of understanding or appreciation of the natural world, and fair enough; I view this in the same way that people I work with are baffled or even amazed at my lack of knowledge of football, or of any sport come to that, each to their own as they say. But there is a difference; when I inadvertently witness a football match on a television I do not go and obtain a suitable weapon and proceed to smash the television in order to eliminate the football teams, I simply ignore it as it is of no interest to me. Go to any supermarket or hardware suppliers, especially those with a garden centre attached, and you can find a vast array of insecticides for use in the home as well as in the garden, the choice is bewildering and the number of companies offering these substances is large, and these facts demonstrate three things: that the products sell very well, that they are profitable, and that people are willing to buy and use them without worrying about the environmental consequences. The same goes for herbicides, which indirectly has the same effect on beetle populations, and the same goes for fungicides. This is insect killing on an industrial scale but at a personal level. And speaking of which, pesticides and herbicides are also used in genuinely staggering quantities by the agricultural and horticultural industries. 

Despite what is published and what is believed, a good number of these various ‘cides’ are used, intentionally or otherwise, indiscriminately. Where we live in the south of England house flies are virtually a thing of the past, and despite ever more infrequent refuse collections so are the once very common green- and bluebottles. During the warmer months I regularly see patches of white powder in gardens where people have applied insecticides to remove ants. Companies are available year-round to come along and remove wasp nests from houses or sheds or apply residual insecticide to premises where food is prepared. The list could go on but the point is made. This ready acceptance of poisonous chemicals and our willing and often eager use of them demonstrate a general public indifference to destroying other organisms, and perhaps insects in particular, in order to achieve some perceived level of safe and hygienic living. This is a truly abhorrent collective state of mind which admittedly is not subscribed to by all of us but the pesticide industry and the high street would suggest a strong and general adherence. And this environmental vandalism is further compounded by the fact that many of these disgusting chemicals are persistent in the environment and tend to accumulate up the food chain, the sad story of DDT comes to mind but any aromatic compound will act in the same way and we have not stopped using them, the silent spring may have passed but we are now firmly into the silent summer. The subject of land use is another matter, how we use land for building or roads or railways or new towns or car parks is irrelevant, that we partition it for our own use is nothing short of outrageous when viewed against the needs of other species. It is often the case that a biological survey is required by law before land can be considered for destruction in wildlife terms, this will involve looking for unusual or rare species and may sway the final decision, but here we are dealing with human nature. Enough said; this is an entirely different subject which, though related to our discussion, is better left to another article.

Killing beetles can be achieved in a variety of ways but not all are useful to the entomologist e.g. stamping on a beetle is a very effective way of killing it but the scientific utility of the results is highly variable and often disappointing. Several readily available methods will produce acceptable results and are in general use. A live specimen can be put directly into alcohol and it will remain intact and preserved for as long as it remains immersed, similarly a specimen can be dipped into near-boiling water and then set or stored in some other way e.g. by freezing. Both methods produce results; the use of alcohol is often desirable for preserving large numbers of specimens from trapping or other survey results where it would not be practical to deal with them immediately; samples from each trap can be quickly stored in alcohol and the data added and these can be stored (or ignored) safely for years if necessary. In this way I was once able to take samples of thousands of pollen beetles from pheromone traps and preserve each sample in a separately labelled tube of alcohol so that the results could be analyzed over the following year. But for the average collector with an interest in surveying or bio-blitzing or maybe just the desire to form a good reference collection the method of killing must include some precision regarding the end result. When a specimen is removed from the killing container it is usually desirable to set it and get the work out of the way immediately and there is nothing worse than trying to set specimens that are not perfectly relaxed, and if the work of killing is not done properly the specimens will definitely not be in the best state to be set. It is very tempting to remove specimens from the killing container after an hour or so and get them dealt with but this is often a mistake, not just for the fact that some may almost miraculously come back to life-we once had a specimen of Chrysolina oricalcea that survived after 24 hours in a strong killing tube (and we let it go out of respect) - but because they will often be difficult to set. When a specimen is in prime condition to be set the appendages can be moved with a needle and they will remain in place, i.e. they will not retract into the original position, and when a specimen is in this state it can be easily set, even if it is a tiny ladybird or phalacrid or any one of a number of otherwise awkward little things that need to be set using micro-pins at X20. To achieve this perfect state I leave specimens in a killing tube with a few drops of ethyl acetate for between 6 and 24 hours, then an hour or so before setting I open the tube and add a few drops of water to the tissue and reseal it. For me this produces the best results and is convenient as I usually deal with specimens late at night or early in the morning before work so that they are in good condition to be set when I am ready to deal with them. Over the years I have heard of, and indeed tried, many other chemicals to kill specimens but absolutely nothing gives results as good as ethyl acetate, and even though it has a powerful aroma it is not unpleasant or dangerous to work with, and it has the further advantage that it is easily obtainable. The subject of suffering might come to mind i.e. how humane are these methods? Well, that sort of thing cannot be known and anyway each of us will have differing opinions but I like to think that ethyl acetate is quick and produces little suffering, I like to think it is soporific and that the specimens do not endure pain but that is a personal opinion, but then again it eases my conscience when I think about how years ago cyanide was used, immersing specimens in alcohol is probably also quite humane, again a personal opinion, and I can imagine a few people who might consider this a reasonably desirable way to go. There is no guilt-free way of doing this but ultimately, if it bothers one enough, there are plenty of interests that do not include it.

Identifying Specimens

Identifying beetles for the first time can be a daunting process, a stag beetle is distinctive enough but even here females are posted on facebook to be confirmed against the lesser stag beetle. Oil beetles are confused with bloody nosed beetles and cardinal beetles with Lagria. The process of identifying is therefore not a trivial one and even the most straightforward of things cannot be taken for granted. Obtaining reliably identified specimens is going to be essential at first, and these are going to be like gold dust, providing the means to move on with the various groups. But becoming familiar with the fauna is going to be a slow process and progress should be made where it is possible rather than trying to force it; time spent carefully identifying a specimen will be worth it as that species will remain distinctive in the mind for a long time whereas having a load of specimens identified by an expert will then require a long period of learning and familiarity; the best ways to become familiar with a species are either to identify it from keys and confirm it from reliable pictures, or struggle for a while, note down the possibilities and why it does not fit, and then get the specimen identified and learn what went wrong. Either way will do the trick but getting a collection identified by somebody else and then taking it for granted is both pointless and lazy, and it will not produce the expertise needed to move on. Struggle and succeed or struggle and fail but this stuff will need to be struggled with and there is no other way. The tiny alexid Sphaerosoma will completely baffle a beginner but an experienced coleopterist will know immediately that it is not a coccinellid or cryptophagid or whatever from a glance at the antennae, expertise indeed but available to anybody with the determination and patience to succeed with this stuff.

Curating the Collection

Once a few reliably-named specimens have been amassed it remains to be decided what to do with them. The obvious first choice will be a store-box, and the larger the better, shallow for shorter or ‘English’ pins and deeper for continental pins. The choice of which pin to use will be based on personal liking but nowadays most people seem to prefer continental pins, and this is not such a bad thing as they allow plenty of room for data labels but they do look rather silly with very small cards mounted. On the other hand they are available in a range of diameters and finishes, generally of very good quality and sharp, and they are available from a number of dealers which offers a good choice but does not seem to make them any less expensive. A store-box will house a good number of specimens and it looks attractive when laid-out with labels printed in various fonts and sizes of text. Rows and columns are easily arranged and new species easily added with only a small amount of re-arrangement.  And when one gets full another can be added. But there comes a time when the final intention and extent of the collection must be considered, and here the problems begin. A single family - any single family - can be accommodated successfully in a store-box or a small series of store-boxes, the boxes can be laid out with a full set of labels covering the entire list of our chosen family and adequate room can be left for the species as they are obtained. An external label will be needed for each box in order to avoid needlessly and frustratingly opening boxes until the right one is found. And the boxes will need to be stored upright so that they can be selected without moving the lot, no problem for a small collection of, say, the UK carabids or longhorns, a bit more tricky for the weevils and a nightmare for the staphs. So before deciding upon the final layout it is absolutely crucial to decide upon the intended extent of the collection. For many dedicated coleopterists this is an easy decision because the intended extent will be the entire UK list of more than 4000 species. That’s a lot of store-boxes and it is very definitely too many store-boxes because they may accommodate a fair

Drawer 28.jpg

number of specimens but they are most assuredly not designed to save space, even in modest numbers. Another irksome feature of store-boxes is that they need to be opened in order to see what is inside and this becomes crucial; in the early days the collection will be well-understood in terms of what and how many of each species are available for reference, but as the collection grows this will not apply, neither to species or numbers. Here a database is essential and this is how ours, written on Microsoft Access, works. Each specimen is assigned a number and this is written and clearly visible from above, alongside the data, on one of the specimen labels, this number forms the first entry in the database and is followed by the genus, species, author, capture data, identifier, reference work from which it was identified or ‘comp.’ and then ecological data, the final entry concerns the location in the collection. As well as allowing locations to be found our database allows species and genera or lists from collecting locations to be filtered, and with more than 11000 entries this is very useful. Each new specimen is assigned the next number and added accordingly, thus eight specimens of e.g. Apion frumentarum may be assigned widely separate numbers but can be easily filtered out of the database and found in the collection by filtering the species name. But store-boxes are still a pain and sooner or later the serious coleopterist must accept the worst and shell-out for a cabinet or a series of cabinets because our list, allowing for the occasional new species, fits rather well and without too much fuss into forty large cabinet drawers. In our case four ten-drawer cabinets although we also use five or six store-boxes and an extra small cabinet because there are always lots of things to sort out and, in our case, European specimens and all sorts of other interesting and diversionary stuff that all coleopterists will come across as they collect.

An empty cabinet drawer will need to be labelled but so far as we know there is no printed label list available so they will need to be designed and printed from Microsoft Word or a similar programme. Choose fonts and styles of writing that appeal because there is no standard way of doing this and you will have to either live with and enjoy your labels for a very long time or, if you get it wrong, spend a very long time trying to get it right. A large cabinet drawer will comfortably accommodate seven columns of specimens; measure the internal width of the drawer, divide it by the number of columns you want and this is the width of your label; it will be around 60mm and if they are printed in rows on decent card and sliced out neatly you will be half way to achieving very neat and pleasing results. This is important because if the labels are not right they just keep looking worse and worse as the specimens are added. Collections become comfortable after a few years, you get used to how they look and function and they become easy to use, but when arranging one for the first time there is a temptation to overwork the layout, to become manic about whether the labels and specimens are in straight columns and lines, whether the specimens are at the same height, the cards and labels displayed to perfection, and this can be absolutely maddening, especially when tackling the first cabinet, but by the third or fourth cabinet experience and common-sense take over and the early suffering eases. You will need a pinning stage and this is not optional if you want to remain sane, on the other hand this will not solve the problem of presenting all the specimens at the same height as the pins will need to be inserted into the foam to the same depth, and so a degree of skill and experience will need to be gained. You will want to purchase a series of packets of mounting cards, probably between six and ten different sizes because this is the easiest way to present specimens neatly. Data labels will need to be considered, they can be printed on a laser-printer but ink-jet printers will not provide sufficient definition at such small sizes, or they can be hand-written; try to get in the habit of writing all labels under the microscope at X10, it’s difficult at first but soon becomes comfortable and easy, and find a decent fine pen, there are several available in the high street or online with permanent ink and a 0.05mm point, at first they tend to deliver too much ink but after a few labels they settle down so it’s a good idea to do batches of 20 or 30 labels each time, and you will need to find some decent card on which to write; the classic Bristol Board tends to be a little too absorbent and so the ink spreads and writing loses its sharpness but it should be easy enough to find a decent pad of heavy paper that will do the trick. Labels should be cut out with scissors and you will probably want to hide as much of the label as possible under the specimen card, so long as the reference number of the specimen is visible then all well and good, life would be much easier if the pre-cut cards could be used as labels but they tend to be far too absorbent. Many coleopterists use pre-cut cards for specimens but write much larger data labels which of course take up far more space than the mounts, this is a problem because each row in the drawer will accommodate a certain number of mounts closely laid out together in neat lines, and these really do look very impressive as the collection grows, being tightly arranged makes it much easier to lay out neat rows and columns but when larger data labels need to be included things become more complicated and difficult to arrange. Of course writing labels to go under larger mounts is easy but producing labels for the smallest mounts, in our case 11x4mm, requires some practice and very steady hands but such things should be second-nature to the coleopterist anyway. Our rows accommodate twelve of the smallest cards and so a column in a large drawer will hold a good few species as well as various labels. Labels are a matter of personal choice; we make them as wide as the columns, we use good 80gsm card and mount each on a single pin at the same height as the specimen mounts (which is very different to how most people do it but we think they look very good and can easily be read from any angle), we use a different colour for each superfamily and various fonts and sizes for the families and genera etc. This sort of thing will not be to all tastes but the real value of the collection is in the specimens and the data and, so long as they are kept safe, other considerations are rather trivial and so should pander to personal taste; trying to copy systems may work for others but we have yet to find one that is so easy to work with and rearrange as our own. Never think that a collection is finished and will remain as it was first laid out; collections should be working tools rather than works of art and specimens will constantly be taken and replaced. And a collection of perfectly regimented rows and columns is never going to work because there are always awkward specimens such as large longhorns or scarabs that will need to be pinned, and such beetles do not come in standard sizes and they always have awkward sticking-out bits This discussion concerns what is practically achievable by the enthusiastic amateur but there are other systems such as lining drawers with separate boxes for each species which are equally impressive but which seem, to us at least, rather daunting. Having chosen pins and mounts, and having devised data- and specimen-labels, all that is needed is to begin with laying out drawers. It will take time to get good results and some people are naturally good at laying out drawers while others, such as myself, are absolutely hopeless, so start at the top left and work down; the first column will be easy as the drawer will guide you but beyond this various rulers and set-squares will be handy. In my case I do not have to worry about laying out drawers because my son has a natural knack of getting them to look right but it really should be appreciated that some can do it easily while others are hopeless and need to take a long time before things look right, keeping this in mind may help keep you sane.

Sibling species such as Oulema duftschmidi (L.) and O. melanopus (R.) are an example of why large series of some beetles have to be collected.

Find Out More

Oulema duftschmidi 1.jpg
Oulema melanopus 1.jpg

The question of how many specimens of each species to include in the collection is a difficult one to answer and will ultimately come down to personal choice. Sometimes there is no need to add any more than a male and a female but this would leave gaps in the drawers, some can live with this and some cannot, in which case rows tend to be completed for the aesthetic reasons. Sometimes there are good reasons for a series such as colour varieties in ladybirds and leaf beetles, although this can get out of hand for the pedantically-minded. These sorts of choices can be satisfied by going out and collecting more material, or not as the case may be. But the reverse situation often occurs as well i.e. given a large number of dead specimens-or even live specimens that we know will soon be dead whatever happens-then how many should we keep for the collection? A few examples will illustrate this dilemma; pitfall trapping or flight interception trapping, especially if done regularly in the same area or if several traps are set out for a one-off survey, can produce numbers-and sometimes large numbers-of perfectly good specimens, and sometimes this may occur gratuitously; we once came across a cattle trough with large numbers of Dascillus and Aphodius as well as loads of other stuff, all dead but all in good condition, so what to do with the specimens? In a similar vein we once obtained lots of Reesa from a basement in Watford, all alive but soon to be killed off as undesirables, what to do with them, certainly it would be difficult to find a good home for them. In all such cases we tend to accumulate large series, in the case of Reesa we have thirty, and most of our Aphodius-type things are in reasonably large series as well but these did not involve gratuitous killing, rather a gratuitous amount of hard work setting and labelling etc. The choice will always be a personal one and in most cases it would be difficult to justify killing simply for the sake of the collection but sooner or later every coleopterist will resort to trapping and when we put out fermenting fruit or carrion or whatever we can expect large numbers of specimens, so maybe consideration should be given to non-lethal rather than lethal traps, but this will involve regular and frequent visits to the traps, especially to submerged water traps and dry pitfall traps. Such things will need to be considered carefully before laying out drawers and ordering cards etc. and if you can network with other coleopterists who might like to consider any excess material so much the better. These things should be considered very carefully, and not just for the sake of the collection.

Cabinet drawers tend to be more or less air-tight and so there should be no fear of pests getting in and destroying the precious contents, on the other hand such things as museum beetles and book-lice may be introduced with specimens and once inside may proceed to breed and extensively destroy your specimens. With a large collection some of the drawers will not be needed for extended periods and so pests may have a good run at destroying specimens before they are noticed, for this reason each drawer should be visually inspected once a month, there is no need to remove the glass lid as any damage will be obvious from the dark specks of frass on or under the cards. Unfortunately some of the best preservatives have been found to be carcinogenic and so are no longer available but small sachets of lethal moth-killing chemicals are available on line and can be pinned into the corner of a drawer to destroy any infection. A modern method of control is to deep-freeze a drawer or box of specimens for a week or so to kill off any infestation but we have not tried this and so cannot comment on its effectiveness. The most common preservatives, now banned, were aromatic di-halides, and in the past even sodium cyanide was used, both lethal in their own sweet way, but other chemicals can be used if you are adventurous and know a friendly organic chemist. Mould may also be a problem if the cabinets are kept in cold conditions, moulds can usually be detected early and treated with a brush and some commercial mould-killer, available at any supermarket or hardware store, and this stuff works best if dissolved in isopropanol as it increases the solvency and allows it to penetrate into the whole specimen. Beachwood creosote (it stinks) can be added to the drawers in special glass vials which prevent it from spilling if the drawer is tilted, and this stuff will control mould very well. Another annoyance will be the occasional discoloured mounting card, this happens with various groups, especially ladybirds, water beetles, dung beetles and the odd carabid, and it may occur long after the specimen has been added to the collection. The only answer is to re-mount the specimen on a clean card but during this process it may be de-greased by soaking in a strong fat-solvent such as xylene (it stinks) or by washing the specimen with sodium hydroxide (no smell) and then clean water, the specimen will need to be thoroughly dried afterwards but even then there is no guarantee that more residue will not enter the card, this is a nuisance but eventually the specimen will stop discolouring the mounts.

If you take the time to arrange a series of cabinets with labels of the entire UK beetle fauna and make sure to leave gaps along the way, or perhaps at the end of each drawer, you will have the potential for a decent-sized reference collection but it can be a very deflating experience to actually add your specimens because chances are there will be lots of large gaps as well as lots of spaces occupied by only a single specimen; what before, when housed in a few storeboxes, seemed like an extensive and large collection may now seem rather lost and superficial. But this may be the point when the real recording begins, when you decide it’s about time to do some serious sampling.

bottom of page