Carding is the act of gluing a beetle to a small piece of card. Ideally, the beetle should be in a fairly natural pose, the right way up, and with all 6 legs and both antennae spread out. Neat carding is worth the effort as it makes the resulting specimens easier to identify and more valuable as reference specimens to compare to others. It may seem that some coleopterists go to an inordinate amount of effort to make their specimens look ‘pretty’ – but there are good pragmatic reasons for carding as well as aesthetic reasons.
Carding can be extremely difficult and time-consuming, and it probably only becomes a simple, rapid task after lots of practice. However, there are a few tips that can save you a lot of headaches. Carding is not the fun part of being a coleopterist and if you want to spend more time on the fun stuff, it is worth learning how to do the chores quickly and to a high standard. I reckon that one immaculately carded specimen is worth a dozen contorted badly-carded specimens. So getting it right saves time in the long run.
First, always try to start with relaxed specimens. Ideally, specimens should be killed with ethyl ethanoate and kept cool in an airtight tube out of direct sunlight for an hour or more after death. Between an hour and a few days after death, transfer the specimens to dilute acetic acid in an airtight tube. I use pickling vinegar (5% acetic acid) bought from a supermarket but anything between 2% and 10% seems to work. You can immerse the specimens in the dilute acetic acid but I prefer to lie them on top of some tissue paper which is sopping with acid. I have kept specimens in satisfactory condition for up to 10 years like this.
Relaxing very stiff specimens
For stiff and/or elastic specimens try using forceps to stretch the legs out. This requires very delicate handling not to stretch the legs to breaking point, and the antennae are even more delicate. If bits get broken off, simply glue them alongside the beetle when the rest is in position. If that’s not working just make the best of a bad job. There are those who claim to be able to relax specimens after they have become stiff and I have followed several of their recommendations without a glimmer of success. I consider this a Dark Art but try this.
Now (January 2011), thanks to Andreas Herrmann, I’ve got a clear description of a technique which has been tried and tested by German coleopterists, using pepsin solution.
Identify before carding
It is always best to identify a specimen before carding it, so that underside characters, or characters such as crossed elytral epipleura, can be seen more easily. Also, if you are going to need to do a dissection, it is far easier to do so before you’ve carded the specimen. However, once out of the tube, specimens will dry out quickly, especially if they are being identified under the hot light of a tungsten-filament light source. I identify specimens on some damp tissue paper and use cold fluorescent lighting which helps to prevent them drying out and stiffening up.
Equipment you will need for carding:
- tissue paper
- pipette and a jar of water
- 2 very small paint-brushes
- forceps (storksbill and watch-makers’ forceps ideally)
- mounting cards
- water-soluble glue: I use Scotch Scrapbooker’s Glue. Read why here.
- a cork block or similar for pinning
- card for labels
- a staging block may be used to get all labels at the same height on the pins – not essential kit!
- a very fine-nibbed pen with indelible ink
Working on a sheet of tissue paper, first pipette a couple of drops of water onto the specimen to wash off the dilute acetic acid. Lay the beetle on its back and spread the appendages out into roughly the positions you want them to be in after carding. Easy to say but exactly how you do this depends mainly on the size of the specimen and also to a great extent on personal preference. This seems to be an area where no two coleopterists are alike. One has to do two equally fiddly things at once: hold the specimen still with one hand, and spread out the appendages with the other.
If the specimen is big enough, hold it still with your fingers. Smaller specimens will need to be held using watchmaker’s forceps. Tiny specimens will need to be held in position with a mounted micro-pin. Or read this for an even better idea. I find that several layers of damp tissue packed into the very shallow lid of a cigar tin is a good base to work on.
Spreading out the appendages can be really easy if your specimen has been thoroughly relaxed in acetic acid. Thoroughly relaxed means the appendages are fully plastic (freely movable to any position) with no elasticity (they stay exactly where they’re put). With larger specimens, brush the appendages out. It is best to brush out both hind-legs first. Once they are brushed out, they can be held down while the remaining appendages are teased out. Once this is done, turn it right way up and the beetle is ready to card. For most beetles, brushing is too coarse a method and a mounted micro-pin with a hooked tip is what I use. I hook each appendage and pull it out into position. A hooked pin will be essential for those species which retract their appendages into recesses on the underside (e.g. pill-beetles Byrrhidae, Trixagus (Throscidae), Anthrenus (Dermestidae)): getting a mounted specimen of one of those species with all appendages displayed is black-belt carding!
Using the glue brush, paint a thin film of glue onto a suitable area of card, and then pick the beetle up and place it onto the glue. Using the forceps again, arrange the legs and antennae, and the palps if you want to be a real perfectionist (if you identify before carding, you will know whether the palps have any diagnostic features), making sure all appendages are stuck down. Try to minimise the amount of glue you get on the upper surface of the beetle. The glue will dry out pretty quickly – the thicker you paint it on, the more time you have to arrange appendages, but the more likelihood you will get glue all over the specimen! In case of disaster, remember that you can always wash your beetle in water, pat it dry with tissue, and start again.
Once glued down, trim the card to size, if necessary, and pin through the base of the card. A thimble will be necessary for driving pins through thick card, or if using the less sharp makes of pin. Use a cork block underneath.
James McGill’s carding techniques
James has developed his personal techniques for carding beetles to a very high standard (black belt, 5th dan!) and has kindly written up his advice here.
A staging block is useful for getting card and labels onto the pin at standard height, but is not essential kit by any means.
Labels should be added to the pin immediately, including at least the essential information, e.g.
det. MGT, vi.2000
coll. MG Telfer
‘det.’ means ‘determined by’. For some reason, entomologists always speak of determinations rather than identifications. It is good practice to record the date of the identification, as our understanding of limits of a species changes through time.
‘coll.’ means ‘collected by’ on my labels, but other entomologists often use ‘leg.’ to mean ‘collected by’ and ‘coll.’ to mean ‘in the collection of’.
It is really worth getting your labels as small as you can while still being clearly readable. Storage space for a collection (store boxes and cabinets) is one of the major expenses for a beetle collector and it makes no sense to be filling up your cabinet drawers with huge labels on tiny beetles! Laser printers can print perfectly clear labels down to 4 point font or smaller.
If a specimen is re-identified at a later date, it is good practice to add another ‘det.’ label, rather than replace the original one. This is not to embarrass the original identifier, but to track changes in opinions, to emphasise where mistakes can be made, and in the case of specimens which are in support of reports or published records, allowing subsequent users of the collection to trace specimen to record.
There are a few tricky species-groups which may be identified differently depending on which set of features you place your trust in. Different coleopterists may come to different determinations. Hence the value of recording who identified the specimen, and when.
If you know a lot more about the origin of your specimen – the habitat or microsite, what it was feeding on etc., it is very useful to add this information on a separate label.
It is very quick and easy to soak carded beetles off, to look at underside features when needed. As long as a water-based glue has been used, if you wet the surface of the card with a paintbrush, the adhesive softens in 30 seconds, and the beetle can be gently lifted off with forceps. Because it is fully dried out (within a week or so of being carded), it retains its position – flat with appendages spread – so can be dropped neatly onto a freshly-glued piece of card after its underside has been examined. Unless it is soaked for a long time, the legs and antennae will not need arranging again.