I’ve been developing a special interest in weevil beetles and armed with my Coleopterist Handbook I’ve been finding more and more species. Due to the diversity of this group I decided to keep some voucher specimens to aid in my learning.
During the summer I tried to card some voucher specimens for further IDs but found that due to their shape and size, it is extremely difficult to set them well with all appendages showing.
Does anybody have any helpful suggestions that may aid with this please? I guess I will need some specialist tools and a microscope to become really proficient with this procedure, but I’m most interested in learning how best to card such small beetles and the best equipment.
I know the problem. They inconsiderately die with all their legs tucked under them. You need to relax them. You can buy relaxing fluid. I don’t know what it consists of but I think it causes the muscles to absorb water and become flexible. But it would be easier to make a relaxing jar using laurel leaves, which will double as a killing jar and storage. Pull some fresh laurel leaves and crush/tear them. Pack about a centimetre layer in the bottom of an airtight container and a layer of tissue paper on top to absorb moisture. If it is good laurel it will quickly go brown and you will smell marzipan when you take the lid off. That should relax your beetle specimens after they have been in for a few days. If it doesn’t give off a marzipan smell, try a different bush.
Thank you for the message @jhbratton and for the advice. I will try that method with the laurel leaves this summer when I’m back at home and see if I can can get them into better shape when I’m carding them.
Depending on the size of your beetles and the difficulty of identification, a microscope may not be essential, but for anything under about 1 cm you will probably find it easier to see what you are doing if you have some kind of magnification, whether a magnifier/loupe or a microscope.
At the risk of stating the obvious, the type of microscope that you want for this is a stereo microscope (sometimes called a dissecting microscope). I point this out because it took me rather longer than I would like to admit to grasp this basic difference in microscope construction. A stereo microscope has two eyepiece lenses* at slightly different angles to produce a greater depth of field/3D-effect which is helpful when working with insect specimens. A compound microscope has a flat field of view and allows for higher magnification; it is therefore good for looking at slide-mounted samples such as cells and spores and microorganisms but less suitable for preparing specimens because of the short working distance.
*Hence, if you speak a European language other than English, you might know this as a “binocular”, which can be somewhat confusing to those of us for whom binoculars are something used for looking at distant objects like birds.
And it is possible to get binocular compound microscopes which are more comfortable to use than single eyepieces.
Apart from higher magnification in compound microscopes, the biggest difference between compound and dissecting is that the image is reversed under a compound microscope. So should you want to poke the specimen with a pin to shift it, a pin in your right hand will come into the field of view from the left.