A Method for Preserving Certain Insects and Arachnids

by Richard L. Howey, Wyoming, US

Over the years, I have collected a variety of beetles, spiders, millipedes, and centipedes. Most I have kept preserved in fluid and a few I have dried. Over time those in fluid gradually lose some of their color and are often rather drab as a result. Specimens which are dried become drab quite quickly and if they are of any size they usually need to be preserved in fluid before drying.

Recently I was sorting through some small jars which had gone unattended for some years. I found some splendid millipedes about three inches long which I had collected one summer in the woods of Oregon, some once brightly-colored blister beetles found locally, and a nice-sized wolf spider. I dried the wolf spider, two blister beetles, and two millipedes. I removed them from their alcoholic graves and placed them in three inch Petri dishes. I fitted the bottoms of the dishes, with flat cotton pads used as facial cleaners which are available in many pharmacies. These circular pads are trimmed to fit the Petri dish which has a loose-fitting cover. The pads help absorb the alcohol retained by the specimen and the loose-fitting cover aids evaporation.

After several days, I examined the specimens. The millipedes dried very nicely, but looked drab and dusty; there was some shrinkage of the abdomen in the blister beetles and the wolf spider, but not an unacceptable amount. However, they too looked drab and there was a thin layer of dusty precipitate from the preservative on them as well. I let them sit for several more days, trying to decide whether to leave them in a dry state or to put them back into the preserving fluid.

In the end I got a hare-brained notion to try something quite different
nail polish. I had a bottle of a good quality clear nail varnish which I had been using as a mounting medium for some micro-fossils. The varnish comes with a small applicator brush and I applied a thin layer to the beetles, the millipedes and the wolf spider and returned them to their respective Petri dishes.

The first thing I noticed on examining them two days later was the eyes. The eight eyes of the spider shone like tiny yellow stones and the details of the compound eyes of the beetles and the millipedes were much more visible than previously. The other thing that jumped out at me was the restoration of the rich greens, yellows, blues and deep reds of the blister beetles.

The varnish should, if carefully applied, seal off the specimens and protect them from the ravages of mites, fungi, and other pests. This is a preliminary experiment and may in the long run prove only moderately satisfactory, but I am encouraged enough to experiment further. I suspect that professional entomologists would deplore such treatment, but in the end, the crucial consideration is what you want to observe and preserve.

Comments to the author Richard Howey welcomed.


Editor's notes:
The author's other articles on-line can be found by typing in 'Howey' in the search engine of the Article Library, link below


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Published in the January 2000 edition of Micscape Magazine.

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