A review of adhesives for entomotaxy

Abstract

Insect specimens that are too small to be pinned safely are usually affixed to a piece of card on a pin or to the pin itself using an adhesive. This practice has been in place for more than two centuries, and >400,000 such mounts continue to be accessioned annually in collections. Entomologists appear to agree on the ideal properties of adhesives used in specimen preparation---that they remain (1) archival, (2) reversible, (3) easy to prepare and use, and (4) safe. There remains no consensus, however, regarding which adhesives satisfy these criteria. Entomologists continue to use fixatives they were taught to use (institutional inertia) or which have good initial working properties, even though their archivability and reversibility have never been tested or have been shown to be suspect. Museum professionals recently identified this topic, adhesives applied to natural history specimens, as one that could be informed by research and knowledge from other domains. This review includes a comprehensive list of adhesives used in entomotaxy, with brief summaries of their properties as examined in the contexts of archaeology, paleontology, art restoration, and polymer chemistry. The general conclusion is that no adhesive has the properties sought by entomologists, and several commonly used brands or classes of adhesive should never be used for entomotaxy, including most clear nail polishes, shellac, and certain polyvinyl acetate-based dispersions, like Elmer's Glue-All.

Sampling and curation of rove beetles (Insecta, Coleoptera, Staphylinidae) for comprehensive and DNA-grade collections to enhance biodiversity exploration in Northern Eurasia

“…If a specimen is glued to card or point, a water-soluble glue (Herkules, EntomoAlex-gr, EntoSphinx, Erick Krause) ( Fig. 10 A) and others) is preferred over other glues (Canada balsam, casein-based glues, some PVA variations and others) ( Deans 2018 ). Small Petri dishes ( Fig.…”

The Ouellet-Robert Entomological Collection: new electronic resources and perspectives

“…1). The poor scores are largely due to specimens having become unglued from their points (Deans 2018). Meanwhile, most of the Odonata are contained in paper envelopes and thus not easily examined, and many of the alcohol-preserved Diptera are low on preservative; these two parts of the collection, therefore, received many substandard scores.…”

Tiny wasps, huge diversity – A review of German Pteromalidae with new generic and species records (Hymenoptera: Chalcidoidea)

“…This is especially true for point mounting, although the specimens are more in danger of being damaged when handled without care. Deans (2018) provides an in-depth review of potential glues for entomotaxy; however, with no clear recommendation. Choice is therefore dependent on the needs of the user.…”

“…Choice is therefore dependent on the needs of the user. Although not recommended by Deans (2018) , shellac is used by the authors to great effect, as it has the ideal properties and mounting results are excellent. Mounted specimens should be stored in air-tight insect drawers under dark and climate stable conditions in order to preserve colours and avoid damage.…”