Entomology Collection Curation

Statement of Purpose

These links and documents contain information about curating entomology collections.

Introduction

Entomology collections have methods that have been used successfully for many hundreds of years, and proper use of these methods will ensure long-term preservation of these unique specimens. Traditionally, entomology curation has been divided into three main types of preservation:

1. Dry Collections (Pinned, Secondary Mounts, Envelopes)
2. Slide Collections
3. Collections

Unlike many other vertebrate or other animal groups, most insects can be preserved dry, on specially-made archival stainless steel insect pins or in envelopes, or temporarily in airtight boxes or containers. This type of curation is relatively unique to this group. Other methods for insects overlap quite extensively with other groups, so they will not be covered on this page (See links above for slide and fluid collections).

Pinned collections

Pinning is the most common method of preserving insects. Insect pins consist of a stainless steel with outer layers of enamel and a resin pinhead. Pinned insects are placed in foam unit trays. The unit trays are stored in wooden drawers, which in turn are stored in cabinets.

Hazards

• Old insect pins were made with brass or copper which reacts with lipids in the insect's body over time to produce verdigris . Verdigris is a waxy substance which looks like green metal filaments. It can destroy a pinned insect if allowed to continue. Use gloves when handling specimens that are covered in verdigris and avoid touching it with your bare skin.
• Insect curators historically used naphthalene mothballs to protect against pest insects. This is not recommended anymore, as naphthalene can be harmful to human health. Be conscious about any chemical smells that emerge from collections and monitor how they are affecting you.
• Insect pins are sharp - beware!

Handling

• Only handle a pinned insect by the head of the pin
• Do not touch the insect
• Pull the pin out of the foam as vertically as possible
• Moving to one side as you pull up can cause the pin to flick as it leaves the foam, potentially damaging the insect
• When replacing an insect in its tray, push the pin into the foam as far as it will go without bumping the insect's labels or legs into the foam

Storage

• Pinned insects should be placed in straight rows in their trays
• The insects should not touch each other, and their labels should not overlap
• Insect drawers should seal to protect the specimens from pests and environmental extremes
• Cabinets should also seal to protect against pests, environmental extremes, water, and light
• Pinned insects can be stored with the pins sitting vertically in a horizontal foam substrate (ideal) or displayed on a wall with the pin affixed horizontally in a vertical foam substrate
• Do not display insects in direct sun
• Indirect and low-UV light is best for display purposes

Envelopes

Although pinning specimens when they are fresh is preferable, the storage method known as papering (or envelopes) has long been used successfully for larger specimens of Lepidoptera, Trichoptera, Neuroptera, Odonata, and some other groups. It is a traditional way of storing unmounted butterflies and is satisfactory for some moths, although moths too often will have their relatively soft bodies flattened, legs or palpi broken, and the vestiture of the body partly rubbed off. To save space in most large collections, file Odonata permanently in clear plastic envelopes instead of pinning them.

Papering in the field initially consists of placing specimens with the wings folded together dorsally (upper sides together) in folded triangles or in small rectangular envelopes of glassine paper. Glassine envelopes have become almost universally used in recent years because of the obvious advantages of translucency and ready availability.

In most collections, glassine has become superseded by plastic, cellophane, or polystyrene for archival long term storage. Do not store fresh specimens immediately in airtight containers or plastic envelopes or they will mold. Always associate collection data immediately with any specimens.

Sealing

With all envelopes, properly sealing them is of paramount importance. Unsealed envelopes are incredibly likely to eventually get some sort of pest infestation. Sealing can be accomplished by folding over one edge of the envelope and securing with a metal paper clip. Clips that cannot be removed without damaging the envelope are not recommended.

One recent alternative is using resealable envelopes, as in Blades et al. 2017. The long-term durability of these envelopes has not yet been evaluated, but seems promising.

Labeling

All printed labels should follow other labeling best practices for printing, ink, and paper type. Natural History Collections. The standard envelope size (at least in the United States and Canada) allows for a 3x5 inch archival envelope label. Labels are printed in one corner and the specimen rests inside the blank space {Figure XX] so that no data is obscured.

Material

The material for the envelope varies, but the following should be avoided for long-term storage:

• Paper envelopes - the lack of transparency and potential acidity of non-archival paper makes using paper envelopes for long term storage a poor choice. There is also a higher chance of pest incursion in paper envelopes.
• Glassine envelopes - the lack of transparency makes these a poor choice. There is also a higher chance of pest incursion in glassine envelope if not sealed properly.

Blades et al. 2017 (page 19) provide an excellent summary of different enveloping materials.

The following materials can be used under the right circumstances:

• Cellophane - transparent and long lasting, and readily available. Cons include high static electrical potential and biodegradability. Cellophane also “breathes” so it can be used even if specimens are not completely dry.
• Mylar M-30 - transparent, archival, and readily available. Cons include high static electrical potential, low pest resistance, and higher cost.
• Polypropylene - transparent, archival, and low static charge. Very few cons if sealed properly.
• Polyethylene - transparent, archival, low cost, low static charge. Also increases availability if designed with a resealable edge. However these are not rigid and can rely on the archival card label for stability.

Contributors

Jianjia Gettinger, Garret Jolma, Tommy McElrath

Source Material

An efficient storage system for adult Odonata specimens, with application for other museum collections.

Collecting and Preserving Insects and Mites.

Curatorial Care of Natural History Collections.

Links

Pinned Insect Quick Reference Guide

Insect Storage Techniques for Small Collections