Once a specimen is killed, further processing may be required to preserve it over time. Specimens mounted on insect pins or stored in envelopes will dry and become brittle. However, they can be degraded by sunlight or fed upon by book lice (Psocoptera) or dermestid (carpet) beetles (see section, “Insecticides”, below). If humidity in storage boxes is high, specimens will mold quickly, so it is important to keep them dry as in room maintained at moderate temperatures using air conditioning and heating.
Long-term storage considerations:
Effects of light. For insects displayed in the open, they should be placed in indirect light. Exposure to direct sunlight causes color pigments to fade, although colors formed by prism-like butterfly wing scales (e.g., iridescent colors on tropical Morpho butterflies) or other physical features of insect cuticles (e.g., metallic beetles) are unaffected. Light also keeps book lice and dermestid (carpet) beetle larvae away, so there is less of a need for preservative chemicals.
Effects of humidity. One of the fastest ways to ruin an insect collection is to store it in a high humidity environment. Mold will quickly grow, enveloping entire specimens. In the eastern half of Texas, and throughout the tropics, collections quickly mold if not kept in conditions kept dry using air conditioners and heaters.
Insecticides. Specimens kept in the dark, such as in closets, drawers or storage boxes will soon be devoured by book lice and dermestid (carpet) beetle larvae unless protected. These pests of insect collections seem to be able to get into even tightly-sealed boxes, although air-tight seals will help prevent attack to some degree. Generally, however, some type of chemical protection is required. Moth balls containing the repellent – napthalene, or the fumigant – paradichlorobenzene (PDB), have historically been used to protect insect collections. Caution must be used, however, because these materials will “melt” styrafoam often used as a pinning surface in storage boxes. Some specialty products have become available using insect strips containing vapona or DDVP (2,2- dishlorovinyl dimethyl phosphate), e.g. Hercon® Vaportape® Insecticidal Strip, sold through entomological specialty product sources such as Bioquip. Use these materials in tightly sealed collection boxes.
If collection boxes, shadow boxes or display domes become infested with book lice or dermestid (carpet) beetles, place them in a freezer for a number of days to kill these pests.