[Nhcoll-l] Precautions for Dermestid Colony

[Thomas Labedz]

Rachel
For decades I kept an active dermestid colony for cleaning of vertebrate
skeletons in the general preparations room across the hall from the main
research collections at the University of Nebraska State Museum. In nearly
40 years of operation the very few dermestid infestations found in the
collections were traceable not to the colony, but to staff and visitors
bringing already infected specimens (or more likely corrugated cardboard
boxes with infected specimens) into the building. However, this record
required constant vigilance and strict protocols rigorously enforced by
myself. Upon my retirement earlier this year, not having confidence the
colony would be monitored as rigorously, I terminated it. Having a colony
that is close to collections necessitates strong protocols, but can be
done. Everyone has to be on board with it. If staff or staff time cannot
adequately monitor a colony I'd recommend moving the colony off site. Let
me briefly explain how my operation worked.
The colony was in a double-walled, tightly sealed, custom-built, plexiglass
"terrarium" that had ventilation ports in the lid with a small-mesh screen
sandwiched between layers of plex. The box being about the size of a
10-gallon aquarium. It required periodic (approx. annual) cleaning to
remove build-up of dermestid frasse. This cleaning was done outside the
building. Only clean, dry carcasses were put in the colony. The bug box
could hold an entire deer head, or dozens of small, mouse-sized carcasses
in individual screen trays. When this colony was "hot" I could easily
prepare 40-50 small mammal skulls, or 1-2 dozen small mammal skeletons, or
a duck-sized skeleton every 24 hours. When the colony was "hot", little
else got done except skeletal preparation. Baiting out and freezing excess
dermestids let me control the pace of preparation. Prepared skeletal
material got a short rinse in mild ammonium hydroxide to kill remaining
dermestids, another rinse in water, and set to dry. After drying, labeling,
numbering, skeletons were placed in containers and everything frozen for
two weeks prior to moving to the collections. Everything was inspected by
myself. Anything suspect was re-run through the freezers. Nothing was
allowed out of the prep room without being frozen. Any newly arrived
unprepared material was frozen, along with its containers.
Over the years I did not have trouble with dermestids trying to fly from
the colony except under certain circumstances. Mold or fungal problems in
the colony resulting from too much wet material being added. If the frasse
layer in the colony becomes wet and begins to compost, this developing heat
drives the beetles out. Mite infestations on the beetles appear to cause
them to try to escape. Larva naturally will crawl and explore looking for
food. Everytime the lid was opened the perimeter of the lid and box was
examined for wanderers, but smooth plexiglass is difficult for them to
climb.
Side note. an odd source of dermestids found in the collections area were
traced back to the exterior of our building having an annual kestrel nest.
Prey items attracted dermestids which then found their way into the
building.
Good luck,
Thomas

Thomas E. Labedz, retired Collections Manager
Division of Zoology
University of Nebraska State Museum

On Wed, May 1, 2024 at 9:41 AM Vinsel, Rachel M <rvinsel2 at illinois.edu>
wrote:

> Hi All,
>
>
>
> Does your institution use a dermestid colony for cleaning specimens?  If
> so, I’d be interested to hear where they are housed in proximity to your
> vulnerable collections and what measures you take to prevent escapees from
> entering the collections.
>
>
>
> Best,
>
> Rachel Vinsel
>
> Illinois Natural History Survey
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