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Christopher G. Brown, Effective Use of Disinfectant Spray to Combat Fungal Growth on Preserved Insects, American Entomologist, Volume 61, Issue 3, Fall 2015, Pages 149–150, https://doi.org/10.1093/ae/tmv048
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For centuries, specimen collections have been a critical tool for understanding the living world ( Winkler 2004 ) and with advancements in genetics and a greater understanding of anthropocentric effects on environmental change, they are becoming even more important to taxonomic and conservation studies ( Suarez and Tsutsui 2004 , Winkler 2004 , Pike and Ehrlich 2010 ). Insect collections, in which insects are pinned to a board and allowed to dry, similarly help form our understanding of the diversity of one of the most diverse groups of organisms on Earth. Therefore, much effort is spent to maintain collections and prevent damage from other organisms, such as dermestid beetles and fungi. There is even a society dedicated to this purpose: Society for the Preservation of Natural History Collections (SPNHC).
Mold is a significant problem for any collection, especially in humid areas ( Wood Lee 1988 ). It damages specimens, makes them visually unappealing, and renders them useless for research. Prevention is the best treatment for mold, but once fungi have invaded a collection, treatments range from deep-freezing and radiation to harsh chemical treatments ( Wellheiser 1992 ). However, these methods may be hazardous to the specimens (and their collectors) or impractical for large collections or small budgets. In addition, little advice is given for the treatment of mold in insect collections specifically ( Rondon and Corp 2015 ). Here, I provide a reliable, inexpensive, and safe method for the treatment of mold in insect collections.
Treatment Methods
This study utilizes specimens from a private teaching collection (owned by the author), consisting of insects pinned to polystyrene foam and in several plastic storage containers, which were kept in a residential closet for many years. On 1 November 2014, I noticed widespread mold growth on specimens across several orders of insects and in all the containers. This infection was most likely caused by the addition of specimens that were killed and stored in a freezer, then pinned without providing adequate time for accumulated condensation to dry. The wet specimens were pinned and added on 22 July 2014 in Lawrenceville, GA. The mold consisted of gray hyphae and fruiting bodies ( Fig. 1 A) covering several specimens in all the containers. The type of fungus was not determined, but it greatly resembles Rhizopus or Mucor (Family Mucoraceae).
On 6 January 2014, two additional moldy specimens were treated with Lysol (Parsippany, NJ), a common household disinfectant in which 0.1% alkyl dimethyl benzyl ammonium saccharinate and 58% ethanol are the active ingredients. To apply the treatment, I held the insect by the pin a few centimeters from the can of disinfectant and sprayed the specimen from several angles, covering it in liquid ( Fig. 1 B). The specimens were immediately returned to their original containers and allowed to dry.
Efficacy
Upon spraying, the hyphae and fruiting bodies seemed to disappear ( Fig. 1 B). After drying, there were no obvious remaining fungi and no discernable changes in the color or shape of the insects when measured one hour, one week, and nine weeks after spraying ( Fig 1 C-E). I observed no damage to the specimens from the force of the spray; no legs or antennae fell off and there was no noticeable loss of scales or hairs. Spraying even restored sheen to the cuticle of beetles (Coleoptera) and cave crickets (Rhaphidophoridae), which had been absent during the fungal infection. However, the spray did cause labels written in ink to run.
This method also removed mold from a dried tarantula (probably Aphonopelma chalcodes ) and a large walking stick (Phasmatidae) mounted separately in box frames. Using a stereoscope, I found no evidence of damage to the cuticle caused by the fungus or disinfectant, indicating that the mold grew on the insect, rather than in it, and that the disinfectant did not further dry out the specimen. Insects with fungal growth that were kept in the same containers and next to treated specimens had no change in fungal appearance.
Conclusion
Although prevention, which can be achieved by keeping collections in cool, dry conditions, remains the best treatment for mold in insect collections ( Rondon and Corp 2015 ), common household disinfectant spray could be an effective method for treating collections that have been infected with mold. Unfortunately, the species of mold tested here was not determined, so whether this treatment works for other types is unknown.
Acknowledgements
Thanks to Jennell Talley for her encouragement and to Rebecca Nichol Roberts and James Russell for formative comments on the manuscript.
References Cited