Troutnut Forum

>

Photography

> Found in my tying materials

The usual suspects with stored skins are dermestid beetles, but there was nothing in the photos that I could associate with them. Although there appeared to be some eggs in the center of the photo, I suspected that the long "rods" were the (sometimes shriveled and broken) remains of some type of larvae. The slight suggestion of segmentation on some of them and the little projections on the tapered ends made this seem likely.

My next thought was that these might be tineid moth larvae--which are pests of wool, fur, and hair--but they didn't look right. Tineid larvae usually have brown heads, can be up to 1/2" long, and are associated with silken webs and cases (which you did not mention).

As it turned out, the culprit that I now suspect is not one I knew to be a pest of fly-tying materials. I believe that the bunny boogers are probably maggots--the larvae of Piophila casei (Diptera, or true flies), also known as "cheese skippers." I won't go into all of the fascinating and disgusting details I learned about this species, but the little projections on the tapered ends of the larvae (actually the heads) are basically "meat rakes." The little cluster in the center of the photo could fit a description of the eggs: "The eggs of the cheese skipper are 0.63-0.74 mm long (Lui and Greenberg 1989) and 0.18-0.2 mm wide....The chorion (shell) of each egg is oval/cylindrical and a smooth, pearly white color."

The casei larvae "appear white or yellowish-white to the unaided eye." Here is a photo of an intact--probably half-grown--larva (notice the hooks on the tapered head):
http://entnemdept.ifas.ufl.edu/creatures/urban/flies/cheese_skipper03.htm

And here is some info about their feeding habits:

Piophila casei usually feed on overripe (three or more months old) and moldy cheese, and slightly salted or putrid-smelling meats, such as ham, bacon, and beef. Larvae are typically found on high-protein substrates ranging from salted beef to smoked fish and animal carcasses (Smith and Whitman 2000)....Forensic entomologists have used the presence of P. casei larvae as a tool to assist in the estimation of time of death for human remains. Though they can appear on remains less than two months old in geographic locations such as Florida, the flies sometimes do not appear on an exposed corpse until three to six months postmortem (after death), usually after the body has completed the "active decay" decomposition stage and is beginning to dry (Nanzi et al 2008). Entomologists utilize knowledge of the current instar of collected larvae, coupled with measurements of weather and temperature conditions, to provide an estimation of the postmortem interval (Benecke 1998).

They seem to be a fairly minor and somewhat uncommon pest of improperly processed hides (especially when compared to dermestid beetles) and have a rather short life cycle. However, the larger concern would be that the adult flies could find their way to your food. Accidental ingestion of the larvae is a cause of enteric myiasis and the flies may be vectors of other diseases.

BTW, although commonly used, cedar is only slightly effective in deterring tineid mothes. Camphor or lavender oil may be more effective and easier to refresh. Cedar will not deter dermestid beetles and even the potent PDB mothballs are not very effective (and melt plastics, though I suppose that's more of a concern for me). I would suggest storing all "home-processed" skins in separate sealed bags, and keeping them away from other materials. In the case of an infestation, you might want to try dry-ice fumigation.