Saturday, November 17, 2012

Bludging with Beetles: The skin-eaters (Dermestidae)

Not a white box: Skin-eater larva trapped in the bathtub
The Home Bug Gardener has been a busy boy and not all of his time has been spent shovelling snow. Last week the Joint Annual Meeting of the Entomological Societies of Canada and Alberta graced Edmonton with its presence. For five days (and for many months beforehand) it was bugs, bugs, bugs. Also known as the Local Organizing Committee, the local entomologists get to host the rest of the nation, and that means all work and no play. By the time it was over, I looked up to see nothing but deep drifts of accumulated snow and work to dig through. There must be something better to do.
Mystery dermestid beetle
In just a few short weeks it will be time to celebrate those hardy (or pesky) bugs that snuggle-up with us for the winter (synanthropes) or love the cold (cryophiles): John Acorn's Second Annual Winter Bug Challenge. The challenge is to the birders who will be beginning their Winter Bird Counts next month. John's hope is that we can find at least as many species of arthropods actively enjoying the Alberta winter as the birders can find birds. The hairy larva at the top is one such almost record from last winter. Although we know the family, adults are needed for species identification. Possibly, this is a larva of the Larder Beetle, the only dermestid adult we have on our in-home list. But out-of-doors during the warmer months roam other more or less mysterious dermestids. Literally 'Skin + eating' (derm + este), dermestids like their skin dead and dry. Any proteinaceous scurf will do, including dead insects, dried meats, and meat byproducts like cat food. Since I accidentally kick one of the cat bowls at least once a week, I'm sure we have bits of dry cat food crumbling in corners and toasting in floor vents. In any case, a Larder Beetle or two is not an uncommon find (although we have yet to get a good picture of one).
Carpet Beetle (Anthrenus sp.) enjoying a carpet of Goutweed flowers
But looking through BugGuide, I rather doubt our bathtub-bound hairball is Dermestes lardarius. Looks more like the larva of a Carpet Beetle in the genus Anthrenus, perhaps like the one above enjoying a goutweed flower (the generic name comes from the Greek for flower). Wool is another one of those animal products that dermestids will eat and several are known as 'carpet beetles' from their predilection for woollen carpets. Alas, we have no woollen carpets, but languorous patches of cat fur sprout spontaneously in front of our heat vents. I suppose there are worse ways to while away the winter days than watching a carpet beetle larva transforming cat fur into a scaly beetle.  A jar, some cat hair, and a beetle larva is all it would take. Perhaps not as much fun as watching a caterpillar transforming milkweed into a Monarch butterfly, but this is Edmonton in the winter.

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