Saturday, December 29, 2012

Bludging with Beetles: Ptinus fur, a spider beetle

Habanera pepper seed & cautious spider beetle
The Anobiidae is a family of beetles with the charming common name of 'Death-watch and Spider Beetles'. Among the thousands of species known worldwide, fewer than a hundred live in Canada and only one, so far as we know, inhabits the Home Bug Garden: Ptinus fur (Linnaeus,1758), the White-marked Spider Beetle. The far more ominous sounding Death-watch Beetle Xestobium rufovillosum (De Geer, 1774) bangs its head against the rafters to attract a mate on calm summer nights (you can watch and hear one here). I suppose if you can't sleep this might sound discomforting, but nowhere near as perturbing as the noises the squirrels make in our attic.
Somewhat battered male Ptinus fur ~3 mm long
Like the Death-watch Beetle, the White-marked Spider Beetle is nocturnal but with a body that is less than half as long. As well as being tiny, these beetles like it chilly - the one above just came out of a 4C refrigerator, but was running around too fast to get a decent picture. No worries, though, there are several excellent pictures on the web, such as this habitus shot at BugGuide and this spectacular stack-image on Flicker. The Flicker picture by John Hallmen consists of 153 separate images, each with a slightly different focus, that were merged into a single high resolution picture.

We find White-marked Spider Beetles in our basement every winter. They have a broad diet, including stored foods, but a long generation time (over a year) and aren't usually considered major pests. As long as we are only finding a few, I don't think I will worry about them, and they count towards the Winter Bug Challenge - over 50 species of arthropods so far.

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