Rotten Log Project

Velvety bark beetle - REK

Ventral view of the velvety bark beetle

We have been collecting specimens for a rotten log project, creating a worksheet of examples for teachers.  I came up with the two specimens below and struck out on my attempts to identify them beyond being in the Polyphagia suborder.   I sent this beetle photo to Bugguide.net and got a response within 10 minutes from Invertebrate Dude, one of many contributors who patrol the pages, helping to identify specimens.

This is the Velvety Bark Beetle, Penthe pimelia, a rather insulting name as pimelia means fatty.  It is a member of the Tetratomidae family of polypore fungus beetles.  They are usually found under the bark of fungus infested rotting logs where they eat the fruiting bodies of fungi.

The other beetle was more more formidable, equipped with jaws that meant business.  It was rapidly identified as a False Mealworm Beetle (Alobates pensylvanica)* by Blaine Mathison.  The name false mealworm suggests a short future for some of the larvae which are raised for fish food in some aquariums.  It is a darkling beetle, long and larger, its elytra shinning and dotted with small punctures.  It is found under the bark of decaying logs where both the adults and larvae are predators of other rotting log insects.

* "pensylvanica" is not a typo.  Latin avoided double consonants although some sources chose to use pennsylvanica anyway.

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