This week’s subject is a teeny beetle with skimpy biographical information. It’s hardy enough to survive winter as an adult, and has features that can fake out an expert.
I saw this clever little beetle (the dark bit near the center of this picture) on a lobe of an eye-catching green fungus. I thought to myself, “Some insects must eat fungi, maybe this one does?”
At home with the photos, the folks at BugGuide.net once again helped pinpoint its identity: This is a narrow-waisted bark beetle in the Rhinosimus genus.
As you might guess, “rhino” refers to the beetle’s long snout. It’s long enough, perhaps, to fool an entomologist. One comment in BugGuide notes that some of the most recent research into this beetle is from 1981. Anecdotally, that research was only pursued because a scientist thought the beetle was a weevil (known for their extensive snouts). It’s not in the weevil superfamily, but in the darkling beetle superfamily, Tenebrionoidea.
The second part of the name, -simus, means flattened. According to one source, Rhinosimus use the tool-like schnoz to wedge their mouths under the outer layers of tree bark, so they can eat the softer material underneath. So it seems this beetle might have been more interested in the log than the green fungus growing on it.
And that’s nearly everything I’ve been able to glean about this under-studied beetle. The only other interesting tidbits are: 1. Beetles in the Salpingidae family (to which it belongs) have been found preserved in amber, and 2. A Rhinosimus species is featured in an illustration from 1833 that includes a rhinoceros, a Rhingia hoverfly, and a rhinoceros beetle. Prints of the page, which is from a dictionary of natural history, are for sale for $15 on Amazon.
See more of Karen’s work here.
Information on Rhinosimus eating habits: https://www.cambridge.org/core/journals/canadian-entomologist/article/abs/the-larva-and-adult-biology-of-rhinosimus-viridiaeneus-coleoptera-salpingidae/A00E8330CD00F55CB4074871454E871B. Accessed 1/10/22.
Comments on its weevil-like look: https://bugguide.net/node/view/745706/bgpage. Accessed 1/10/22.