Hermit Beetle (and relative)

2008 August 16

We’d all just come into the house after going for a walk, and I heard Sam shouting from the kitchen “Mom, Mom, a beetle! A beetle!”, and then I heard S_ reply, “A beetle? Where is . . . Holy Cow!” So I come over to look, and they’ve got this huge scarab beetle, just about two inches long[1].

That’s Sam’s hand it’s crawling on. She’s 3, so scale it accordingly. She really liked the beetle, probably because it was large and cool-looking, and didn’t really try to get away. It just slowly crawled over her hands.

It is pretty clearly a “Hermit Beetle”, Osmoderma eremicola. According to the references I see, it’s also known as the “Odor-of-Leather Beetle” because it’s supposed to smell like “Russian Leather”, whatever that is[2]. The thing is, the way people talk about it, the odor is supposed to be really strong and noticeable, but with this one it is practically nonexistent.

They are also supposed to be very easy to keep as pets, they can be kept in an enclosure and fed sugary things (sugar syrup, juices, bits of fruit, and the like). Their jaws are nothing serious, but perfectly capable of dealing with, say, a peach slice or a piece of banana.

So, we still have him in a small plastic aquarium, along with another one that we found a couple of days later, outside crossing the road[3]. The thing is, the second one turns out to be not the same species – it has rough wing covers rather than smooth wing covers, and is a bit smaller, so it is probably the related species Osmoderma scabra

(it’s on my finger this time. These beetles are actually pretty easy to photograph, but only when they are on somebody’s hands; they sit still and hang on just as nice as you please. Put them down on a smooth surface, though, and they try to scrabble around just like other beetles are prone to do). Anyway, compare with the smooth wing covers on the kitchen specimen:

The two of them mostly ignore each other, although they occasionally tussle a bit when they both get into the same corner of the aquarium. So, out of three species in the Osmoderma genus in North America, I’ve got two of them here (and the third one is alluded to in Bug Guide, but they don’t have a picture or an entry for it)

I’m not sure why they are called “Hermit beetles”. Sure, they are evidently solitary as adults, but then, most insects are solitary, so it doesn’t seem worthwhile to name them just on that basis. The larvae evidently live in hollow hardwood trees, and a good way to find them is to look for a hollow tree that has just blown over, and check for them in the pile of debris at the bottom of the hollow. The larvae are obviously pretty large, and when they pupate they make a shell for themselves out of glued-together debris.

Normally, their life span is a couple of years, although a big part of that is hibernating through the winter. I’ve read that when they are domesticated, it is possible to get a generation every 6-8 months.

I’ve been invited to the Houghton public library to give a presentation on the local bugs on August 18, so I’m hoping we can keep these alive and frisky until then so that they can be shown off. These are easily the largest local beetles I’ve seen, and this is the first year I’ve seen them, so the kids should be suitably impressed.

[1] IN THE KITCHEN! I mean, here this beetle is, the size of a small mouse[4]. How did it get in? Do we really have cracks and openings in the basement large enough to let something this size get in? It seems the answer is “yes”.

[2] I’m not quite sure what “Russian Leather” is (a cologne? a particular leather tanning process? something else?), and I’ve never knowingly smelled it, so this means nothing to me.

[3] The second one doesn’t have much of an odor, either.

[4] A bit of perspective: the velvet mite I posted a couple of weeks ago, is about the size of this beetle’s eye!

5 Responses
  1. August 16, 2008

    What a handsome fellow!

    Is Russian Leather anything like Old Spice? Is it the reason female beetles wait for their males to come home from the…well, wherever it is that male beetles come home from?

    Congratulations on being invited to give the talk. I’d be interested in finding out how many people come and what kind of questions you get.

  2. August 17, 2008

    Nice writeup on this interesting genus of scarabs. The 3rd species (O. subplanata) is very similar to O. eremicola but is western. Roughly, populations with smooth elytra east of the Mississippi River are O. eremicola, while those west of it are O. subplanata.

  3. Lon permalink
    August 18, 2008

    This finally nudged me into looking up what Russia leather is. Vegetable-tanned, finished with various oils. The scent comes from birch oil, in particular, if the couple web sites I found are to be believed (this is one of those odd little factoids that is unlikely to be fudged on, IMO).

    This web site:
    says: “Russia leather is a type of vegetable tanned leather, but has very distinctive oils used during the currying process. This oil has an aromatic scent, and because of this the leather has certain properties. These properties include insect resistance and mold and mildew resistance. This type of leather was used in book bindings and hat sweat bands. This type of leather was embossed with a pattern in the grain surface of the leather, such as a diamond pattern as well as others. The leather is known for its distinctive red color, but was also dyed black. This leather is no longer tanned.”

    Looking at the linked picture from that page, it appears to have a glazed appearance. Which leads me to wonder if the birch oil referred is/was sometimes less oil-like and more glue- or varnish-like, as per this bit from the Wikipedia article on birch:

    “Extracts of birch are used for flavoring or leather oil, and in cosmetics such as soap or shampoo. In the past, commercial oil of wintergreen (methyl salicylate) was made from the Sweet Birch (Betula lenta). “Birch tar” or “Russian Oil”, extracted from birch bark[2], is thermoplastic and waterproof; it was used as a glue on, for example, arrows, and also for medicinal purposes.”

  4. August 18, 2008

    I suspect the “Russian oil” name is probably from the odor of a stepped-on dead beetle.

  5. August 19, 2008

    An update: both beetles survived just fine on a diet of fruit chunks (mostly bananas and peaches) and sugar-water-soaked paper towels for almost 3 weeks. They were a big hit with the kids in the library at our presentation last night. One family had a very nice bug-capture cage that they brought, with yet a *third* one of these beetles, so evidently it’s a good year for them. I let our two go afterwards, and they crawled off into the woods none the worse for wear.

    The Library presentation was a lot of fun, there were about 20 people there (about half kids and half adults). I showed some of the better pictures I’ve taken, then they played with the beetles, ant lions, several kinds of spiders, a monarch butterfly caterpillar, and a wasp nest, with me, S_, and one of our friends (who has actually been employed to examine spiders in the past) answering questions. We also brought Sam’s pet tarantula, just for good measure.

    Surprisingly, all of the critters survived, even though the ant lions kept getting dug up so the kids could watch them bury themselves in the sand again.

    Then we all took our cups and magnifying glasses out in the Library lawn to see what we could catch (at least 6 different species of grasshoppers, earwigs, woodlice, a few tiny bugs that we coudn’t see well enough to identify, and a very nice web of a funnel-weaver spider, among others). There were a fair number of questions of the “what’s a good ID book for this area?” type, and it looked like everyone had a good time.

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