Small Dung Beetle – Calamosternus
Sam found this little (only about 5 mm long) beetle for me on May 21, 2011 (Yes! It is from this year!). It was determined to make life difficult for me by running around, so this is the best shot I could get while it was upright.
Once upside down, it seemed more or less resigned to its fate, so I could at least get pictures of the underside.
Including the underside of the head:
The “fingered” antennae and the forelegs modified for digging suggested to me that it was one of the scarab beetles. When I asked on BugGuide, Paul Skelley thought that it was most likely one of the Pasture Cockchafers[1], genus Aphodius. Specifically, he thought it was probably Aphodius (Calamosternus) granarius, a cosmopolitan dung beetle that was originally from Chile but has since become widespread in most of the places around the world where people keep farm animals. Yet again, we have a non-native species, but at least this one isn’t from Europe or Asia.
As dung beetles, they are generally considered beneficial. There are a few thousand species of dung beetles, and since they speed up the breakdown of animal dung, they help keep us from ending up buried in the stuff. This particular species just seems to eat it, they don’t roll it into amusing balls the way that some of the other species do.
There were also a couple of little brown lens-shaped objects sticking to the beetle. They look to be sticky on their bodies, and to also have a single long, whiplike appendage:
They stuck pretty firmly, there was no sign of them getting moved or dislodged while I was chasing the beetle around for pictures.
I didn’t see any sign of legs, mouths, or really much of any features other than that whip-tail on these attachments, so I wasn’t so sure that they were even animals – I thought maybe they were something like spore capsules from some kind of moss. But, the general opinion on BugGuide was that they were immature mites in the family Uropodidae. It seems that, when they are young, these mites have a legless stage where they just ride around on beetles to get from one place to another. One of the people on BugGuide said “Mites are just strange”, and that is probably as good of a summary as any.
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[1] And now for a little entomology etymology[2]: in this case, “cock” is a reference to roosters, and “chafer” is an archaic word for “beetle”, so a direct translation would be “rooster beetle”. The classic cockchafer is a large European beetle, which looks like their equivalent of the “May Beetles” and “June Bugs” in North America. The “rooster” reference may be either to the antenna tips (which flare up like a rooster’s comb), or to the way that children would put males together to make them fight, like a very small version of cockfighting. The “pasture cockchafer” actually doesn’t look like it is all that closely related to the “classic” cockchafer.
[2] The words “entomology” (study of insects) and “etymology” (study of word origins) are frequently confused with each other because of their similar spellings, but rarely occur together in a single sentence. I just couldn’t pass up the opportunity.
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It sounds to me like they just dehydrate feces.
“Dung beetles eat dung excreted by herbivores and omnivores. Their preferred excretion comes from herbivores. Many of them also feed on mushrooms and decaying leaves and fruits. They do not need to eat or drink anything else because the dung provides all the necessary nutrients. The larvae feeds on the undigested plant fibre in the dung, while the adults do not eat solid food at all. Instead they use their mouthparts to squeeze and suck the juice from the manure.”
Is that true? It would leave the harder work of breaking down the solid and possibly more complex organic molecules to someone or something else. Or is it that rain and dew rehydrate what’s left and you get a convergent cycle of dining and rehydration until most everything is reduced to more useful, simpler forms?
By the way, I loved the mites. There’s just something about them I find wacky and fun.
The mites are deutonymphs of the Uropodoidea. They attach to their insect carriers via an anal pedicure – blob of glue they secrete and draw out into a stalk.
PS – they are not legless, but many of the Uropodoidea (best to use the superfamily, since family relationships are not stable) have pedofossae – leg ditches – cavities into which they can withdraw their legs.
I remember the difference between entomology and etymology this way: entomology studies small crawly things like ents. Etymology is the other word.
KT: Having spent rather a lot of my childhood ankle-deep in manure, from observation I think that just drinking the dung fluids would be pretty nourishing for them. The liquids in dung are pretty thick and dark. And, rainfall would generate more. I think this is yet another case of insects using other animals, bacteria, and fungi to digest their food for them. And yes, mites are pretty whacky.
Dave: Thanks for the added information about mites!
Anne: That’s a good mnemonic. Unless the person using it is too big of a fan of “Lord of the Rings”, in which case they might get to thinking that Entomology is the study of sentient walking trees.
I can’t help it – this little guy is extremely cute when he is on his back. I just want to have little tiny fingers to tickle his tiny little belly – if he could even feel that.
Someone else got to use the two ety… and ento… words in a sentence some months ago, in reply to one of my comments about some sort of cuckholding critter. I’m too lazy to look up the original entries, but I got a good laugh out of the response. The etymology of words and names has helped me understand our language and human history better, whilst I remember the word entomology quite well because I briefly dated an entomologist once. Who would think we’d be playing with words on a blog for people who like to play with bugs?