Bess Beetle with Mites

Passalidae with a hip hairdo
Location: Arlington, Texas, heavily wooded area
March 25, 2011 7:23 pm
I used your website to id this as a bess bug, but I’m wondering what the little red bumps are around its horn? Parasites? They didn’t appear to be moving, but it was running about so it was hard to tell.
Signature: Moo

Bess Beetle with Mites

Hi Moo,
We get very excited when we learn that submitters to our site have been able to make a difficult identification using our site.  Those are Mites on the Bess Beetle.  We are uncertain if they are parasitic or if they are using the Bess Beetle for transportation purposes, an action known as phoresy.  If we knew that Bess Beetles flew, we would suspect Phoretic Mites, but it appears the elytra of the Bess Beetle might be fused.  This needs research.  According to Fossweb Teachers Bess Beetle page:
They all have hard, shell-like forewings, or elytra, from which their name is derived. In Greek, koleos means “sheath,”and ptera means “wing.” This unique structure functions as a tough protector of the beetle’s delicate hind wings and soft abdomen. When the beetle decides to fly, the hind wings unfold and do their job. At rest they tuck themselves back under the hard elytra. The site also discusses the Mites thus:  “Mites. Eating fungus that grows on decaying wood, providing care for larvae, communicating through sounds—these are all fascinating features of bess beetles. But they have another interesting feature—they have coevolved with at least one kind of mite. Mites are commonly found hitchhiking on the body of the bess beetle. Some of these mites are found only on bess beetles, suggesting a relationship that has evolved along with the organisms. It’s not clear that the beetles benefit from the mite, but because of their exoskeleton, they aren’t harmed in any way. It may be that the mites live on secretions given off by the beetle, or they may just find protection from the beetle while they share the decaying wood. The mites are not known to damage the beetles, don’t bite or harm students, and do not leave the classroom habitat basins. Should mites get on a student’s hand, they are easily brushed off.”

Nice! I’m completely in love with these beetles, so glad to know it wasn’t being eaten or anything. 🙂

1 thought on “Bess Beetle with Mites”

  1. We brought home two Bess Beetles from school. One of them died and when we picked it up a two centimeter worm (parasites) crawled out. How do we dispose of it?


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