The ArthroBlogger
Fun stories. Random facts. All the arthropods.
An Awkward Way to Hitchhike
Due to the likelihood of being kidnapped, hitchhiking would probably be my least recommended method of travel. Unless you’re a beetle, in which case hitchhiking can be a very convenient means of getting from one place to another for very little energy expenditure. Just ask Nymphister kronaueri, a recently discovered species that bears a striking resemblance to an army ant’s abdomen (here’s a picture).
Yep. Welcome to The ArthroBlogger, folks, where now that we’ve done a post on dung beetles, we can talk about literally anything—like beetles pretending to be ant butts!
Unfortunately, said beetle doesn’t have a common name yet. Fortunately, that means I get to make up a temporary name for it! Henceforth, Nymphister kronaueri shall be known as the “butt beetle.”
Obviously, this is a very mature science blog. Only the most distinguished entomologists spend their free time here.
Butt beetles hail from Costa Rica, where they were first discovered during a 2013-2014 research survey on species known to be symbiotic with Neotropical army ants. Did you know there’s actually a term for organisms that hang out with ants? They’re called myrmecophiles, which literally means “ant lovers,” and butt beetles are hardly the only ones out there. The fungi, aphids, and other organisms ants are known for “farming” are considered myrmecophiles, as well as other plants, animals, or fungi that rely on ants for any part of their life cycle. Army ants in particular are known to harbor tons of myrmecophiles, and the butt beetles’ pals, Eciton burchellii army ants, are friends with over 300 other species!
Army ants are unique for having giant nomadic colonies: every two to three weeks or so, the entire colony of up to millions of individual ants will enter a “nomadic phase.” During this phase, the colony will stay in one spot during the day but travel at night before eventually settling down in a new location. This transitional period is a great time for phoretic species, or species that travel by latching onto another animal, to hitch a free ride to the ant colony’s new destination. So, what do butt beetles do to stand out from the other phoretic myrmecophiles? Well, as mentioned previously, they do a really great job of looking like ant butts.
To join the ant parade, a butt beetle will clamp onto an army ant’s trunk just above its abdomen. Once it tucks in its legs and antennae, the disguise is complete—to the human eye, an army ant with a butt beetle hitchhiker will look like it has two abdomens! This doesn’t really do anything for the ant beside making it look funny, but it doesn’t hurt the ant either, so they don’t seem to mind walking around with an extra butt for a little while.
Who knows, though—maybe the butt beetles do provide something beneficial for the ants. We’ve known about this species’ existence for less than a decade now, so there’s still a lot left to learn about them, especially their relationship with army ants. Maybe they share food with the ants, or maybe they’re really tidy and help keep the ant colony clean.
Or maybe having two butts is considered a fashion statement in the ant world. We just don’t know. Only time will tell the significance of the butt beetles.
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