Montana Public Radio

Bug Bytes: Beetle Butt

Jun 12, 2020

You look like an ant’s behind!

Why, thank you for noticing.

Normally, if someone told you that you resembled the backside of an animal, you’d take offense. But in the case of a newly discovered species of beetle, it’s just how they role…or ride, more accurately.

When studying a specific species of army ant, researchers noticed a number of ants that looked strange. From above, they looked pretty normal …the typical head, thorax, and abdomen. But the side view was bizarre. An ant with two abdomens?

Credit https://commons.wikimedia.org/wiki/File:N._kronaueri_on_army_ant.gif

When collected and preserved in solution, the second abdomen fell off …revealing that this was not an abdomen at all. It was an unknown species of beetle that looks just like an army ant’s butt. By clamping its jaws around an ant’s waist, the beetle invisibly tags along for a ride.

Army ants are unrelenting predators, moving in mass and overpowering and devouring any hapless insects, worms and small vertebrates they come across. Not a species to be messed with.

While these beetles do an incredible job of appearing like an ant’s posterior, army ants are blind. So, the fact that they look the look doesn’t help them avoid detection by ants, but could help them hide from more visual predators like birds.

To really blend in, the beetle’s butt-mimicry is taken to a higher level. Their exoskeleton has an unusual microscopic structure that is similar to that of the ants. So, in this case it’s more important to feel like a butt to the other ants than to look like a butt.

Not much is known about this beetle. What it feeds on or how it benefits from tagging along with the ant swarm is a mystery. But one thing is for sure, it’s certainly a more unique and entertaining display of mimicry.