A rove beetle is proof that something you might first take for a nondescript creepy crawly creature has astounding capabilities. It all has to do with their wings.
Notice how the wing covers, or elytra, on this beetle are stubby? They’re like a mini backpack, whereas most beetles have elytra that cover their entire abdomen. This allows them to bend and twist, and crawl through and around small spaces.
Rove beetles, in the Staphylinidae family, are predators and they form one of the largest families of any animal, with over 60,000 species in the world and at least 4,400 in North America. I don’t yet have genus identifications on these beetles, partially because there are 540 to choose from.
Back to those wings… How does a set of full-length wings tuck under those short wing covers? It’s an impressive feat of origami, though as you can see, sometimes they don’t tuck fully out of sight.
A 2014 paper, linked below, showed that not only is the folding pattern complex, but the two wings fold simultaneously and, here’s the crazy part, each wing has a different crease pattern. They manage the folding by a combination of “swinging” and “lifting” the flexible abdomen.
But wait! Their quick-fold wizardry doesn’t stop there. Each beetle can fold its wings in two ways, either starting with the right side or the left, so that each wing can fold in two different patterns! This means that points along the wing veins can fold like mountains and / or like valleys when needed. The research paper includes diagrams, and even videos, of the manipulations.
One thing the authors didn’t look at was how the wings unfold and deploy, but it’s assumed the wings retain a lot of elastic energy that’s released when they want to fly.
The beetle on this leaf is demonstrating another characteristic of Staphylinidae: Its threatening, arched-back pose. This posture is more intimidating when larger rove beetles do it. On this little one, it’s kind of cute.
Stay curious!
See more of Karen’s work here.
Sources:
Asymmetric hindwing folding article: https://www.pnas.org/doi/10.1073/pnas.1409468111. Accessed 3/1/22.
A good overview of the family: https://entnemdept.ufl.edu/creatures/misc/beetles/rove_beetles.htm. Accessed 3/1/22.
