I found a whirligig beetle in the neighborhood pool once. I was one of the only people in the water that day, so I could spot it from almost anywhere in or out of the pool and spent a lot of the afternoon following it around and watching how it swam from underwater. Good times.
Fun fact: I was going to just make this a generic water beetle post, but there’s way too many species to cover them all in one fell swoop so I settled on whirligig beetles. Who got their name from being able to spin in circles really fast.
This, people, is why I love arthropods so much: none of them really act the way we think bugs are supposed to act. They don’t spend all their time plotting when to sting you or strategically spinning webs so you’ll walk into them, but rather occupy themselves singing, dancing and doing zoomies on your pond. Gotta love ‘em.
In case you’ve just been calling them “water beetles” like me and have no idea what kind of insect I’m talking about, whirligig beetles are those black, elongated beetles that resemble living sunflower seeds without the white stripes. Like water striders, whirligig beetles rely a lot on vibrations in the water. The beetles can locate insect prey by the vibrations they emit upon falling into and struggling in the water, but they also make vibrations themselves to search for mates. Both water striders and water beetles use their middle and hind legs like paddles to row themselves around, although striders glide peacefully on the water while the beetles zip around like speedy little racecars. In fact, the beetles’ abilities may even exceed those of the striders, as they possess two sets of eyes that allow them to see under and above water at the same time. Water beetles also aren’t afraid to dive deeper into the water if they need to escape predators, but striders can’t swim too well if their legs break the surface tension.
Whirligig beetles are like the ducks of the arthropod world in that sense that they have conquered land, water and sky: they’re exceptional swimmers both above and below the water’s surface, and they have wings so they can fly to a new body of water if need be (which explains how that beetle got in the swimming pool). They also live on land for a brief period of time as pupae – all they need to do now is be able to survive in the vacuum of space, and they’ll be unstoppable.
…Speaking of unstoppable, if y’all will accept tardigrades as arthropods, you can be sure I’ll be doing a post on them later. Those things are ridiculous.
I always assumed that whirligig beetles had gills because of how much time they spend underwater, but they actually only have gills as larvae and lose them during metamorphosis. To overcome this setback, the beetles carry an air bubble on the end of their abdomen like a little scuba tank so they can breathe underwater for long periods of time! I’m serious! Look up pictures, it’s so cute!
When I was looking up pictures of this myself, I came across a little video titled “A Whirligig Beetle Releases an Air Bubble Underwater,” and I was thinking to myself “he released it purposefully? Oh maybe I got my facts wrong and the bubble isn’t a scuba tank, it’s just the beetle exhaling dramatically or something,” but no, y’all, this video had me cracking up. The beetle’s just climbing over a rock or something and accidentally lets go of the bubble, and as it shoots away he jerks an arm back in a haphazard attempt to catch it before darting up after it. You can almost hear him saying “oh shoot!” as he realizes the bubble’s gone. I’m putting the link here so y’all can watch it for yourselves; I’ve probably hyped it up too much now but I thought it was hilarious.
Another adorable factoid about these adorable arthropods is that they smell like apples. I mean, come on. How. Cute. Is. That. And it’s functional, as many whirligig beetle predators don’t like the smell of apples. I think God had a lot of fun making these little guys.
You may be wondering why the whirligig beetles keep their air bubble on their abdomen instead of over their mouths. The thing is, many insects don’t actually breathe through mouths and noses the way we do. Instead, they have holes in their abdomen called spiracles that connect to the trachea inside their abdomen. The spiracles act like the insect’s nostrils, and the trachea basically acts the same way our own tracheas do, except they send oxygen directly into the insect’s tissues and organs through a network of little tubes rather than into a set of lungs and the bloodstream. This method of breathing transports carbon dioxide and oxygen a lot slower than own respiration systems do, but thanks to the insect’s small size, it gets the job done just fine.
Even beside their adorable habits, spotting a cluster of whirligig beetles on your pond is always a cause for cheer. Not only will they clean up pesky bugs or dead and decaying matter that falls in the water, but their very presence is a sign of good water quality. Plus, some of those pesky bugs they eat are mosquito larvae!
Y’all know I love to change up arthropod names, but “whirligig” just encompasses the beetle’s personality so well that I feel like it has to stay. You win this round, taxonomists: you may add a second tally to your side of the scoreboard.
That’s right, I didn’t forget about cicadas. Sometimes arthropod names are poetic… but most of the time they aren’t. For example, flies – if you want to hear me rant about the least creative name in the entire animal kingdom, come back in a few weeks. ArthroBlogger out.