Meet the Underwater Fly that Rules Mono Lake by Living Underwater

Over 100 years ago, writer Mark Twain observed the case of some “incredibly weird” flies in Mono Lake, near Mammoth Lakes, California. The Mono Lake flies (Ephydra hians) could go underwater to scavenge for food and lay eggs, and then emerge completely dry.

Mono Lake is a rare observance on its own, as it contains approximately three times the amount of salt as seawater. No fish or other vertebrates can survive in the water, leaving only algae and brine shrimp to call the lake their home. And, of course, these underwater flies.

Mono Lake. Photo by Lisa Yount.

All flies have some sort of water repellent qualities in order to survive in the rain or wet conditions. Most accomplish this with small hairs covered in wax but with the large amount of ions in Mono Lake, the water is able to forgo the hairs and soak the fly.

So, how can the Mono Lake fly dive and stay dry?

The Mono Lake Alkaline Fly creates a protective bubble of air around its body when crawling into the lake. Yes, they create a little submarine bubble to crawl down into the water and have their go at any algae they want to eat. How about that?!

These flies have more waxy hair than your average fly – hairs that are particularly effective at repelling against the carbonate rich water. They also have large claws that allow them to grasp onto the rocks under the surface without letting the buoyant bubble float.

You want to know the coolest part? They pop their eyes out of the bubble, letting them cruise around the bottom of the lake without the distorted vision of the bubble.

The unique qualities of these flies were observed by Michael Dickinson from the California Institute of Technology.

“It’s just a killer gig,” Dickinson said. “There’s nothing underwater to eat you, and you have all the food you want. You’ve just got to dive in perhaps the most difficult water in which to stay dry on the planet. They figured it out, and so get to enjoy an extremely unique life history.”

How’s that for evolution! So if you’re around Mono Lake and see something like this:

Those are some of the most unique insects on the planet (and yes, still a little gross).

Active NorCal

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