Natures wonders: aquatic beetle walks under water surface (Introduction)

by David Turell , Monday, June 28, 2021, 18:53 (1033 days ago) @ David Turell

Newly discovered:

https://www.sciencenews.org/article/beetles-walk-on-water-upside-down-underneath-surface

"A water-dwelling beetle can scuttle upside-down along the underside of the water’s surface, as if the water were a solid pane of glass, researchers report June 28 in Ethology. It’s the first detailed documentation of a beetle moving in this manner, which is known only in precious few animal groups.

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"As Gould quickly filmed the scene, the beetle walked under the water’s surface just as it would on a flat, solid surface, periodically resting and changing direction.

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"Gould and Valdez identified the insect as a minute moss beetle (family Hydraenidae), but Fikáček thinks it’s actually a water scavenger beetle (family Hydrophilidae). He says he’s seen both beetles move this way.

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"What’s still unclear is how the insect physically manages this feat, but the researchers have an idea. Gould’s recording of the beetle showed an air bubble trapped along the creature’s upturned belly. The team thinks the bubble’s buoyancy may be flipping and pinning the beetle to the underside of the water’s surface. That allows the insect to put pressure on the water-air boundary with every step, creating what Gould observed as tiny hills of water sprouting from the beetle’s feet.

“'It would have been really interesting to know which parts of the animals are [water-repellant] and which are not, as well as information on feet anatomy,” says Tom Weihmann, a movement physiologist at the University of Cologne in Germany not involved with this study. The beetle might be pushing off against the water like the researchers describe, he says, but this would mean the beetle’s feet are attracted to water, contrasting with a water-repellant body.

"Gould and Valdez think the beetle might use this water-walking superpower to stay far away from ambush predators that lurk along the bottom of these pools. But this must be sussed out with additional research."

Comment: another weird discovery. Note the scientists try to see how the beetle fits into its econiche. dhw always tries to ignore this important aspect of all phases of past and present evolution.