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They cling to the water surface alone. They cling, they don't "stand" on it. Their whole shell and body is inside the water, and the shell hangs from the body
by enriquto 5y ago
They cling to the water surface alone. They cling, they don't "stand" on it. Their whole shell and body is inside the water, and the shell hangs from the body, which is firmly attached to the surface. If I disturb the surface they fall to the bottom.
This is a very common behaviour of pond snails. Just search "snail water surface" on google to see many pictures of it.
The beetle seems to do the opposite thing, though. It is buoyant so it floats to the surface, on which it stands and walks with its legs as it would do on the ground. The air\surface interface is very strong for small critters.
- krisoft 5y agoThank you very much for the explanation. I didn’t know about this. Super exciting. For others who might be interested I found this video showing the behaviour: https://youtu.be/hOLbyAzLmbQ https://youtu.be/hOLbyAzLmbQ
- jacksonkmarley 5y ago> The beetle seems to do the opposite thing, though. Why is it the opposite? From the description it seems exactly the same.
- enriquto 5y agoFrom the point of view of the beetle, he's not walking upside down. Physical forces attract him to the "ground" (the underside of the water surfaces) and he just walks normally, as if he was affected by gravity instead of buoyancy. The snail is definitely "upside down", for the physical force (gravity) wants to separate her from the "ceiling" on which she clings.
- jacksonkmarley 5y agoAha, I get it, interesting point.