Beetle walking upside down under water surface filmed in Australia • Hacker News Board

Re: Beetle walking upside down under water surface filmed in Australia

#31

Post by enriquto » Sat, Jul 10, 2021, 2:31 PM UTC

jacksonkmarley wrote: post #30

enriquto wrote: post #14

Earlier quoted context omitted.

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…

> The beetle seems to do the opposite thing, though. Why is it the opposite? From the description it seems exactly the same.

From 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.

Re: Beetle walking upside down under water surface filmed in Australia

#32

Post by [deleted] » Sat, Jul 10, 2021, 2:31 PM UTC

solarengineer wrote: post #2

This reminded me about "How can the Bumblebee fly even though it's not aerodynamically capable of doing so? Because no one told it about this limitation". Upon some search, for an accurate quote, I learned that this is a myth, and that Bumblebee flight does not violate the laws of physics [0] [0] http://www.todayifoundout.com/index.php/2013/08/bumblebee-fl...

[deleted]

Re: Beetle walking upside down under water surface filmed in Australia

#33

Post by enriquto » Sat, Jul 10, 2021, 3:34 PM UTC

atombender wrote: post #11

There are other insects (and common outside Australia) that do this: Specifically, water boatmen which live underwater and have little legs that they use to push themselves around with. This includes the "lesser boatman", Corixidae and Pleidae , and the "greater boatman", Notonectidae . In particular, Notonecta glauca (or common backswimmer) swims on its back and will walk under the water surface searching for prey:…

Notonecta glauca is my favourite animal. It is a fearsome predator that can swim, walk and fly. Also, one of the few animals that can take-off from underwater!

Re: Beetle walking upside down under water surface filmed in Australia

#34

Post by mcbishop » Sat, Jul 10, 2021, 3:58 PM UTC

jeofken wrote: post #4

What a humourus coincidence that it was in Australia the upside-down walking beetle was found.

Upside-down beatles down under.

Re: Beetle walking upside down under water surface filmed in Australia

#35

Post by Ftuuky » Sat, Jul 10, 2021, 4:07 PM UTC

invincing wrote: post #17

crvdgc wrote: post #7

I vaguely remember there's a science fiction story about an underwater civilization where the buoyant force servers like gravity for us. Since the force points outwards, for that civilization, the planet is "up above" their head and the space is "down below".

https://www.youtube.com/watch?v=VIs00QjiJZQ

This is one of the coolest things I've seen in a long time.

Re: Beetle walking upside down under water surface filmed in Australia

#36

Post by ComodoHacker » Sat, Jul 10, 2021, 4:32 PM UTC

jeofken wrote: post #4

What a humourus coincidence that it was in Australia the upside-down walking beetle was found.

Perhaps this species was brought there from US and struggled to adapt. Or rather adapted in its own way.

Re: Beetle walking upside down under water surface filmed in Australia

#37

Post by [deleted] » Sat, Jul 10, 2021, 4:58 PM UTC

crvdgc wrote: post #7

I vaguely remember there's a science fiction story about an underwater civilization where the buoyant force servers like gravity for us. Since the force points outwards, for that civilization, the planet is "up above" their head and the space is "down below".

[deleted]

Re: Beetle walking upside down under water surface filmed in Australia

#38

Post by daxfohl » Sat, Jul 10, 2021, 5:02 PM UTC

crvdgc wrote: post #7

I vaguely remember there's a science fiction story about an underwater civilization where the buoyant force servers like gravity for us. Since the force points outwards, for that civilization, the planet is "up above" their head and the space is "down below".

Surface Tension by James Blish?

Re: Beetle walking upside down under water surface filmed in Australia

#39

Post by pvaldes » Sun, Jul 11, 2021, 11:14 AM UTC

Yep, aquatic beetles are able to do this, and snails do it all the time. Is a well known fact.

Re: Beetle walking upside down under water surface filmed in Australia

#40

Post by pvaldes » Sun, Jul 11, 2021, 11:16 AM UTC

MrJagil wrote: post #9

dvdbloc wrote: post #5

Earlier quoted context omitted.

Do they do this when you put food in the tank? Funny you mention it because I just noticed my snails doing this the other day… it sounds weird but I have engineers come to my house just to see it because they don’t believe it

Do you have video?

Is pretty cool to see and all you need is a lamp. Aquatic snails walk under the surface all night. Some fishes vacuum the surface clinging upside down also.