[HN Gopher] Beetle walking upside down under water surface filme...
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Beetle walking upside down under water surface filmed in Australia
Author : namu-313
Score : 180 points
Date : 2021-07-09 06:11 UTC (1 days ago)
(HTM) web link (www.theguardian.com)
(TXT) w3m dump (www.theguardian.com)
| trhway wrote:
| as it walking using surface tension it is somewhat like a space
| worker using magnet boots.
| [deleted]
| crvdgc wrote:
| 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".
| invincing wrote:
| https://www.youtube.com/watch?v=VIs00QjiJZQ
| Ftuuky wrote:
| This is one of the coolest things I've seen in a long time.
| badjeans wrote:
| Down and Out by Ken Wharton?
|
| https://eandt.theiet.org/content/articles/2017/02/science-fi...
| [deleted]
| daxfohl wrote:
| Surface Tension by James Blish?
| sen wrote:
| That's such a great idea for a story, especially if you start
| thinking about the size of the oceans, connecting to inland
| lakes via river networks, etc.
| atombender wrote:
| 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: https://www.researchgate.net/figure/Lateral-view-on-the-
| wate....
| enriquto wrote:
| 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!
| xunn0026 wrote:
| We noticed a month ago a few water snails crawling upside down
| the water surface.
| solarengineer wrote:
| 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]
| enriquto wrote:
| A beetle? In my aquarium I have _snails_ walking upside down
| under the water surface!
| krisoft wrote:
| Just to clarify: are your snails walking on the water-air
| surface upside down? Or they are underwater but clinging to
| some surface other than the water-air one?
|
| Assuming it is the first, do they breach the surface tension?
| enriquto wrote:
| 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.
| jacksonkmarley wrote:
| > The beetle seems to do the opposite thing, though.
|
| Why is it the opposite? From the description it seems
| exactly the same.
| enriquto wrote:
| 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.
| krisoft wrote:
| Thank 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
| knnnuehu wrote:
| Snails dont have legs or limbs. And "walking" is a legged gait.
|
| Limbless loco is a seperate story -https://en.m.wikipedia.org/w
| iki/Terrestrial_locomotion#Limbl...
|
| Snails are pretty cool though with their mucus turning
| everyting around them friction free so they are badically ice
| skating. Have no clue what happens in water though.
| dtgriscom wrote:
| I'd believe that they could hang upside down with their feet at
| the surface. I wouldn't believe that they could actually propel
| themselves across the surface; any movement would be due to
| water currents.
| enriquto wrote:
| They definitely propel themselves. Even if I stop the filter
| so that there's no water circulation, they can walk on the
| surface just as fast as they do on the glass (which is quite
| slow, but still).
|
| Think about it: water striders propel themselves quite fast
| on the surface of water, from the other side. The air/water
| interface is a though barrier to break for small beings. Thus
| they can use it for support, from either side.
| dvdbloc wrote:
| 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
| MrJagil wrote:
| Do you have video?
| itsdsmurrell wrote:
| How is this a story. I've seen this myself.
| james-bcn wrote:
| Agreed. I don't understand why they are making such a fuss
| about this. It seems trivial and expected, and is not an
| uncommon site (if you like looking into ponds like me).
| adenozine wrote:
| Maybe a lot of upvotes have not witnessed this themselves.
|
| Not everything is going to be a new thing just for you. Don't
| you find it a little comforting that other people are now
| becoming aware that beetles are able to do this?
| jcims wrote:
| Yeah but the article says this is the first time it's been
| recorded.
| bredren wrote:
| I believe there is some emerging friction between
| academically authenticated knowledge and that observed by
| mere "amateurs."
|
| https://www.npr.org/2021/06/20/1006352654/enthusiastic-
| amate...
|
| And see villager observations here:
| https://www.nytimes.com/2021/06/22/science/moray-eels-eat-
| la...
| jeofken wrote:
| What a humourus coincidence that it was in Australia the upside-
| down walking beetle was found.
| mcbishop wrote:
| Upside-down beatles down under.
| ComodoHacker wrote:
| Perhaps this species was brought there from US and struggled to
| adapt. Or rather adapted in its own way.
| ablanton wrote:
| I bet his toilet flushes the other way too!!
| brabel wrote:
| It does! https://www.youtube.com/watch?v=mXaad0rsV38
| tomcooks wrote:
| Down under, really?
| Andrew_nenakhov wrote:
| Australia is the most appropriate place for such findings.
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(page generated 2021-07-10 23:02 UTC)