Richard Dawkins, in either ‘The Selfish Gene’ or ‘The Blind Watchmaker’, describes the arms race between bats and insects. Quite a fascinating affair—just bats' own evolution is intriguing: how do they differentiate between their own and others' echolocation signals? Well they have a ‘code’ in the signal specific to each specimen. And then, insects ‘learn’ to mimic bats' signals so a bat thinks it's another bat there and not a dinner. Etc etc.
This discovery might be at least the third one this year in this same field, if another one mentioned in the article isn't the one I've seen on HN.
qzw 1234 days ago [-]
> Holderied says it could be possible to make materials ‘10 times more efficient at absorbing sounds than what we are using in our homes and offices’. Think sound-absorbing wallpaper, not panels, he adds.
I would love to have something like that. All these open floor plan offices and open concept homes are loud AF.
wumms 1234 days ago [-]
There's a catch for a moth fur farm startup though (plush might work better):
> The acoustic cloak works between 20kHz and 160kHz
marcosdumay 1234 days ago [-]
To use in construction one must have to answer some very difficult questions like how well does the material survive dust and the cleaning process? How long does it last by itself? How does it interact with the other constraints like fire resistance, allergies, etc?
And after all that, filtering low frequencies is still a hopeless task.
dylan604 1233 days ago [-]
Not to mention flammability of the material.
zeristor 1234 days ago [-]
One does have to consider the frequency, I’m assuming dampening high frequency sound is easier than low frequency.
grawprog 1233 days ago [-]
As someone who's lived under an inconsiderate asshole who would play loud bass heavy music at 2-3am. Yes, low frequency sounds are much harder to dampen. Especially when they shake your roof and walls.
gabereiser 1233 days ago [-]
After listening to best softies of the 80s for 3 hours from my neighbors walls, yes please.
I also play guitar so to have a “jam box” would be great. Like a vocal box where you’re isolated but for really REALLY loud guitars.
RileyJames 1233 days ago [-]
That’s a thing, primarily used for recording, but your use case would work.
They’re called isolation boxes, easy enough to DIY build one.
According to the story it's not about jamming the sonar but giving of a warning that the moth is toxic. Sort of the acoustic equivalent of bright colors that some toxic animals have.
jussij 1233 days ago [-]
I stand corrected. As you point out the moth species I quoted uses this 'bad experience' signal as it's sonic defense.
However, this study found:
The moths’ ultrasound production clearly confused the bats, according to researchers, who reported that bats faced with sonar-jamming moths often tried to catch moths from empty air, apparently because the moths’ ultrasound signals had left the bats confused about the actual location of their prey. This kept working over several repetitions of the experiment with the same bats. For the researchers, this confirmed that moths were actually jamming bats’ sonar in order to escape, not just trying to startle them or mimic another, less tasty, moth.
Now if only they had ladders to climb out of bathtubs, they'd be unstoppable.
miohtama 1234 days ago [-]
Would be nice to understand how natural selection lead to this material and what were the steps. First you had a moth with some fur that absorbed maybe 0.1% ultrasound and then it started to increase from there generation and generation?
meowface 1234 days ago [-]
I wonder if some of these processes might start out with a kind of genetic anti-resiliency that's selected for. Moths seem to have a wide variety of wing patterns and heavily rely on them for camouflage and mimicry (like when eyes are mimicked). Maybe the genes related to wing surfaces reduced in number over time, making wings more sensitive to mutation and variation. Kind of like increasing the wing learning rate at an evolutionary level.
That could increase the odds that they'd eventually stumble upon things like this anti-sonar texturing, and that more advanced versions of it would start to appear. Maybe it could also have a role in the infamous peppered moth/pollution story.
And by contrast, maybe nature would also select for extreme resiliency of critical genes, like ones related to heart function and efficiency of resource use, so that they'd be less sensitive to generational variation.
I'm sure this could all still be explained even without that, but it's interesting to think about.
I was actually about to use the term "meta-evolution" while writing that post, since that's what it seemed like, though I wasn't sure if meta-evolution was already considered just a subset of overall evolution.
Your whitepaper definitely makes a lot of sense to me. Has there been a lot of other research done on this?
amurale 1234 days ago [-]
Something like that. Evolution = natural variation + natural selection.
In any given population there is natural variation: fastest moth, hairiest moth, whitest moth, etc. After evolutionary pressure is applied, the other moths are preferentially devoured, and the hairiest moth becomes the dominant variation with the most offspring.
For a similar historic account, read about the black form of the peppered moth which rapidly took over the moth population, caused by evolutionary pressure + single mutation in the year 1819.
Well the ones that didn’t do this got eaten by bats, it’s very easy to see how survival of the fittest works CB in this case. Designing an eye with evolution seems somewhat harder...
>Designing an eye with evolution seems somewhat harder...
It's absolutely trivial. You just start with light sensitive skin. Then evolve a cavity to create a pinhole lens and then finally fill the hole with a lens. Making the eyeball move is optional but shouldn't be too tricky.
1234 days ago [-]
douglaswlance 1233 days ago [-]
A single moth had a mutation that made it wings ever so slightly scaled in a way the absorbed a tiny fraction of bat sonar. This allowed it to reproduce slightly more than the rest of the population, so its mutation was reinforced.
vmception 1233 days ago [-]
With our current understating of placing all specialization on mutation and natural selection, it requires the unsaid of millions of useless iterations and dead moths and starving bats.
8bitsrule 1234 days ago [-]
Well that answers my question about some moths are so furry. Selection at work!
Ftuuky 1234 days ago [-]
I know nothing about this kind of metamaterials [0] but would it be possible to replicate them at an industrial scale? For things such as superior acoustic insulation and so on?
My completely uneducated guess is that this is probably similar in approach to ‘Vantablack’, in that you'll have to orient the scales a certain way relative to each other and the base. So they'll need to be likewise ‘grown’ on the surface, in a slow and very expensive process. (Though apparently there are VB variants as spray paint, presumably with lower absorption.) Of course, this is after someone even figures out how to make such scales and slap them together on the base.
This discovery might be at least the third one this year in this same field, if another one mentioned in the article isn't the one I've seen on HN.
I would love to have something like that. All these open floor plan offices and open concept homes are loud AF.
> The acoustic cloak works between 20kHz and 160kHz
And after all that, filtering low frequencies is still a hopeless task.
I also play guitar so to have a “jam box” would be great. Like a vocal box where you’re isolated but for really REALLY loud guitars.
They’re called isolation boxes, easy enough to DIY build one.
https://www.youtube.com/watch?v=xFxH9sVe3Ls
https://www.sciencemag.org/news/2016/01/moths-avoid-capture-...
Just more examples of the power of evolution.
However, this study found:
The moths’ ultrasound production clearly confused the bats, according to researchers, who reported that bats faced with sonar-jamming moths often tried to catch moths from empty air, apparently because the moths’ ultrasound signals had left the bats confused about the actual location of their prey. This kept working over several repetitions of the experiment with the same bats. For the researchers, this confirmed that moths were actually jamming bats’ sonar in order to escape, not just trying to startle them or mimic another, less tasty, moth.
https://www.gizmodo.com.au/2015/05/moths-rub-their-genitals-...
Which obviously goes to show there are many different types of weird an wonderful interactions going on between bats and moths.
https://steveblank.com/2009/03/23/if-i-told-you-i%E2%80%99d-...
That could increase the odds that they'd eventually stumble upon things like this anti-sonar texturing, and that more advanced versions of it would start to appear. Maybe it could also have a role in the infamous peppered moth/pollution story.
And by contrast, maybe nature would also select for extreme resiliency of critical genes, like ones related to heart function and efficiency of resource use, so that they'd be less sensitive to generational variation.
I'm sure this could all still be explained even without that, but it's interesting to think about.
Your whitepaper definitely makes a lot of sense to me. Has there been a lot of other research done on this?
In any given population there is natural variation: fastest moth, hairiest moth, whitest moth, etc. After evolutionary pressure is applied, the other moths are preferentially devoured, and the hairiest moth becomes the dominant variation with the most offspring.
For a similar historic account, read about the black form of the peppered moth which rapidly took over the moth population, caused by evolutionary pressure + single mutation in the year 1819.
https://www.bbc.com/news/science-environment-36424768
It's absolutely trivial. You just start with light sensitive skin. Then evolve a cavity to create a pinhole lens and then finally fill the hole with a lens. Making the eyeball move is optional but shouldn't be too tricky.
[0] https://www.pnas.org/content/early/2020/11/17/2014531117
This pavillion is the largest object on which VB was used to my knowledge: https://www.youtube.com/watch?v=xxkvKJmlyHQ
However, it's hard to imagine VB being grown on it instead of sprayed, and the next-largest candidate seems to be the BMW X6.