[HN Gopher] Why blue animals are so rare
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       Why blue animals are so rare
        
       Author : qiakai
       Score  : 73 points
       Date   : 2024-06-26 06:46 UTC (16 hours ago)
        
 (HTM) web link (www.popsci.com)
 (TXT) w3m dump (www.popsci.com)
        
       | UniverseHacker wrote:
       | I was hoping to see something about velella, they have a
       | shockingly brilliant blue.
       | 
       | Weird that this website seems broken with an un dismissable popup
       | on an iphone... not exactly a rare user device.
        
       | mikewarot wrote:
       | Just saw a Blue Jay last week.
       | 
       | Chicory has nice blue flowers.
       | 
       | Both are common in Chicagoland.
        
         | cjensen wrote:
         | There are many birds which are blue, but none of them have blue
         | pigments [1]. It's a light-scattering effect.
         | 
         | [1]
         | https://blog.education.nationalgeographic.org/2016/05/09/the...
        
           | kayodelycaon wrote:
           | Important bit from the article:
           | 
           | When white light strikes a blue feather, the keratin pattern
           | causes red and yellow wavelengths to cancel each other out,
           | while blue wavelengths of light reinforce and amplify one
           | another and reflect back to the beholder's eye ...
           | [D]ifferent shapes and sizes of these air pockets and keratin
           | make different shades of blue."
        
           | TinkersW wrote:
           | All color is a light scattering effect.. this article makes
           | zero sense to me..
        
             | Myrmornis wrote:
             | https://en.wikipedia.org/wiki/Structural_coloration seems
             | like a decent explanation.
        
               | User23 wrote:
               | The best explanation I've read is Feynman's delightful
               | _QED_.
        
       | ortusdux wrote:
       | "Unlike other bees, they prefer to live alone and not in busy
       | hives. "
       | 
       | IIRC, the vast majority of bees are solitary (90%?)
        
       | thrdbndndn wrote:
       | Isn't it pretty common in marine animals?
       | 
       | Lots of fish, dolphins, whales, etc. Or do they count as grey?
        
         | cubefox wrote:
         | Only cartoon fish are blue.
        
           | gilleain wrote:
           | Blue tang?
        
         | snoutie wrote:
         | Also think so. Plenty of fish are vibrant blue, the blue whale
         | is grayish blue but still blue.
         | 
         | Also plenty of birds are blue are they not?
         | 
         | And I totally forgot about butterflies and other insects as
         | well
        
       | robofanatic wrote:
       | While growing up in Asian country, butterfly pea plants with
       | bright blue flowers were common.
        
         | elevaet wrote:
         | They make an amazing brilliant tea!
        
           | s1mplicissimus wrote:
           | or was it ... the white jade bush?
        
       | twism wrote:
       | lots of blue birds
        
         | twism wrote:
         | "Blue birds, blue jays, cerulean warblers, peacocks: all blue
         | birds, but none of them are actually blue"
         | 
         | I stand corrected
        
           | lupusreal wrote:
           | > _none of them are actually blue_
           | 
           | The article is just trying to be controversial or something;
           | they _are actually_ blue. Structure colors are no less real
           | than pigment colors. It 's not an optical illusion or some
           | glitch in human perception, bounce white light off a bluejay
           | and pass it through a prism, a strong blue line will be
           | apparent. That blue light really is there, therefore they
           | _really are_ blue.
           | 
           | This notion that only colors coming from pigments are true
           | colors is completely arbitrary nonsense.
        
             | nullc wrote:
             | They're "true colors" but they aren't the same. Pigment
             | colors you can generally grind up and turn into a paint,
             | structural colors not so much. Structural colors are also
             | often angle and polarization sensitive, not so with pigment
             | colors.
        
       | cpfohl wrote:
       | _My_ favorite blue animal:
       | 
       | https://duckduckgo.com/?t=h_&q=Dendrobates+Tinctorius+Azureu...
        
         | user070223 wrote:
         | The Sinai agama turns blue during the breeding season to
         | attract females and it might be why blue connote to ribaldry
        
         | pvaldes wrote:
         | Glaucus atlanticus
        
       | peanut_worm wrote:
       | Blue jays are a pretty easy example of structural coloration
        
       | BurningFrog wrote:
       | Someone told me that chefs use blue bandaids, because there is no
       | blue food.
        
         | nytesky wrote:
         | Not just colored blue, but embedded metal to be detectable
         | 
         | https://www.reddit.com/r/todayilearned/comments/5dg5qs/til_t...
        
       | Jun8 wrote:
       | Here's a good answer from SE:
       | https://biology.stackexchange.com/questions/56476/why-are-so...
       | (spoiler: we don't know). But the second answer speculates that
       | blue light was the most available to the ancestors of current
       | plants (due to properties of Earth's atmosphere) so they evolved
       | to absorb it.
       | 
       | Related question is why plants are green:
       | https://biology.stackexchange.com/questions/450/why-do-plant...
        
       | Amorymeltzer wrote:
       | The linked
       | post--<https://set.adelaide.edu.au/news/list/2019/08/20/why-is-
       | the-...>--is much better about answering the question, rather
       | than listing some examples.
       | 
       | Basically:
       | 
       | - Blue is rare in plants since it means leaving high energy
       | behind.
       | 
       | - Many animals are a color because of there food, and see above.
       | 
       | - Thus, any blue is trickier, and usually done via scattering and
       | mixing rather than a pigment. "The only exception in nature is
       | the obrina olivewing butterfly, which is the only known animal to
       | produce a true blue pigment."
        
         | pvaldes wrote:
         | > "The only exception in nature is the obrina olivewing
         | butterfly, which is the only known animal to produce a true
         | blue pigment."
         | 
         | That is a bold claim, but a false one. A few butterfly species
         | share that pigment. Mussels also have other blue pigments based
         | in carothenes that don't depend on iridiscence.
        
           | dotancohen wrote:
           | Also, there is a snail that was revered millennia ago for
           | some blue ink that could be extracted from it. Several
           | religions, notably Judaism among them because it is still
           | around today, attach significance to this difficult-to-obtain
           | colour.
        
             | lores wrote:
             | That's the dye from Hexaplex Trunculus, but it's more of a
             | bluish purple than a true blue. There seems to be modern
             | ways to turn it into a true blue, but whether the ancients
             | had an unknown method is debated and unproven. It's worth
             | noting that colour names in ancient times were a lot more
             | blurry than now (the famous sea the colour of wine of
             | Homer), and blue is still one of the most blurry.
        
       | jcynix wrote:
       | The article mentions plants too. But I can list a number of blue
       | plants in my vicinity (OK, sometimes a touch of purple too) or
       | even in the garden:
       | 
       | [Centaurea cyanus](https://en.wikipedia.org/wiki/Centaurea_cyanus
       | ?wprov=sfla1)
       | 
       | [Digitalis](https://en.wikipedia.org/wiki/Digitalis?wprov=sfla1)
       | 
       | [Centaurea](https://en.wikipedia.org/wiki/Centaurea?wprov=sfla1)
       | 
       | [Scabiosa](https://en.wikipedia.org/wiki/Scabiosa?wprov=sfla1)
       | 
       | [Phacelia](https://en.wikipedia.org/wiki/Phacelia?wprov=sfla1)
       | 
       | and last but not least many varieties of
       | [Campanula](https://en.wikipedia.org/wiki/Campanula?wprov=sfla1)
        
         | spullara wrote:
         | 3 of those I would call purple rather than blue.
        
           | jcynix wrote:
           | I agree, but purple seems to be a similarly rare color IMO.
           | 
           | I could offer
           | 
           | [Chicory](https://en.wikipedia.org/wiki/Chicory?wprov=sfla1),
           | [Myosotis](https://en.wikipedia.org/wiki/Myosotis?wprov=sfla1
           | ) and
           | [Borage](https://en.wikipedia.org/wiki/Borage?wprov=sfla1)
           | 
           | as replacements ...
        
         | sdeframond wrote:
         | Some _flowers_ are blue indeed.
         | 
         | They are made to stand out, so it is like they are a purposeful
         | exception to the rule
        
         | RoyalHenOil wrote:
         | Blue flowers are extremely common because pollinators are
         | attracted to them.
         | 
         | I am pretty sure that they were referring to the plant itself
         | being blue (like leaves and stems), not the flowers.
        
       | datameta wrote:
       | Fascinating article. But early on I had one question - why is a
       | blue that is made by sunlight hitting hair nanostructures
       | considered a "simulation" thereby differentiating it from color
       | made through sunlight interaction with biochemistry of surfaces
       | and subsurfaces?
       | 
       | To draw that out further, by the same logic we might consider
       | properties of human-made metamaterials also simulations?
        
         | ChainOfFools wrote:
         | I believe all of the colors of butterfly wings, and of all
         | feathered animals are produced in the same way? I've always
         | assumed that "simulation" has a local definition in the study
         | of biological color reproduction, where light interactions with
         | ultra fine structure at the atomic level is the default, or
         | perhaps maybe on the time scale of evolution, the oldest means
         | of reproducing color.
         | 
         | Contrast this witb a much coarser structural phenomenon
         | manifesting at a level much closer to macroscopic is thus
         | considered to be a "cheaper" simulation of that effect, in
         | order to derive its same selective benefits but with less of a
         | radical genetic shift required for the production of the right
         | proteins etc.
        
       | jcynix wrote:
       | As for animals, they need to avoid predators. I'd say that blue
       | isn't the best color to hide in most areas. So selection should
       | favor other colors, unless the color is used as a warning, e.g.
       | to signal a poisonous creature.
        
         | barrell wrote:
         | Also IIRC (and cursory searches seem to agree) blue is the most
         | common/prominent color other animals see
        
       | esafak wrote:
       | On a related note, blue LEDs are also the most rare, for
       | engineering reasons, and their production led to a Nobel Prize:
       | https://www.nobelprize.org/prizes/physics/2014/press-release...
        
         | SushiHippie wrote:
         | Video about the history of blue LEDs by veritasium:
         | 
         | https://youtube.com/watch?v=AF8d72mA41M
        
         | knodi123 wrote:
         | "...once Nakamura succeeded in creating a commercially viable
         | prototype, 3 orders of magnitude (1000 times) brighter than
         | previously successful blue LEDs, Nichia pursued developing the
         | marketable product. The company's gross receipt surged from
         | just over Y=20 billion ([?]US$200 million) in 1993 to Y=80
         | billion ([?]US$800 million) by 2001, 60 percent of which was
         | accounted for by sales of blue LED products."
         | 
         | And IIRC, in return for that he got a $180 bonus from his
         | employer, and a bit later, a Nobel prize.
        
       | zepearl wrote:
       | My favourite flower, which I have just discovered: Phacelia
       | (blue/violet color) (
       | https://en.wikipedia.org/wiki/Phacelia_tanacetifolia )
       | 
       | 1) Seeds easy to find in most stores.
       | 
       | 2) Each strand has an array of flowers which bloom serially =>
       | quite long blooming timespan (and damage by bad weather is
       | limited if it affected only the flowers).
       | 
       | 3) Bumblebees absolutely love them (this year I put exclusively
       | Phacelia seeds into 1 of my 2 big pots on the balcony, with max
       | seed density, and often there were up to 10 bumblebees at once
       | per pot checking them), and I absolutely love bumblebees (they
       | look clumsy, they're kind of funny + they absolutely ignore me,
       | respectively when they happen to fly in my direction and they
       | notice me they take a turn as soon as their flight envelope
       | allows them to)
       | 
       | 4) This might be just random or caused by some other factor like
       | weather/neighbours/whatever, anyway:
       | 
       | since I planted this year Phacelia flowers and the bumblebees
       | started coming I have hardly seen any wasps nor especially
       | hornets (I've seen twice a hornet flying by, but it took a large
       | curve from my balcony - during the same timespan at the other
       | sides of my flat I noticed four times hornets investigating in
       | front of the windows). Last year (without Phacelia/bumblebees) I
       | had a lot more problems with wasps&hornets => maybe wasps &
       | hornets noticed the bumblebees and thought "ah, already
       | taken/busy!" and therefore marked my balcony as a no-go zone?
       | 
       | EDIT:
       | 
       | I recommend the app "PlantNet" for Android (
       | https://play.google.com/store/apps/dev?id=829216199869931637... )
       | & iOS ( https://apps.apple.com/ch/app/plantnet/id600547573 ):
       | take a picture of your plant/flower and you get the name.
        
       | crmd wrote:
       | >Organisms that appear blue must absorb very small amounts of
       | energy, while reflecting high-energy blue light. Since
       | penetrating the molecules that are capable of absorbing this
       | energy is a complex process, the color blue is less common than
       | other colors in the natural world.
       | 
       | I'm not a biologist, but these sentences immediately reminded me
       | of reading articles about my company/technology after press
       | briefings and feeling like they butchered a basic concept (or
       | more correctly, I failed to explain it in an accessible way).
       | Like, the sentences are grammatically correct but don't make
       | technical sense.
        
         | elcritch wrote:
         | You're not wrong. It appears to be a very garbled technical
         | explanation. Mainly that organisms need to absorb low
         | frequency/energy light while reflecting higher frequency/energy
         | light. I'm guessing that chemically that's harder to do.
        
       | user070223 wrote:
       | Reminder to everyone:
       | 
       | Plants are green(On earth) because they reflect the green color
       | (which the sun spectrum is strongest) because they have probably
       | adapted to better regulate different lightning condition during
       | the day, for this they use two different pigments (chlorophyll
       | a(blue), chlorophyll b(red); or other pairs)
        
         | setopt wrote:
         | One of the best ways to improve crop yields via genetic
         | engineering might be to create black plants.
        
           | al_borland wrote:
           | If that was optimal, I would expect it would be the standard
           | by now. Not through genetic engineer, but through basic
           | evolution over millions of years.
        
             | ianferrel wrote:
             | Evolution is optimizing for survival, not crop yield.
        
               | buzzm wrote:
               | Exactly; see pollinators comment above. Although as tech
               | progresses... perhaps we can make black plants as
               | attractive to genetically modified pollinators. Do I
               | sense a slippery slope here?
        
               | bawolff wrote:
               | Having more energy available (all things being equal
               | which they aren't) is advantous to both survival and crop
               | yields.
        
             | RoyalHenOil wrote:
             | That will only be the case if light absorbence is the
             | primary limiting factor for the plant. If something else is
             | a bigger limiting factor (e.g., nutrients, pests, water,
             | temperature, pollinators, and so on), then a more darkly
             | colored plant will not be meaningfully more likely to
             | survive and reproduce than its lightly colored neighbors.
             | 
             | Outside of human-directed breeding, we typically only see
             | darkly colored plants in locations with low light and with
             | few other evolutionary pressures: deep understory tropical
             | plants, for example.
             | 
             | Meanwhile, in locations with high light and other
             | evolutionary pressures, plants can sometimes evolve to be
             | quite pale. For example, desert succulents are often very
             | light colors because they need to deflect light to keep
             | cool and preserve water.
        
       | User23 wrote:
       | There are also no blue pigments in any plant. The various blueish
       | flowers use other tricks to reflect blue light.
        
         | RoyalHenOil wrote:
         | To be fair, indigo is a blue pigment and it is present in many
         | different plant species. (Mind you, it does not make the plant
         | blue; it only becomes blue after exposure to oxygen.)
        
       | karaterobot wrote:
       | Hmm, interesting. I thought it was like with popsicles, how the
       | blue ones get eaten first.
        
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