June 10, 2026 • 10 mins
Butterfly wings often come in striking, iridescent colors -- but it's not from pigments (or not entirely). Learn how microscopic structures give butterfly wings their flash in today's episode of BrainStuff, based on this article: https://animals.howstuffworks.com/insects/butterfly-colors.htm
See omnystudio.com/listener for privacy information.
Listen
Watch
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Lauren vogelbaumb here. Butterflies possess some of the most striking
color displays found in nature, especially considering their small size.
As they fly from flower to flower gathering nectar, their
brightly colored wings shimmer and shift before your eyes. Pilots
(00:27):
flying above the rainforests of South America can see the
bright blues of the morpho butterfly up to half a
mile away. A butterflies patterns and colors can act as camouflage,
help identify or attract mates, or confuse or worn off predators.
Part of what makes butterflies colors so intense is that
you're not just looking at ordinary pigmented color. They also
(00:51):
have what's called structural color, which appears when the physical
structure of a surface has tiny layers and shapes that
reflect light to your eyes in specific ways. Okay, many
things in nature get their color from chemical pigments that
absorb certain wavelengths of light and reflect others. For example,
(01:11):
the pigment chlorophyll gives many plants their green color. The
chlorophyll soaks up the blue and red wavelengths of the
spectrum but not the green, so that's what you see
when it bounces off a plant to your eye. Most
butterflies get their different shades of brown, gray, and black
from melanin, which is the same pigment that might make
(01:33):
your skin deepen or tan or freckle in the summer
and can help give humanize their color. Some butterflies with reds, oranges, yellows, creams,
and even blues and blue greens get that color from
various pigments, but structural color doesn't come from pigments. We
talked about this a bit in our episode about human
(01:54):
eye colors. Human eyes never contain any blue pigment. Rather,
eyes that are pure blue have very low concentrations of
melanin in the iris, so when light hits that pale
but still textured and fibrous iris, the light scatters, and
blue light happens to scatter really well, so that's what
(02:14):
we perceive. Butterfly wings are made up of wafers of kitan,
given support and shape by a structure of veins. Kitan
is the same strong stuff that our hair and nails
are made of, and makes up butterflies and other insects
exoskeletons too. It's transparent by itself, but can carry pigments
(02:36):
and or structural color. If you look closely at a
butterfly's wings with your naked eye, you might notice it
looks a little soft or fuzzy, feathery, or sort of satiny.
That's because their wings are covered in thousands or millions
of tiny scales, overlapping like tiles on a roof. The
(02:58):
name of their taxonomical order means scaled wings. These scales
are each less than one hundred micrometers in size, smaller
than the width of a human hair or a droplet
of mist on a foggy morning, and these scales often
do contain pigment like melanin, but it's sometimes the microscopic
(03:19):
shape of the surface of the scales that gives a
wing its color, just like with human eyes. The most
vibrantly blue butterflies contain no blue pigments. The microstructure of
butterfly scales can come in different shapes that produce different
colors and effects on different species. So let's take the
(03:39):
blue morpho butterfly for example. Its wings are a shimmering
blue that can look almost aqua to near indigo, depending
on how the light hits them and the angle that
you're observing them from. A couple of things are happening here.
The overall blue color comes from the structure of the
blue morphose scales. Each blue scale has a surface covered
(04:02):
in many rows of tiny tree shapes. If you look
at it under a scanning electron microscope like you do,
each row looks sort of like the cross section of
a lego pine tree, like if you took a little
cookie cutter in the shape of a spindly Christmas tree
and pushed plato through it to create a long rope
in a tree shape. And each scale has an orderly
(04:26):
orchard of these tree shaped rows on it. These shapes
are transparent, but when normal full spectrum light shines onto
the scale, it hits the top of these tree rows
and bounces off of each branch on the tree. And
there's about six to ten branches, and these microstructures are
just the right shape and size to reflect blue and
(04:50):
only blue light. The rest gets scattered or absorbed by
the brown melanin on the undercoating of the scales. Notably,
this only word an open air. If you get the
scales wet, that changes how light reflects off of them,
and they'll appear clear with the brownish undercoating. But okay,
(05:10):
what about the iridescence of the butterfly's wing. Iridescence is
the quality of colors shifting as your point of view changes.
You can see it in mother of pearl, on fish scales,
and on peacock feathers. It happens when light passes through
a transparent, multi layered surface and is reflected towards your
(05:30):
eye more than once. The multiple reflections can compound one
another to intensify colors, or can disrupt one another to
dim or cancel out colors as the light travels to
your eye. It's helpful here to remember that light is
a wave and can be described as a wave length,
a wavelength being the distance between identical points on a wave.
(05:54):
A waves can also be described by their phase, the
position of their crests or high points, and trough or
low points. When two waves have the same phase, their
crests and troughs would align if you stack them on
top of one another. A simple example of iridescence is
the colors that appear on soap bubbles. The soap self
(06:16):
is transparent and the bubble's surfaces are reflective, so a
light first passes through the bit of the bubble that's
closest to you, which reflects some of that light to
your eye. But light also passes through to the far
bit of the bubble, which also reflects some light back
to you. Depending on the time it takes the second
(06:36):
reflection to join the first, plus a few other factors,
the two waves may or may not line up or
have the same phase. If the phase of the two
waves is different by some multiple of one full wavelength,
the waves are said to have constructive interference. If the
two waves differ by half a wave length or an
(06:57):
odd multiple of debt, they have destructive interference. The math
there is a little beyond our scope today, but basically,
the degrees of constructive and destructive interference change as your
point of view changes, thus bringing different colors to your eye.
Here's how it works. Constructive interference causes two waves to
(07:20):
complement each other and thus amplify a given color. That's
why eardescence can create such intense, almost glowing colors. Destructive
interference causes the two waves to cancel each other out,
dimming a given color. So bouncing off of a single
and technically transparent surface you'll see different colors or shades
(07:44):
as those factors of distance and interference change. The same
principle of eardescence behind soap bubbles applies to a blue
morpho butterfly's wings. Because of the structure of the aforementioned scales,
the branches on the turn and the heights of the
different rows create multiple reflections that can constructively or destructively
(08:06):
interfere with each other. This changes the exact intensities and
shades of blue that hit your eye from different portions
of the wing, or as the butterfly moves, or as
you move around it, and again. The blue morpho is
just one species of butterfly. Other species in the genus
and other genera of butterflies have microstructures on their wing
(08:29):
scales that produce entirely different colors and effects. For example,
the peacock's swallowtail has tiny cups on its scales that
reflect yellow from the bottom but blue from the sides.
The two colors combine to appear green when you look
at the wing head on, but if you look at
it from the flat edge, you can only see the blue.
(08:52):
Some structural color displays on butterflies even extend into the
ultraviolet part of the spectrum, which is visible to those
butterflies but not to humans and not even to all
other butterflies, thus helping them identify potential mates and beyond displays,
the structure of the scales can help butterflies manage things
(09:12):
like water runoff and body temperature. These microstructures are so
intricate that we don't know how to replicate them yet,
but researchers hope that studying how butterflies build their wing
scales will help us figure out how to build better
and more beautiful materials in the future. Today's episode is
(09:36):
based on the article where do Butterflies get their striking colors?
On how stuffworks dot Com written by Jennifer Horton. Brainstuff
is production of iHeartRadio in partnership with how stuffworks dot
Com and is produced by Tyler Klang. Four more podcasts
from my heart Radio visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to. Your favorite shows include
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Lauren vogelbaumb here. Butterflies possess some of the most striking
color displays found in nature, especially considering their small size.
As they fly from flower to flower gathering nectar, their
brightly colored wings shimmer and shift before your eyes. Pilots
(00:27):
flying above the rainforests of South America can see the
bright blues of the morpho butterfly up to half a
mile away. A butterflies patterns and colors can act as camouflage,
help identify or attract mates, or confuse or worn off predators.
Part of what makes butterflies colors so intense is that
you're not just looking at ordinary pigmented color. They also
(00:51):
have what's called structural color, which appears when the physical
structure of a surface has tiny layers and shapes that
reflect light to your eyes in specific ways. Okay, many
things in nature get their color from chemical pigments that
absorb certain wavelengths of light and reflect others. For example,
(01:11):
the pigment chlorophyll gives many plants their green color. The
chlorophyll soaks up the blue and red wavelengths of the
spectrum but not the green, so that's what you see
when it bounces off a plant to your eye. Most
butterflies get their different shades of brown, gray, and black
from melanin, which is the same pigment that might make
(01:33):
your skin deepen or tan or freckle in the summer
and can help give humanize their color. Some butterflies with reds, oranges, yellows, creams,
and even blues and blue greens get that color from
various pigments, but structural color doesn't come from pigments. We
talked about this a bit in our episode about human
(01:54):
eye colors. Human eyes never contain any blue pigment. Rather,
eyes that are pure blue have very low concentrations of
melanin in the iris, so when light hits that pale
but still textured and fibrous iris, the light scatters, and
blue light happens to scatter really well, so that's what
(02:14):
we perceive. Butterfly wings are made up of wafers of kitan,
given support and shape by a structure of veins. Kitan
is the same strong stuff that our hair and nails
are made of, and makes up butterflies and other insects
exoskeletons too. It's transparent by itself, but can carry pigments
(02:36):
and or structural color. If you look closely at a
butterfly's wings with your naked eye, you might notice it
looks a little soft or fuzzy, feathery, or sort of satiny.
That's because their wings are covered in thousands or millions
of tiny scales, overlapping like tiles on a roof. The
(02:58):
name of their taxonomical order means scaled wings. These scales
are each less than one hundred micrometers in size, smaller
than the width of a human hair or a droplet
of mist on a foggy morning, and these scales often
do contain pigment like melanin, but it's sometimes the microscopic
(03:19):
shape of the surface of the scales that gives a
wing its color, just like with human eyes. The most
vibrantly blue butterflies contain no blue pigments. The microstructure of
butterfly scales can come in different shapes that produce different
colors and effects on different species. So let's take the
(03:39):
blue morpho butterfly for example. Its wings are a shimmering
blue that can look almost aqua to near indigo, depending
on how the light hits them and the angle that
you're observing them from. A couple of things are happening here.
The overall blue color comes from the structure of the
blue morphose scales. Each blue scale has a surface covered
(04:02):
in many rows of tiny tree shapes. If you look
at it under a scanning electron microscope like you do,
each row looks sort of like the cross section of
a lego pine tree, like if you took a little
cookie cutter in the shape of a spindly Christmas tree
and pushed plato through it to create a long rope
in a tree shape. And each scale has an orderly
(04:26):
orchard of these tree shaped rows on it. These shapes
are transparent, but when normal full spectrum light shines onto
the scale, it hits the top of these tree rows
and bounces off of each branch on the tree. And
there's about six to ten branches, and these microstructures are
just the right shape and size to reflect blue and
(04:50):
only blue light. The rest gets scattered or absorbed by
the brown melanin on the undercoating of the scales. Notably,
this only word an open air. If you get the
scales wet, that changes how light reflects off of them,
and they'll appear clear with the brownish undercoating. But okay,
(05:10):
what about the iridescence of the butterfly's wing. Iridescence is
the quality of colors shifting as your point of view changes.
You can see it in mother of pearl, on fish scales,
and on peacock feathers. It happens when light passes through
a transparent, multi layered surface and is reflected towards your
(05:30):
eye more than once. The multiple reflections can compound one
another to intensify colors, or can disrupt one another to
dim or cancel out colors as the light travels to
your eye. It's helpful here to remember that light is
a wave and can be described as a wave length,
a wavelength being the distance between identical points on a wave.
(05:54):
A waves can also be described by their phase, the
position of their crests or high points, and trough or
low points. When two waves have the same phase, their
crests and troughs would align if you stack them on
top of one another. A simple example of iridescence is
the colors that appear on soap bubbles. The soap self
(06:16):
is transparent and the bubble's surfaces are reflective, so a
light first passes through the bit of the bubble that's
closest to you, which reflects some of that light to
your eye. But light also passes through to the far
bit of the bubble, which also reflects some light back
to you. Depending on the time it takes the second
(06:36):
reflection to join the first, plus a few other factors,
the two waves may or may not line up or
have the same phase. If the phase of the two
waves is different by some multiple of one full wavelength,
the waves are said to have constructive interference. If the
two waves differ by half a wave length or an
(06:57):
odd multiple of debt, they have destructive interference. The math
there is a little beyond our scope today, but basically,
the degrees of constructive and destructive interference change as your
point of view changes, thus bringing different colors to your eye.
Here's how it works. Constructive interference causes two waves to
(07:20):
complement each other and thus amplify a given color. That's
why eardescence can create such intense, almost glowing colors. Destructive
interference causes the two waves to cancel each other out,
dimming a given color. So bouncing off of a single
and technically transparent surface you'll see different colors or shades
(07:44):
as those factors of distance and interference change. The same
principle of eardescence behind soap bubbles applies to a blue
morpho butterfly's wings. Because of the structure of the aforementioned scales,
the branches on the turn and the heights of the
different rows create multiple reflections that can constructively or destructively
(08:06):
interfere with each other. This changes the exact intensities and
shades of blue that hit your eye from different portions
of the wing, or as the butterfly moves, or as
you move around it, and again. The blue morpho is
just one species of butterfly. Other species in the genus
and other genera of butterflies have microstructures on their wing
(08:29):
scales that produce entirely different colors and effects. For example,
the peacock's swallowtail has tiny cups on its scales that
reflect yellow from the bottom but blue from the sides.
The two colors combine to appear green when you look
at the wing head on, but if you look at
it from the flat edge, you can only see the blue.
(08:52):
Some structural color displays on butterflies even extend into the
ultraviolet part of the spectrum, which is visible to those
butterflies but not to humans and not even to all
other butterflies, thus helping them identify potential mates and beyond displays,
the structure of the scales can help butterflies manage things
(09:12):
like water runoff and body temperature. These microstructures are so
intricate that we don't know how to replicate them yet,
but researchers hope that studying how butterflies build their wing
scales will help us figure out how to build better
and more beautiful materials in the future. Today's episode is
(09:36):
based on the article where do Butterflies get their striking colors?
On how stuffworks dot Com written by Jennifer Horton. Brainstuff
is production of iHeartRadio in partnership with how stuffworks dot
Com and is produced by Tyler Klang. Four more podcasts
from my heart Radio visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to. Your favorite shows include
BrainStuff News
Host
Lauren Vogelbaum
Popular Podcasts
Hey Jonas!
Hey Jonas! The official Jonas Brothers podcast. Hosted by Kevin, Joe, and Nick Jonas. It’s the Jonas Brothers you know... musicians, actors, and well, yes, brothers. Now, they’re sharing another side of themselves in the playful, intimate, and irreverent way only they can. Spend time with the Jonas Brothers here and stay a little bit longer for deep conversations like never before.
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com