BrainStuff Classics: Why Did Fruit Evolve in Different Colors?

Brightly colored fruit stands out against green leaves, but why is some red or pink, while others skew yellow or purple? And why are some fruits smellier than others? Learn what new research says about fruits' evolution in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Lauren voel Bomb here with another classic podcast episode. This
one looks into the beautiful diversity of fruits and flowers
and how plants evolved them in order to attract not us,
but a variety of local non human animals. Hey brain Stuff,

(00:26):
Lauren vogel Bomb here. Imagine having to get a specific
person's attention in a crowded room without being able to
move a muscle or make any noise at all. It
sounds impossible, doesn't it. Well, this is the predicament plants
have found themselves in since time immemorial. How does one
get the attention of a fast moving animal when one
is silent, motionless, and also a shrub. Plants have solved

(00:47):
the problem, though, because necessity is the mother of invention,
and also because they've had around one hundred million years
to work on it. Many angiosperms of flowering plants, that is,
require the help of animals to spread their seeds around, since,
as we've discuss, they're incapable of doing so themselves. It's
one thing for mango tree to drop its fruit and
grow another little tree right underneath the parent, but It's

(01:07):
quite another for a monkey to take a piece of
fruit half a mile away and drop the seed in
a previously mango free zone. This is where the rubber
meets the road when it comes to angiosperm dissemination, and
the evolution and ultimate thriving and survival of these plants
has depended on individual species concocting new ways to manipulate
the animals they're most likely to come in contact with.

(01:29):
Two recent studies out of Germany examined the mechanisms by
which plants learned to flag down the right animals. It
turns out that those sound and movement are good strategies
for getting someone's attention. Animal heads are also turned by
smell and color, and according to this research, plants have
worked those angles pretty hard. The first study, published in
the journal Biology Letters, investigates how the color of certain

(01:52):
fruits can attract specific seed dispersers. The research team compared
experiments with fruit eating primates and wildlife preserves in both
the use Uganda and on the island of Madagascar. They
found that fruit bearing plants had evolved to cater to
the specific visual capabilities of the main seed dispersing animals
in each place. Though the landscapes in the two parks

(02:12):
are very similar. Ugandan seed dispersers, monkeys, apes, and birds
have tricolor vision like humans, whereas the lemurs in Madagascar
are red green color blind. The ripe berries on fruiting
plants reflected this. In Uganda, ripe red fruit on dark
green foliage showed up better to the animals native to
that area, whereas in Madagascar, the ready to eat fruits

(02:33):
were mostly yellow, a color more visible to lemurs. Similarly,
according to the other study published in the journal Science Advances,
the fruit in Madagascar is also more fragrant. Those plants
didn't want to leave their seed dispersal entirely up to
the visual acuity of a bunch of lemurs. Ripe figs
on the island are very smelly, which makes sense given

(02:54):
that colorblind lemurs would have been able to find the
smelliest fruits in the forest more easily than they could
find the most brightly colored. The figs that produced the
most odoriferous cocktail of chemical compounds as they ripened were eaten,
and thus their seeds dispersed more often on Madagascar, suggesting
that plants know exactly what they're doing. Evolutionarily speaking. Today's

(03:18):
episode is based on the article Plants evolve scents and
colors to attract animals. Four Seed Dispersal on how stuffworks
dot Com written by Jesslinshields. Brain Stuff is production of
iHeartRadio in partnership with how Stuffworks dot Com and is
produced by Tyler Klang. For more podcasts my heart Radio,
visit the iHeartRadio app, Apple Podcasts, or wherever you listen
to your favorite shows.