Why are flowers pretty?
Vincent E. Kargatis
and pleasant-smelling? The cursory answer is to encourage pollination by
pollinating insects. But then these animals (insects) would require:
1. olfactory sense. Sure, no problem, but why would a smell that would
attract these insects smell good to us? (I'm under the impression that most
all aromatic flowers do smell attractive.)
2. color vision. Do insects/pollinators actually have color vision? I don't
know, but I guess I'd be surprised to find out they did.
Thanks for any answers, obvious or not. :)
--
| Vincent Kargatis | "By the way, I hate your dog, |
| Dept. of Space Physics & Astronomy | and I think jazz is STUPID!" |
| Rice University, Houston, TX | - to Steve Martin's character |
| [v...@spacsun.rice.edu] | in ALL OF ME |
Neil Rickert
>This is something I've wondered about for a while. Why are flowers colorful
>and pleasant-smelling? The cursory answer is to encourage pollination by
>pollinating insects. But then these animals (insects) would require:
>
>1. olfactory sense. Sure, no problem, but why would a smell that would
>attract these insects smell good to us? (I'm under the impression that most
>all aromatic flowers do smell attractive.)
There are flowers with quite evil smells. You won't find these in your
neighbor's garden, for your neighbor prefers sweet smells.
>2. color vision. Do insects/pollinators actually have color vision? I don't
>know, but I guess I'd be surprised to find out they did.
White flowers would reflect more light than green, and hence stand out.
If a pollinator happens to be more sensitive to blues and violets, then
blue and violet flowers might have the same effect. The insect need
not have color vision. A different color would cause the flower to be
either lighter or darker than the foliage, and hence stand out from the
background. And there is always the possibility that some of the
coloration is the side effect of chemical changes in the flower, much
as happens to produce the autumn leaf colorings.
Alan Smith
>and pleasant-smelling? The cursory answer is to encourage pollination by
>pollinating insects. But then these animals (insects) would require:
>1. olfactory sense. Sure, no problem, but why would a smell that would
>attract these insects smell good to us? (I'm under the impression that most
>all aromatic flowers do smell attractive.)
Not all of them do, though. Some smell like rotting meat. Maybe the
attractiveness of the flower is not an adaptation on the flower's part, but
an adaptation on ours.
>2. color vision. Do insects/pollinators actually have color vision? I don't
>know, but I guess I'd be surprised to find out they did.
Be surprised. In fact, be very surprised, because some pollinating insects
can see colors we can't. Look at flowers with a UV camera some time.
>
Stephen Watson
>This is something I've wondered about for a while. Why are flowers colorful
>and pleasant-smelling? The cursory answer is to encourage pollination by
>pollinating insects. But then these animals (insects) would require:
>1. olfactory sense. Sure, no problem, but why would a smell that would
>attract these insects smell good to us? (I'm under the impression that most
>all aromatic flowers do smell attractive.)
Actually, I believe some orchids smell like rotting meat. They are
pollinated by carrion flies
>2. color vision. Do insects/pollinators actually have color vision? I don't
>know, but I guess I'd be surprised to find out they did.
Actually, it's wierder than that. Lots of insects can see into the UV
range (though only in "monochrome" mode?). And when looked at under
UV, many of those blooms look quite different: big stripes and things
leading the insect into the centre of the flower etc.
(Reference:...mumble, shrug, uh...Some old episode of NOVA or an
article in SciAm or something like that ;-)
--
| wat...@sce.carleton.ca | The foregoing opinions are All My Own Work. Nyah! |
"Let Justice roll, roll down like water / and righteousness like a flowing
stream / 'til the morning come, and the darkness cease / and the weapons of
war become the instruments of Peace" - Ken Medema, after Amos 5:24 & Isaiah 2:4
Paul S. Winalski
In article <2lqlfm$n...@larry.rice.edu>,
|>and pleasant-smelling? The cursory answer is to encourage pollination by
|>pollinating insects. But then these animals (insects) would require:
|>
|>1. olfactory sense. Sure, no problem, but why would a smell that would
|>attract these insects smell good to us? (I'm under the impression that most
|>all aromatic flowers do smell attractive.)
Maybe because the chemicals involved work by stimulating the olfactory sense
in a way that is perceived as pleasurable by the organism in a general way.
There are a lot more similarities in the way that organisms work (even ones
as different as insects and mammals) than differences.
|>2. color vision. Do insects/pollinators actually have color vision? I don't
|>know, but I guess I'd be surprised to find out they did.
In many cases, the insects are actually responding to patterns on the flowers
that are only visible in the near ultraviolet, which the insects can see and
we cannot. Color vision is not necessarily involved, but the ability of the
flower to stand out from the background is.
--PSW
Kathleen Anderson
: v...@spacsun.rice.edu (Vincent E. Kargatis) writes:
: >This is something I've wondered about for a while. Why are flowers
: >colorful and pleasant-smelling? The cursory answer is to encourage
: >pollination by pollinating insects. But then these animals (insects)
: >would require:
: >1. olfactory sense. Sure, no problem, but why would a smell that would
: >attract these insects smell good to us? (I'm under the impression that
: >most all aromatic flowers do smell attractive.)
: Actually, I believe some orchids smell like rotting meat. They are
: pollinated by carrion flies
Ginko flowers smell awful too (rotting meat odor), which is why
landscapers who know what they're doing plant only male ginkos, but even some
deliberately cultivated flowers smell pretty bad (eau de rotten fruit, old
socks, ripe garbage, etc). It has to do with who the pollinators are and
what attracts them.
: >2. color vision. Do insects/pollinators actually have color vision?
: >I don't know, but I guess I'd be surprised to find out they did.
: Actually, it's wierder than that. Lots of insects can see into the UV
: range (though only in "monochrome" mode?). And when looked at under
: UV, many of those blooms look quite different: big stripes and things
: leading the insect into the centre of the flower etc.
Both of these topics are addressed in _Insects and Flowers: The BIology
of a Partnership_ by Friedrich G. Barth (Princeton, 1991), a very readable
and reasonably priced paperback. Botany texts would be another place to look.
--
Kathleen Anderson
vst...@sfsu.edu
Marvin Minsky
A different but somewhat similar problem that interests me is: Why
does the camouflage that, say, flounders use work so effectively on
us humans. I hope most of you have seen them in a fish tank with a
"natural" looking floor of sand and gravel and other stuff. Usually
you can't even tell that the fish is there until it moves.
Our common ancestors with these fish must lie some 400 megayears back
-- so it seems quite amazing that they are genetically programmed to
have camouflage patterns that fool us mighty advanced mammals. Could
be, I suppose, that the texture detection hardware of their vision
system hasn't changed much since then. Or perhaps it did, but in the
presence of other predators that were evolving texture-detection
schemes more like ours. Anyway, isn't it interesting how well they
can fool us?
Jim Sullivan
|> v...@spacsun.rice.edu (Vincent E. Kargatis) writes:
|>
|> >This is something I've wondered about for a while. Why are flowers colorful
|> >and pleasant-smelling? The cursory answer is to encourage pollination by
|> >pollinating insects. But then these animals (insects) would require:
|>
|> >1. olfactory sense. Sure, no problem, but why would a smell that would
|> >attract these insects smell good to us? (I'm under the impression that most
|> >all aromatic flowers do smell attractive.)
|>
|> Actually, I believe some orchids smell like rotting meat. They are
I've heard of this as well. But flowers smell "sweet" due to
bees having a sense of smell. The odor I think is of the nectar.
Both bees and humans are attracted to sweets so it shouldn't be
that unusual that both species find the same smell attractive.
I'm partial to honeysuckle myself though drinking a lot of the nectar
gives me a tummy ache :^)
|>
|> >2. color vision. Do insects/pollinators actually have color vision? I don't
|> >know, but I guess I'd be surprised to find out they did.
|>
|> Actually, it's wierder than that. Lots of insects can see into the UV
|> range (though only in "monochrome" mode?). And when looked at under
|> UV, many of those blooms look quite different: big stripes and things
|> leading the insect into the centre of the flower etc.
|>
|> (Reference:...mumble, shrug, uh...Some old episode of NOVA or an
|> article in SciAm or something like that ;-)
I saw the same episode. Bees see into the UV and flowers which
appear bland to us (daphodiles) are quite "colorful" and contrasting
in UV.
--
Jim Sullivan
Brian Foley
: This is something I've wondered about for a while. Why are flowers colorful
: and pleasant-smelling? The cursory answer is to encourage pollination by
: pollinating insects. But then these animals (insects) would require:
: 1. olfactory sense. Sure, no problem, but why would a smell that would
: attract these insects smell good to us? (I'm under the impression that most
: all aromatic flowers do smell attractive.)
Because they often smell "sweet" and sweet foods are high in
carbohydrates and sugars which makes them good food for mammals as well
as insects.
: 2. color vision. Do insects/pollinators actually have color vision? I don't
: know, but I guess I'd be surprised to find out they did.
They not only see color, but they also see some colors that
humans cannot see. Some of the flowers that look plain white to human
eyes actually have patterns that can be detected in the ultraviolet range.
: Thanks for any answers, obvious or not. :)
: --
: | Vincent Kargatis | "By the way, I hate your dog, |
: | Dept. of Space Physics & Astronomy | and I think jazz is STUPID!" |
: | Rice University, Houston, TX | - to Steve Martin's character |
: | [v...@spacsun.rice.edu] | in ALL OF ME |
--
********************************************************************
* Brian Foley * If we knew what we were doing *
* Molecular Genetics Dept. * it wouldn't be called research *
* University of Vermont * *
********************************************************************
Terence Mark
>This is something I've wondered about for a while. Why are flowers colorful
>and pleasant-smelling? The cursory answer is to encourage pollination by
>pollinating insects. But then these animals (insects) would require:
>1. olfactory sense. Sure, no problem, but why would a smell that would
>attract these insects smell good to us? (I'm under the impression that most
>all aromatic flowers do smell attractive.)
>2. color vision. Do insects/pollinators actually have color vision? I don't
>know, but I guess I'd be surprised to find out they did.
Honey bees have color vision. von Frisch showed this when
he trained honey bees to collect a sugared solution from a dish that
was placed on a blue card. He later put an empty dish on a blue card,
with lots of other grey cards of different shade around the target card,
and found that the bees had no problem in finding the blue card. The bees
should not have been able to find it if they weren't able to perceive
color.
terry
tm...@psych.ucla.edu
--
Terry Mark
tm...@psych.ucla.edu
robert nusbickel
The answer is yes. many insects, I can speak specifically of honey bees,
have color vision but their vision and perception is very different than
ours. For instance, the can see much farther into the UV spectrum than
can humans. so, flowers look very different to honey bees than they dop
to us. some flowers actually resemble little landing strips, to guide the
bees iin, when seen in the UV spectrum.
hope this helps.
Andy N.
James G. Acker
: Honey bees have color vision. von Frisch showed this when
: he trained honey bees to collect a sugared solution from a dish that
: was placed on a blue card. He later put an empty dish on a blue card,
: with lots of other grey cards of different shade around the target card,
: and found that the bees had no problem in finding the blue card. The bees
: should not have been able to find it if they weren't able to perceive
: color.
A recent article in _New Scientist_ appears to demonstrate that
they also have "contour" vision. The bees were trained to respond
to triangles, and then when the optical illusion induced by three circles
with pie-slice pieces cut out of them was used in place of the triangles,
the bees responded to that, too.
===============================================
| James G. Acker |
| REPLY TO: jga...@neptune.gsfc.nasa.gov |
===============================================
All comments are the personal opinion of the writer
and do not constitute policy and/or opinion of government
or corporate entities.
Peter W Severance
> A recent article in _New Scientist_ appears to demonstrate that
>they also have "contour" vision. The bees were trained to respond
>to triangles, and then when the optical illusion induced by three circles
>with pie-slice pieces cut out of them was used in place of the triangles,
>the bees responded to that, too.
While such experiments seem to almost be the starting point of experimental
perceptual psychology, if you dig into the literature, you'll find a lot
of criticism of the premises of such experiments. It's the equivalent of
modeling turbulence by observing the behavior of a sail. Too few degrees of
freedom, over-simplified models, and extravagant leaps of faith to bring
your assumptions in line with the real world. I've been out of the field
for a while, and can't point you to any literature, but it's out there...
Intellectually satisfying, yes, good science, no.
--
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Peter Severance Running Wild Magazine run...@world.std.com
Mark Isaak
Have you ever noticed that flypaper is always yellow? That's because yellow
is the color that attracts the most flies (and a variety of other insects,
especially wasps).
At night, black light (ultraviolet) is commonly used to attract insects.
--
Mark Isaak "There lives more faith in honest doubt,
is...@aurora.com Believe me, than in half the creeds." - Tennyson
lomb...@uni2a.unige.ch
Path: NewsWatcher!user
From: lomb...@uni2a.unige.ch (Lombard FranCois)
Subject: Re: Why are flowers pretty?
Message-ID: <lombardf-1...@129.194.16.78>
Followup-To: sci.bio.evolution
Sender: use...@news.unige.ch
Organization: Centre Informatique pedagogique
References: <2lqlfm$n...@larry.rice.edu> <940312182...@yuma.ACNS.ColoState.EDU>
Date: Fri, 18 Mar 1994 17:04:06 GMT
In article <940312182...@yuma.ACNS.ColoState.EDU>,
ars...@lamar.ColoState.EDU (Alan Smith) wrote:
> In article <2lqlfm$n...@larry.rice.edu> v...@spacsun.rice.edu (Vincent E. Kargatis) writes:
> Some smell like rotting meat.
And some of them are pollinated by flies, whose personal taste about smell
is rather different fro ours... (eg Ivy)
FranCois Lombard
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Centre informatique pedagogique
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Tel ..41 22 318 05 30 Fax ..41 22 781 03 50
lomb...@uni2a.unige.ch
Path: NewsWatcher!user
From: lomb...@uni2a.unige.ch (Lombard FranCois)
Subject: Re: Why are flowers pretty?
Message-ID: <lombardf-1...@129.194.16.78>
Followup-To: sci.bio.evolution
Sender: use...@news.unige.ch
Organization: Centre Informatique pedagogique
Distribution: World
Date: Fri, 18 Mar 1994 17:10:35 GMT
In article <2m03ku$k...@news.csus.edu>, vst...@sfsuvax1.sfsu.edu (Kathleen
Anderson) wrote:
> Ginko flowers smell awful too (rotting meat odor), which is why
> landscapers who know what they're doing plant only male ginkos, but even some
> deliberately cultivated flowers smell pretty bad (eau de rotten fruit, old
> socks, ripe garbage, etc). It has to do with who the pollinators are and
> what attracts them.
Wait a minute, Ginko is a really special "flower". it's a sort of relic of
a transition to real conifers and then flowers (I know this is approximate
systematics, but that isn't relevant here).
In fact it's pollinated by wind, like conifers, and the female creates
ovulas which get comparatively enormous storage even before it gets
pollinated. Quite a loss since a lot of them don't get pollinated.
The real achievement of this system is a (conifers) seed, that only becomes
a seed, full of storage to be able to grow, if it IS pollinated.
Those non-fecundated ovulas, and those that fall on infertile ground (tar,
cement, cars,...) just rot and smell awfully bad.
So finally :
This has nothing to do with pollination
--
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