h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

A question came up here a few weeks ago that none of the gardeners, wardens, or anyone else onsite was able to answer.

Why are most of the flowers that bloom in early spring yellow?

Wild primroses, daffodils, dandelions, and even the flowers on things like forsythia and broom - all of them are yellow. You get a few white ones as well, but not much else until quite a bit later.

Is it something to do with light frequencies?

I don't know the answer to this, but I have often wondered about it myself. I'll hang around until someone comes up with some suggestions.

dunno either but some things to consider:
1) They stand out against the green of spring growth and brown/earth left over from winter, hence easier to find for animals.
2) they might be yellow to us, but given that flower pigmentation is really there to guide pollinators in, and they can see from UV to IR depending, is there any commonality in their UV/IR signatures? I.e. the yellowness could just be side effect.
3) only other effect on pigmentation I can think of is for energy absorbtion - in which case yellow ain't a very good colour.

We've had quite a few blues, Irises and a little Speedwellishy flower. The pink Camelia is always the first shrub to bloom. In fact it's just about finished now.

What about purple crocus?
Pink camelias?
Blue chionodoxa?

I'm not saying there aren't others, but at least 75-80% (by volume, if not types of flower) of the ones that bloom first seem to be yellow.

Now that it's getting later in the season, we're seeing violets and bluebells and things like that, but it was all very yellow before!

(And obviously, a lot of the more colourful ones don't grow wild.)

I'm thinking Ictoan's theory number 1 would be the right answer on Natural Selection grounds. But, again, I don't know for sure.

B

I agree with Ictoan and Mu Beta that a pollinator's ability to perceive a flower's color will determine which plants reproduce.

My point is closely related - the pollinators in one biome may not be identical to the pollinators in another biome.

Chionodoxa (blue flowers) also called 'glory of the snow' comes from the middle east.

what effect has man had in this

what was planted to look pretty

and

did the planter like yellow

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Camellia's are japanese aren't they?

One has to be careful that you consider only native flowers in answering this I think. Our own hybrids and cultured modifications and foreign invaders shouldn't really count.

Is the daffodil even native to the UK?

Another thing to consider in attracting insect pollinators is that insects may not be primarily attracted by sight. Many flowers produce a plethora of scents and aromas, many of which are well know to be insect attractants.

Interesting question. If you look at tree blossom, that doesn;t strike me as overly yellow. Laburnum maybe but most of it is pink or white in my immediate thoughts.

Orcus - yes the daffodil is a native species to the UK


http://shop.btcv.org.uk/shop/level2/31/stock/797

I remember being taken to a valley where they were in flower once when I was a student botanist - they are much tinier than the bred types.

Scented flowers tend not to be very colourful - they attract moths and night-time insects. The really colourful ones are pollinated by insects that rely on sight.

Hmm, I'm not so sure about that.

I do research into a class of chemicals called terpenoids Which are found aplenty in plants and many of them are produced in abundance by plants with spectacular flowers. Geraniums produce huge quantities of geraniol for example. Sweet peas are spectacular and very heavily scented as are ornamental tobaccos and roses.

I'm not convinced there's a correlation between scent and flower prowess. The most spectacular flower in the world is also the smelliest is it not?

Mind you, you can see flowers from further away than smell them I guess - even as an insect.
I can't imagine the insect attractants, repellents and hormones produced by plants can get very far before they enter a general mix that is difficult/impossible to locate to a particular flower.


I've just started a research collaboration with a national research institute on crop research and protection in a project where we're aiming to use modified terpenoids to repel aphids from crops. They have a natural alarm pheromone called germacrene D and we're going to try to make analogues of this that will be stable in the environment and therefore just send aphids elsewhere rather than the more usual method of using toxic insecticides.

If anyone will know anything about this it'll be these guys. I'll ask them next time I see them.

"therefore just send aphids elsewhere"
What a wonderful marketing strategy!
Farmer/Gardener A buys product, all the aphids move to Farmer/Gardener B. Who then buys the product. Repeat until everyone has it and all the aphids have moved to France. Genius

"you can see flowers from further away than smell them I guess - even as an insect."
Hmmmmm, really not too sure about that Orcus. Our sense of smell is pretty useless but many other animals can smell stuff they can't see. Plus smell has the advantage of not requiring line of sight.

I know that some moths can locate another individual of their species from over a mile away by smell alone.

True but stir it all around in the air and it will mix up. This is inevitable

Good point about the moth. I'm guessing that doesn't work so well in bad weather though.


We currently use potent neurotoxins as insecticides - and aphids are still going from farmer A to farmer B anyway. I doubt this would change much aphids will always be around - but we'd not be filling the environment with nerve agents anymore. I rather think that's the point

Or you could try the organic solution:

(Lizards have solved Springfield's pigeon problem)

SKINNER
Well, I was wrong. The lizards are a godsend.

LISA
But isn't that a bit short-sighted? What happens when we're overrun by lizards?

SKINNER
No problem. We simply unleash wave after wave of Chinese needle snakes. They'll wipe out the lizards.

LISA
But aren't the snakes even worse?

SKINNER
Yes, but we're prepared for that. We've lined up a fabulous type of gorilla that thrives on snake meat.

LISA
But then we're stuck with gorillas!

SKINNER
No, that's the beautiful part. When wintertime rolls around, the gorillas simply freeze to death.

That's more or less what my father is researching at his job, Orcus!