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[UV] Competition - which competition?

Dr Klaus Schmitt

Dr Klaus Schmitt

Well-known member
I was shooting Zinnias today, when I saw one flowering aside another bright yellow flower.
I noticed the Zinnias being frequently visited by bees and bumblebees, whereas the similar
looking yellow one had only few guests.

Well, the reflected UV image shows clearly why IMHO...

original.jpg


Even covered by other plants it makes itself clearly seen (see blurry BG Zinnia).
So not really "competition" for that UV-bright Zinnia (340-360nm).
 
Asher Kelman

Asher Kelman

OPF Owner/Editor-in-Chief
Hi Klaus,

This is indeed remarkable! Notice how the UV bright flower also has shorter and stockier petals and in color the yellow is more orange than its neighbors. The center of the flower is also much more protuberant. The border of the ends of the petals are also very different. Any chance this is a different variety?

Asher
 
Dr Klaus Schmitt

Dr Klaus Schmitt

Well-known member
The left one is a Coreopsis and the right one is a Zinnia. The latter obviously developed during evolution this bright UV pattern.
 
V

Vivek Iyer

New member
While I am happy to see ultraviolet images which are technically sound, I would venture to offer some criticism on the interpretations.

First off, is that Zinnia a natural flower or a man made cultivar? I very much doubt if evolution can be attributed to something based on an ultraviolet image.

Second, the fundamental questions on the premises are: Do bees and flies need UV to get to flowers and the nectar?

Do plants need bees to propagate? ;)
 
Asher Kelman

Asher Kelman

OPF Owner/Editor-in-Chief
Vivek Iyer said:
While I am happy to see ultraviolet images which are technically sound, I would venture to offer some criticism on the interpretations.

First off, is that Zinnia a natural flower or a man made cultivar? I very much doubt if evolution can be attributed to something based on an ultraviolet image.

Second, the fundamental questions on the premises are: Do bees and flies need UV to get to flowers and the nectar?

Let me address the last question,

Vivek Iyer said:
Do plants need bees to propagate? ;)
Click to expand...

Some plants, like Dandelions don't even need anything but pollen from the wind or its own flower landing on the stigma. The pollen tube grows down but the DNA is not used. That is aborted but signals the ovum to undergo development by parthenogenesis. Other plants are pollinated by wind or by insects. I'm not sure, but I would imagine that humming birds pollinate plants too. So bees may not be necessary, but some vector is needed, (except as in the case of the dandelion by parthenogenesis), and generally, the insects do the job of transporting the pollen.

Vivek Iyer said:
I very much doubt if evolution can be attributed to something based on an ultraviolet image.
Click to expand...

Why not? Evolution has no limits to factors that can be used in natural selection. There just has to be selective pressure, competition for resources and variability in genotype and gene expression. It makes sense for insects and plants to have as many clues as possible. The concept that UV helps the insect find flowers that are ready for visits is attractive. Whether or not it's in deed the case, is a matter of experimental proof. So far, from : anecdotal observations, it seems highly plausible.

Asher
Click to expand...
 
V

Vivek Iyer

New member
Asher Kelman said:
[
Let me address the last question,



Some plants, like Dandelions don't even need anything but pollen from the wind or its own flower landing on the stigma. The pollen tube grows down but the DNA is not used. That is aborted but signals the ovum to undergo development by parthenogenesis. Other plants are pollinated by wind or by insects. I'm not sure, but I would imagine that humming birds pollinate plants too. So bees may not be necessary, but some vector is needed, (except as in the case of the dandelion by parthenogenesis), and generally, the insects do the job of transporting the pollen.




Asher
Click to expand...

Very well stated, Asher. My point is that UV vision is being used to oversell our existence.

There are possibly more under water plants than the ones with flowers on the ground. There are also many evening bloomers which open the flowers after the Sun has very well set.

Evolution and the Zinnia- just to clarify- my question was if that Zinnia (which looks more presentable to us in UV) was a man made cultivar or a product of natural evolution to lure the bees as suggested by Klaus.
 
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