[UV, VIS] Rudbeckia - inside out

[kds315*]

Noticed today, how different the UV reflectance of a freshly unfolding flower (here Rudbeckia fulgida) could be, comparing the outside and inside of the flower petals. Totally invisible to the human naked eye, but surely not to pollinating insects!

Lumix GH1-UVIR, Cerco 94mm lens, Baader-U resp. UV/IR Cut filter



standardized UV color palette using ReflectionDisc:

[Minolfan]

That is fascinating! For no serious difference in colour for inside and outside, but strong contrast in UV!

[tobbsman]

stunning !

Why is it that the blossom in the back is deep yellow, while the (most) others turn totally to violett color ?

Cheers
Tobias

[kds315*]

Outside = violet, inside= yellow in UV. In VIS all is yellow.

[tobbsman]

yes, but why ? ...

Cheers
Tobias

[kds315*]

Good question - I think it makes no (biological) sense that a flower attracts an insect when the flower is not ready yet, nor has anything rewarding to offer i.e. sending out signals that would rather lead to" frustrated pollinators" which would most likely quickly learn not to visit such flowers anymore. So, having the outside "shield" the opening flower, makes it at least partially less attractive to insects, unless it is fully opened and has nectar and then also rewards pollinators for their visit. Plant-Insect-Interaction is a complex yet fascinating topic and the guy I publish with has even a professorship in London about that.

[patrickh]

Klaus

Your offerings are always stunning and informative


and beautiful


patrickh

[kds315*]

Thanks Patrick!