[click on image to see a larger one]
Triptych of human vision, UV and simulated bee vision (left to right):
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This Gazania's outer petals reflect strongly UV around 372nm, wheras the inner parts are much darker hence forming UV nectar guides for bees. There are also highly UV reflecting marks inside around a dark UV center, all invisible to us humans but clearly visible to bees, and all this gets nicely visible here, also in simulated bee vision.
I have written about Gazania previously HERE
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos