Shot using off the shelf D70, X35mm lens, UV LED lamp.
[click on image yields a larger one]
VIS shot:

UV shot using Baader-U filter (310-390nm):

"Bee Vision" Filter XBV shot:

It gets quite obvious, that this flower has a double (inner + petal tips) UV prominent pattern which it uses to attract pollinators. Both gets nicely visible in the UV and "Bee Vision" shot using these specialized filters + light source.
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