Angiosperms attempt virtually every "trick" imaginable to increase
pollination, from higher protein %, powerful odors, to nectar
production, colors, there's an enormous list of evolved traits.  Blooming
windows are extremely short, obviously the species would evolve to maximize
every biological signal to attract pollinators.

From a purely energetic standpoint, a species would benefit by maximizing
odor - as the energetics are considerably lower than, say manufacturing
heavy nectar loads.  I'm not exactly sure how certain plants accomplish
scents - I know that certain plants that do not produce nectar, still have
potent scents just from the pollen.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html