>
> >Does anyone know of any research on what makes one pollen attractive and
> another unattractive?  ...I do not think it is odor.  Some attractive
> plants have hardly any odor while some unattractive plants have quite a
> nose to them.  If it is odor it is something bees smell that I do not smell.


There is limited research on this subject, Dick.  Particle size is a
component, but since pollen foragers do not eat the pollen that they are
gathering, I'm not sure how important taste is.

But smell certainly is!  In general, European honey bees are hard wired to
prefer Old World pollens over a number of New World pollens (such as field
corn, cucurbits, and sunflowers--although they will work these if that's
all that is available).

But odor, man can they detect and choose based upon odors that my normally
sensitive olfaction cannot detect.  I've done experiments with different
pollens and pollen sub components offered free choice in dry form in cups.
I can shuffle the cups around, and the foragers respond immediately by
shifting to the new location of their favorite.

As far as pollen subs are concerned, a fair amount of research has been
done on phagostimulants.  Again, they may have nothing to do with
nutritional quality.  For example, rum is a strong phagostimulant, as is
lemongrass oil.  These are completely different from the "Factor X" that
appears to be missing nutritionally.

The easiest phagostimulant for pollen subs is any form of sugar, although
bees often will simply lick the sugar off the other particles and discard
them.
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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