>That is interesting.  I have never seen a bee work different plants and have so far not seen different coloured pollen in one load,

Actually, there is a large body of work that has been done on flower constancy. 

> A pollinator that restricts its visits to one flower type, even when other rewarding types are accessible, can be said to exhibit flower constancy. 

> The striking features of constancy are that individual pollinators, even members of the same bee colony, specialize on different flower types, and each may switch its specialty from time to time. 

> Because a constant visitor avoids flowers with acceptable rewards, the behavior is inefficient unless there are constraints such as an inability to learn quickly or to remember simultaneously how to deal with many flower types. 

> If such constraints are the basis for constancy, it should be most pronounced when flowers in a mixture differ strongly in morphology or color. I observed bees foraging in outdoor flower arrays and found that constancy always increased with increasing differences among flower types.

Waser, N. M. (1986). Flower constancy: definition, cause, and measurement. American Naturalist, 593-603.

             ***********************************************
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