In general it may be said that the evidence from the literature seems to
support the conclusion that where abundance of pasturage of a single attractive
species is available bees will work that particular species almost exclusively,
though they may shift from one species to another at different times of
the day, when certain species are more attractive at certain definite periods.

On the other hand, where a great variety of bloom is available, without a
predominance of any one species, there is a greater tendency to gather mixed
loads, but the evidence is conflicting as the extent to which this occurs.

the degree of constancy exhibited by the insects
varies considerably with the situation, availability and attractiveness
being important factors. Where large exposures of bloom of an attractive
species are available all forms studied appear to prefer to follow a single host.
The degree of constancy became less, the greater the multiplicity of hosts,
with an insufficiency of any particular one to furnish adequate pasturage.

It would also appear that, by selecting particular periods of the year and a
particular host distribution, one could obtain almost any result desired, with
respect to the constancy of any species.

Brittain, W. H., & Newton, D. E. (1933). 
A study in the relative constancy of hive bees and wild bees in pollen gathering. 
Canadian Journal of Research, 9(4), 334-349.

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