> From: KIRK VISSCHER <[log in to unmask]>
> Subject: drifting foragers
>
> There has been a great deal of talk in the biology literature of the
> fallacy of the "adaptationist" assumption that if we observe something in
> Nature (e.g. honey bee workers drifting between colonies) there must be
> some way in which it serves the evolutionary interests of the organisms
> involved.  Well, it just ain't necessarily so.  In this case, one could
> argue that in Nature before Apiculture, honey bee colonies were quite
> dispersed.  Under these conditions, the chance of a forager encountering
> another colony would be relatively remote.  So there would be no selective
> pressure for bees to evolve adaptations to prevent them accepting another
> colony as home.  When we cram them together in an apiary, they sometimes
> are not sufficiently oriented to precise location of their own hive that
> they wander into others.  I think its remarkable that it doesn't happen more!
 
I tend to agree, and I have some data to throw into the pot, albeit
Sweat Bee data...in my paper on philopatry in Halictus rubicundus
(Behav Ecol Sociobiol 27: 37-42, '90) I gave data on worker fidelity
in this primitively social species, as follows:
of 542 workers, 11 (2%) switched "allegiance" and acted as a worker in
a nest other than the one they were born in;
errors in orientation led to occasinal "visits" to non-natal nests
(some 83 cases out of >>50,000 observations), but on such occasions
workers left soon and relocated theirnatal nests (only 6 bees made the
same mistake twice or more).
   Considering that nests were typically something less than 20 cm
from their nearest neighbor, and the probably fairly high degrees of
relatedness between neighbors, it indeed would appear that there is
some selective pressure at work; these bees *normally* nest in fairly
dense aggregations, and they appear to be quite capable of
discriminating among nests (unlike communal species such as
Agapostemon virescens). A good rule of thumb appears to be that if a
bee is social and nests in aggregations, "drifting" will be at a bare
minimum.
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