BoundedRationality_TheAdaptiveToolbox.pdf

256 Thomas D. Seeley
scout bees were still far from an agreement. The second day (July 21) began with
both sites continuing to receive strong, nearly equal advertising by the dancers;
however, over the course of the morning, the dancing for site G strengthened
while that for site B weakened. If rain had not shut off the debate at the end of the
morning, it seems likely that all the dances would have been for site G by sometime
in the afternoon of July 21. As it was, the bees that danced on the morning of
July 22 were unanimous in advertising site G, and at 11:58 hours the swarm lifted
off and flew in the direction of site G.
Is the site chosen by a swarm the best of the sites discovered by the swarm's
scout bees? Although we cannot answer this question for the case just shown,
because the 11 sites located by the bees were never located by us in the surround
ing woodlands, the results of another study indicate that swarms are actually
quite accurate in choosing the best site (Seeley and Buhrman, unpublished
work). In this study, three swarms of bees were transported one at a time to a
windswept, treeless island along the coast of Maine. There we presented each
swarm with an array of five nestboxes in a fan-shaped array, with each nestbox
200 m from the swarm. Of the five nestboxes, four offered a mediocre home
site — a 15-liter cavity — and one offered an excellent home site — a 40-liter
cavity. (A 15-liter cavity provides barely enough space for the honey-filled
combs that will fuel a colony's heat production during the cold, flowerless
months of winter, whereas a 40-liter cavity provides ample storage space.) The
record of each swarm's search for and choice among these five alternative nest
sites is shown in Figure 14.3. We see that in each case the scout bees discovered
one or more of the mediocre sites well before they located the excellent site,
sometimes several hours in advance, and that they recruited other bees to the mediocre
site. However, we also see in each case that once the excellent site was
discovered, the bees recruited very strongly to this site so that within a few hours
the number of scout bees at the excellent site greatly exceeded the number of
scouts at any of the mediocre sites. Ultimately, each swarm lifted off and flew toward
the excellent site. It is clear, therefore, that these three swarms demonstrated
high accuracy in making the decision of where to live.
Individual-level View
It is tempting to think of the individual scout bees operating like the members of
a human jury to produce a consensus: different options are presented, each individual
evaluates the various options and forms an opinion, and if there is not a
consensus then the members discuss the relative strengths of the leading options
until the discordant individuals change their minds and everyone is in agreement.
For bees, this would require rather complex cognitive skills. In particular,
it would require that each bee acquire knowledge of the alternative nest sites,
compare these alternatives and decide which seems best, and yet remain open to
switching its opinion under the influence of additional information from other