A couple of folks responded directly to me on the subject above and I
eventually received the "definitive" response from Chris Plowright (my
comments to him are preceded by "}", his to me by ">") and he graciously
gave his permission for me to repost his comments:
}...If foragers' comings and goings are random then I would think
}that counts made at entrances using bee counters should very
}closely resemble the click patterns of Geiger counters measuring
}radioactive decay (don't have an intuitive grasp of what that
}would be like either but I'd guess that individual clicks
}predominate). If bee-counts and Geiger counts do not resemble
}each other I would say that the bee activities are not random.
>From: [log in to unmask]
>
> My interest in the comings and goings of bees and wasps was stimulat-
>ed by a paper published by R.E. Blackith in the late 1950's. Blackith
>claimed that the frequency distributions of sorties and entries conf-
>ormed more to negative-binomial than to Poisson expectations (i.e. the
>events were "clumped" rather than random). He took this as evidence
>that the insects were in some way "facilitating" each other rather than
>coming and going as independent agents.
> Two papers were published as a result of work done in my lab on this
>topic. Here are the references and the abstracts:
>
> Plowright, R.C. 1979. Social facilitation at the nest entrances of
> bumble bees and wasps. Insectes Sociaux, 26: 223-231.
> SUMMARY. The evidence presented by Blackith for social facilitation
> at the nest entrances of wasps and bumble bees is re-examined.
> New data are presented and additional analyses of those used by
> Blackith are reported. It is concluded that the phenomenon is a
> statistical artifact generated by incorrectly assuming homogene-
> ity in a Poisson process that is in fact non-homogeneous due to
> changes in overall activity.
>
> Pallett, M.J., and R.C. Plowright 1979. Traffic through the nest
> entrance of a colony of Vespula arenaria (Hymenoptera: Vespidae).
> Canadian Entomologist, 111: 385-390.
> ABSTRACT. Statistical analysis of traffic data at the nest entrance
> of a colony of the yellowjacket, Vespula arenaria (F.), showed no
> evidence for the operation of social facilitation of the type
> described by Blackith (1957). As in bumble bees, the appearance
> of contagion in the temporal distribution of exits and sorties is
> the result of overall change in flight activity and is not due to
> social interaction between wasps.
>
>Since the publication of these papers, several students and I have, from
>time to time, continued to collect nest-entrance data from bumblebee
>colonies. Sad to say, no evidence for social facilitation has come to
>light. Nevertheless, our findings have not altogether gone unchallenged
>(e.g. Robin Edwards' book on wasps). When one sits, beer in hand, in a
>lawn chair watching the bees coming and going through the entrance of a
>large Bombus colony, it is hard not to accept that the events are not
>occurring in "bursts". But, as you rightly point out, exactly the same
>can be said of the distribution of clicks coming from a Geiger counter.
> The key point of logic with regard to social facilitation at nest
>entrances is developed in the last paragraph of my Insectes Sociaux
>paper:
> "Statistical arguments aside, if social facilitation were to occur at
> the nest entrances of wasps and bumble bees, it should be possible to
> detect it by careful observation of the behavioral processes occurring
> at and around the nest-entrance. All experienced observers that I
> have consulted agree that the majority of foraging wasps return to,
> and enter, their nests with a marked lack of hesitation. This leads
> to a final and important point. Although subsequent authors have
> generally referred only to the results which Blackith obtained for
> sorties, . . . his results for entries are in every way similar . . .
> We must logically accept that if social facilitation is involved it
> operates at some distance from the nest so as to ensure that the
> insects arrive in groups when they complete their flight to the nest.
> This seems highly unlikely."
>
> I hope that the foregoing is of use to you.
> Regards, Chris Plowright.
******
As I mentioned in one of my postings on the subject I didn't
believe that groups leaving were the same as those coming back
but that the groupings (if they existed) were probably the result
of orientation behavior in combination with behavior threshold
interactions. Chris seems to indicate that the sorties and
entries do, in fact, mimic atomic decay-- which would indicate
that nothing behavioral is actually taking place and the
"groupings" are a result of random activity. (Unless, those
little subatomic particles are in cahoots and are reaching
concensus opinions on when to make a break for it... hmmm... ;-)
- Conrad Berube
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