Workers in most insect societies exhibit a division of labor known as
age polyethism, so named because workers tend to perform different tas
ks at different times in their lives. The most common explanation for
this phenomenon involves a weak causal link between a worker's age and
its occupation. However, available estimates of age effects are gener
ally confounded with other sources of variability. Further, there is c
onsiderable variation in the age at which each task is performed. Cons
equently, the role of age in division of labor remains unresolved. An
alternative model, christened 'foraging-for-work', explains age polyet
hism without a causal link between age and occupation. The specific al
gorithm, however, is too restrictive to apply in many task situations,
and it is inconsistent with existing data on how workers actually loc
ate and select tasks in certain contexts. Therefore, it cannot serve a
s a general model for task location/selection or for age polyethism. T
he model's conceptual basis, however, that an age-neutral mechanism ca
n generate age polyethism, is an important contribution that demands f
urther study. The current dialogue over proximate mechanisms of age po
lyethism has helped to clarify the pattern of behavioral ontogeny in h
oney bees. A conservative interpretation of existing data is that beha
vioral ontogeny is characterized by a nest phase followed by a foragin
g phase. The timing of the transition between these phases is determin
ed more by the environment and physiological processes than by age. Wh
ether nest tasks also follow a necessary sequence is less certain and
requires further study. (C) Inra/DIB/AGIB/Elsevier, Paris.