PROXIMATE MECHANISMS OF AGE POLYETHISM IN THE HONEY-BEE, APIS-MELLIFERA L

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.