Forager specialization and the control of nest repair in Polybia occidentalis Olivier (Hymenoptera : Vespidae)

We measured patterns of individual forager specialization and colony-wide rates of material input during periods of response to experimental nest damage and during control periods in three colonies of the tropical social wasp Polybia occidentalis.

(1)	Most foragers specialized on gathering a single material. While active, foragers rarely switched materials, and most switching that did occur was between functionally related materials — prey and nectar (food materials) or wood pulp and water (nest materials).
(2)	Individuals differed greatly in activity level, here expressed as rate of foraging. Workers that foraged at high rates specialized on a single material in almost all cases. Specialized, highly active foragers comprised a minority (about 33%) of the working foragers in each colony, yet provided most of the material input.
(3)	Individual wasps that responded to experimental nest damage by foraging for nest materials did not gather food on days preceding or following manipulation.
(4)	On the colony level, nectar and prey foraging rates were not affected by foraging effort allocated to nest repair within days, or when comparing control days with days when damage was imposed. The emergency foraging response to nest damage in P. occidentalis did not depend on effort recruited away from food foraging.

Offprint requests to: S. O'Donnell