Organization and regulation of nest construction behavior in Metapolybia wasps

Field observations and experiments revealed that construction behavior of M etapolybia wasps is based on parallel processing and distributed decision m aking. Sixteen behaviors were used to separate five behavioral groupings: s pecialized water forager, flexible pulpforager, active builder, active gene ralist, and idle. The idle category proved to be the source and the sink of the other task groups, although specialist foragers tend to retain their d uties or take over other active roles. Nest construction is partitioned int o three tasks. Pulp foragers transfer wood-pulp to rite nest where other wa sps (builders) distributive and process it further. The builders incorporat e this material into the nest structure on the basis of individual decision s. Water foragers provide the extra water necessary for both building and p ulp collecting. Material exchange takes place on the nest between pairs or in small groups. The duration and frequency of different behaviors, the num ber of wasps belonging to different behavioral groups, and the different sc ale of specialization in different groups suggest that the colony-level per formance and speed are governed by the activity of rite pull, foragers, who receive information about both the water saturation level of the colony an d the activity of the builders through local interactions. Several predicti ons of this hypothesis were supported by disturbing the normal construction behavior though removing or decreasing the number of individuals belonging to different behavioral groups or supplying additional breaking material.