Organization and Regulation of Nest Construction Behavior in Metapolybia Wasps

Field observations and experiments revealed that construction behavior of Metapolybia wasps is based on parallel processing and distributed decision making. Sixteen behaviors were used to separate five behavioral groupings: specialized water forager, flexible pulpforager, active builder, active generalist, 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 duties or take over other active roles. Nest construction is partitioned into three tasks. Pulp foragers transfer wood-pulp to the nest where other wasps (builders) distribute and process it further. The builders incorporate this material into the nest structure on the basis of individual decisions. Water foragers provide the extra water necessary for both building and pulp collecting. Material exchange takes place on the nest between pairs or in small groups. The duration and frequency of different behaviors, the number of wasps belonging to different behavioral groups, and the different scale of specialization in different groups suggest that the colony-level performance and speed are governed by the activity of the pulp foragers, who receive information about both the water saturation level of the colony and the activity of the builders through local interactions. Several predictions of this hypothesis were supported by disturbing the normal construction behavior through removing or decreasing the number of individuals belonging to different behavioral groups or supplying additional building material.