Patterns of Nest Occupancy and Provisioning in Cerceris rufopicta Smith (Hymenoptera: Sphecidae)

Data are presented on prey choice, nest architecture, natural enemies, daily activity patterns, and seasonal patterns of nest occupancy in a population of Cerceris rufopicta Smith in northeastern Kansas. Most behaviors observed in this population are quite similar to those reported from populations in Florida, North Carolina, Pennsylvania, and New York. As in the eastern populations, by far the most common prey are two species of beetles in the subfamily Eumolpinae (Chrysomelidae), but late in the season at least one wasp began provisioning primarily with Eugnamptus angustatus. (Herbst), a weevil in the family Rhynchitidae, not previously recorded as prey of C. rufopicta. Nest architecture and natural enemies are very similar to what has been reported for the eastern populations, but provisioning activity in the Kansas population occupies a much greater part of the day, with some wasps continuing to provision even after sunset. This difference is not because individual wasps in Kansas are active for a longer period of time, but because the activity schedules of different individuals within the Kansas aggregation are not closely synchronized. Approximately half of the nests that were monitored over a period of three and a half weeks were occupied by a single wasp. Other nests changed ownership during the course of the study, either because the original owner disappeared and another wasp moved in, or because one wasp drove another away from a nest. During the time that ownership of a nest was being contested it might be simultaneously used by more than one wasp, but no evidence of cooperative joint nesting was seen in this population.