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 b ehaviors observed in this population are quite similar to those report ed from populations in Florida, North Carolina, Pennsylvania, and New York. As in the eastern populations, by far the most common prey are t wo species of beetles in the subfamily Eumolpinae (Chrysomelidae), but late in the season at least one wasp began provisioning primarily wit h Eugnamptus angustatus. (Herbst), a weevil in the family Rhynchitidae , not previously recorded as prey of C. rufopicta. Nest architecture a nd natural enemies are very similar to what has been reported for the eastern populations, but provisioning activity in the Kansas populatio n occupies a much greater part of the day, with some wasps continuing to provision even after sunset. This difference is not because individ ual wasps in Kansas are active for a longer period of time, but becaus e the activity schedules of different individuals within the Kansas ag gregation are not closely synchronized. Approximately half of the nest s that were monitored over a period of three and a half weeks were occ upied by a single wasp. Other nests changed ownership during the cours e of the study, either because the original owner disappeared and anot her 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 coop erative joint nesting was seen in this population.