Analysis of Nesting Behavior Based on Daily Observation of Andrena vaga (Hymenoptera: Andrenidae)

We present a study on nesting behavior of the gregarious solitary bee, Andrena vaga Panzer. Based on the daily observation of individually marked females, we constructed an ethogram, determined a sequence of behavioral elements within the provisioning cycle, estimated their length and computed the transition probability between the elements. We confirmed the existence of distinctive pollen and nectar days in A. vaga and showed apparent differences in the overall daily provisioning pattern in pollen and nectar days as well as in the probability of transition between some behavioral elements. Bees typically performed one provisioning trip and carried no pollen on nectar days, but they performed up to four pollen-provisioning trips on pollen days. The duration of one pollen trip depended on the number and sequence of the trip in a given day, with the shortest trip usually occurring last in the day.