ACTIVITY PATTERNS OF FEMALES OF THE SOLITARY BEE ANTHOPHORA-PLUMIPES IN RELATION TO TEMPERATURE, NECTAR SUPPLIES AND BODY-SIZE

1. Patterns of activity at a large nesting aggregation and at foraging sites are described for females of the solitary bee Anthophora plumip es (Pallas). Changes in the quality and quantity of the resource colle cted by females provisioning cells are related to variation in female body mass and microclimate. 2. Activity at the nest site demonstrated relationships with aspects of the thermal environment experienced by A .plumipes. Measures of temperature showing significant relationships d iffered for females in different stages in the nesting cycle exhibitin g characteristically different behaviour patterns. 3. Larger females e merged from nest tunnels earlier in the morning and provisioned cells at lower ambient temperatures than smaller individuals. Body size ther efore predicts reproductive success at low ambient temperatures. 4. Po llen and nectar loads carried by females increased with ambient temper ature. Because only one cell is completed per day and the size of offs pring is determined by the quality and quantity of resource provided b y the mother, the body size of individuals emerging in the following s eason will depend on interactions between climate and body size, in ad dition to any heritable component. 5. Variation in activity levels at foraging sites is attributed not only to thermal considerations, but a lso to variation in the quality of rewards available at different flor al sources.