Behavioral, Ecological, and Physiological Determinants of the Activity Patterns of Bees

This chapter discusses the behavioral, ecological, and physiological determinants of the activity patterns of bees. An activity pattern is the change in levels of a particular activity through time. Bees are an excellent taxon within which to investigate both the issues of constraint and currency. Their physiological constraints are better understood than those of almost any other invertebrate, allowing an unparalleled opportunity to integrate physiology into behavioral ecology. Many bees require elevated body temperatures (Tb) to fly, and hence thermal properties of their environment significantly constrain their activity. However, many species are heterothermic, being able to elevate their Tb endothermically when necessary, which gives some degree of escape from the usual thermal constraints on other entirely ectothermic insects. The chapter discusses the factors structuring activity patterns in a wide range of bees. Observed activity patterns are generated by interactions between properties of the bees themselves (intrinsic factors) and properties of their environment (extrinsic factors). Intrinsic factors include physiological differences between species and between the sexes. Extrinsic factors are the fluctuating properties of the environment, and are either abiotic or biotic.