Physiological correlates of foraging efforts in honey-bees: oxygen consumption and nectar load

Quantitative economic analysis of the process of nectar collection by worker Apis mellifera suggests that the dependence of energetic expenditure during slow manoeuvring flight on the size of the nectar load sets an important physiological constraint to foraging strategies of individuals. In this study, rate of oxygen consumption was measured over a range of body masses for single workers. Measurements were obtained for bees in free forward flight at 0.5 m s^-1 in a wind tunnel and at an ambient temperature of 32°C. Rate of oxygen consumption (VO₂, in ml h^-1) for pooled individuals increased with body mass as VO₂ = 0.514 m^0.629, where m = body mass in mg. Further measurements were made for hovering bees (three individuals) with VO₂ = 0.417 m^0.648. Oxygen consumption in motionless and walking bees was quite variable. -from Authors