The contributions of life history and inter-individual variation to the study of energetic supply and demand in Bombus impatiens

Abstract

In insects, flight energetics varies greatly among species but the source of this variation remains unknown. This thesis addresses phenotypic plasticity and matching of cellular and whole-animal metabolism in a bumblebee (Bombus impatiens). Bumblebees begin flying prior to full metabolic maturation, suggesting a window of greater metabolic plasticity. Bees were induced to fly before fully maturing, but although flight training resulted in elevated metabolic rates compared to controls, there was no change in biochemical activities of any tested enzymes. Similarly, while statistical models of flight parameters explained the majority of inter-individual variation in measures such as metabolic rate and wing beat frequency, there was no direct link between whole-animal metabolism and cellular energy production pathways. This suggests that muscle energy production and whole-animal metabolic demands are not plastically synchronised, and that inter-specific variation is likely not solely the result of phenotypic plasticity.