ENERGY-METABOLISM, ENZYMATIC FLUX CAPACITIES, AND METABOLIC FLUX RATES IN FLYING HONEYBEES

Honeybees rely primarily on the oxidation of hexose sugars to provide the energy required for flight. Measurement of VCO2 (equal to VO2, bec ause VCO2/VO2 = 1.0 during carhohydrate oxidation) during flight allow ed estimation of steady-state flux rates through pathways of flight mu scle energy metabolism, Comparison of V-max values for flight muscle h exokinase, phosphofructokinase, citrate synthase, and cytochrome c oxi dase with rates of carbon and O-2 flux during flight reveal that these enzymes operate closer to V-max in the flight muscles of flying honey bees than in other muscles previously studied. Possible mechanistic an d evolutionary implications of these findings are discussed.