Metabolic rates related to muscle activity in bumblebees.

1. Oxygen consumption, thoracic temperature, and action potentials from the fibrillar muscles were concurrently recorded in queens and workers of Bombus vosnesenstni. 2. The oxygen consumption of 'inactive' bees (quiescent and/or producing fewer than 0-3 spikes/sec) was markedly temperature-sensitive, with a Qlo of 3-4 for thoracic temperatures of 25-35 °C3. The oxygen consumption of bees with active fibrillar muscles was directly correlated with spike frequency; a single spike was associated with the consumption of 2-3-2-6 fil O2lgthNo oxygen debt was observed. 4. The oxygen consumption per spike during flight was similar to that during warm-up. 5. Oxygen consumption per gram thorax was similar in queens and workers engaging in similar activity. 6. The results are compared with those from other insects and their adaptive significance is discussed.