Mechanical and electrical activity in the indirect flight muscles of the honey bee

Abstract

1. Recordings were made from single elements in the indirect flight muscles of the honey bee with the usual insulated metal electrodes uninsulated at the tip. With the “indifferent” electrode in the head few neighboring elements showed up. All recorded elements had random phase differences. 2. In the dorsoventral (DV) muscles about 80% of the spikes are not followed by striking junctional components, 20% are. Practically all spikes from the dorsolongitudinal (DL) muscles have a junctional component following. 3. The DV-muscles in the intact animal shorten linearily with increasing action potential frequency (Fig. 6). The DL-muscles are stretched slightly. 4. Approximately 50 to 100 msec before the onset of oscillations the action potential frequency in both groups of muscles (DV and DL) increases to 30–60 Hz for 2 to 4 action potentials. The DV-muscles shorten (evidently isotonically) about 20 to 40 μ and start oscillations with a lengthening. An experiment performed by Boettiger (p. 438) might explain the events that start the oscillations. The oscillations end about 180 to 200 msec after the ending of the action potentials. The DV-muscles return to their resting length in the next 200 to 1,000 msec. 5. The duration of the action potentials depends strongly on the temperature (Fig. 4). 6. The wingbeat frequency increases with the action potential frequency (Fig. 10).