Fig. 7. The results of an FFT analysis on one feeding bout (direction=V axis; frequency=3 Hz). This is how the frequency and amplitude coefficients for calculating rate of energy gain were obtained. Discarding the first peak, which is an artifact due to removing the mean position (see Materials and methods), the remaining three highest peaks are the coefficients used (all included peaks are circled). (A) shows the FFT of moth position for the H axis, (B) for the V axis, and (C) for the L axis.