Examination of the means of the average power of the combined first two and the combined last two taps of drumming bouts in courtship songs ±SD. In nearly all instances, tapping becomes louder during an individual drumming bout within courtship songs across all four species. Numbers closer to the abscissas are louder. a = average of the first two taps, b = average of the last two taps in bouts of four taps or more. * = t-tests comparing the means of first two taps to the last two taps, within each species, showed the p-values were all < 0.0001, showing that the taps are significantly louder at the end of drumming bouts (A. exigua n = 5 songs, 45 drumming bouts; A. tinnulacita n = 4, 29; A. tinnulenta n = 4, 98; A. thomasi n = 5, 75).