These are the data for phase locking by a single male tree cricket. The different symbols represent data collected for different t. Notice that when the entrainment period is 25% larger than the male’s natural period (t=1.25) the male is not able to phase lock and his phase drifts during successive chirps of the stimulus. However, when the entraining period is 13% greater than the male’s period (blue, t=1.13) the male phase locks with his phase remaining constant at about 0.6 of the entraining period. The male was also able to phase lock to entraining periods that were shorter than his natural period (t=0.99 and 0.91, ie a faster rhythm). Note that it typically takes 3 to 4 cycles for the male to obtain phase locking. The male is capable of phase locking to stimuli having a wide range of periods.