These two plots compare the phase locking to an entraining stimulus of a tree cricket with that of a simple oscillator. The phase response of the model was determined by a least-squares fit of a function to the PRC of the male. We assumed the model completed its phase shift during the chirp period immediately following the stimulus and then iterated the PRC for each successive chirp in the stimulus. The tree cricket shows phase locking over a wide range of stimulus rates. The model simulated the phase locking of the cricket when the period of the stimulus was about 6% greater than the natural period of the male (t=1.06). However, the model was incapable of phase locking over the range of rates that the tree cricket was able to phase lock. The difference is in the assumption of the model. In the phase response experiments, tree crickets often show significant phase shifts several periods (2-3) after the stimulus has been presented.