Phonotaxis in the cricket,Gryllus bimaculatus DeGeer: comparisons of choice and no-choice paradigms

Summary

• 1. The phonotactic tracking behavior of females on a locomotion compensator was studied in the field cricket,Gryllus bimaculatus DeGeer. Synthetic stimuli were played back in choice and no-choice experiments to determine the behavioral tuning to calling song temporal properties.

• 2. In ‘to-and-fro’ sequential tests, best tracking occurred when stimuli had syllable periods between 35 and 50 ms (Figs. 2, 3). The variability of tracking scores within and among individuals was lowest when syllable periods were 40 and 45 ms, indicating an even narrower tuning to syllable period.

• 3. Context-dependent after-effects were seen in some females (Figs. 2, 3). That is, the range of syllable periods tracked by females in sequential experiments was broad or narrow, depending upon the order of stimulus presentation (i.e. from ‘unattractive’ to ‘attractive’ syllable periods or vice versa (see Fig. 3)).

• 4. In choice experiments, the optimal range of syllable periods was similar to that found in to-and-fro sequential (no-choice) experiments. As the syllable period of the alternative stimulus was moved farther away from that of the standard stimulus (45 ms), the preference for the standard persisted even when its SPL was attenuated by5 to 20 dB relative to the SPL of the alternative (Fig. 4).

• 5. Several females tracked both the standard and alternative stimuli in sequential ‘pre-tests’, but clearly preferred (tracked) the standard over the alternative in subsequent choice tests (Figs. 5–9). This difference in the results of choice and nochoice experiments was most prominent when the alternative syllable period was between 55 and 60 ms (Fig. 10). These results can be explained by recent findings of trade-off phenomena in calling song recognition inG. bimaculatus.