Flexibility as a Strategy for Avoiding Call Overlap in Male Anhui Treefrogs

Male-male vocal competition is critical for mating success in anuran species;however,it remains unknown that how males regulate their competitive strategies dynamically during competition because calling is highly time-consuming,energetically demanding and likely to increase predation risks.Since different parts of calls will encode different information for vocal communication,we hypothesized that competitive strategies of male frogs may be modulated by the temporal and spectral features of different call notes.To test this hypothesis,the natural advertisement calls(OC),its modified versions with the first call note replaced by white noise(WN)or other notes and with the fifth call note replaced by WN,were played back to the Anhui tree frogs(Rhacophorus zhoukaiyae).Results showed that 1)males produced more competitive calls in response to acoustic stimuli compared to their baseline calling during silence;and 2)males emitted more non-overlapping calls compared to overlapping calls in response to the acoustic stimuli.These results are consistent with the idea that males are flexible to acoustic signals and their competition strategies are modulated dynamically by social contexts.