Meeting Abstract

P3-61   -   Investigating the role of call periodicity and higher harmonic frequencies in mate attraction in the plainfin midshipman fish Balebail, S*; Rogers, LS; Li, Z; Reicherter, A; Kim, C; Yang, S; Sisneros , JA; University of Washington; University of Washington; University of Washington; University of Washington; University of Washington; University of Washington; University of Washington sujayb@uw.edu

Type I or “singing” male plainfin midshipman (Porichthys notatus) likely produce the largest contiguous advertisement calls of any known vertebrate, lasting for up to 2 hours. The advertisement call is periodic, with energy distributed amongst the fundamental frequency (F₀ ~ 100 Hz), and several higher harmonic frequencies (F_1-19) which are integral multiples of F₀. Previous studies have demonstrated that a pure tone at F₀ is sufficient to attract females suggesting a limited role for the higher harmonic frequencies in mate attraction. However, the ability to recognize the "pitch" or periodicity of the advertisement call in the absence of F₀ might be important for call recognition and localization in the shallow rocky intertidal breeding grounds of this fish, where higher harmonics propagate longer distances. In the current study, we performed acoustic trapping experiments in the natural habitat to investigate the following hypotheses: 1) The higher harmonic components of the advertisement call are sufficient for mate-call recognition and attraction, 2) The periodicity of the advertisement call is an important factor in mate attraction. We found that traps playing a synthetic version of the advertisement call ("Quasi-natural call") attracted more females than a silent trap (N=10; P<0.001). A trap playing the quasi-natural call with missing F₀ attracted more females than a silent control trap but the difference was not significant (N=7; P=0.06). There was no difference between the number of females captured in a trap playing an aperiodic version of the quasi-natural call (but having the same F₀) compared to a trap playing the quasi-natural call (N=6; P=0.18). Therefore, our study indicates that although F₀ is the most important component of the advertisement call, higher harmonic frequencies appear to be sufficient for attracting females. A larger sample size is required to confirm this result. We also observed fewer type I males in a trap playing the quasi-natural call compared to a silent trap (N=10; P<0.05), suggesting that in addition to attracting females, the advertisement call also functions as a warning signal to type I male competitors.