title: An exception to the matched filter hypothesis: A mismatch of male call frequency and female best hearing frequency in a torrent frog.
abstract: The matched filter hypothesis proposes that the tuning of auditory sensitivity and the spectral character of calls will match in order to maximize auditory processing efficiency during courtship. In this study, we analyzed the acoustic structure of male calls and both male and female hearing sensitivities in the little torrent frog (Amolops torrentis), an anuran species who transmits acoustic signals across streams. The results were in striking contradiction to the matched filter hypothesis. Auditory brainstem response results showed that the best hearing range was 1.6-2 kHz consistent with the best sensitive frequency of most terrestrial lentic taxa, yet completely mismatched with the dominant frequency of conspecific calls (4.3 kHz). Moreover, phonotaxis tests show that females strongly prefer high-frequency (4.3 kHz) over low-frequency calls (1.6 kHz) regardless of ambient noise levels, although peripheral auditory sensitivity is highest in the 1.6-2 kHz range. These results are consistent with the idea thatA. torrentisevolved from nonstreamside species and that high-frequency calls evolved under the pressure of stream noise. Our results also suggest that female preferences based on central auditory system characteristics may evolve independently of peripheral auditory system sensitivity in order to maximize communication effectiveness in noisy environments.
authors.affiliation: Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
authors.forename: Longhui
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Ministry of Education Key Laboratory for Tropical Plant and Animal Ecology College of Life Sciences Hainan Normal University Haikou Hainan China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
authors.forename: Bicheng
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Department of Psychology University of Maryland College Park MD USA.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Brauth
authors.affiliation: Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
authors.forename: Yezhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Chengdu Institute of Biology Chinese Academy of Sciences Chengdu Sichuan China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Cui
keywords: Amolops torrentis; acoustic structure; auditory brainstem response; auditory sensitivity; matched filter hypothesis; stream noise