title: Ultrasonic frogs show extraordinary sex differences in auditory frequency sensitivity.
abstract: Acoustic communication has an important role in the reproductive behaviour of anurans. Although males of the concave-eared frog (Odorrana tormota) have shown an ultrasonic communication capacity adapted to the intense, predominately low-frequency ambient noise from local streams, whether the females communicate with ultrasound remains unclear. Here we present evidence that females exhibit no ultrasonic sensitivity. Acoustic playback experiments show that the calls from male evoke phonotaxis and vocal responses from gravid females, whereas the ultrasonic components (frequencies above 20 kHz) of the calls do not elicit any phonotaxis or vocalization in the females. Electrophysiological recordings from the auditory midbrain reveal an upper frequency limit at 16 kHz in females. Laser Doppler vibrometer measurements show that the velocity amplitude of the tympanic membranes peaks at 5 kHz in females and at ∼7 kHz in males. The auditory sex differences in O. tormota imply that ultrasonic hearing has evolved only in male anurans.
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. shenjx@ibp.ac.cn
authors.forename: Jun-Xian
authors.initials: JX
authors.lastname: Shen
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Xu
authors.forename: Zu-Lin
authors.initials: ZL
authors.lastname: Yu
authors.forename: Shuai
authors.initials: S
authors.lastname: Wang
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Zheng
authors.forename: Shang-Chun
authors.initials: SC
authors.lastname: Fan
mesh_terms: D000161:Acoustic Stimulation; D000819:Animal Communication; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D005075:Biological Evolution; D004594:Electrophysiology; D005260:Female; D006309:Hearing / Q000502:physiology*; D008297:Male; D008636:Mesencephalon / Q000502:physiology; D011898:Ranidae / Q000033:anatomy & histology / Q000502:physiology*; D012727:Sex Characteristics; D014432:Tympanic Membrane / Q000502:physiology; D014465:Ultrasonics