Auditory sensitivity and tympanic middle ear in a vocal and a non-vocal frog

Hear Res. 2024 Mar 15;444:108970. doi: 10.1016/j.heares.2024.108970. Epub 2024 Feb 5.ABSTRACTThe tympanic middle ear is important for anuran hearing on land. However, many species have partly or entirely lost their tympanic apparatus. Previous studies have compared hearing sensitivities in species that possess and lack tympanic membranes capable of sound production and acoustic communication. However, little is known about how these hearing abilities are comparable to those of mutant species. Here, we compared the eardrum and middle ear anatomies of two sympatric sibling species from a noisy stream habitat, namely the "non-vocal" Hainan torrent frog (Amolops hainanensis) and the "vocal" little torrent frog (Amolops torrentis), the latter of which is capable of acoustic communication. Our results showed that the relative (to head size) eardrum diameter of A. hainanensis was smaller than that of A. torrentis, although the absolute size was not smaller. Unlike A. torrentis, the tympanic membrane area of A. hainanensis was not clearly differentiated from the surrounding skin. The middle ear, however, was well-developed in both species. We measured the auditory brainstem responses (ABRs) of A. hainanensis and compared the ABR thresholds and latencies to those previously obtained for A. torrentis. Our results suggested that these two species exhibited significant differences in hearing sensitivity. A. hainanensis (smaller relative eardrum, nonvocal) had higher ABR thresholds and lo...

Source: Hearing Research - February 17, 2024 Category: Audiology Authors: Longhui Zhao Meihua Zhang Yuanyu Qin Tongliang Wang Xiaofei Zhai Jianguo Cui Jichao Wang Source Type: research