Auditory brainstem responses in the Chinese tiger frog Hoplobatrachus chinensis (Osbeck, 1765) (Anura: Dicroglossidae) reveal sexually dimorphic hearing sensitivity

Abstract

Hearing sensitivity affects survival and reproduction in animals that communicate vocally. The Chinese tiger frog exhibits sexual dimorphism in body size, reflecting the evolution of mating behaviour and life-history strategies. In this study, we recorded auditory brainstem responses (ABRs) to determine hearing sensitivity in both female and male frogs. We also compared male and female hearing characteristics with the shape of the tympanic membrane in light of previous studies showing that smaller middle ear cavities improve hearing sensitivity. We found that ABR thresholds differ significantly between males and females, with the greatest sensitivities in both sexes at frequencies close to the dominant frequency of male calls. ABR thresholds were significantly lower in females compared to males for frequencies in the 0.9-1.3 kHz range and at 1.6 kHz. The tympanic membrane diameter was significantly smaller in females (5.94 ± 0.87 mm) than in males (6.71 ± 0.49 mm). Our results indicate that sexual selection has in all likelihood differentially affected male and female hearing sensitivity as well as the shape of the tympanic membrane in frogs.

Auditory brainstem responses in the red-eared slider Trachemys scripta elegans (Testudoformes: Emydidae) reveal sexually dimorphic hearing sensitivity

“…We found that female and male T. scripta elegans have a similar range of sensitivities (0.2–0.9 kHz), whereas the ABR threshold of females was significantly lower than that in males. These results provide convincing evidence that sexually dimorphic hearing sensitivity has emerged in turtles, and that the hearing of females is more sensitive than that of males, which is consistent with previous findings for frogs and toads (Wang et al 2016, 2019; Yang et al 2018).…”

“…At present, sexual selection (Lovich and Gibbons 1992; Willemsen and Hailey 2003), fecundity effort (Kupfer 2009; Olsson et al 2010), and niche divergence (Thom et al 2010) are the three major hypotheses that have been proposed to explain the evolution and maintenance of sexual size dimorphism (SSD). Although most studies on sexual dimorphism have concentrated on body size or shape, sexually dimorphic hearing sensitivity has also been reported in some species of amphibians (Narins and Capranica 1976; Wang et al 2016, 2019; Yang et al 2018). Remarkably, such sexually dimorphic hearing sensitivity may primarily result from sexual dimorphism of the auditory organs (particularly tympanic membranes) and their physical properties (Dijk et al 2002; Feng et al 2006; Shen et al 2011; Liu et al 2014; Wang et al 2016).…”

“…Although most studies on sexual dimorphism have concentrated on body size or shape, sexually dimorphic hearing sensitivity has also been reported in some species of amphibians (Narins and Capranica 1976; Wang et al 2016, 2019; Yang et al 2018). Remarkably, such sexually dimorphic hearing sensitivity may primarily result from sexual dimorphism of the auditory organs (particularly tympanic membranes) and their physical properties (Dijk et al 2002; Feng et al 2006; Shen et al 2011; Liu et al 2014; Wang et al 2016).…”

Functional basis of the sexual dimorphism in the auditory fovea of the duetting bushcricketAncylecha fenestrata

“…By comparing the biomechanical and electrophysiological frequency tuning with morphological properties along the crista acustica in A. fenestrata, our study provides evidence for an auditory fovea as a sex-specific adaptation that reflects the asymmetric signalling in the reciprocal acoustic communication of these duetting bushcrickets. Sexual dimorphism in hearing organs had been reported predominantly in insects [41][42][43][44][45] and anurans [46][47][48][49][50], but was also shown in geckos [51] and humans [52]. These anatomical differences often reflect sex-specific adaptations of the hearing system to improve the auditory sensitivity or selectivity for acoustic properties of conspecific mating signals or other sounds that have different behavioural relevance to males and females of the same species [23,53,54].…”

Developmental plasticity of hearing sensitivity in red-eared sliderTrachemys scripta elegans

“…Auditory brainstem response (ABR) measurement is a noninvasive and rapid method to measure hearing sensitivity; its use has been validated for frogs [26, 27], toads [28], and reptiles [18, 29]. Our aim was to demonstrate that aging is accompanied by changes in turtle hearing sensitivity by measuring ABR, to assess ontogenetic changes in post-hatchling-to-reproductive T. scripta elegans adults.…”