Vocal communication between male Xenopus laevis

Abstract

This study focuses on the role of male-male vocal communication in the reproductive repertoire of the South African clawed frog, . Six male and two female call types were recorded from native ponds in the environs of Cape Town, South Africa. These include all call types previously recorded in the laboratory as well as one previously unidentified male call: chirping. The amount of calling and the number of call types increased as the breeding season progressed. Laboratory recordings indicated that all six male call types were directed to males; three of these were directed to both sexes and three were directed exclusively to males. Both female call types were directed exclusively to males. The predominant call type, in both field and laboratory recordings, was the male advertisement call. Sexual state affected male vocal behaviour. Male pairs in which at least one male was sexually active (gonadotropin injected) produced all call types, whereas pairs of uninjected males rarely called. Some call types were strongly associated with a specific behaviour and others were not. Clasped males always growled and clasping males typically produced amplectant calls or chirps; males not engaged in clasping most frequently advertised. The amount of advertising produced by one male was profoundly affected by the presence of another male. Pairing two sexually active males resulted in suppression of advertisement calling in one; suppression was released when males were isolated after pairing. Vocal dominance was achieved even in the absence of physical contact (clasping). We suggest that males gain a reproductive advantage by competing for advertisement privileges and by vocally suppressing neighbouring males.

Social rules govern vocal competition in the barn owl

“…The proximate mechanism leading to the modulation of call timing may be due to nestlings resetting their calling onset when perceiving a nestmate's call (Greenfield et al, 1997;Takahashi, Narayanan, & Ghazanfar, 2013), but with an additional complexity, as past relative investment and change in investment influenced the current calling decision. Ultimately, temporally organizing vocal production according to a competitor's signal is probably a way to optimize signal efficiency (Ficken, Ficken, & Hailman, 1974;Gerhardt, 1994;Tobias et al, 2004), as discussed below.…”

Male Phonotropism and Answer Calls Elicited by Female Vocalizations in the African Clawed Frog, Xenopus laevis

“…Both calls consisted of a fast trill and a slow trill (Tobias et al, 2004). The fast trill in advertisement calls varied from 0.208-0.341 sec (mean 0.275 6 0.051 sec) and contained 11.85 6 1.69 clicks, whereas the slow trill varied in duration from 0.806-1.324 sec (mean 5 1.028 6 0.176 sec) and contained 28.06 6 2.72 clicks.…”

“…Six types of male and two types of female calls have been described in Xenopus, which vary in the frequency, rhythmic patterning, and intensity of distinctive click-like acoustic features, and are believed to encode information relevant to courtship (Tobias et al, 2004). In males, advertisement calls consist of alternating fast clicks (19-msec interclick intervals [ICIs]) and slow (38-msec ICIs) trills.…”

Tone and call responses of units in the auditory nerve and dorsal medullary nucleus of Xenopus laevis

“…This study is the first detailed account of peripheral and hindbrain auditory responses in the fully aquatic anuran X. laevis, a species in which vocal behavior plays a prominent role in social communication (Tobias et al 1998(Tobias et al , 2004. We devised a method of directly stimulating the tympanum that allows us to present clean tympanic stimuli that match underwater sounds in frequency and sound level, and can be quantitatively compared to laser vibrometry measurements of the tympanum during underwater sound broadcasts (Christensen-Dalsgaard and Elepfandt 1995).…”

“…The male advertisement call, for example, alternates between slow and fast trills and suppresses calling in neighboring males. The advertisement call differs from the male answer call (which is not commonly suppressive in male-male interactions) in the relative duration of the slow and fast trills and in the between-click amplitude modulation of the fast trill (Tobias et al 2004). The ability of the auditory system to respond differentially to different click rates and temporal patterns is essential for appropriate behavioral responses.…”