The effects of sex and reproductive condition on auditory evoked responses in the round goby, Neogobius melanostomus.

Abstract

Effectively receiving and responding to mating signals is critically important in acoustically communicating vertebrate species, particularly for individuals that are reproductively mature. Behavioral responses to mating and advertisement signals in these individuals are often more intense than in their non-reproductive counterparts, which might be explained in part by changes in the response properties of the auditory system. The current study examined the potential for auditory plasticity of hearing sensitivity in relation to reproductive state in the round goby. This fish breeds in high density aggregations, with males guarding nests and producing low frequency (150–180 Hz dominant frequency) vocalizations that both males and females can localize. Auditory sensitivities in both sexes were assessed in reproductive and non-reproductive individuals using auditory evoked responses to tone pips that ranged from 100 to 600 Hz. Females were more sensitive than males across their hearing range. When assessed based on reproductive status, reproductive females were more sensitive than non-reproductive females and males at 100 Hz. Thresholds in males were similar between reproductive and non-reproductive individuals. These results suggest that hearing sensitivity in the round goby is sexually dimorphic at selected frequencies and is enhanced with reproductive maturity in females. [Work supported by NSERC.]