Female finches prefer courtship signals indicating male vigor and neuromuscular ability

Abstract

Female songbirds use male song to discriminate among individuals and evaluate their quality as potential mates. Previous behavioral experiments in many species, including the species studied here, have shown that females will solicit copulation in response to song even if no male is present. Those data demonstrate that female mate choice is closely tied to song features, but they leave open the question of which song parameters are most influential in female mate selection. We sought to identify features of male song that are salient for mate choice in female Bengalese finches. Using a novel experimental approach, we simultaneously tested the possible influence of specific notes or note transitions, the number of different note types in the male's repertoire, the complexity of note content and note sequence, and the stereotypy of note content and note sequence. In additional experiments, we also tested the influence of the pitch and tempo of note production. Our results demonstrate that females generally preferred songs containing increased tempo in the context of species-typical frequency bandwidth, consistent with the idea that females prefer songs that are especially challenging to produce. Female preference for song features that pose a neuromuscular challenge has also been reported in other species. Our data extend those observations into a species that thrives in a laboratory setting and is commonly used in studies of the neural basis of behavior. These results provide an excellent new model system in which to study female preference and the neural mechanisms that underlie signal evaluation and mate choice.

Auditory and sexual preferences for a father’s song can co-emerge in female Bengalese finches

“…Regardless of the developmental mechanism of preference for the father’s song, our results together with previous reports of song preference in female Bengalese finches measured by other behavioral responses (e.g., operant conditioning, phonotaxis, and vocalizations) [ 14 , 15 ] imply the importance of considering individual variations in female song preference in this species. In previous studies, researchers have explored acoustical and temporal song characteristics that are preferred across individuals in female Bengalese finches [ 14 , 52 – 54 ]. For example, in a call-back assay experiment where song tempo or pitch were manipulated, the authors found that the majority of females preferred faster songs while changes in pitch were not a good predictor of female response [ 52 ].…”

Heritable differences in synaptic zinc-transporter levels drive variation in learned birdsong

“…Most simply, this might include variation in the temporal dynamics of other movements; however, it likewise could include variation along any axis of behavior that is influenced by changes to the synaptic strength or excitability within underlying neural circuitry. This is especially interesting from the perspective that song is a courtship behavior that female birds use in part to select their mates ( 17, 20 ). The joint influences of experience and heritability on tempo render it an informative signal about the relatedness of the singer ( 77, 78 ), while the possibility that other behavioral traits covary with tempo suggests that It might additionally provide females with signals about inter-individual differences that are relevant to assessment of a male’s fitness and compatibility.…”

“…Birdsong-a complex motor skill acquired through cultural transmission and subserved by well-delineated neural circuitry (7)(8)(9)(10)-offers an attractive model for studying heritable sources of variation in learned behavior. In particular, song tempo-a defining characteristic of the male's courtship song and motor skill performance more generally (11)(12)(13)(14)(15)(16)-is shaped both by experience during learning from a tutor and by heritable factors (17)(18)(19)(20)(21)(22)(23). Moreover, while the characteristic tempo at which an adult bird sings varies by only a few percent from day to day, the tempos at which different individuals sing can span more than a factor of two (11,13,22).…”

Female Bengalese finches recognize their father’s song as sexually attractive

“…Regardless of the developmental mechanism of preference for the father's song, our results together with previous findings [14,15] imply the importance of considering individual variations in female song preference in the Bengalese finch. In previous studies on this species, researchers have explored acoustical and temporal song characteristics that are preferred across individuals [14,[38][39][40]. For example, in a call-back assay experiment where song tempo or pitch were manipulated, the authors found that the majority of females preferred faster songs while changes in pitch were not a good predictor of female response [38].…”

“…In previous studies on this species, researchers have explored acoustical and temporal song characteristics that are preferred across individuals [14,[38][39][40]. For example, in a call-back assay experiment where song tempo or pitch were manipulated, the authors found that the majority of females preferred faster songs while changes in pitch were not a good predictor of female response [38]. There are other studies that are especially relevant to the characteristics of Bengalese finch song and its evolutionary process.…”