Individuality, as well as genotype, affects characteristics and temporal consistency of courtship songs in male mice

Abstract

ABSTRACTCourtship songs in mice have been investigated to understand the mechanisms and ecological relevance of vocal communication. There is evidence that courtship song characteristics vary between different genotypes, but little is known on whether individuals, even within the same genotype, differ from each other in the composition, complexity, and temporal consistency of their songs. In a first study, we aimed to systematically identify song features typical of different genotypes, by assessing the composition and complexity (i.e., entropy) of the syllabic sequences of male laboratory mice from four different strains (Mus musculus f. domestica: C57BL/6J, BALB/c, DBA/2 and B6D2F1). Mice were individually presented with a swab containing fresh female urine for 5 minutes to elicit courtship songs. The four strains differed not only in the composition but also in the complexity of their syllabic sequences. In a second study, we investigated within-strain individual differences in temporal consistency and recurring motifs (i.e., identical sets of syllables that are repeated within a song), using BALB/c and DBA/2 mice. The same procedure as in the first study was followed, but in addition testing was repeated weekly over three weeks. Both strains showed some level of individual temporal consistency; BALB/c in the overall amount of emitted vocalisations and DBA/2 in the expression of specific syllable types. However, hierarchical cluster analysis revealed remarkable individual variability in how consistent song characteristics were over time. Furthermore, recurring motifs were expressed at varying levels depending on the individual. Taken together, not only genotype but also individuality can affect variability in courtship songs in mice, suggesting the existence of different courtship strategies (e.g., higher song consistency to facilitate individual identification) related to varying levels of behavioural plasticity.HIGHLIGHTSCourtship songs in mice can serve as a model to study vocal communicationWe explore how genotype and individuality affect courtship songs’ characteristicsGenotypes differ in composition and also in complexity of syllabic sequencesWe find remarkable individual variability in how consistent songs are over timeResults suggest the existence of variation in male courting behaviour