Female urine-induced male mice ultrasonic vocalizations, but not scent-marking, is modulated by social experience.

Despite the evidence for a communicative function of rodent scent marks and ultrasonic vocalizations, relatively little is known about the impact of social factors on these two forms of communication. Here, we tested the effects of two important social factors, prior exposure to a female and freshness of female urine, on male scent marks and ultrasonic vocalizations elicited by female urine. We also asked whether a recently reported strain difference between the highly social strain C57BL/6J (B6) and the mouse model of autism BTBR T+tf/J (BTBR) herein is specifically seen in response to female urine or also detectable in response to male urine traces. Results show that the emission of female urine-elicited ultrasonic vocalizations was dependent on previous female experience, while scent-marking behavior was not affected. A positive correlation was detected between scent-marking behavior and ultrasonic calling in the most biologically relevant context, male mice exposed to fresh female urine after female experience. Correlations were less prominent or missing in less biologically relevant contexts, e.g. in male mice exposed to fresh female urine without previous female experience, indicating that previous female experience is affecting both the emission of female urine-elicited ultrasonic vocalizations and the correlation between olfactory and acoustic communication. The strain difference in scent-marking behavior and ultrasonic calling between B6 and BTBR appears to be specific to female urine-elicited behavior as it was not seen in response to male urine traces, highlighting the relevance of the social context in which mouse communication is evaluated.