Fig 1.
Spectrograms of representative ultrasonic vocalizations (USVs) produced by male mice during same-sex social encounters.
USVs were classified based on frequency (50-kHz vs. 70-kHz) and the presence of frequency jumps, yielding four USV types: “70-kHz plain”, “70-kHz jump”, “50-kHz plain”, and “50-kHz jump”. See methods for more details regarding ultrasonic vocalization classification.
Fig 2.
Social history influences the total number and duration of ultrasonic vocalizations (USVs) emitted by male mice.
(a) Total number of USVs emitted by pairs of male mice with different social histories. (b) Mean duration of USVs emitted by pairs of male mice with different social housing histories. Bar heights represent means ± S.E.M; bars with different letters are statistically different (Kruskal-Wallis tests with Bonferroni post-hoc tests, p < 0.05). IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history.
Fig 3.
Social history influences the proportional use of different ultrasonic vocalization (USV) types emitted by pairs of male mice.
(a) Proportional use of 70-kHz plain USVs. (b) Proportional use of 70-kHz jump USVs. (c) Proportional use of 50-kHz plain USVs. (d) Proportional use of 50-kHz jump USVs. Bar heights represent means ± S.E.M; bars with different letters are statistically different (Kruskal-Wallis tests with Bonferroni post-hoc tests, p < 0.05). IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history and USV types.
Fig 4.
Mean durations of specific USV types emitted by pairs of male mice with different social histories.
(a) Mean durations of 70-kHz plain, 70-kHz jump, 50-kHz plain, and 50-kHz jump ultrasonic vocalizations (USVs) emitted by IND-IND and IND-SOC pairs of male mice. SOC-SOC pairs were not included in this two-way analysis, because few SOC-SOC pairs emitted all four USV types. Bar heights represent means ± S.E.M; bars with different letters indicate statistical differences among different USV types (Bonferroni post-hoc tests, p < 0.05). There was also a main effect of pair type: IND-SOC pairs emitted longer duration USVs than IND-IND pairs. (b) Mean duration of 70-kHz plain USVs emitted by pairs of male mice with different social histories. Bar heights represent means ± S.E.M; bars with different letters are statistically different (Bonferroni post-hoc tests, p < 0.05). IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history.
Fig 5.
Social history influenced the total durations of social investigation behaviors performed by pairs of male mice.
(a) Nose-to-nose investigation exhibited by pairs of male mice with different social histories. (b) Anogenital investigation exhibited by pairs of male mice with different social histories. Bar heights represent means ± S.E.M; bars with different letters are statistically different (Kruskal-Wallis tests with Bonferroni post-hoc tests, p < 0.05). IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history.
Fig 6.
Number of mounting occurrences performed by pairs of male mice with different social histories.
For IND-SOC pairs, IND males mounted SOC males. Bar heights represent means ± S.E.M; bars with different letters are statistically different (Kruskal-Wallis test with Bonferroni post-hoc tests, p < 0.05). IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history.
Fig 7.
Mounting behavior is correlated with several aspects of ultrasonic vocalizations emitted by pairs of male mice with different social histories.
(a) Mounting versus total ultrasonic vocalizations (USVs). (b) Mounting versus USV duration. (c) Mounting versus proportional use of 70-kHz plain USVs. (d) Mounting versus proportional use of 50-kHz jump USVs. Black circles: IND-IND pairs; white circles: IND-SOC pairs; gray circles: SOC-SOC pairs. IND = individually housed male; SOC = socially housed male. See methods for additional details regarding housing history.