Phase-Specific Vocalizations of Male Mice at the Initial Encounter during the Courtship Sequence

Mice produce ultrasonic vocalizations featuring a variety of syllables. Vocalizations are observed during social interactions. In particular, males produce numerous syllables during courtship. Previous studies have shown that vocalizations change according to sexual behavior, suggesting that males vary their vocalizations depending on the phase of the courtship sequence. To examine this process, we recorded large sets of mouse vocalizations during male–female interactions and acoustically categorized these sounds into 12 vocal types. We found that males emitted predominantly short syllables during the first minute of interaction, more long syllables in the later phases, and mainly harmonic sounds during mounting. These context- and time-dependent changes in vocalization indicate that vocal communication during courtship in mice consists of at least three stages and imply that each vocalization type has a specific role in a phase of the courtship sequence. Our findings suggest that recording for a sufficiently long time and taking the phase of courtship into consideration could provide more insights into the role of vocalization in mouse courtship behavior in future study.

小鼠可发出包含多种音节的超声发声（ultrasonic vocalizations）。这类发声会在社交互动过程中被观测到，具体而言，雄性小鼠在求偶阶段会产生大量音节。既往研究表明，发声行为会随交配行为发生变化，提示雄性小鼠的发声模式会根据求偶序列的不同阶段进行调整。为探究这一过程，本研究在雌雄小鼠互动期间录制了大量小鼠发声样本，并通过声学特征将这些声音划分为12种发声类型。研究结果显示，雄性小鼠在互动初始的1分钟内主要发出短音节，后续阶段则更多产生长音节，而在爬跨行为发生时则主要发出谐波声。这种依赖于情境与时间的发声变化表明，小鼠求偶过程中的声学交流至少包含三个阶段，同时也暗示每种发声类型在求偶序列的特定阶段中均承担着独特功能。本研究结果提示，在未来的相关研究中，通过延长录制时长并结合求偶阶段进行分析，可进一步深入揭示发声行为在小鼠求偶行为中的作用机制。