Abstract: Sexual dimorphism in call frequency is widespread in a variety of animals. Despite possessing comparatively poor vision, bats conduct their activities at night. They primarily employ acoustic signals for spatial navigation, prey tracking, and social information transfer. Here, we use adult least horseshoe bats, Rhinolophus pusillus, to assess whether sexual dimorphism in the frequency of echolocation calls facilitates sex recognition. Analyses revealed that echolocation calls of R. pusillus showed marked gender differences in frequency parameters. In the playback periods, the number of response calls was the highest for white noise, followed by male echolocation call, and was the lowest for female echolocation call. The number of bat response calls, however, increased progressively after the playback of white noise, female echolocation call, and male echolocation call. The intensity of bat response calls showed a rapid decrease in the presence of white noise versus echolocation call stimuli. These results indicate that frequency parameters of echolocation calls encode information on caller sex in least horseshoe bats, which facilitates sex recognition within the population. Our findings provide some implications for the potential role of echolocation calls in mate choice among bats.

Key words: Chiroptera (Bats), Echolocation call, Rhinolophus, Sexual dimorphism

摘要： 许多动物的叫声频率呈现性二态现象。蝙蝠夜间活动，主要利用声音信号导航空间、追踪猎物、传递交流信息。本研究选择成体菲菊头蝠作为研究对象，检验回声定位声波频率性二态是否有利于性别识别。研究发现，菲菊头蝠回声定位声波频率参数具有显著性别差异。播放白噪音、雄性回声定位声波及雌性回声定位声波期间，实验个体的反应叫声数量依次递减。播放白噪音、雌性回声定位声波及雄性回声定位声波后，实验个体的反应叫声数量依次递增。白噪音诱导反应叫声强度高于回声定位声波诱导反应叫声强度。研究结果表明，菲菊头蝠回声定位声波的频率参数编码发声者性别信息，有利于种群内部的性别识别。本研究暗示，回声定位声波可能在蝙蝠配偶选择中扮演一定作用。

关键词: 翼手目（蝙蝠）, 菊头蝠, 回声定位声波, 性二态