Behavioral Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany.
Cognitive Ethology Laboratory, German Primate Center, Göttingen, Germany.
Am J Primatol. 2018 Sep;80(9):e22920. doi: 10.1002/ajp.22920.
Females across a range of animal taxa produce vocalizations and signals uniquely associated with periods of mating. While such signals may ultimately function to increase female attractivity to males, conflicting findings challenge the extent to which these signals co-vary in accordance with the probability of conception. Female black capuchin monkeys (Sapajus nigritus) display an elaborate repertoire of both vocal and visual components as part of their socio-sexual behavior, and previous analyses have shown that the rates of production of visual, but not vocal, components provide graded information on female ovulation. It remains possible, however, that the acoustic parameters of these sexual calls, rather than their rate of productions, co-vary with female fertility. To test this, we analyzed structural and temporal call parameters from estrous calls and post-copulatory calls recorded over five consecutive mating seasons in 12 sexually mature females at Iguazú National Park, Argentina. Calls given during the fertile phase of the female ovarian cycle were compared with those given during the non-fertile phase, as determined by profiles of female reproductive hormones. Similarly, within the fertile phase, we tested whether temporal or spectral acoustic parameters of calls gradually change with the approach of ovulation. We did not find any significant relationship between call parameters and the two measures of female fertility in either female estrous calls or post-copulatory calls. However, some differences between pre- and post-copulatory calls were apparent. Overall, our results indicate that sexual calls in black capuchin females do not provide precise information about the timing of ovulation, but may allow listeners to make probabilistic inferences about whether copulations have taken place. This, combined with previous findings, suggests that females in our study may use signals in different modalities to convey information about their fertility and sexual behavior with varying degrees of precision.
跨动物类群的雌性会发出独特的声音和信号，这些声音和信号与交配期有关。虽然这些信号最终可能有助于增加雌性对雄性的吸引力，但相互矛盾的研究结果挑战了这些信号与受孕概率的变化程度。雌性黑帽卷尾猴（Sapajus nigritus）在其社交性行为中表现出复杂的声音和视觉成分，之前的分析表明，视觉成分的产生率而不是声音成分的产生率为女性排卵提供了分级信息。然而，这些性叫声的声学参数而不是其产生率与雌性生育能力变化相关的可能性仍然存在。为了检验这一点，我们分析了在阿根廷伊瓜苏国家公园连续五个交配季节中 12 只性成熟雌性在发情期和交配后发出的叫声的结构和时间参数。通过女性生殖激素的图谱，将发情周期中女性可生育阶段发出的叫声与不可生育阶段发出的叫声进行比较。同样，在可生育阶段，我们测试了叫声的时间或频谱声学参数是否随着排卵的临近而逐渐变化。我们没有发现发情期或交配后叫声的叫声参数与女性生育能力的两种衡量标准之间存在任何显著关系。然而，发情前和发情后叫声之间存在一些差异。总体而言，我们的研究结果表明，黑帽卷尾猴雌性的性叫声并没有提供关于排卵时间的精确信息，但可能允许听众对交配是否发生做出概率推断。这一点，加上之前的发现，表明我们研究中的雌性可能会使用不同的信号来传达其生育能力和性行为的信息，其精确程度各不相同。
