Solitary species often employ chemocommunication to facilitate mate localization. In the solitarily foraging, nocturnal mouse lemurs (Microcebus spp.), females advertise their short period of estrus acoustically and by increased scent marking, whereas males search widely for receptive females. Both sexes can be trained by operant conditioning to discriminate conspecific from heterospecific urine scent. However, it is not known, if males during and outside the reproductive season show different spontaneous interest in conspecific female urine, and if urine from estrous females elicits a higher investigation response than that from diestrous females. We established a spontaneous discrimination paradigm and quantified olfactory investigation responses of 21 captive male mouse lemurs of M. lehilahytsara and M. murinus when presenting 1 conspecific and 1 heterospecific female urine odor sample simultaneously. Overall, M. murinus investigated stimuli significantly longer than M. lehilahytsara. Moreover, males of M. murinus showed significantly longer olfactory investigation at conspecific urine samples during but not outside the reproductive season. This indicates that female urinary cues are spontaneously discriminated by male M. murinus and that this discrimination is more relevant during the reproductive season. However, males of both species did not show different responses toward urine samples from estrous versus diestrous females. Finally, male age did not correlate with the overall duration of olfactory investigation, and investigation levels were similar when testing with fresh or frozen urine samples. In conclusion, this new spontaneous discrimination paradigm provides a useful additional tool to study olfactory communication of nocturnal primates from the receiver’s perspective.

中文翻译：

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在两个夜间灵长类动物（Microcebus murinus和M. lehilahytsara）中自发嗅觉辨别的实验评估。

孤独的物种通常采用化学通讯来促进伴侣的定位。在单独觅食的夜间鼠狐猴（Microcebus spp。）中，雌性通过发声和增强的气味标记来宣传短发情期，而雄性则广泛寻找雌性。可以通过手术条件训练男女来区分同种异物和异种尿味。然而，尚不清楚，在繁殖季节内外，雄性是否对同种雌性尿表现出不同的自发兴趣，以及发情雌性的尿是否比雌雄性雌性引起更高的调查反应。我们建立了自发的歧视范例，并量化了21只圈养的雄性小鼠狐猴的嗅觉调查反应。M. lehilahytsara和M. murinus同时呈现1个同种和1个异种女性尿液气味样品时。总体而言，M.鼱刺激调查显著长于M. lehilahytsara。此外，在生殖季节之外但不在生殖季节之外，对M. murinus的雄性在同种尿样中显示出更长的嗅觉研究。这表明雌性泌尿线索由雄性M. murinus自发区分。并且这种歧视在生殖季节更加重要。但是，这两种物种的雄性对发情和雌性雌性的尿液样本均未显示出不同的反应。最后，男性年龄与嗅觉调查的总持续时间无关，并且在用新鲜或冷冻尿液样本进行测试时调查水平相似。总之，这种新的自发歧视范式为从接收者的角度研究夜间灵长类动物的嗅觉交流提供了有用的附加工具。