Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany.
Zoology III Department of Animal Ecology and Tropical Biology, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
Proc Biol Sci. 2024 Jan 10;291(2014):20231693. doi: 10.1098/rspb.2023.1693.
Intraspecific chemical communication in frogs is understudied and the few published cases are limited to externally visible and male-specific breeding glands. Frogs of the family Odontobatrachidae, a West African endemic complex of five morphologically cryptic species, have large, fatty gland-like strands along their lower mandible. We investigated the general anatomy of this gland-like strand and analysed its chemical composition. We found the strand to be present in males and females of all species. The strand varies in markedness, with well-developed strands usually found in reproductively active individuals. The strands are situated under particularly thin skin sections, the vocal sac in male frogs and a respective area in females. Gas-chromatography/mass spectrometry and multivariate analysis revealed that the strands contain sex- and species-specific chemical profiles, which are consistent across geographically distant populations. The profiles varied between reproductive and non-reproductive individuals. These results indicate that the mandibular strands in the Odontobatrachidae comprise a so far overlooked structure (potentially a gland) that most likely plays a role in the mating and/or breeding behaviour of the five species. Our results highlight the relevance of multimodal signalling in anurans, and indicate that chemical communication in frogs may not be restricted to sexually dimorphic, apparent skin glands.
蛙类种内化学通讯研究较少，少数已发表的案例仅限于外部可见的雄性特化繁殖腺。齿蟾科是一个西非特有、由五个形态上隐蔽的物种组成的复杂类群，其成员具有沿着下颌下部延伸的大型、脂肪状的类似腺体的结构。我们研究了这种类似腺体的结构的一般解剖结构，并分析了其化学组成。我们发现该结构存在于所有物种的雄性和雌性个体中。该结构在明显程度上存在差异，通常在生殖活跃的个体中发现发育良好的结构。这些结构位于特别薄的皮肤区域下，雄蛙的声囊和雌蛙的相应区域。气相色谱/质谱联用和多元分析表明，这些结构包含性别和物种特异性的化学特征，这些特征在地理上遥远的种群中是一致的。这些特征在生殖和非生殖个体之间存在差异。这些结果表明，齿蟾科的下颌结构包含一个迄今为止被忽视的结构（可能是一种腺体），它很可能在这五个物种的交配和/或繁殖行为中发挥作用。我们的结果强调了多模态信号在无尾两栖动物中的相关性，并表明蛙类的化学通讯可能不仅限于性二态、明显的皮肤腺体。
