Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
Mitrani Department of Desert Ecology, The Swiss Institute for Dryland Environments and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
Evolution. 2023 Jul 27;77(8):1829-1841. doi: 10.1093/evolut/qpad101.
Sexual selection has long been thought to increase species diversification. Sexually selected traits, such as sexual signals that contribute to reproductive isolation, were thought to promote diversification. However, studies exploring links between sexually selected traits and species diversification have thus far primarily focused on visual or acoustic signals. Many animals often employ chemical signals (i.e., pheromones) for sexual communications, but large-scale analyses on the role of chemical communications in driving species diversification have been missing. Here, for the first time, we investigate whether traits associated with chemical communications-the presence of follicular epidermal glands-promote diversification across 6,672 lizard species. In most analyses, we found no strong association between the presence of follicular epidermal glands and species diversification rates, either across all lizard species or at lower phylogenetic scales. Previous studies suggest that follicular gland secretions act as species recognition signals that prevent hybridization during speciation in lizards. However, we show that geographic range overlap was no different in sibling species pairs with and without follicular epidermal glands. Together, these results imply that either follicular epidermal glands do not primarily function in sexual communications or sexually selected traits in general (here chemical communication) have a limited effect on species diversification. In our additional analysis accounting for sex-specific differences in glands, we again found no detectable effect of follicular epidermal glands on species diversification rates. Thus, our study challenges the general role of sexually selected traits in broad-scale species diversification patterns.
性选择长期以来被认为可以增加物种多样性。性选择特征，例如有助于生殖隔离的性信号，被认为可以促进多样化。然而，迄今为止，探索性选择特征与物种多样化之间联系的研究主要集中在视觉或听觉信号上。许多动物通常使用化学信号（即信息素）进行性交流，但关于化学通讯在推动物种多样化中的作用的大规模分析尚属空白。在这里，我们首次调查了与化学通讯相关的特征（即滤泡表皮腺的存在）是否会促进 6672 种蜥蜴物种的多样化。在大多数分析中，我们没有发现滤泡表皮腺的存在与物种多样化率之间存在很强的关联，无论是在所有蜥蜴物种中还是在较低的系统发育尺度上。先前的研究表明，滤泡腺分泌物在蜥蜴的物种形成过程中充当种间识别信号，以防止杂交。然而，我们表明，具有和不具有滤泡表皮腺的姐妹种对之间的地理范围重叠没有差异。这些结果表明，滤泡表皮腺要么主要不在性通讯中起作用，要么性选择特征（此处为化学通讯）对物种多样化的影响有限。在我们考虑腺体性别差异的额外分析中，我们再次没有发现滤泡表皮腺对物种多样化率有明显影响。因此，我们的研究挑战了性选择特征在广泛的物种多样化模式中的一般作用。
