Kahn Penelope C, Cao Dennis D, Burns Mercedes, Boyer Sarah L
Biology Department Macalester College St. Paul Minnesota.
Chemistry Department Macalester College St. Paul Minnesota.
Ecol Evol. 2018 Jun 22;8(14):7103-7110. doi: 10.1002/ece3.4232. eCollection 2018 Jul.
Nuptial gifts are material donations given from male to female before or during copulation and are subject to sexual selection in a wide variety of taxa. The harvestman genus has emerged as a model system for understanding the evolution of reproductive morphology and behavior, as transitions between solicitous and antagonistic modes of courtship have occurred multiple times within the lineage and are correlated with convergence in genital morphology. We analyzed the free amino acid content of nuptial gift secretions from five species of using gas chromatography-mass spectrometry. Multivariate analysis of the free amino acid profiles revealed that, rather than clustering based on phylogenetic relationships, nuptial gift chemical composition was better predicted by genital morphology and behavior, suggesting that convergent evolution has acted on the chemical composition of the nuptial gift. In addition, we found that, species with solicitous courtship produce gifts consisting of a 19% larger proportion of essential amino acids as compared to those with more antagonistic courtship interactions. This work represents the first comparative study of nuptial gift chemistry within a phylogenetic framework in any animal group and as such contributes to our understanding of the evolution of reproductive diversity and the participant role of nuptial gift chemistry in mating system transitions.
婚赠礼物是雄性在交配前或交配期间给予雌性的物质馈赠，在各种各样的分类群中都受到性选择的影响。收获蛛属已成为理解生殖形态和行为进化的一个模型系统，因为在该谱系中求偶的殷勤模式和对抗模式之间的转变已经多次发生，并且与生殖器形态的趋同相关。我们使用气相色谱 - 质谱分析法分析了五种收获蛛婚赠礼物分泌物中的游离氨基酸含量。对游离氨基酸谱的多变量分析表明，婚赠礼物的化学成分不是基于系统发育关系聚类，而是通过生殖器形态和行为能更好地预测，这表明趋同进化作用于婚赠礼物的化学成分。此外，我们发现，与求偶互动更具对抗性的物种相比，求偶殷勤的物种产生的礼物中必需氨基酸的比例要大19%。这项工作代表了在任何动物群体的系统发育框架内对婚赠礼物化学的首次比较研究，因此有助于我们理解生殖多样性的进化以及婚赠礼物化学在交配系统转变中的参与作用。
