Dowling Jenélle, Webster Michael S
Cornell Lab of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA
Cornell Lab of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA.
Biol Lett. 2017 Jan;13(1). doi: 10.1098/rsbl.2016.0682.
When mates are limited, individuals should allocate resources to mating tactics that maximize fitness. In species with extra-pair paternity (EPP), males can invest in mate guarding, or, alternatively, in seeking EPP. Males should optimize fitness by adjusting investment according to their attractiveness to females, such that attractive males seek EPP, and unattractive males guard mates. This theory has received little empirical testing, leaving our understanding of the evolution of mating tactics incomplete; it is unclear how a male's relative attractiveness influences his tactics. We conducted observations and experiments on red-backed fairy-wrens (Malurus melanocephalus) to address this question. We found that older, more attractive (red-black) males sought EPP, whereas unattractive (brown) males invested in alternative tactics-physical and acoustic mate guarding. Younger red-black males used intermediate tactics. This suggests that males adopt mating tactics appropriate to their attributes. Males obtained similar reproductive success, suggesting these alternative tactics may maximize each male's paternity gain. Though it is likely that female choice also determines paternity, rather than just male tactics, we establish that the many interconnected components of a male's sexual phenotype influence the evolution of his decision-making rules, deepening our understanding of how mating tactics evolve under sexual selection.
当配偶数量有限时，个体应将资源分配到能使适应性最大化的交配策略上。在存在婚外父权制（EPP）的物种中，雄性可以投入精力进行配偶守护，或者选择寻求婚外父权。雄性应根据自身对雌性的吸引力来调整投入，从而优化适应性，即有吸引力的雄性寻求婚外父权，而缺乏吸引力的雄性守护配偶。这一理论几乎没有得到实证检验，使得我们对交配策略进化的理解并不完整；目前尚不清楚雄性的相对吸引力如何影响其策略。我们对红背细尾鹩莺（Malurus melanocephalus）进行了观察和实验来解决这个问题。我们发现，年龄较大、更具吸引力（红黑色）的雄性寻求婚外父权，而缺乏吸引力（棕色）的雄性则采取其他策略——身体和声音上的配偶守护。较年轻的红黑色雄性则采用中间策略。这表明雄性会采用与其自身特征相适应的交配策略。雄性获得了相似的繁殖成功率，这表明这些不同的策略可能会使每个雄性的父权收益最大化。虽然很可能雌性选择也决定了父权归属，而不仅仅是雄性策略，但我们证实了雄性性表型的许多相互关联的组成部分会影响其决策规则的进化，加深了我们对交配策略在性选择下如何进化的理解。
