Abstract

Despite strong selective pressures inherent in competition for mates, in species with non-resource-based mating systems males commonly engage in non-agonistic interactions with same-sex visitors at display arenas. Bowerbirds perform courtship dances on elaborate display structures — known as bowers — that are built and defended by one resident male. Several reports have suggested that bower owners tolerate the presence of specific male visitors at their display arenas, referred to here as ‘subordinates’. Subordinate males may learn the skills required for successful sexual signalling via prolonged social interactions at adults’ arenas, but little is known about whether courtship proficiency changes with experience and/or whether subordinates actively contribute to enhancing the resident male’s mating success. In this study, we investigated male-male associations in wild spotted bowerbirds (Ptilonorhynchus maculatus). We first sought to determine whether courtship behaviour differs based on bower ownership status. We then examined whether social interactions between bower owners and subordinate males may qualify as courtship coalitions. Our analysis of courtship postural components did not reveal differences in timing or relative occurrence of postural components between subordinate males and bower owners, whereas we found evidence that male-male associations in spotted bowerbirds may provide an example of rudimentary courtship coalitions. In particular, higher subordinate attendance is associated with lower destruction rates by neighbouring rivals and with overall higher mating success, and male pairs are stable in subsequent years. This study provides novel information about social dynamics among male bowerbirds, and further insights into the evolution of coalitionary behaviour in male displays.

Significance statement

Same-sex associations between established males and subordinate visitors on display arenas are common in birds, yet poorly understood. Using video recordings from a population of wild spotted bowerbirds, Ptilonorhynchus maculatus, we performed a quantitative analysis on motor courtship components across males, and on their social interactions on display arenas to investigate the nature of male–male partnerships. Our results showed that motor courtship performance in subordinate visitors is not suggestive of an early ontogenetic stage, as previously speculated. Moreover, though bower ‘owners’ and subordinate males do not coordinate their behaviour during courtship or bower building, male–male partnerships may qualify as a rudimentary or incipient form of courtship coalitions. Subordinate males are tolerated at bowers, the magnitude of subordinate attendance correlates with owner males’ mating success, and repeated interactions between individuals reveal consistent partner associations.

中文翻译：

---

斑点园丁鸟 (Ptilonorhynchus maculatus) 中的雄性协会表现出求爱联盟的属性

摘要

尽管在配偶竞争中存在强大的选择压力，但在具有非资源型交配系统的物种中，雄性通常会在展示场所与同性访客进行非竞争性互动。园丁鸟在精心制作的展示结构（称为凉亭）上表演求爱舞蹈，这些结构由一名常住雄性建造和保护。几份报告表明，凉亭所有者容忍特定男性访客出现在他们的展示场所，此处称为“下属”。下属雄性可能会通过在成人场所进行长时间的社交互动来学习成功发出性信号所需的技能，但对于求偶熟练程度是否会随着经验而变化和/或下属是否积极有助于提高常驻雄性的交配成功率知之甚少。在这项研究中，斑嘴龙). 我们首先试图确定求偶行为是否因凉亭所有权状况而异。然后，我们检查了凉亭所有者和下属男性之间的社交互动是否符合求爱联盟的条件。我们对求爱姿势成分的分析没有揭示下属雄性和凉亭所有者之间姿势成分的时间或相对发生的差异，而我们发现有证据表明斑点园丁鸟中的雄性协会可能提供了基本求爱联盟的一个例子。特别是，较高的下属出勤率与相邻竞争对手的较低破坏率以及整体较高的交配成功率相关，并且雄性配对在随后的几年中保持稳定。这项研究提供了关于雄性园丁鸟社会动态的新信息，

意义声明

已建立的雄性和下级访客在展示场所之间的同性联系在鸟类中很常见，但人们却知之甚少。使用来自野生斑点园丁鸟种群 Ptilonorhynchus maculatus的视频记录, 我们对男性的机动求爱成分以及他们在展示场上的社交互动进行了定量分析，以调查男性与男性伙伴关系的性质。我们的结果表明，下属访客的运动求爱表现并不像之前推测的那样暗示早期个体发育阶段。此外，尽管凉亭“所有者”和下属雄性在求爱或凉亭建造期间不会协调他们的行为，但雄性伙伴关系可能是求偶联盟的基本或初期形式。下属雄性在凉亭是被容忍的，下属出席的程度与主人雄性的交配成功相关，个体之间的反复互动揭示了一致的合作伙伴关系。