Breeding synchrony and extrapair paternity in a species with alternative reproductive strategies

Breeding synchrony may affect the tradeoff between pursuing multiple mates and avoiding paternity loss, translating into differences in the rate of extrapair paternity (EPP). However, diverse empirical relationships between breeding synchrony and EPP remain challenging to explain. We examined whether the relationship between breeding synchrony and EPP varied with male morph, age, body size, or breeding density in the white-throated sparrow Zonotrichia albicollis. In this species, males of two genetically determined morphs pursue alternative mating strategies. Breeding synchrony positively correlated with EPP within polygamous white morph males, which have high rates of EPP and cuckoldry, but was unrelated to EPP within tan morph males, which prioritize mate guarding and paternal care. As previously reported, males that gained EPP were primarily white males. Males gained EPP more often than expected by chance during their mate’s fertile period and on neighboring territories. Since extrap...

繁殖同步性或可影响追求多配偶与避免父权丧失之间的权衡，进而体现在婚外父权（extrapair paternity, EPP）发生率的差异上。然而，繁殖同步性与婚外父权之间多样的实证关联迄今仍难以得到合理解释。我们以白喉带鹀（Zonotrichia albicollis）为研究对象，探究二者的关系是否会随雄性色型、年龄、体型或繁殖密度发生变化。该物种中，两种由遗传决定的雄性色型分别采取差异化的交配策略：实行一夫多妻制的白色型雄性，其婚外父权与配偶被窃率均较高，繁殖同步性与婚外父权呈正相关；而优先采取配偶守卫与父本抚育策略的棕褐色型雄性，其繁殖同步性与婚外父权则无关联。正如此前研究所报道的，获得婚外父权的个体主要为白色型雄性。雄性在其配偶的可育期以及邻近领地中，获得婚外父权的概率显著高于随机水平。由于婚外