两性之间的配子大小差异是性别角色概念的核心,然而,性别内配子大小变化与性别角色变化的关系在多大程度上尚不清楚。比较和理论研究表明,当离合器尺寸不变时,一夫多妻制与鸡蛋大小的减少有关,当雌性不能垄断多个雄性时,雌性对配偶的竞争增加有利于早期繁殖。为了了解是否以及如何繁殖物候,鸡蛋大小,交配行为在个体层面上是相关的,我们研究了15年来在野外观察到的424只白雪公主雌性的生殖历史。鸡蛋大小,但不是一妻多夫,对于个别女性来说是高度可重复的。与理论预测一致,我们发现,一夫多妻制的雌性是最早的繁殖者,早期的离合器包含比后来开始的离合器更小的卵。卵的大小和交配行为都没有显示出明显的与年龄有关的恶化迹象,相反,通过年龄或当地招募获得的先前经验使女性能够提早筑巢。一起来看,这些结果表明,配子大小的变化与个体水平的交配行为无关,and,因此,这种变化的适应性潜力似乎是有限的。
Gamete size variation between the sexes is central to the concept of sex roles, however, to what extent gamete size variation within the sexes relates to sex role variation remains unclear. Comparative and theoretical studies suggest that, when clutch size is invariable, polyandry is linked to a reduction of egg size, while increased female-female competition for mates favors early breeding when females cannot monopolize multiple males. To understand whether and how breeding phenology, egg size, and mating behavior are related at the individual level, we studied the reproductive histories of 424 snowy plover females observed in the wild over a 15-year period. Egg size, but not polyandry, were highly repeatable for individual females. Consistent with theoretical predictions, we found that polyandrous females were the earliest breeders and that early clutches contained smaller eggs than clutches initiated later. Neither egg size nor mating behavior showed clear signs of an age-related deterioration, on the contrary, prior experience acquired either through age or local recruitment enabled females to nest early. Taken together, these results suggest that gamete size variation is not linked to mating behavior at the individual level, and, consequently, the adaptive potential of such variation appears to be limited.