In gynodioecious plant species, both female and hermaphrodite individuals produce fruit, but only hermaphrodites produce pollen. Such sex-specific differences in reproductive investment may contribute to dimorphism, but the magnitude and ecological effects are still unclear, especially for gynodioecious tropical trees where collecting flowers and determining the sex is complex. We documented flowering and fruiting over three years in a natural population of Ocotea oblonga (Lauraceae) trees in a tropical moist forest, Panama. We determined sex from freshly collected flowers, counted and measured fruit, and used long-term growth data for each individual. We confirmed that O. oblonga is gynodioecious. No tree switched sex or had flowers of both sexes. The population was hermaphrodite-biased. We found no ecological differences in reproductive investment (seed, fruit, or tree size, or growth rate) between the sexes, indicating that the sex differential in the cost of reproduction is much smaller in woody gynodioecious taxa than in dioecious taxa. Females produced more fruit than hermaphrodites, which may contribute to their persistence in the population. Accordingly, and contrary to most studies of temperate gynodioecious populations, our study of a tropical tree shows no differential cost of reproduction in a hermaphrodite-biased population. Consequently, other factors such as seed fertility or herbivory could drive the biased sex ratio in this population.

中文翻译：

---

雌雄同体的Ocotea longlonga （Lauraceae）的开花性别比和繁殖成本

在雌雄同体的植物物种中，雌雄同体均产生果实，但只有雌雄同体产生花粉。生殖投资中的这种性别差异可能会导致二态性，但是其程度和生态影响仍然不清楚，特别是对于雌雄同株的热带树木，那里的花朵采集和确定性别很复杂。我们记录了在热带潮湿森林（巴拿马）中自然生长的Ocotea longlonga（Lauraceae）树超过三年的开花结果。我们从刚采集的花朵中确定性别，对水果进行计数和测量，并使用每个人的长期生长数据。我们确认了O.oblonga是雌雄同体的。没有树发生性关系或有两性花。人口是雌雄同体的。我们发现两性之间在生殖投资（种子，果实，树的大小或生长率）上没有生态学差异，这表明木本雌雄同体的分类单元中生殖成本的性别差异要比雌雄同体的分类单元小得多。雌性的果实比雌雄同体的果实更多，这可能有助于其在种群中的持久性。因此，与大多数对温带雌雄同体种群的研究相反，我们对热带树木的研究表明，在雌雄同体的种群中，繁殖成本没有差别。因此，其他因素，例如种子的繁殖力或草食性，可能会导致该种群的性别比出现偏差。