Surviving in a Cosexual World: A Cost-Benefit Analysis of Dioecy in Tropical Trees
Surviving in a Cosexual World: A Cost-Benefit Analysis of Dioecy in Tropical Trees
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DOI：
10.1086/690137
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发表时间：
2017-03-01
影响因子：
2.9
通讯作者：
Jongejans, Eelke
中科院分区：
文献类型：
--
作者：
Bruijning, Marjolein;Visser, Marco D.;Jongejans, Eelke
与雌雄同体相比，雌雄同体有一个人口统计学上的劣势：只有大约一半的生殖成虫产生种子。因此，雌雄异株物种必须具有适应度优势，以通过增加生存、生长和/或繁殖来补偿这一成本。我们使用全生命周期方法来量化与雌雄异株相关的人口成本和收益，同时控制与其他功能特征相关的雌雄异株和两性物种之间的人口差异。这种新方法的优点是，我们可以专注于不同树木群落中繁殖系统的影响。我们使用长期人口统计数据和新收集的生殖数据，建立了巴拿马巴罗科罗拉多岛两性和雌雄异株树木种群的复合积分投影模型。综合所有成本和效益表明，补偿是通过增加种子产量实现的，因此没有雌雄异株的净成本。再生产对人口增长的贡献很低，这也促进了补偿。估计雌雄异株对树木生长和存活的积极影响很小，对种群增长率也不显著。我们的模型显示，对于长寿的生物体来说，生育雄性的成本比通常预期的要低。因此，雌雄异株物种几乎不需要补偿来维持与两性物种相似的种群增长率。
Dioecy has a demographic disadvantage compared with hermaphroditism: only about half of reproductive adults produce seeds. Dioecious species must therefore have fitness advantages to compensate for this cost through increased survival, growth, and/or reproduction. We used a full life cycle approach to quantify the demographic costs and benefits associated with dioecy while controlling for demographic differences between dioecious and hermaphroditic species related to other functional traits. The advantage of this novel approach is that we can focus on the effect of breeding system across a diverse tree community. We built a composite integral projection model for hermaphroditic and dioecious tree populations from Barro Colorado Island, Panama, using long-term demographic and newly collected reproductive data. Integration of all costs and benefits showed that compensation was realized through increased seed production, resulting in no net costs of dioecy. Compensation was also facilitated by the low contribution of reproduction to population growth. Estimated positive effects of dioecy on tree growth and survival were small and insignificant for population growth rates. Our model revealed that, for long-lived organisms, the cost of having males is smaller than generally expected. Hence, little compensation is required for dioecious species to maintain population growth rates similar to those of hermaphroditic species.