Sex-Ratio Selection in Species with Helpers at the Nest: Some Extensions of the Repayment Model
Sex-Ratio Selection in Species with Helpers at the Nest: Some Extensions of the Repayment Model
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DOI：
10.1086/284661
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发表时间：
1987-04
期刊：
影响因子：
--
通讯作者：
C. M. Lessells;M. Avery
中科院分区：
文献类型：
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作者：
C. M. Lessells;M. Avery
虽然在性别分配的经典模型中，父母的适应性仅仅来自于他们儿子和女儿的繁殖，但在巢中有雄性帮手的物种的父母也会通过儿子的帮助来获得适应性。因此，进化稳定（ES）的性别比例可能偏向于男性（Trivers and Hare 1976; Clark 1978; Gowaty and Lennartz 1985）。最近，Emlen等人（1986 a）提出了一个分析模型，可以计算具有辅助物种的ES性比。他们优雅的模型是特别受欢迎的，因为它允许预测ES性别比例的参数，这些参数在现场很容易测量，便于模型的测试。在这里，我们以他们的偿还模型为出发点，并使用它来推导出一个更简单的替代表达式的ES比例的男性，以显示如何ES性别比例取决于额外的因素，他们没有考虑（包括帮助者的性别及其与被帮助者的关系），并预测红冠啄木鸟的ES性比（Lennartz 1983; Gowaty and Lennartz 1985; Lennartz等人，印刷中）。
Although in classical models of sex allocation parents accrue fitness solely from their sons' and daughters' reproduction, parents of species with male helpers at the nest accrue fitness through their sons' help, as well. As a consequence, the evolutionarily stable (ES) sex ratio may be biased toward males (Trivers and Hare 1976; Clark 1978; Gowaty and Lennartz 1985). Recently, Emlen et al. (1986a) have provided an analytical model that allows the calculation of ES sex ratios in species with helpers. Their elegant model is particularly welcome, since it allows the prediction of ES sex ratios from parameters that are readily measurable in the field, facilitating the testing of the model. Here we take their repayment model as a starting point and use it to derive a simpler alternative expression for the ES proportion of males, to show how the ES sex ratios depend on additional factors not considered by them (including the sex of helpers and their relationship with the helped adult), and to predict the ES sex ratio for red-cockaded woodpeckers Picoides borealis (Lennartz 1983; Gowaty and Lennartz 1985; Lennartz et al., in press).