The polygyny threshold model predicts that a female chooses an already-mated male if the direct benefits of higher territorial quality compensate for the cost of mate sharing. The sexy son hypothesis (SSH) expands this framework from direct to indirect benefits assuming that polygynously-mated females give birth to sexy and subsequently polygynous sons. Although the SSH has generated much debate, empirical evidence is inconclusive. I argue that lack of support could be related to the SSH formulation of the polygyny threshold as a population-level mechanism making the female choice of a polygynous male either advantageous or disadvantageous regardless of any other difference between potential mates. Using a simulation approach, I show that individual variation in males’ quality should be considered because, otherwise, the empirical validation of the hypothesis is hampered, giving rise to patterns that are apparently irreconcilable with the SSH predictions.

中文翻译：

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个体变异在性感儿子假说中被忽视的作用

一夫多妻阈值模型预测，如果更高领土质量的直接好处补偿了配偶共享的成本，则雌性会选择已经交配的雄性。性感儿子假说 (SSH) 将这一框架从直接利益扩展到间接利益，假设一夫多妻的雌性生下性感的儿子，随后又生出一夫多妻的儿子。尽管 SSH 引起了很多争论，但经验证据尚无定论。我认为，缺乏支持可能与一夫多妻阈值的 SSH 表述有关，作为一种人口级别的机制，无论潜在配偶之间的任何其他差异如何，女性选择一夫多妻的男性都是有利的或不利的。使用模拟方法，我表明应该考虑男性质量的个体差异，否则，