Bet-hedging and the evolution of multiple mating
Bet-hedging and the evolution of multiple mating
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发表时间：
2003-02
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通讯作者：
C. Fox;Claudia M. Rauter
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作者：
C. Fox;Claudia M. Rauter
人们提出了两个相关的赌注对冲假设来解释雌性多次交配的进化。第一个研究检查了雌性在单一类型环境中的适应性，并预测多次交配可以通过降低所有雌性卵子都被劣质雄性受精的可能性来提高适应性。第二个研究检查了不同环境的适应性，并预测多次交配的雌性会降低其所有卵子被不适合当前环境的雄性受精的可能性。我们通过比较在三种不同寄主植物上饲养的马利筋虫（Lygaeus kalmii）的半同胞与全同胞家族的几何平均适应性，测试了多重交配是否确实提供了赌注对冲模型预测的适应性益处。半同胞家庭的后代的平均适应度（从卵到成体的存活率）的方差总是低于全同胞家庭的后代。这意味着多次交配的父母与一次交配的父母的后代的几何平均适应度在环境中平均增加了 4.1%，在环境中平均增加了 1.3%。这些适应度的增加足以使多次交配基因型快速取代一次交配基因型。我们得出的结论是，父母的多次交配减少了后代适应度的变化并增加了几何平均适应度。我们认为，对冲假设至少可以解释昆虫中观察到的交配频率的某些变化。
Two related bet-hedging hypotheses have been proposed to explain the evolution of multiple mating by females. The first examines fitness of females within a single type of environment, and predicts that multiple mating can increase fitness by reducing the probability that all of a female's eggs are fertilized by a poor-quality male. The second examines fitness across environments and predicts that females who mate multiple times reduce the probability that all of their eggs are fertilized by a male that is unsuited to the current environment. We tested whether multiple mating actually provides the fitness benefits predicted by bet-hedging models by comparing the geometric mean fitness across generations of half-sib versus full-sib families of the milkweed bug, Lygaeus kalmii, reared on three different host plants. The variance in mean fitness (egg-to-adult survivorship) was always lower for offspring in half-sib families than for offspring of full-sib families. This translated into an average increase in geometric mean fitness of 4.1% within environments and 1.3% among environments for offspring of multiple-mated versus once-mated parents. These fitness increases are sufficient to produce rapid replacement of a once-mating genotype by a multiple-mating genotype. We conclude that multiple mating by parents reduces variation in offspring fitness and increases geometric mean fitness. We suggest that bet-hedging hypotheses are viable explanations for at least some of the variation in mating frequency observed in insects.