An experimental test to separate the effects of male age and mating history on female mate choice

Should females prefer older males as mates? Male survival to old age might indicate the presence of fitness-enhancing genes that increase offspring fitness. However, many correlational studies show that mating with older males can lower female fecundity, and even reduce offspring fitness due to epigenetic or germline mutation effects. One problem in quantifying female choice based on male age is that age is usually confounded with mating history. This begs a question: Do females choose males based on their age, or their mating history? The answer requires an experimental approach, but few such studies exist. Here we test if experimentally-induced variation in the mating history of old and young males (12 week difference in post-maturity age) affects female choice in the eastern mosquitofish (Gambusia holbrooki). To vary mating history, adult males were either allowed to freely mate with females for three weeks, or they only had visual contact with females. Immediately thereafter, we ran...

雌性是否更倾向于选择年长雄性作为配偶？雄性能够存活至老年，或许暗示其携带了可提升后代适合度的优质基因。然而，诸多相关性研究表明，与年长雄性交配会降低雌性的繁殖力，甚至因表观遗传或种系突变效应而降低后代适合度。基于雄性年龄量化雌性择偶偏好的核心难题在于，年龄通常与交配史存在混淆效应。这引出了一个关键疑问：雌性究竟是依据雄性的年龄，还是其交配史来选择配偶？解答该问题需要采用实验方法，但目前此类实验研究为数不多。本研究旨在检验：人为操控性成熟后年龄相差12周的成年与年轻雄性的交配史变异，是否会影响东部食蚊鱼（Gambusia holbrooki）的雌性择偶行为。为操控交配史，实验将成年雄性分为两组：一组可自由与雌性交配三周，另一组仅能与雌性进行视觉接触。在此之后，我们随即开展……