一妻多夫交配方式的演化與生態機制是一個重要且有挑戰性的研究主題。對體 外受精的蛙類來說，同時性的一妻多夫交配定義為任一產卵事件中，來自兩個以上 的雄性精子讓卵受精，包括一個雌性同時與多個雄性假交配，兩性同時釋放精與卵 的生殖方式。樹蛙科卵泡生殖的物種，是同時性一妻多夫交配發生比例最高的蛙類 類群，是研究一妻多夫交配的演化機制之最佳生物題材。本研究擬以 3 年為期，以 樹蛙科的白頷樹蛙為對象，利用野外的行為觀察、蝌蚪的生活史表現、遺傳及親子 關係分析、及改變生殖資源的數量，探討一妻多夫交配方式在演化適應及生態上的 意義。第 1‐2年將以野外標放、夜間觀察及蝌蚪飼養實驗，比較同時性一妻一夫及 一妻多夫交配所產的卵之受精成功率與蝌蚪的適存度表現，探討同時性一妻多夫的 交配方式，是否能提高雌蛙的生殖成功。並將以微衛星基因座，進行雄蛙及受精卵 的親子關係分析，研究同時性一妻多夫的交配是否因多個雄性提供精子，而增加一 窩子代內的遺傳多樣性，讓雌蛙獲得遺傳上的利益。第 3年的研究擬利用人為的方 式增加白頷樹蛙的生殖產所，研究生殖場所的增加，是否影響白頷樹蛙生殖族群的 密度、操作型性比、產卵數量、及交配方式等生殖生態，探討生殖場所數量對交配 系統及同時性一妻多夫交配比例的影響。
Study of the evolutionary causes and consequences of polyandry is an important and challenging subject in evolutionary biology. For anurans with external fertilization, simultaneous polyandry is defined as any egg deposition event where sperm from two or more males fertilize eggs, including the mating that a female mates with multiple males at the same time. Simultaneous polyandry has been observed in 10 species of foam‐nesting frogs in Rhacophoridae, and these foam-nesters serve as good animal models to study the evolution of polyandry. The objective of this project is to study the adaptive significances of simultaneous polyandry in a foam‐nester, Polypedates braueri by field observation, field experiment, and genetic analyses. During the first two year, the first experiment is going to compared the fertilization success between the egg clutches, and the fitness of tadpoles that deposited by simultaneous monogamous and polyandrous matings, which will help us to find out whether polyandry can increase female fecundity and reproductive success. In the second experiment, we will reveal if multiple paternity occurs within a clutch naturally deposited by simultaneous polyandrous mating via genetic analyses between male and female frogs and fertilized eggs. The occurrence of multiple paternity may providing an evidence that simultaneous polyandry could increase of the offspring's genetic diversity within a single clutch. In the third year, we are planning to increase the number of artificial ponds in the field, and to analysis the outcomes of effects of different number of reproductive sites on population density, operational sex ratio, and mating behavior.
