【作者】 王慧；

【导师】 吴华；

【作者基本信息】 华中师范大学 ， 动物学， 2014， 硕士

【摘要】 性选择对于动物的繁殖和进化至关重要,正是由于性选择(性内竞争和配偶选择)的作用导致与其适合度相关的性征进化,很多性选择的研究表明,这些性征不仅与交配成功相关也与繁殖成功密切相关。与身体大小相关的雄雄竞争和雌性选择对繁殖成功的影响在很多物种中都已经报道,且在很多动物中,身体较大的个体往往在争斗中具有一定的优势,从而增加了其交配和繁殖成功的机会,在两栖类配偶选择的研究中发现,优势个体往往是那些个体较大或年长的个体。研究清楚影响物种繁殖成功的因素对了解其繁殖行为和繁殖策略有重大意义。而对于两栖纲树蛙属的峨眉树蛙(Rhacophorus omeimontis),目前的研究,仅仅局限于交配和产卵行为、产卵地的选择、泡沫巢的特征、以及身体大小和年龄对峨眉树蛙雄性交配成功率的影响,而对影响其繁殖成功的因素还尚不可知。而且之前对于峨眉树蛙的研究,仅仅用雄性能够接近的雌性数量或者交配成功率来代表其繁殖成功,但是严格意义上来讲,交配成功或者是否能够接近雌性都不能准确地代表其繁殖成功率,因为只有拥有能够存活下来的子代才能认为某个个体获得了繁殖成功,这必须借助遗传分子标记。因此本研究用峨眉树蛙作为研究对象,利用微卫星分子标记对其进行了父权鉴定,并分析了雌雄个体体长和抱对性比对繁殖成功的影响。本实验共记录到154个(雌性29个；雄性125个)峨眉树蛙的体长,对29个抱对的窝卵数、抱对性比及受精率进行了统计,通过9个微卫星位点在22个父权鉴定成功的抱对中发现,几乎84.6%的抱对中都是多父系,抱对性比为1-8,不是所有的雄性都有后代。通过分析得知,抱对雌性的体长与窝卵数和受精率、雄性体长与其子代比例间均没有较明显的相关性；抱对性比与窝卵数和子代比例间也没有明显相关性,但是抱对性比与受精率之间明显相关(P<0.05)。在所有抱对中,雄性中存在着较严重的繁殖偏倚,并随着抱对性比的增加而显著降低(P<0.001)。随着雄性的增多,得到繁殖利益的雄性也增多,雄性的繁殖偏倚随之降低。与此相对应的,随着抱对中参加繁殖雄性的增加,受精率也随之增加,这个结果很好的解释了峨眉树蛙中一雌多雄的繁殖模式,一雌多雄的交配策略增加了个体的繁殖成功,这种一雌多雄潜在的繁殖利益很可能是造成峨眉树蛙中高水平多父系的一个原因,也是造成一雌多雄繁殖模式的原因。更多还原

【Abstract】 Sexual selection is quite crucial to breeding and evolution of animals. It leads to the evolution of traits related to fitness. Many studies have shown that these traits are not only associated with mating success, but also closely related to the reproductive success. Furthermore, the influence of male-male competition and female choice based on body size on reproductive success has also been reported widely. And in most animals, individuals with lager body size can benefit more from the competition and enhance the chance of mating. Especially in amphibians, dominant individuals tend to be the lager or older ones.It’s a great significance for studying the factors affecting reproductive success of animals, by which we can understand the reproductive behavior and reproductive strategies of species. For Rhacophorus omeimontis, current studies are limited to mating behavior, spawning, spawning sites, foam-nest features, the influence of body size and individual age on mating success, and the factors affecting the reproductive success have not yet been explained. Also in previous studies, the reproductive success tends to be represented by the number of males which can approach to females. But strictly speaking, this method is inadequate because an individual may get reproductive success only if they have survived offspring. In order to solve the uncertain problems above, we need to import genetic molecular markers.In our studies, we have used microsatellite makers to identify paternity in the Omei tree frog, and analyzed the impact of body size and sexual ratio on reproductive success. About 154 individuals (29 females; 125males) of body size,29 clutches in clutch size, sexual ratio and fertilization rate were collected from breeding site. We found that, almost 84.6% of clutches were multi-paternity from paternity analysis in nine microsatellite loci. The clutching sex ratio was one to eight and not all males had offspring.There were no significant correlations between females’body size and clutch size or fertilization rate, male body size and the proportion of offspring, and the same with the clutching sex ratio and the proportion of offspring. However, a significant correlation was found between sexual ratio and fertilization rate (P<0.05). In all clutches, there was an obvious reproductive skew in males, and it decreased extremely significantly with clutching sex ratio increasing (P<0.001).Along with the increase in the number of mating males, the number of males gaining fitness enhanced and the male-biased reproductive skew decreased. Correspondingly, fertilization rate increased with the increase in clutching sex ratio. These results explained clearly the polyandry in R. omeimontis, which bring higher fitness for them. Such potential benefit is likely to be one reason of high levels of multi-paternity in R. Omeimontis.更多还原