Studies on genetic variability and its significance in population ecology of wildlife

遗传随机性是导致种群灭绝的众多潜在原因之一。本研究的目的是了解遗传变异如何随着种群规模的减少或栖息地的破坏而变化，以及遗传变异的降低如何影响动物的繁殖产量。在种群减少的过程中，种群可能遭受显著的遗传退化，即遗传变异的降低，这可能导致适应度(生存和繁殖)的相应下降。由于体能通常可以被测量为波动不对称(FA)，我们分析了FA与各种健康相关特征的关系，如存活增长率、领地和/或在几种动物中的繁殖成功。我们发现在蜻蜓、蝴蝶和蚊子等昆虫中，交配成功率与FA呈负相关。对几种雀形目鸟类的FA测量表明，种群密度和分布范围与FA的种群平均值呈负相关，FA可能受到遗传和环境胁迫的影响。我们测试了密度对一种鱼(Oryzias Latipe)生长和FA的影响。结果，密度对平均生长速度有影响，但对FA没有影响。这表明，至少在该物种中，遗传效应比密度(环境)效应在FA的中介中更重要。

Genetic stochasticity is one of many potential causes of extinction in samall populations. The objects of this research is to know how genetic variability changes according to the reduction of population size or habitat destruction, and how the decrease in genetic variability influences the reproductive output of animals.In the process of population decrease, populations may suffer a significant genetic deterioration, namely a decrease in genetic variability, which may lead to a corresponding decrease in fitness (survival and reproduction). As Fitness can often be measured as fluctuating asymmetry (FA), we analyzed FA in relation to various fitness-related characters, such as survival growth rate, territoriality and/or reproductive success in several animals. We found negative correlation between mating success and FA in insects including dragonflies, butterflies and midges. FA measurements on several passerine birds revealed that population density and the distribution ranges were negatively correlated with population mean of FA.FA may be influenced both by genetic and environmental stresses. We tested the effect of density on the growth and FA of a fish (Oryzias latipes). As a result, we detected density effects on average growth rate but not on FA.This suggests that a genetic effect is more important in the mediation of FA than density (environmental) effect at least in this species.