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

遗传随机性是小种群灭绝的许多潜在原因之一。本研究的目的是了解随着种群规模的减小或栖息地的破坏，遗传变异性如何发生变化，以及遗传变异性的降低如何影响动物的繁殖产量，在种群减少的过程中，种群可能会发生显著的遗传退化，即遗传变异性降低，从而导致相应的适合度（生存和繁殖）降低。由于健身往往可以衡量波动的不对称性（FA），我们分析了FA与各种健身相关的字符，如生存增长率，领土和/或繁殖成功的几种动物。在蜻蜓、蝴蝶和蠓等昆虫中，交配成功率与FA呈负相关。对雀形目鸟类的FA测定结果表明，种群密度和分布范围与种群平均FA值呈负相关，FA值可能受遗传和环境胁迫的共同影响。我们测试了密度对鱼（Oryzias latipes）生长和FA的影响。其结果是，我们检测到的平均增长率的密度效应，但没有FA。这表明，遗传效应是更重要的FA比密度（环境）的影响，至少在这个物种的调解。

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.