Studies on methods to evaluate the viability of wildlife populations

在种群减少的过程中，种群可能会发生显著的遗传退化，即遗传变异的减少，从而导致相应的适应度（生存和繁殖）的降低。由于适应度通常可以用波动不对称（FA）来衡量，我们分析了FA与几种动物的各种适应度相关特征的关系，如存活率、生长率、领土性和/或繁殖成功率。我们发现蜻蜓、蝴蝶和蠓等昆虫的交配成功率与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种群平均值呈负相关。雄性豆娘Mnais costalis在形态和行为上都是多态的，典型的是作为透明翅膀的无领地性的“偷窃者”和橙色翅膀的领地性的“战士”存在。用色度计测量的翅膀中橙色色素的数量在个体之间有所不同，随着繁殖季节的进行而减少。在实验室中维持高营养和低营养饮食的年轻个体在翅膀上形成的色素数量不同。高营养组的雄性比低营养组的雄性翅膀发育得更快。雄性和morpha的年轻成虫喂食^<14>C放射性标记的色氨酸或酪氨酸（分别是色素单体色素和黑色素的前体）。同色性只存在于两种变种雄性的伪翅柱头上，而不存在于雌性中。橙色雄虫的翅膀细胞中存在酪氨酸，而透明雄虫的翅膀细胞中不存在酪氨酸，这表明橙色色素至少部分是由黑色素构成的。这些数据表明，至少有一些色素水平必须持续保持在橙色雄性的翅膀上，而这种维持是昂贵的，因为它在低营养水平下受到损害。

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.Males of the damselfly Mnais costalis (Odonata : Calopterygidae) are morphologically and behaviourally polymorphic, typically existing as clear-winged non-territorial 'sneaks' and orange-winged territorial 'fighters'. The amount of orange pigment in the wing, as measured with a chromameter, varied between individuals and decreased as the reproductive season progressed. Young individuals maintained in the laboratory on high and low nutrient diets differed in the amount of pigment that developed in the wing. Males in the high nutrient group developed darker wings faster than those in the low nutrient group. Young adults of both sexes and morpha were fed ^<14>C radiolabelled tryptophan or tyrosine (precursors of the pigments ommochrome and melanin respectively). Ommochrome was restricted to the pseudopterostigma of the males of both morphs and was not present in females. The presence of tyrosine in the wing cells of orange males but not of clear males indicated that the orange pigment is at least partly constituted from melanin. These data show that at least some pigment levels must be continuously maintained in the wings of orange males, and that maintainance is costly since it is compromised at low nutrient levels.