Dissertation Research: Sex Ratio in an Autoparasitoid Wasp

一个动物物种中雌性的比例 影响人口增长率，因此很重要 来了解种群动态 虽然同样数量的 每种性别在许多动物中产生，一些群体的成员， 例如寄生蜂，通常表现出高度可变的性别 比率。 了解产生这些变量的机制 性别比例是预测人口波动的必要条件。 在 此外，可变的性别比例提供了一个很好的机会， 适应的过程，因为最佳的性别比例可以是 使用进化模型预测，与理论的拟合可以是 很容易通过实验测量。 在一群微小的寄生蜂中 雌虫在不同的寄主上产卵。 雌性卵产在同翅目昆虫的幼虫体内，如粉虱 和介壳虫，而男性卵产在身体内的 未成熟的雌性黄蜂，而他们仍然在发展中国家 同翅目寄主 雄蜂寄生在雌蜂身上， 自己的物种。 这项研究涉及调查性别 自寄生蜂恩蚜小蜂雌虫的分配行为 pergandiella，寄生于粉虱。 特别是 研究人员正在调查雌性如何分配卵子， 由于性别比例的限制， 适当主机的可用性。 鸡蛋的图案 在两个主机奠定将在赛季时， 两台主机的可用性不同，密度也不同。 在 实验室，可能改变性别分配行为的因素 如宿主密度、以往经验和女性年龄， 考察 结果将在以下背景下进行解释： 进化论 这个系统提供了一个独特的机会来测试性别比例 理论 费舍尔预测自然选择应该使 在每个性别上的资源投资。 一般来说，这会导致 1：1的性比，但在自寄生蜂中， 因资源有限而异。 当卵子数量有限时， 女儿们的数量应该是相等的，但是当主人们 限制，性别比例应该反映相对 两个主机的可用性。 此外，自寄生蜂具有 在许多情况下用于生物控制规模， 粉虱害虫，往往与巨大的经济和环境 减少农药使用量带来的好处。 性 比例是这些黄蜂种群生物学的核心， 因此，了解控制性的机制 比率将提高我们评估黄蜂物种的能力， 控制害虫种类的潜力。

The proportion of females in an animal species directly influences the rate of population growth, and thus is important for understanding population dynamics. Although equal numbers of each sex are produced in many animals, members of some groups, such as the parasitic wasps, often exhibit highly variable sex ratios. Understanding the mechanisms that produce these variable sex ratios is necessary to predict population fluctuations. In addition, variable sex ratios offer a good opportunity to study the process of adaptation, since optimal sex ratios can be predicted using evolutionary models, and the fit to theory can be easily measured experimentally. In a group of minute parasitic wasps in the family Aphelinidae females lay male and female eggs in different hosts. Female eggs are laid inside nymphs of Homoptera, such as whitefly and scale insects, while male eggs are laid inside the body of immature female wasps while they are still developing within the homopteran host. Males are parasitic on female wasps, often of their own species. This study involves investigating the sex allocation behavior of females of an autoparasitoid, Encarsia pergandiella, which parasitizes whiteflies. In particular, the investigator is investigating how females allocate eggs to be sons and daughters given the constraint on sex ratio imposed by the availability of the appropriate hosts. The pattern of egg laying in the two host will be examined over the season when the availability of the two hosts, and the density varies. In the laboratory, factors which may alter the sex allocation behavior such as host density, previous experience and female age will be examined. The results will be interpreted in the context of evolutionary theory. This system offers a unique opportunity to test sex ratio theory. Fisher predicted that natural selection should equalize the investment of resources in each sex. Generally this leads to a 1:1 sex ratio, but in autoparasitoids the predicted sex ratio varies with the limited resource. When eggs are limiting, sons and daughters should be produced in equal numbers, but when hosts are limiting, the sex ratio should reflect the relative availability of the two hosts. In addition, autoparasitoids have been used in many instances to biologically control scale and whitefly pests, often with tremendous economic and environmental benefits due to reduced numbers of pesticide applications. Sex ratio is central to the population biology of these wasps, and, therefore, an understanding of the mechanisms that control sex ratio will improve our ability to evaluate wasp species for their potential to control pest species.