DISSERTATION RESEARCH: Determining anucleated sperm function in Lepidoptera

传统上，精子细胞的功能被认为是男性将DNA转移到卵子并产生后代的一种方式。没有携带DNA的精子细胞不能使卵子受精，因此这种精子细胞在蝴蝶和飞蛾中的存在令人费解。几乎所有这些昆虫都能产生两种类型的精子：一种是传统的携带DNA的精子，另一种是缺乏DNA的精子。在所有这些情况下，男性利用这种缺乏DNA的精子比传统精子多得多。这种精子类型的绝对丰富意味着它在生殖过程中扮演着一些未知的功能角色。这项提议旨在揭示这些缺乏DNA的精子细胞的进化意义。这项研究还将有助于技术的开发，使科学家能够以一种比传统饲养方法更便宜、更不容易失败的方式来维持重要的转基因血统。这样的协议甚至可以扩展到受威胁的物种，以创建基因库。将通过夏季科学工作坊向公众宣传。在许多动物谱系中，单个雄性产生多种精子类型的情况已经独立出现。在所有经过充分研究的案例中，证据表明，只有一种类型的精子保留了使卵子受精的能力，但这些未受精的精子的功能尚不清楚。这一点在蝴蝶和飞蛾身上表现得最为明显；这一目的雄性产生一种缺乏核DNA的次级精子类型。这些无核细胞对男性来说是一笔巨大的投资，数量是有核精子的20倍，但不可能让卵子受精来直接提高男性的健康水平。自从无核精子被发现以来，人们提出了几种假说来解释无核精子的存在，但到目前为止还没有进行过严格的测试。该项目将在两个交配策略不同的鳞翅目物种中开发和完善人工授精方案，以共同的框架彻底测试不同选择背景下的无核精子的功能。

The function of sperm cells is traditionally thought to be a way for males to transfer DNA to eggs and create offspring. Sperm cells that do not carry DNA cannot fertilize an egg, thus the existence of such sperm cells in butterflies and moths is puzzling. Almost all of these insects make two types of sperm: both traditional, DNA-bearing sperm, and a second type that lacks DNA. In all of these cases, males make far more of this DNA-lacking sperm than traditional sperm. The sheer abundance of this sperm type implies it plays some yet-unknown functional role in reproduction. This proposal aims to uncover the evolutionary significance of these DNA-lacking sperm cells. The research will also aid in the development of technologies that will allow scientists to maintain important genetically modified lineages in a way that is both cheaper and less vulnerable to failure than traditional rearing methods. Such protocols could even be extended to threatened species to create a gene bank. Outreach to the public will occur via summer science workshops.Production of multiple sperm types by a single male has independently arisen in many animal lineages. In all well-studied cases, evidence suggests that only one type of sperm retains its ability to fertilize eggs but the function of these non-fertilizing sperm remains unclear. Nowhere is this more apparent than in butterflies and moths; males of this order produce a secondary sperm type that lacks nuclear DNA. These anucleated cells represent a significant investment for a male, outnumbering their nucleated sperm by 20-to-1, but cannot possibly fertilize eggs to directly increase male fitness. Several hypotheses have been proposed since the discovery of anucleated sperm to explain the existence of anucleated sperm, but to-date no rigorous tests have been undertaken. This project will develop and refine artificial insemination protocols in two lepidopteran species that differ in mating strategy in order to thoroughly test the function of anucleated sperm in different selective backgrounds with a common framework.