Evolution of Phoresy and Feeding Associations in the Mite Order Parasitiformes

摘要寄生虫的起源是生物学中一个经久不衰的问题。由于寄生在螨类中多次出现，它们是研究这一现象的一个很好的分类群，螨类还表现出许多其他类型的关联，允许关于不同类型的关联之间的过渡的假设。Phoresy特别令人感兴趣，因为它在螨类中是一种常见的现象。在这种类型的联系中，一种有机体(一种蠕虫)利用另一种有机体(昆虫或脊椎动物)从一个地方移动到另一个地方。它不涉及对宿主的取食，也不涉及在运输期间的发育。不同的作者提出，恐惧症可能是寄生等喂养联系的先兆，这个项目的目标是测试这一想法。测试群是两个螨目中较小的寄生虫目，目前包括大约77个科。测试寄生到寄生的假说可以通过确定寄生在寄生的血统中的血统是否是磷化的，这是在这一假说下预测的模式。这种方法需要对历史关系有很好的了解，但不幸的是，对这一组中的这种关系的了解是不完整的。因此，该项目的很大一部分致力于得出得到充分支持的寄生虫目内部关系的假说。这将使用形态和分子数据的组合来完成。分子数据包括部分18S和28S核糖体RNA基因的序列数据，以及核蛋白编码基因延伸因子1-α。这一组具有普遍生物学意义的部分原因是它包括具有重要医学价值的扁虱和经济上重要的蜜蜂寄生虫Varroa。寄生虫和寄生虫在寄生目动物中都很常见，这使它成为这个项目的一个很好的候选者。通过提供寄生目动物之间关系的严格假设，这项研究将提高我们对许多生态、医学和经济上重要的螨类的理解，并使这组螨类成为进化生物学中广泛问题的模式系统。

ABSTRACT The origin of parasitism is one of the enduring questions in biology. Because parasitism has arisen multiple times among mites, they are an excellent taxon in which to study this phenomenon Mites show also many other types of associations, allowing hypotheses on transitions among diverse types of associations. Phoresy is of particular interest, as it is a common phenomenon in mites. In this type of association one organism (a mite) uses another organism (insect or vertebrate) to move from one place to another. It does not involve feeding on the host, or development during the period of transport. Various authors have proposed that phoresy might be a precursor to feeding associations such as parasitism, and the goal of this project is to test that idea. The test group is the mite order Parasitiformes, the smaller of the two mite orders, currently including about 77 families. Testing the phoresy to parasitism hypothesis can be done by determining whether lineages that are parasitic nest within lineages that are phoretic, a pattern predicted under this hypothesis. This approach requires good knowledge of historical relationships, but unfortunately, knowledge of such relationships in this group is incomplete. A large part of the project is therefore devoted to deriving well supported hypotheses of relationships within Parasitiformes. This will be done using a combination of morphological and molecular data. Molecular data consist of sequence data for parts of the 18S and 28S nuclear ribosomal RNA genes, and the nuclear protein coding gene Elongation Factor 1-alpha.This group is of general biological interest in part because it includes ticks of medical importance and the economically important bee parasite Varroa. Both parasitism and phoresy are common within Parasitiformes making it a good candidate for this project. By providing rigorous hypotheses of relationships among Parasitiformes, this research will improve our understanding of numerous ecologically, medically, and economically important mites and make this group of mites available as a model system for broad questions in evolutionary biology.