Radiation in sexual and parthenogenetic oribatid mites (Acari, Acariformes)

甲螨是数量最多、种类最多的陆生节肢动物之一。几个甲螨种群可能会辐射，尽管它们是独有的孤雌生殖方式(例如，南甲科、山甲科、刺甲科、北甲科、软甲科)，并存活了很长一段时间。这两个发现都与关于性的进化和维持的理论相矛盾。孤雌生殖谱系被认为是短暂的和进化的死胡同。为了研究甲螨的辐射和多样性，我们打算研究三个主题：(1)我们打算评估有性类群是否比无性类群辐射更快。因此，我们正在比较亲缘关系密切的无性类群和亲缘关系密切的有性群间的遗传多样性(COI和HSP82区域)。(2)用延长因子-1-aa评价甲螨中无鞭毛目的系统发育地位。姬螨是一个完全有性行为的群体，最近被认为是完全孤雌生殖的甲螨科的姐妹群体。如果这是真的，那么在动物界中，无鞭毛目是唯一一个重新进化有性生殖并随后密集辐射的分类单元(描述了大约10000个种)。(3)我们想要研究的假设是，土壤中的通用性捕食者减少了土壤节肢动物(如甲螨)之间的生物相互作用，并使大量物种能够共存。此外，利用稳定同位素技术(15-N，13-C)对甲螨的营养位置进行了评估，以确定这些动物是否生活在土壤食物网的不同营养位置，从而表明营养生态位的分化。

Oribatid mites (Acari: Acariformes) are among the most abundant and diverse terrestrial arthropods. Several oribatid mite groups probably radiated despite their exclusively parthenogenetic mode of reproduction (e.g. Nanhermanniidae, Camisidae, Trhypochthonidae, Nothridae, Malaconothridae) and survived long periods of time. Both findings contradict theories on the evolution and maintenance of sex. Parthenogenetic lineages are assumed to be short lived and evolutionary dead ends. To investigate the radiation and diversity of oribatid mites we intend to investigate three topics: (1) We intend to evaluate whether sexual taxa radiated faster than asexual taxa. We are therefore comparing the genetic diversity (COI and HSP82 region) between closely related asexual taxa with that of closely related sexual groups. (2) We want to evaluate the phylogenetic position of the Astigmata within the oribatid mites using the elongation factor-1-aa. The Astigmata (Acari: Acariformes) are an entirely sexual group which has recently been hypothesised to be the sister group of an entirely parthenogenetic group of oribatid mites, the Trhypochthonidae. If this is true, the Astigmata are the only taxon in the animal kingdom that re-evolved sexual reproduction and then intensively radiated (about 10000 species of Astigmata are described). (3) We want to investigate the hypothesis that generalist predators in soil reduce biotic interactions between soil arthropods (e.g. oribatid mites) and enable the coexistence of a large number of species. Furthermore, using stable isotope techniques (15-N, 13-C) the trophic position of oribatid mites is evaluated to find out if these animals inhabit different trophic positions in the soil food web thereby indicating trophic niche differentiation.