Dissertation Research: The Importance of Tychoparthenogenetic Reproduction in Natural Populations of the Stenonema femoratum

生物学中最基本但在很大程度上仍未得到解答的问题之一是，为什么大多数有机体通过交配(双亲繁殖)而不是自体受精或克隆(单亲繁殖)进行繁殖。解决这一问题的理想研究系统是双亲和单亲生育在同一种群中共存的系统。单性生殖是一种单性生殖(从未受精卵中产生后代)，其特征是在正常有性繁殖种群中来自雌性的未受精卵孵化成功率较低；因此，双亲和孤雌生殖都发生在同一种群中。为了利用这样的研究系统来解决为什么大多数生物表现出双亲繁殖的问题，重要的是首先确定：1)孤雌生殖能力是否因种群而异；2)雌性在自然条件下利用其孤雌生殖能力的程度；3)酪氨酸生殖是否受基因控制。这项研究解决了这三个标准，这将为进一步研究双亲繁殖所带来的优势以及为什么在大多数生物体中发生双亲繁殖提供必要的信息。这项研究正在使用一种水生昆虫--金色隐翅虫来解决这些标准。了解双亲和孤雌生殖对生物种群的影响很重要，因为生物繁殖的方式可以对种群长期生存的能力产生重大影响。水生昆虫种群的长期生存对于许多以水生昆虫为食物来源的重要猎食鱼来说至关重要。

Semlitsch9801568One of the most fundamental yet largely unanswered questions in biology is why most organisms reproduce by mating (biparental reproduction) and not by self-fertilization or cloning (uniparental reproduction). The ideal study system with which to address this question is one in which both biparental and uniparental reproduction coexist within the same population. Tychoparthenogenesis is a type of parthenogenesis (production of offspring from unfertilized eggs) characterized by low hatching success of unfertilized eggs from females in normally sexually reproducing populations; therefore, both biparental and parthenogenetic reproduction occur within the same population. To use such a study system to address questions about why most organisms exhibit biparental reproduction, it is important to first determine: 1) whether parthenogenetic capacity varies among populations; 2) the extent to which females utilize their parthenogenetic capacity under natural conditions; 3) whether tychoparthenogenesis is genetically controlled. This research addresses these three criteria that will provide necessary information for further studies investigating the advantages conferred by biparental reproduction and therefore, why it occurs in most organisms. This research is addressing these criteria using an aquatic insect, the mayfly, Stenonema femoratum. Understanding the influence of biparental and parthenogenetic reproduction on populations of organisms is important because the way in which organisms reproduce can have significant impacts on the ability for populations to persist in the long-term. Long-term survival of aquatic insect populations is critical for many important game fish that rely on aquatic insects as a food source.