Dissertation Research: An Analysis of Plethodon Hybrid Zones: Ethology and Isolation

这是一项研究新物种形成过程的建议。该项目侧重于两个关键过程：(1)交配行为不相容的根源，以及(2)杂交不能和杂交性无能的根源。林地火蜥蜴(Plethodon属)被用于拟议的工作，因为在所有有脊椎的陆上动物中，它们的混血区是最知名的。此外，初步工作(超过4000对交配试验)表明，所提出的行为研究是可行的。总体计划是在(1)一个物种(P.jordani)的一系列山顶分离物(P.jordani)和(2)两个物种(P.jordani和P.teyahalee)之间的一系列接触带中进行交配兼容性和杂交可行性的研究。在这些区域中的一些，两种种不杂交(重叠区)，而在另一些区域，它们形成相对狭窄的杂交区或广泛的杂交群。将被检验的进化预测是：(1)性不相容是在空间分离的人群中进化的性行为差异的副产品。(2)如果空间上分离的两个种群重新接触，性不亲和性就会加强。(3)不亲和性在重叠区比杂交区更明显，在相对狭窄的区比在广泛的杂交群中更严重。(4)杂交种丧失生存能力是空间分离种群进化变化的副产品。

This is a proposal to study the processes by which new species are formed. the project focuses on two key processes: (1) the origin of incompatibility in mating behavior, and (2) the origin of hybrid inviability and hybrid sexual incompetence. Woodland salamanders (genus Plethodon) are being used for the proposed work because, of all land-based animals with backbones, their hybrid zones are the best known. Furthermore, initial work (over 4000 pair mating trials) has shown that the proposed behavioral studies are feasible. The overall plan is to conduct studies of mating compatibility and hybrid viability in (1) a series of mountain- top isolates of one species (P. jordani) and (2) a series of contact zones between two species (P. jordani and P. teyahalee). In some of these zones, the two speices do not hybridize (overlap zones), while in others they form relatively narrow hybrid zones or extensive hybrid swarms. The evolutionary predictions that will be tested are: (1) Sexual incompatibility evolves as a by-product of differences in sexual behavior that evolve in spatially separated populations. (2) Sexual incompatibility is strengthened if two spatially separated populations come back into contact with each other. (3) Sexual incompatibility is more pronounced in overlap zones than in hybrid zones, and is greater in relatively narrow zones than in extensive hybrid swarms. (4) Hybrid inviability evolves as a by-product of evolutionary change in spatially separated populations.