Reinforcement in a Zone of Overlap and Hybridization

丹尼尔·霍华德和约翰·多尔蒂提出的这项研究解决了生物学中的一些最困难的问题；即，当一个物种分裂为两个物种时，生殖隔离(不同物种个体之间没有杂交)是如何发展的，特别是，在生殖障碍的进化中，针对杂交的选择是什么角色？这些问题的答案对于理解地球上生物多样性的发展和保护至关重要。这些问题将通过研究正在分裂形成新物种的地面蟋蟀来解决。从这项研究中获得的答案将与所有有性繁殖有机体相关。过去三年的研究已经确定，雄性叫声的差异是新形成的物种--筋膜阿洛尼莫比斯和阿洛尼莫比斯--之间的潜在生殖障碍。在物种形成的关键阶段识别这一潜在障碍，为研究物种形成过程中生殖隔离的演变提供了难得的机会。在接下来的三年里，增援假说将得到检验。这一假说表明，在与A.Socius发生叫声置换的区域，筋纹夜蛾表现出的叫声置换代表着一种生殖障碍，这种障碍是由于对杂交的选择而进化出来的。这项工作将包括：(1)雄性叫声的地理变异，(2)雌性对叫声的反应，(3)歌声差异的遗传学，(4)杂交交配的成本，以及(5)精子竞争。拟议中的研究不仅将对强化假说进行严格的检验，还将提供有关可能导致生殖隔离的性状的基本信息。只有将作为生殖障碍的特定性状的遗传学、行为生态学和发育生物学研究与地理分布模式分析相结合，生物学家才能了解物种形成的过程。这项拟议的研究应该会导致更严格的研究，以获得筋膜亚种和社会亚种之间的生殖隔离。这些物种正在迅速成为研究生物过程的模型系统。从应用的角度来看，蟋蟀科(蟋蟀)包括一些非常严重的农业害虫。这项拟议的研究将提供急需的有关蟋蟀生殖生物学的信息--这些信息可以用来帮助开发生物防治计划。

The research proposed by Daniel Howard and John Doherty addresses some of the most difficult problems in biology; namely, how does reproductive isolation (the absence of interbreeding between individuals of different species) develop as one species splits into two and, in particular, what is the role of selection against hybridization in the evolution of reproductive barriers? Answers to these questions are central to an understanding to the development and conservation of biological diversity on earth. The questions will be approached by studying ground crickets that are in the process of splitting to form new species. Answers obtained from the study will be relevant to all sexually reproducing organisms. Research over the past three years has identified male calling song differences as a potential reproductive barrier between the newly forming species, Allonemobius fasciatus and A. socius. The identification of this potential barrier during a critical stage of species formation provides a rare opportunity to study the evolution of reproductive isolation during a speciation event. During the next three years, the hypothesis of reinforcement will be tested. This hypothesis states that the calling song displacement exhibited by A. fasciatus in areas where it occurs with A. socius represents a reproductive barrier that has evolved as a consequence of selection against hybridization. The work will include investigations of : (1) geographic variation in male calling song, (2) female response to song, (3) the genetics of song differences, (4) the cost of a hybrid mating, and (5) sperm competition. The proposed studies will not only provide a rigorous test of the hypothesis of reinforcement, but they will provide fundamental information on a trait potentially responsible for reproductive isolation. Only by combining studies of the genetics, behavioral ecology, and developmental biology of specific traits serving as reproductive barriers with analyses of geographic distribution patterns, will biologists arrive at an understanding of the process of speciation. The proposed research should lead into even more rigorous studies of the acquisition of reproductive isolation between A. fasciatus and socius. These species are rapidly becoming a model system for the study of biological processes. From an applied perspective, the family Gryllidae (crickets) includes some very serious agricultural pests. The proposed research will provide badly needed information on the reproductive biology of crickets - information that can be used to help develop biological control programs.