Evolutionary ecology and molecular phylogenetic analysis of interactions between closely related species

研究了日本特有的步甲亚属(步甲亚属Carabus，步甲亚属Carabidae，鞘翅目Ohomopterus)的种间相互作用。在同翅目昆虫中，寄生物种之间存在着杂交带，尤其是Insulicola种组和Yaconinus种组。在实验室对日本锦鸡儿和南方锦鸡儿、台湾锦鸡儿和中村锦鸡儿的种间杂交进行了分析。这些配对在生殖器特征上的差异影响了种间交配的成本。Iwakianus和C.maiyasanus的生殖器特征有很大的不同，种间交配的成本足够大，足以维持它们的平行分布。海岛锥虫和C.a之间。生殖器性状差异小、种间交配成本低的中村种，在田间，在两个物种的中间地带建立了杂交种群。因此，次级接触处的种间相互作用可能有助于步甲的发散和网状物种形成，这取决于接触处的种间差异。我还利用两个线粒体基因和五个核基因研究了同翅目昆虫的分子系统发育。分子系统发育分析的结果表明，频繁的杂交导致线粒体的内渗，从而导致线粒体谱系和形态物种之间的不一致。我调查了本州中部和东部的四个物种的线粒体多态，发现了这些物种之间的定向导入，并为相应物种的自然杂交提供了证据。本研究论证了网状事件在步甲进化中的意义。

This study focused on interspecific interactions between the carabidbeetles of the subgenus Ohomopterus (genus Carabus, Carabidae, Coleoptera), which is endemic to Japan and consists of 15 species. In Ohomopterus, there are hybrid zones between parapatric species, especially of Insulicola species group and Yaconinus species group. I analyzedinterspecific hybridization between Carabus iwawakianus and C.maiyasanus, andbetweenC.insulicola andC.arrowianus nakamurai in the laboratory. These pairs differedin the difference in genital characters which affects the cost of interspecific mating. The genital characterswere much different between C.iwawakianus and C.maiyasanus, and the cost at interspecific mating was large enough to maintain theirparapatricdistribution. BetweenC.insulicola andC.a. nakamurai which hada small differencein genital characters, the cost at interspecific mating was small, In the field, hybrid populations were established at intermediate zones of the two species. Thus, interspecific interactions at secondary contacts may contribute both divergence and reticulate speciation in the carabid beetles, depending on the interspecific difference at the contacts. I also studied molecular phylogeny of Ohomopterus by using two mitochondrial genes and five nuclear genes. The results of molecular phylogenetic analysis suggests that hybridizations oftenresultedin introgression of mitochondria, which producedincongruencepatterns between mitochondrial lineage and morphological species. I investigated mitochondrial polymorphisms in four species in central and eastern Honshu, and detecteddirectional introgressions among these species, with evidences for natural hybridizations of corresponding species. This study demonstrated the significance of reticulate events in the evolution of carabid beetles.