Consequences of hybridization between Ohomopterus insulicola and O. arrowianus (Coleoptera, Carabidae) in a segmented river basin: parallel formation of hybrid swarms
Consequences of hybridization between Ohomopterus insulicola and O. arrowianus (Coleoptera, Carabidae) in a segmented river basin: parallel formation of hybrid swarms
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分段流域中 Ohomopterus insulicola 和 O. arrowianus（鞘翅目、步甲科）杂交的后果：杂交群的平行形成
DOI：
10.1006/bijl.2000.0444
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发表时间：
2000
影响因子：
1.9
通讯作者：
K. Kubota
中科院分区：
文献类型：
--
作者：
T. Sota;F. Kusumoto;K. Kubota
本文描述了岛生步甲（Carabus（Ohomopterus）insulicola）和岛生步甲（Carabus（Ohomopterus）insulicola）之间的杂交区。（O.）采用实验杂交和形态学分析的方法，对日本本州岛中部伊那谷的arrowianusnakamurai进行了研究。分析的主要形态特征是雄性生殖器的功能部分（交配片），这也是分类学上的关键诊断特征。步甲的栖息地被贯穿伊那谷的天龙河及其支流分割开来。Ohomopterus insulicola和O. a. nakamurai分别发生在流域的上游和下游地区，并在该流域形成了一个假定的杂交群（O.岛生亚种pseudinsulicola）在天龙川东侧的边界地区被发现。O. insulicola和O. a. nakamurai产生的F1代在形态上与O. I.假沟生前合子生殖隔离是不完全的，虽然F1雄性有精子生产功能障碍，几乎不育。只有一对F1产生F2。F1代雌性与亲本种雄性回交产生的后代在生殖器形态上与亲本种相似。基于判别函数的形状的交配片实验杂交，我们表明，类似的混合群存在于两侧的天龙河，但在位置相距25公里。这证明了具有类似结果的杂交事件的平行性。杂交种群由中间形态特征的甲虫组成，不含明显的亲本形式。这种中间种群的建立可能是由于在没有亲本物种频繁迁移的情况下，在隔离的当地地点选择可育杂交种而促进的。这项研究表明，一个分段的流域提供了一个机会，建立新的进化谱系杂交。
A putative hybrid zone between flightless carabid beetles, Carabus (Ohomopterus)insulicola and C. (O.) arrowianus nakamurai in the Ina Valley, central Honshu, Japan, was studied using experimental hybridization and morphological analysis. The principal morphological character analysed was a functional part of the male genitalia (the copulatory piece), which is also the key diagnostic character in taxonomy. The habitat of the carabid beetles is fragmented by the Tenryu River, which runs through the Ina Valley, and its tributaries. Ohomopterus insulicola and O. a. nakamurai occur in the upstream and downstream areas of the river basin, respectively, and a putative hybrid swarm (O. insulicola ssp. pseudinsulicola) is found in the boundary area on the east side of the Tenryu River. Experimental hybridization between O. insulicola and O. a. nakamurai resulted in F1offspring that were morphologically similar to O. i. pseudinsulicola. Pre-zygotic reproductive isolation was incomplete, although the F1males had a dysfunction in sperm production and were almost sterile. Only a single F1pair produced F2. Backcrosses of F1females of males of the parental species resulted in offspring that were similar to the parental species in genital morphology. Based on the discriminant function for the shape of the copulatory piece resulting from the experimental hybridization, we demonstrate that similar hybrid swarms exist on both sides of the Tenryu River, but in locations 25 km apart. This demonstrates parallelism in hybridization events with similar consequences. The hybrid swarms consisted of beetles with intermediate morphological characters and did not contain obvious parental forms. The establishment of such intermediate populations may have been facilitated by selection for fertile hybrids in segregated local sites in the absence of frequent immigration of parental species. This study suggests that a segmented river basin provides an opportunity for establishing novel evolutionary lineages resulting from hybridization.