Aoki Kyoko, Kato Makoto, Murakami Noriaki
Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Kyoto 606-8501, Japan.
Makino Herbarium, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
Insects. 2011 Apr 21;2(2):128-50. doi: 10.3390/insects2020128.
The Quaternary climate cycles played an important role in shaping the distribution of biodiversity among current populations, even in warm-temperate zones, where land was not covered by ice sheets. We focused on the Castanopsis-type broadleaved evergreen forest community in Japan, which characterizes the biodiversity and endemism of the warm-temperate zone. A comparison of the phylogeographic patterns of three types of phytophagous weevils associated with Castanopsis (a host-specific seed predator, a generalist seed predator, and a host-specific leaf miner) and several other plant species inhabiting the forests revealed largely congruent patterns of genetic differentiation between western and eastern parts of the main islands of Japan. A genetic gap was detected in the Kii Peninsula to Chugoku-Shikoku region, around the Seto Inland Sea. The patterns of western-eastern differentiation suggest past fragmentation of broadleaved evergreen forests into at least two separate refugia consisting of the southern parts of Kyushu to Shikoku and of Kii to Boso Peninsula. Moreover, the congruent phylogeographic patterns observed in Castanopsis and the phytophagous insect species imply that the plant-herbivore relationship has been largely maintained since the last glacial periods. These results reinforce the robustness of the deduced glacial and postglacial histories of Castanopsis-associated organisms.
第四纪气候周期在塑造当前种群间生物多样性分布方面发挥了重要作用，即使在没有被冰盖覆盖的暖温带地区也是如此。我们聚焦于日本的栲属类型的阔叶常绿森林群落，该群落是暖温带生物多样性和特有性的特征。对与栲属相关的三种植食性象鼻虫（一种寄主专一的种子捕食者、一种泛化的种子捕食者和一种寄主专一的潜叶虫）以及栖息在森林中的其他几种植物物种的系统发育地理模式进行比较后发现，日本主要岛屿东西部之间的遗传分化模式在很大程度上是一致的。在纪伊半岛到中国-四国地区，濑户内海周边检测到了一个遗传缺口。东西部的分化模式表明，过去阔叶常绿森林至少分裂成了两个独立的避难所，分别由九州南部到四国以及纪伊到房总半岛的南部组成。此外，在栲属植物和植食性昆虫物种中观察到的一致的系统发育地理模式意味着，自末次冰期以来，植物-食草动物关系在很大程度上得以维持。这些结果强化了所推断的与栲属相关生物的冰川和冰后期历史的可靠性。
