Sakurai Atsushi, Hamanishi Yo, Maeto Kaoru, Naito Chikahiko
Graduate School of Natural Sciences and Technology, Kobe University, Kobe, Hyogo, Japan.
Zoolog Sci. 2009 May;26(5):325-9. doi: 10.2108/zsj.26.325.
The tenthredlnld sawflles Macrophya apicalis and M. infumata, which range throughout Japan and adjacent areas, are very similar in external morphology and share the same host plant, Sambucus sieboldiana. We Investigated their genetic distances within the genus and their lntraspecific variation, and estimated their time of divergence to clarify the history of their speciation and colonization. We collected 33 specimens of the two species from several locations in the Japanese archipelago (Hokkaido, Honshu, Shikoku, and Kyushu) and Cheju Island (Korea). We extracted total DNA from each specimen, and PCR amplified and sequenced 1300 bp of the cytochrome oxidase subunit I (COI) gene. We constructed phylogenetlc trees by using the UPGMA and maximum likelihood methods. We estimated divergence times based on previously published COI substitution rates. The genetic distance between the two species indicated that their ancestors differentiated in the late Miocene, probably on the Asian continent. Based on the calculated time of intraspecific diversification in Japan, we estimated that both species immigrated to Japan in the early Pleistocene and crossed the Tsugaru Strait land bridge between Hokkaido and Honshu after the middle Pleistocene. Genetic analysis of the two sibling species elucidated their relative taxonomical positions within the genus, and their intraspecific variation. Estimated from previously published COI evolutionary rates, the time of arrival of both species in Japan is consistent with the history of colonization of the country by other animals during the last ice age.
叶蜂科锯蜂属的顶端大锯蜂和烟色大锯蜂分布于日本全境及周边地区，它们在外部形态上非常相似，且共享同一寄主植物——Siebold接骨木。我们研究了它们在属内的遗传距离及其种内变异，并估计了它们的分歧时间，以阐明其物种形成和定殖的历史。我们从日本列岛（北海道、本州、四国和九州）及济州岛（韩国）的多个地点采集了这两个物种的33个标本。我们从每个标本中提取总DNA，并对细胞色素氧化酶亚基I（COI）基因的1300 bp进行PCR扩增和测序。我们使用UPGMA和最大似然法构建了系统发育树。我们根据先前发表的COI替换率估计分歧时间。这两个物种之间的遗传距离表明它们的祖先在中新世晚期分化，可能是在亚洲大陆。根据计算出的日本种内多样化时间，我们估计这两个物种都在更新世早期迁入日本，并在更新世中期之后穿过北海道和本州之间的津轻海峡陆桥。对这两个近缘物种的遗传分析阐明了它们在属内的相对分类地位及其种内变异。根据先前发表的COI进化速率估计，这两个物种到达日本的时间与该国在上一个冰河时代被其他动物定殖的历史一致。
