Detection of intra-snacific variations and analysis of nonulation structure in spider mites, using genetic markers

荨麻疹叶螨（Tetranychus urticae）和kanzawai叶螨（T.kanzawai）是两种高度多食性的蜘蛛螨，在日本广泛存在。本研究比较了两种物种滞育特性的变化，确定了两种类型的荨麻（绿色和红色）和kanzawai （K和T）之间的系统发育关系。日本夜蛾的滞育率变化很大，北部滞育率为100%，而西南部的本州和九州的滞育率几乎为零，但不同寄主类型的种群间滞育率差异不大。另一方面，kanzawai具有较强的滞育能力，日本4个主要岛屿的种群滞育率接近100%。然而，在冲绳群岛的种群中，滞育率急剧下降。茶源居群的滞育能力弱于草本和落叶寄主居群。COI基因（线粒体细胞色素氧化酶亚基I）分析表明，这两种形式的荨麻疹螨在一个聚类中被识别出来，并且存在具有系统发育差异的单倍型，这表明日本发生了多次偶然的荨麻疹螨迁移。利用DNA序列（COI和ITS1）构建的系统发育树不能明确区分T型和K型kanzawai。结果表明，T型是由K型衍生而来。

Two species of spider mites, Tetranychus urticae and T.kanzawai, are both highly polyphagous and occur widely in Japan. This study compared the variation in diapause characteristics of the two species and determined the phylogenetic relationship between the two forms of T.urticae (green and red) and also between those of T.kanzawai (K and T).The diapause of Japanese T.uticae is highly variable and diapause percentage ranged from 100% in the north to nearly zero in southwestern Honshu and Kyushu, but no difference was detected among populations from different host types. On the other hand, T.kanzawai had a strong diapause capacity and populations in the 4 main islands of Japan exhibited nearly 100% diapause. However, diapause percentage drastically decreased in populations from Okinawa Islands. T.kanzawai populations derived from tea had weaker diapause capacity than those derived from herbaceous and deciduous hosts.Analysis of COI gene (mitochondrial cytochrome oxidase subunit I) showed that the two forms of T.urticae were recognized in a single cluster and the existence of haplotypes with phylogenetical divergence suggested that multiple accidental immigrations of the mite had occurred in Japan.The phylogenetic trees constructed using the DNA sequences (COI and ITS1) failed to clearly distinguish between the two types T and K of T.kanzawai. The results suggested that the T types were derived from the K type.