Effects of host plant dioecy on leafminers and their parasitoids

本研究旨在探讨茶科叶潜蝇营养生长方式、叶片营养成分和次生物质含量的性别差异对潜叶潜蝇及其寄生蜂群落生态的影响。但雄株和雌株间的日本血吸虫密度差异是年际变化的，未能达到预期的目的。相反，我们揭示了以下情况：1.日本斑潜蝇只在一年以上的叶片上产卵，在当年叶片上几乎没有产卵。老叶的含氮量、氮碳比均低于当年叶，表儿茶素含量高于当年叶。当日本血吸虫雌虫被迫在当年叶片上产卵时，孵化出的幼虫很快就被转化的叶片组织细胞包围。因此，雌虫几乎不在当年叶上产卵的适应意义在于避免对地雷敏感的叶片，而不是营养品质较差的叶片。被实验杀死的采叶幼虫的叶片开始溃烂的时间比活体幼虫的叶片更早、更快。这表明日本锥虫幼虫对寄主植物提早剥离采出的叶片有抑制作用。与日本血吸虫相似的寄生蜂群由12个种组成。其中一只是科诺比昂特，其余的都是笨蛋。在这个群落中共存的机制似乎是独特体对优势独生体的重寄生率相当高，独特体的寄主范围很广。对大阪府大学和北海道大学保存的标本和野外采集的标本进行了调查，发现有4个种为科学新种。此外，还发现了栎属一新种。(壳斗科)在印度尼西亚的Jawa岛采集到，那里没有记录到tischeriids。

We aimed to clarify the effects of sexual difference of Eurya japonica (Theaceae) in vegetative growth pattern and foliar nutritional and secondaty substance contents on the ecology of a leafminer (Coptotonche japoniella, Tischeriidae, Lepidoptera) and its parasitoid community. However, the difference in the density of C. japoniella between male and female plants was yearly variable, so that we failed to attain the original aim. Instead, we revealed the following things:1. C. japoniella oviposited exclusively on leaves over aged one year and scarcely on current-year leaves. Old leaves had smaller amount of nitrogen contents, lower ratio of nitrogen to carbon and larger amount of epigarocatechin than current-year leaves. When females of C. japoniella were compelled to lay eggs on current-year leaves, hatched larvae were soon enclosed by transformed cells of the leaf tissue. Thus, the adaptive significance that females scarcely oviposit on current-year leaves would be to avoid leaves with hypersensitive response to mines rather than leaves with poor nutritional quality.2. Leaves with leafmining larvae killed experimentally began to abscise earlier and more rapidly than leaves with living larvae. This suggests that C. japoniella larvae inhibit the host plant from abscising mined leaves early.3. The parasitoid assemblage assariated with C. japoniella was composed of 12 species. Of them, one was koinobiont, and the others were idiobiont. Coexisting mechanisms in this assemblage seemed to be a quite high rate of hyperparasitism by idiobionts to the dominant koinobiont and wide host ranges of idiobionts.4. On the basis of investigation of specimens preserved in Osaka Prefecture University and Hokkaido University and those collected in the field, four species of Tischeriidae were found to be new to science. Furthermore, a new tischeriid species from Quercus sp. (Fagaceae) was collected in Jawa Island, Indonesia, where no tischeriids had been recorded.