Speciation of phytophagous insects : Testing "Sympatric speciation via host race formation" hypothesis

我们测试了植食性昆虫通过一种称为“寄主小种”的中间状态共生物种的假说，并以Ephachnine瓢虫和大叶金龟子为研究材料。主要研究结果如下：1.根据各种资料，我们证明了两种共域瓢虫--取食野生蓟(蓟属植物)的niponica和取食于蓝升麻(Caulophyllum robogum，Berberidaceae)的yasutomii是通过对各自寄主植物的保真度而繁殖分离的。该种对与其北方分布的兄弟种脓毒瓢虫(同时出现在蓟和蓝升麻上)的比较表明，生活史特征的差异，特别是物候特征，可能是解释观察到的这些瓢虫的同域/异地关系的重要因素。此外，尼波尼卡夜蛾和康氏夜蛾的同地发生可能是由…选择维持的。对于适合度较低的杂交种，无论是在蓟草上还是在蓝棉上，N的数量都比双亲多。在印度尼西亚，作为茄科作物和杂草的一种重要害虫，Vigintioctopunctata已被证明正在扩大其寄主植物范围，以涵盖引进的杂草豆科植物--毛中心草。另一印尼种Henosepetachna sp.3由两个寄主专化小种组成，一个是薇甘菊(菊科)，另一个是银合欢属(唇形科)。这两个小种几乎完全是生殖隔离的，线粒体分析表明两者在爪哇岛上是分开的。结果表明，寄主植物的转移对植食性昆虫的生理和生态都产生了显著的影响，并立即在旧寄主植物和新寄主植物上的种群之间产生了非常强的生殖隔离。结果表明，在寄主介导的植食性昆虫物种形成过程中，寄主小种的状态可能很短，甚至没有意识到。较少

We tested the hypothesis that phytophagous insects speciate sympatrically through an intermediate state called "host races," using epilachnine ladybird beetles and Chrysolina leaf beetles as the research materials. The main results are :1. On the basis of various sorts of information we have demonstrated that two sympatric ladybird beetles, Henosepilachna niponica feeding on wild thistles (Cirsium spp., Asteraceae) and H.yasutomii, on blue cohosh (Caulophyllum robustum, Berberidaceae), are reproductively isolated by their fidelity to respective host plants. A comparison of this species pair and their northerly distributed sibling species H. pustulosa (occurring on both thistle and blue cohosh) suggests that the difference of life history traits, in particular phenological trait, might be important to account for the observed sympatric/allopatric relationships of these ladybird beetles. Furthermore, sympatric occurrence of H. niponica and H. yasutomii might be maintained by the selectio … More n against their hybrids that showed lower fitness than parents on either thistle or blue cohosh.2. In Indonesia, Henosepilachna vigintioctopunctata, known as an important pest of solanaceous crops and weeds, is proven to be expanding their host plant range to cover an introduced weedy legume, Centrosema pubescens.3. Another Indonesian species Henosepilachna sp. 3 is proven to be consisted of two host specific races, one on Mikania (Asteraceae) and another on Leucas (Labiatae). The two races are nearly completely reproductively isolated, and a mitochondrial analysis suggests that the two have diverged on the island of Java.The results showed that the shift of host plants significantly influence the phytophagous insects both physiologically and ecologically, and immediately yields a very strong reproductive isolation between the population on the old host plant and that on the new host. The results suggest that the state of "host races" might be very short or even not realized during the host mediated speciation of phytophagous insects. Less