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

我们测试了一种假设，即植食昆虫通过一种称为“寄主种族”的中间状态共同形成物种，以epilachnine瓢虫和Chrysolina叶甲虫为研究材料。主要结果是：1。在各种信息的基础上，我们已经证明了两种同域瓢虫，以野蓟（Cirsium spp., Asteraceae）为食的Henosepilachna niponica和以蓝麻（Caulophyllum robustum, Berberidaceae）为食的H.yasutomii，由于它们对各自寄主植物的保真度而被生殖隔离。将这对瓢虫与其北部分布的兄弟种（既发生在蓟花上，也发生在蓝升麻上）的比较表明，生活史特征的差异，特别是物候特征的差异，可能是解释这些瓢虫甲虫所观察到的同域/异域关系的重要因素。此外，这两种杂交品种在蓟或蓝升麻上的适合度均低于亲本的情况下，其同域发生可能是通过选择来维持的。在印度尼西亚，众所周知的茄类作物和杂草的重要害虫Henosepilachna vigintioctopunctata已被证明正在扩大其寄主植物范围，以覆盖一种引进的杂草豆科植物Centrosema pubescens。另一印度尼西亚种Henosepilachna sp. 3被证明由两个寄主特定种族组成，一个在薇甘菊（菊科）上，另一个在Leucas（唇形科）上。这两个种族在生殖上几乎完全隔离，线粒体分析表明，这两个种族在爪哇岛上分道扬镳。结果表明，寄主植物的迁移对植食性昆虫的生理和生态都产生了显著的影响，并立即在原寄主植物上的种群与新寄主上的种群之间产生了很强的生殖隔离。结果表明，在寄主介导的植食昆虫物种形成过程中，“寄主种族”的状态可能很短，甚至没有实现。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