Evolutionary biology of the process of host shift in phytophagous ladybird beetles

1.研究了豆斑食植瓢虫复合体的食植性瓢虫与寄主植物之间的共进化关系。等位酶和线粒体DNA分析表明：（1）瓢虫的寄主转移发生在很短的进化时间内，即从茄科植物转移到其它科植物（菊科、罂粟科、小檗科等）;（2）同种异域种群间的遗传差异是由“距离隔离”引起的;（3）寄主特异性是同域共存的E. vigintioctomaculata complex. 2.对蓟属植物的分子生物学、形态计量学和物候学特征进行了研究。分布于北海道南部的Viglntioctomaculata复合体揭示，尽管它们的形态不同，但它们在遗传上非常相似 ...更多信息 和生态差异，这表明祖先蓟物种经历了快速的系统辐射在北海道和周边地区，也许在冰川时期。虽然不是所有的蓟都适合作为瓢虫的寄主植物，但瓢虫利用的蓟种并不构成单系簇.大蓟中所含的物质，作为一种对蓟食E。niponica，经鉴定为刺柳珊瑚苷。但这种黄酮类化合物没有引起另一种蓟食源性物种E.脓疱型4.研究了不同寄主植物上的生长性状的遗传背景，并对不同种群间的生长性状进行了比较。不同地理来源和寄主植物的黄荚紫珠.这些结果表明，寄主植物的转移在不同的E。vigintioctomaculata复合体的进展非常迅速，适应当地的食物环境。瓢虫的低移动性可能增强了这一过程。少

1. Coevolutionary relationships between the phytophagous ladybird beetles of the Epilachna vigintioctomaculata complex and their host plants were investigated. Analyses of allozymes and mtDNA of the ladybird beetles suggested that (1) host shift in the ladybird beetles occurred during a very short evolutionary time, from solanaceous plants to plants of other families (Asteraceae, Papaveraceae, Berberidaceae, etc.) now utilized by certain members; (2) genetic difference between conspecific allopatric populations was resulted from the "isolation by distance": and (3) host specificity functions as a crucial reproductive barrier between coexisting sympatric members of the E. vigintioctomaculata complex.2. Molecular, morphometric, and phenological analyses of thistles (Cirsium), one of the major host plants of the E. viglntioctomaculata complex, distributed in the southern part of Hokkaido revealed that they are genetically very similar to each other in spite of their distinct morphological … More and ecological differences, suggesting that an ancestral Cirsium species underwent rapid phyletic radiation in Hokkaido and surrounding areas, perhaps during the glacial period. Although not all thistles are suitable as the host plants of the ladybird beetles, thistle species utilized by the ladybird beetles did not constitute a monophyletic cluster.3. The substance contained in Cirsium kagamontanum, that act as a feeding deterrent against infestation by a thistle feeding E. niponica, was identified as pectolinarin. But this flavonoid did not induce feeding rejection by another thistle feeding species E. pustulosa.4. Genetic background of growth performance on different host plants was studied and compared between different populations of E. vigintioctolmaculata with different geographic origins and host plants.5. These results suggests that the shift of host plants in various members of the E. vigintioctomaculata complex proceeded very rapidly, as adaptation to local food environments. Low vagility of the ladybird beetles may have enhanced this process . Less