Spatio-temporal dynamics of host-shift in Henosepilachna vigintioctopunctata now in progress in Southeast Asia

在野外观察、食物选择试验、饲养实验和线粒体DNA序列分析的基础上，研究了东南亚地区八爪鱼（Henosepilachna vintioctopunctata）寄主变化的时空动态。该物种的主要寄主植物被认为是茄科植物。然而，使用引进的豆科植物“centro”的种群在马来半岛南部、爪哇、苏门答腊和加里曼丹西部广泛分布。在更东部的地区，它们并不常见或没有。DNA分析表明，在东南亚以茄为食的种群中，中心摄食性状有多个起源。没有令人信服的证据表明，在这两种寄主植物上，vigintioctopunctata存在分化，也没有证据表明寄主从茄属植物转变为centro属植物。即使是采食centro的种群，其幼虫期也较长，体型较小，表明它们在生理上还没有完全适应centro。

On the basis of field observations, food choice tests, rearing experiments and an analysis of mitochondrial DNA sequences, we studied spatio-temporal dynamics of host changes of Henosepilachna vigintioctopunctata in Southeast Asia. The primary host plants of this species are considered to be solanaceous plants. However, the populations utilizing an introduced legume "centro" were widespread in the southern part of the Malay Peninsula, Java, Sumatra, and western Kalimantan. They were not common or absent in more eastern areas. The DNA analysis suggested multiple origins of the centro-feeding trait in solanum-feeding populations in Southeast Asia. No convincing evidence was obtained for the divergence of H. vigintioctopunctata along the two host plants, or for the host change from solanum to centro. Even the centro feeding populations showed an extended larval period and small body size on centro, suggesting that they were not yet fully adapted physiologically to this plant.