MECHANISM OF HOST-RANGE EXPANSION IN PHYTOPHAGOUS BEETLES : EFFECT OF UTILIZATION OF SUBSIDIARY HOST PLANTS BY ADULT BEETLES

植食性甲虫扩展寄主范围的进化过程的细节在很大程度上是未知的。在本研究项目中，我假设成虫对附属寄主植物的利用为幼虫在新寄主上发育提供了潜在的能力，并试图通过实地调查和几个实验室实验来验证这一假设。虽然只有部分结果支持这一假设，但这表明，幼虫在潜在寄主上发育的能力可能是由于成虫对寄主的利用非常罕见，而这一假设仅适用于成虫和幼虫在特定寄主上的存活。

The details of evolutionary process of host-range expansion by phytophagous beetles are largely unknown. In this research project, I hypothesized that the utilization of subsidiary host plants by adult beetles provides potential ability of larvae to develop on the novel hosts, and tried to test this hypothesis by field surveys and several laboratory experiments. Although only a part of results supported the hypothesis, it was suggested that the ability of larvae to develop on a potential host could be conferre by very rare utilization of the host by adults, and the hypothesis would be supported only for adults' and larval survival on a particular host.