权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Evolution of the host range in spider mites

红蜘蛛寄主范围的演变

基本信息

批准号：
07660057
负责人：
TAKAFUJI Akio
金额：
$ 1.47万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Phytophagous mites of the genus Tetranychus are highly polyphagous and occurs on a variety of plant species. However, the host adaptability of the mites, as expressed by their survival and oviposition rates, varies greatly among the plant species, and some species such as chrysanthemums are very unfavorable to them. This study elucidated the mechnisms that determine the host range of the mites, with special emphasis on the two-spotted spider mite, T.urticae, one of the most important agricultural pests. The results of the study are summarized as follows. Genetic, intraspecific variations exist in the host adaptability of T.urticae, and the ecological performance on unfavorable hosts is enhanced very rapidly by an artificial selection that may occur also in agricultural ecosystems. However, whether or not the mites can stay and settle on an unsuitable host is largely affected by their previous experiences on the host through feeding experience and also by the experience of the odur that is emitted by the plant. Even if the mites experienced only the odur, their acceptability of the unfavorable host was greatly increased. Thus, the mites have high behavioral plasticity in adapting to new hosts. Unmated females have much higher plasticity than mated ones, to unfavorable hosts. The analysis using RAPD method suggested that genetic differentiation is not unlikely to occur among different host species in polyphagous spider mites, such as T.urticae. We conclude that the host acceptability of T.urticae, which has a very low dispersal ability, is enhanced by the non-genetic, behavioral change of the mites, and it is then accerelated by genetic selection pressure that will act on the mite population.

叶螨属的植食性螨是高度多食性的，并且发生在多种植物物种上。然而，螨类的寄主适应性，表现在其存活率和产卵率上，在不同的植物种类中差异很大，有些种类如藜属植物对螨类的寄主适应性非常不利。本文以二斑叶螨为研究对象，阐明了二斑叶螨寄主范围的决定机制。研究结果总结如下。二斑叶螨的寄主适应性存在种内遗传变异，在农业生态系统中也可能发生人工选择，从而迅速增强其对不利寄主的生态表现。然而，螨是否能在不合适的宿主上停留和定居，在很大程度上受到它们先前通过进食经验对宿主的经验以及植物散发的气味的经验的影响。即使螨只经历气味，它们对不利宿主的接受性也大大增加。因此，螨类在适应新的宿主时具有高度的行为可塑性。未交配的雌虫比交配的雌虫对不利寄主的可塑性高得多。RAPD分析表明，在二斑叶螨等多食性叶螨中，不同寄主间可能存在遗传分化。我们认为，二斑叶螨的非遗传性行为改变增强了其对寄主的接受性，并通过作用于螨群的遗传选择压力使其对寄主的接受性增强。