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

Mechanisms of sympatric speciation in monophagous sawflies

单食性锯蝇的同域物种形成机制

基本信息

批准号：
05640788
负责人：
NAITO Tikahiko
金额：
$ 1.28万
依托单位：
Kobe university
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Mechanisms of sympatric speciation were investigated for Hemitaxonus japoicus comples, of which the new host race, polyblepharum race is being formed from the original race, tripteron race, in the narrow zone of about 10 km wide around 34ﾟN in the south-western part of Japan without geographical isolation. Adult females of each host race lay eggs on their own host plant. F1 females prefere Polystichum tripteron to P.polyblepharum for oviposition. Host selection may be disruptive, controlled by one gene. Two races use similar but distinct volatile chemichal substants for oviposition stimulants, of which the boiling points are between 100 and 150ﾟC/1mmHg, respectively. The newhost race larvae lose the ability to survive on the old host plant, caused by conditioning that the adult females continue to lay eggs on the new host plant. Asymmetrical mating developing between two racesis an importat post-mating reproductive isolating mechanism to preventthe gene flow from the old host race to the new. There is no remarkable differentiation in chromosome and allozyme polymorphisms between two host races, but the difference of 20 bp in the miner band of pYS family of tandemly repetitive DNA sequences between them may clear the relationship between host race formation and genetic variation. The sibling species H.sasayamensis is supposed to have speciated sympatrically from H.japonicus with host shift and to have been temporall isolated on the most parts of distribution.

摘要本文研究了日本半轴蝽（Hemitaxonus japoicus）复群的同域物种形成机制，发现在日本西南部34个海拔约10 km宽的窄带内，由原寄主种雷公藤（triteron）形成新的寄主种polyblepharum race。每个寄主种的成年雌性在它们自己的寄主植物上产卵。雌F1在产卵时更倾向于雷公藤，而不是雷公藤。宿主选择可能是破坏性的，由一个基因控制。两个种族使用相似但不同的挥发性化学物质作为促排卵剂，其沸点分别在100 ~ 150 C/1mmHg之间。由于成年雌虫继续在新寄主上产卵的条件作用，新寄主的幼虫丧失了在旧寄主上生存的能力。不对称交配是一种重要的交配后生殖隔离机制，可以防止基因从旧寄主种族流向新寄主种族。两种寄主在染色体和同工酶多态性上没有显著差异，但它们之间串联重复DNA序列pYS家族矿工带20 bp的差异可能阐明了寄主形成与遗传变异之间的关系。兄弟种sasayamensis被认为是在宿主转移的情况下与日本血吸虫共缘形成的，并且在分布的大部分地区被暂时隔离。