Shoemaker D DeWayne, Machado Carlos A, Molbo Drude, Werren John H, Windsor Donald M, Herre Edward Allen
Department of Biological Sciences, 3149 Wood Hall, 1903 West Michigan Avenue, Western Michigan University, Kalamazoo, MI 49008-5410, USA.
Proc Biol Sci. 2002 Nov 7;269(1506):2257-67. doi: 10.1098/rspb.2002.2100.
We surveyed for the presence and identity of Wolbachia in 44 species of chalcid wasps associated with 18 species of Panamanian figs. We used existing detailed knowledge of the population structures of the host wasps, as well as the ecological and evolutionary relationships among them, to explore the relevance of each of these factors to Wolbachia prevalence and mode of transmission. Fifty-nine per cent of these wasp species have Wolbachia infections, the highest proportion reported for any group of insects. Further, neither the presence nor the frequency of Wolbachia within hosts was correlated with the population structure of pollinator hosts. Phylogenetic analyses of wsp sequence data from 70 individuals representing 22 wasp species show that neither the close phylogenetic relationship nor close ecological association among host species is consistently linked to close phylogenetic affinities of the Wolbachia associated with them. Moreover, no genetic variation was detected within any Wolbachia strain from a given host species. Thus, the spread of Wolbachia within host species exceeds the rate of horizontal transmission among species and both exceed the rate of mutation of the wsp gene in Wolbachia. The presence and, in some cases, high frequency of Wolbachia infections within highly inbred species indicate that the Wolbachia either directly increase host fitness or are frequently horizontally transferred within these wasp species. However, the paucity of cospeciation of Wolbachia and their wasp hosts indicates that Wolbachia do not persist within a given host lineage for long time-periods relative to speciation times.
我们调查了与18种巴拿马无花果相关的44种小蜂科黄蜂体内沃尔巴克氏体的存在情况及种类。我们利用现有的关于寄主黄蜂种群结构的详细知识，以及它们之间的生态和进化关系，来探究这些因素与沃尔巴克氏体流行率及传播方式的相关性。这些黄蜂种类中有59%感染了沃尔巴克氏体，这是报道的所有昆虫类群中比例最高的。此外，寄主体内沃尔巴克氏体的存在与否及频率与传粉者寄主的种群结构均无关联。对代表22种黄蜂的70个个体的wsp序列数据进行系统发育分析表明，寄主物种之间的近缘系统发育关系和紧密生态关联均未始终如一地与相关沃尔巴克氏体的近缘系统发育亲缘性相关联。此外，在来自给定寄主物种的任何沃尔巴克氏体菌株内均未检测到遗传变异。因此，沃尔巴克氏体在寄主物种内的传播速度超过了物种间的水平传播速度，且二者均超过了沃尔巴克氏体中wsp基因的突变速度。在高度近交物种中沃尔巴克氏体感染的存在以及在某些情况下的高频率表明，沃尔巴克氏体要么直接提高寄主适应性，要么经常在这些黄蜂物种内进行水平转移。然而，沃尔巴克氏体与其黄蜂寄主的共物种形成现象稀少，这表明相对于物种形成时间而言，沃尔巴克氏体不会在给定寄主谱系内长期存在。
