Araujo Sabrina B L, Braga Mariana Pires, Brooks Daniel R, Agosta Salvatore J, Hoberg Eric P, von Hartenthal Francisco W, Boeger Walter A
Laboratório de Ecologia Molecular e Parasitologia Evolutiva, Universidade Federal do Paraná, Caixa Postal 19073, Curitiba, PR 81531-980, Brazil; Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, PR 81531-980, Brazil.
Laboratório de Ecologia Molecular e Parasitologia Evolutiva, Universidade Federal do Paraná, Caixa Postal 19073, Curitiba, PR 81531-980, Brazil.
PLoS One. 2015 Oct 2;10(10):e0139225. doi: 10.1371/journal.pone.0139225. eCollection 2015.
Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.
尽管寄生虫在宿主方面具有高度特异性，但经验证据表明，宿主转换而非共同物种形成是影响宿主 - 寄生虫关联多样化的主导因素。在宽松适应度空间中的生态拟合被认为是一种使生态特化物种能够轻松进行宿主转换的机制。本文使用基于个体的宿主转换模型对该提议进行了测试。该模型考虑了一个接触多种宿主资源的寄生虫物种。随着时间推移，宿主范围的扩大可以很容易地发生，而无需新遗传能力的预先进化。它还会在适应度空间大小上产生非线性变化。宿主定殖能力在过程早期受繁殖体压力强烈影响，后期受适应度空间大小影响。模拟结果表明，共同适应可能由不太适应的表型的暂时丧失引发。此外，寄生虫可以在次优宿主中长期存在，因此可能通过“踏脚石”过程定殖到远缘宿主。
