Should sex-ratio distorting parasites abandon horizontal transmission?
Should sex-ratio distorting parasites abandon horizontal transmission?
复制标题
DOI：
10.1186/1471-2148-11-370
复制
发表时间：
2011-12-21
影响因子：
3.4
通讯作者：
Dunn, Alison M.
中科院分区：
文献类型：
--
作者：
Ironside, Joseph E.;Smith, Judith E.;Dunn, Alison M.
背景：扭曲性别比的寄生虫之所以引起人们的兴趣，是因为它们对宿主种群动态的影响以及它们可能影响宿主性别决定系统的进化。从理论上讲，扭曲寄主性别比的能力允许具有有效垂直(遗传)传播的寄生虫完全免除水平(传染性)传播。然而，最近的经验研究表明，一些扭曲性别比的寄生虫保留了水平传播的能力。结果：使用生物真实参数的数值模拟表明，只有在寄主密度较低和/或具有偏向男性的主要性别比的情况下，雌性化的寄生虫才可能失去水平传播的能力。研究还表明，即使是少量的水平传播也可以使多个雌性化寄生虫在单个宿主种群内共存。最后，研究表明，通过提高寄主的种群增长率，雌性化的寄生虫可以增加自身的水平传播，并允许其他毒力更强的寄生虫入侵。结论：扭曲性别比的寄生虫可能保持一定程度的水平传播的预测对这些生物的流行病学和宿主-寄生虫的相互作用具有重要意义。这也可能解释了自然界中几种扭曲性别比例的寄生虫经常共存的原因。
Background: Sex-ratio distorting parasites are of interest due to their effects upon host population dynamics and their potential to influence the evolution of host sex determination systems. In theory, the ability to distort host sex-ratios allows a parasite with efficient vertical (hereditary) transmission to dispense completely with horizontal (infectious) transmission. However, recent empirical studies indicate that some sex-ratio distorting parasites have retained the capability for horizontal transmission.Results: Numerical simulations using biologically realistic parameters suggest that a feminising parasite is only likely to lose the capability for horizontal transmission if its host occurs at low density and/or has a male-biased primary sex ratio. It is also demonstrated that even a small amount of horizontal transmission can allow multiple feminising parasites to coexist within a single host population. Finally it is shown that, by boosting its host's rate of population growth, a feminising parasite can increase its own horizontal transmission and allow the invasion of other, more virulent parasites.Conclusions: The prediction that sex-ratio distorting parasites are likely to retain a degree of horizontal transmission has important implications for the epidemiology and host-parasite interactions of these organisms. It may also explain the frequent co-occurrence of several sex-ratio distorting parasite species in nature.