Page R D, Clayton D H, Paterson A M
Division of Environmental and Evolutionary Biology, University of Glasgow, UK.
Int J Parasitol. 1996 Feb;26(2):213-8. doi: 10.1016/0020-7519(95)00115-8.
"The student who intends working on the Mallophaga should take warning that he will be tried almost beyond endurance by the paradoxes and complexities which beset his subject but he will also find, in the dual and inter-related aspect of insect and bird, an infinite fascination." (Rothschild & Clay, 1952: pp. 156-157). The study of host louse coevolution will benefit greatly from the phylogenetic perspective offered by recent advantages in molecular systematics. However, in order to make best use of phylogenies we need to appreciate the complexities of the possible relations between host and parasite phylogeny. At the same time, the very complexity of louse-host systems has a potentially useful consequence; the presence of multiple lineages of lice on the same hosts allow for replicated tests of coevolutionary hypotheses. For example, if a number of louse clades infest the same host clade but some lice show more cospeciation than others, we might ask whether there are features of louse biology that correlate with this difference in host tracking fidelity. It may further be possible to ascertain the relative importance of these features in ecological time through controlled transfer experiments. By beginning to appreciate "the paradoxes and complexities" of host-louse evolution, lice may offer us not only "infinite fascination" but also a chance to address important questions in coevolution.
“打算研究食毛目的学生应该得到警告，困扰其研究对象的自相矛盾和复杂情况会让他备受考验，几乎超出其承受能力，但他也会在昆虫与鸟类的双重且相互关联的层面中发现无穷的魅力。”（罗斯柴尔德和克莱，1952年：第156 - 157页）宿主虱子协同进化的研究将极大地受益于分子系统学近期进展所提供的系统发育视角。然而，为了充分利用系统发育关系，我们需要认识到宿主与寄生虫系统发育之间可能存在的复杂关系。同时，虱子 - 宿主系统的极端复杂性产生了一个潜在的有益结果；同一宿主上存在多个虱子谱系，这使得对协同进化假说进行重复检验成为可能。例如，如果多个虱子分支寄生于同一宿主分支，但有些虱子比其他虱子表现出更多的共物种形成现象，我们可能会问，虱子生物学的哪些特征与宿主追踪保真度的这种差异相关。通过可控的转移实验，进一步有可能在生态时间尺度上确定这些特征的相对重要性。通过开始认识到宿主 - 虱子进化的“自相矛盾和复杂情况”，虱子不仅可能带给我们“无穷的魅力”，还为我们提供了一个解决协同进化中重要问题的机会。
