Yan G, Norman S
Department of Zoology, University of Vermont, Burlington 05405.
J Parasitol. 1995 Feb;81(1):37-42.
Host susceptibility and resistance to parasites are often hypothesized to be genetically variable traits. We tested 2 species of Tribolium flour beetles for among-strain variation in susceptibility to the rat tapeworm Hymenolepis diminuta. Twelve genetic strains of Tribolium confusum and 11 strains of Tribolium castaneum were examined. We found T. castaneum was more susceptible to the tapeworm than T. confusum. There was significant among-strain and between-sex variation for both beetle species in infection intensity and prevalence. Among-vial variation was marginally significant. These results add to evidence that host susceptibility to a parasite is a genetically variable trait. We view these results as important findings for understanding natural selection on host-parasite interactions. Traits that are genetically variable can respond to natural selection. Thus, if a beetle's susceptibility to the tapeworm is correlated with fitness and heritable, susceptibility can evolve. Susceptibility is likely to be pleiotropic and have important consequences on issues ranging from parasite transmission to host species interactions and community structure.
宿主对寄生虫的易感性和抗性通常被假设为具有遗传变异性的性状。我们测试了2种赤拟谷盗对大鼠绦虫微小膜壳绦虫易感性的品系间差异。研究了12个杂拟谷盗遗传品系和11个赤拟谷盗品系。我们发现赤拟谷盗比杂拟谷盗对绦虫更易感。两种甲虫在感染强度和感染率方面，品系间和性别间均存在显著差异。小瓶间的差异略微显著。这些结果进一步证明宿主对寄生虫的易感性是一种具有遗传变异性的性状。我们认为这些结果是理解宿主 - 寄生虫相互作用自然选择的重要发现。具有遗传变异性的性状能够对自然选择做出反应。因此，如果甲虫对绦虫的易感性与适合度相关且具有遗传性，那么易感性就可能会进化。易感性可能具有多效性，并且对从寄生虫传播到宿主物种相互作用以及群落结构等一系列问题都有重要影响。
