Data from: Host specificity shapes population structure of pinworm parasites in Caribbean reptiles

Host specificity is one of the potential factors affecting parasite diversification because gene flow may be facilitated or constrained by the number of host species that a parasite can exploit. We test this hypothesis using a costructure approach, comparing two sympatric pinworm parasites that differ in host specificity – Parapharyngodon cubensis and Spauligodon anolis – on the Puerto Rican Bank and St. Croix in the Caribbean. Spauligodon anolis specializes on Anolis lizards, whereas P. cubensis parasitizes Anolis lizards as well as many other species of lizards and snakes. We collected lizards from across the Puerto Rican Bank and St. Croix, sampled them for S. anolis and P. cubensis and generated nuclear and mitochondrial sequence data from the parasites. We used these data to show that P. cubensis is comprised of multiple cryptic species that exhibit limited population structure relative to S. anolis, which is consistent with our prediction based on their host specificity. We also provide evidence that the distribution of P. cubensis species is maintained by competitive exclusion, and in contrast to previous theoretical work, the parasites with the greatest number of host species also reach the highest prevalence rates. Overall, our results are consistent with the hypothesis that host specificity shapes parasite diversification, and suggest that even moderate differences in host specificity may contribute to substantial differences in diversification.宿主特异性 (Host specificity) 是影响寄生虫多样化进程的潜在因素之一，因为寄生虫可利用的宿主物种数量会对其基因流 (gene flow) 产生促进或限制作用。本研究采用协同结构分析方法，以加勒比海波多黎各岸区与圣克罗伊岛为研究区域，对两种宿主特异性存在显著差异的同域蛲虫寄生虫——古巴副咽口线虫（Parapharyngodon cubensis）与安乐蜥棘口线虫（Spauligodon anolis）——进行对比，以检验上述假说。其中，安乐蜥棘口线虫仅特化寄生于安乐蜥属（Anolis）蜥蜴，而古巴副咽口线虫除侵染安乐蜥属蜥蜴外，还可寄生于多种其他蜥蜴及蛇类物种。本研究在波多黎各岸区与圣克罗伊岛全境采集蜥蜴样本，检测样本中是否感染上述两种蛲虫，并获取寄生虫的核基因组与线粒体基因组序列数据。基于上述序列数据，本研究证实古巴副咽口线虫由多个隐存种（cryptic species）构成，相较于安乐蜥棘口线虫，其种群结构分化程度有限，这与我们基于二者宿主特异性做出的预测相符。本研究同时提供证据表明，古巴副咽口线虫隐存种的分布格局由竞争排斥作用维持；与以往的理论研究结果相反，宿主范围最广的寄生虫种群感染率 (prevalence rates) 也最高。综上，本研究结果支持宿主特异性塑造寄生虫多样化进程的假说，并表明即便宿主特异性仅存在中等程度的差异，也可能导致寄生虫多样化程度产生显著分歧。