Poulin R, Mouillot D
Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Parasitology. 2005 Jun;130(Pt 6):709-15. doi: 10.1017/s0031182004007218.
Different animal species have different probabilities of being discovered and described by scientists, and these probabilities are determined to a large extent by the biological characteristics of these species. For instance, species with broader geographical ranges are more likely to be encountered by collectors than species with restricted distributions; indeed, the size of the geographical range is often the best predictor of a species' date of description. For parasitic organisms, host specificity may be similarly linked to the probability of a species being found. Here, using data on 170 helminth species parasitic in freshwater fishes, we show that host specificity is associated with the year in which the helminths were described. Helminths that exploit more host species, and to a lesser degree those that exploit a broader taxonomic range of host species, tend to be discovered earlier than the more host-specific helminths. This pattern was observed across all helminth species, as well as within the different helminth taxa (trematodes, cestodes, nematodes and acanthocephalans). Our results demonstrate that the parasite species known at any given point in time are not a random subset of existing species, but rather a biased subset with respect to the parasites' biological properties.
不同的动物物种被科学家发现和描述的概率各不相同，而这些概率在很大程度上由这些物种的生物学特性决定。例如，地理分布范围更广的物种比分布受限的物种更有可能被采集者遇到；实际上，地理分布范围的大小往往是预测一个物种被描述时间的最佳指标。对于寄生生物来说，宿主特异性可能同样与一个物种被发现的概率相关。在此，我们利用170种寄生于淡水鱼的蠕虫物种的数据表明，宿主特异性与这些蠕虫被描述的年份有关。利用更多宿主物种的蠕虫，以及在较小程度上利用更广泛宿主物种分类范围的蠕虫，往往比宿主特异性更强的蠕虫更早被发现。在所有蠕虫物种以及不同的蠕虫类群（吸虫、绦虫线虫和棘头虫）中均观察到了这种模式。我们的结果表明，在任何给定时间已知的寄生虫物种并非现有物种的随机子集，而是在寄生虫生物学特性方面存在偏差的子集。
