Novoa Anai, Hechinger Ryan F
Scripps Institution of Oceanography-Marine Biology Research Division, University of California San Diego, La Jolla, CA 92037, USA.
Proc Biol Sci. 2024 Dec;291(2037):20242039. doi: 10.1098/rspb.2024.2039. Epub 2024 Dec 19.
The lack of information concerning how parasitism maps onto host geographical distributions represents a striking gap in ecological knowledge. This knowledge gap limits our understanding of a wide range of phenomena, including the consequences of climate change-induced range shifts of both hosts and parasites. To help solve this problem, we created a predictive theoretical framework and quantified latitudinal variation in parasitism by animal and protozoan parasites throughout the entire contiguous geographical ranges of four estuarine fish species. To circumvent frequent limitations in data and to permit revealing of novel biogeographical patterns, we (i) quantified parasitism at the individual host level, (ii) quantified parasite species diversity and biomass load, and (iii) tracked functionally distinct parasitic consumer strategies. Parasite diversity always increased at lower latitudes, and this pattern was largely driven by parasites using trophic transmission. Furthermore, in three of four cases, the role of fish as predator- versus prey-host for trophically transmitted parasite (TTP) species increased at lower latitudes. Parasite diversity patterns followed predictions more consistently than did biomass load, indicating that increased predation at lower latitudes may decrease observed parasite biomass load. These findings suggest a particularly strong role for TTPs and predation in community structure and dynamics at lower latitudes.
关于寄生现象如何映射到宿主地理分布上的信息匮乏，这是生态知识领域一个显著的空白。这一知识空白限制了我们对广泛现象的理解，包括气候变化导致的宿主和寄生虫范围变化的后果。为了帮助解决这个问题，我们创建了一个预测性理论框架，并在四种河口鱼类的整个连续地理范围内，量化了动物和原生动物寄生虫寄生现象的纬度变化。为了规避数据中常见的局限性，并揭示新的生物地理模式，我们（i）在个体宿主层面量化寄生现象，（ii）量化寄生虫物种多样性和生物量负荷，以及（iii）追踪功能不同的寄生消费者策略。寄生虫多样性在较低纬度地区总是增加的，这种模式在很大程度上是由采用营养传播的寄生虫驱动的。此外，在四个案例中的三个中，鱼类作为营养传播寄生虫（TTP）物种的捕食性宿主与猎物性宿主的作用在较低纬度地区增加。寄生虫多样性模式比生物量负荷更符合预测，这表明较低纬度地区捕食增加可能会降低观察到的寄生虫生物量负荷。这些发现表明，TTPs和捕食在较低纬度地区的群落结构和动态中发挥着特别重要的作用。
