Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan.
Graduate School of Environmental Sciences, Hokkaido University, Hokkaido, Japan.
Biol Lett. 2024 Jul;20(7):20240065. doi: 10.1098/rsbl.2024.0065. Epub 2024 Jul 17.
Nematomorph parasites manipulate terrestrial arthropods to enter streams where the parasites reproduce. These manipulated arthropods become a substantial prey subsidy for stream salmonids, causing cross-ecosystem energy flow. Diverse nematomorph-arthropod associations underlie the energy flow, but it remains unknown whether they can mediate the magnitude and temporal attributes of the energy flow. Here, we investigated whether distinct phylogenetic groups of nematomorphs manipulate different arthropod hosts and mediate seasonal prey subsidy for stream salmonids. The results of our molecular-based diagnoses show that and nematomorphs infected ground beetle and orthopteran hosts, respectively. The presumable ground beetle hosts subsidized salmonid individuals in spring, whereas the presumable orthopteran hosts did so in autumn. Maintaining the two distinct nematomorph-arthropod associations thus resulted in the parasite-mediated prey subsidy in both spring and autumn in the study streams. Manipulative parasites are common, and often associated with a range of host lineages, suggesting that similar effects of phylogenetic variation in host-parasite associations on energy flow might be widespread in nature.
线虫寄生虫操纵陆生节肢动物进入溪流，在那里寄生虫繁殖。这些被操纵的节肢动物成为溪流鲑鱼的重要猎物补充，导致跨生态系统能量流动。不同的线虫-节肢动物关联是能量流动的基础，但目前尚不清楚它们是否能够调节能量流动的幅度和时间属性。在这里，我们调查了线虫的不同进化枝是否操纵不同的节肢动物宿主，并介导了溪流鲑鱼的季节性猎物补充。我们基于分子的诊断结果表明， 和 线虫分别感染了步甲和直翅目宿主。推测的步甲宿主在春季为鲑鱼个体提供了食物补充，而推测的直翅目宿主则在秋季提供了食物补充。因此，维持这两种不同的线虫-节肢动物关联导致研究溪流在春季和秋季都出现了寄生虫介导的猎物补充。操纵性寄生虫很常见，通常与一系列宿主谱系相关，这表明在自然界中，宿主-寄生虫关联中进化枝变异性对能量流动的类似影响可能很普遍。
