Ambient fauna impairs parasite transmission in a marine parasite-host system
Ambient fauna impairs parasite transmission in a marine parasite-host system
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环境动物群损害海洋寄生虫宿主系统中的寄生虫传播
作者：
D. Thieltges;M. Bordalo;A. CABALLERO HERNÁNDEZ;K. Prinz;K. Jensen
摘要为了了解可能的因素控制吸虫幼虫之间的第一和第二中间宿主，我们研究了环境动物对海洋潮间带寄生虫-宿主协会寄生虫传播的影响。与选定的共同发生的大型底栖动物物种在围隔中的蛤蚌主机（Cerastoderma）保持在一起获得了较低的寄生虫负荷相比，单独保持的蛤蚌，当有针对性的吸虫Himasthla elongata的尾蚴。减少寄生虫负载的鸟蛤不同的7个大型底栖动物物种之间的测试，是35和91%之间。结果表明：（1）捕食者（Carcinus maenas，Crangon crangon）主动捕食尾蚴，（2）非宿主滤食者（Crepidula fornicata，Mya arenaria，Crassostrea gigas）滤食尾蚴但不被感染，（3）替代宿主（Mytilus edulis，Macoma balthica）被尾蚴感染，从而分散尾蚴对目标宿主的注意力。此外，干扰竞争可能以环境生物干扰鸟蛤的形式发生，导致较低的过滤率和随后较低的寄生虫负荷。我们的研究结果表明，寄生-宿主系统的环境动物的物种组成和相对丰度在控制吸虫在底栖海洋系统中的传播率发挥着重要作用。
SUMMARY To understand possible factors controlling transmission of trematode larvae between first and second intermediate hosts we examined the impact of ambient fauna on parasite transmission in a marine intertidal parasite-host association. Cockle hosts (Cerastoderma edule) kept together with selected co-occurring macrozoobenthic species in mesocosms acquired a lower parasite load compared to cockles kept alone, when targeted by cercariae of the trematode Himasthla elongata. The reduction of parasite load in the cockles differed between the 7 macrozoobenthic species tested and was between 35 and 91%. Three different types of reduction could be distinguished: (1) predators (Carcinus maenas, Crangon crangon) actively preying upon cercariae, (2) non-host filter feeders (Crepidula fornicata, Mya arenaria, Crassostrea gigas) filtering cercariae but not becoming infected and (3) alternative hosts (Mytilus edulis, Macoma balthica) becoming infected by the cercariae and thus distracting cercariae from the target hosts. In addition, interference competition may occur in the form of disturbance of cockles by ambient organisms resulting in lower filtration rates and subsequently lower parasite loads. Our results suggest that the species composition and relative abundance of the ambient fauna of parasite-host systems play an important role in controlling trematode transmission rates in benthic marine systems.