Curtis L A
Biol Bull. 1990 Aug;179(1):105-112. doi: 10.2307/1541744.
Movements of marked individuals of Ilyanassa obsoleta (n = 500) were charted in an intertidal environment for about one week. At the end of observations, 260 marked individuals, which had been sighted 1017 times collectively, were recollected and examined for trematode infections. Six trematode species were found in 19 infection combinations including uninfected, singly, doubly, and triply infected snails. We know that most snails found high on beaches and on sandbars carry Gynaecotyla adunca infections. It has been hypothesized that this host behavior modification is a parasite adaptation to enhance cercarial transmission to a semi-terrestrial next host. Observations reported here support this hypothesis and reveal some of the complexity in the behavior imposed on I. obsoleta by G. adunca. Individuals that were uninfected or infected with other parasites demonstrated no unique movement patterns, but individuals infected with G. adunca made repeated excursions into the upper shore habitat. These excursions were timed so that host-parasites were left emerged at high elevations primarily during nighttime low tides. Because many snails were multiply infected, data presented support the idea that gastropod populations have the potential to be used as systems for the study of the nature of ecological and evolutionary interactions among parasite species.
在潮间带环境中，对500只标记的过时泥螺（Ilyanassa obsoleta）个体的活动进行了约一周的记录。在观察结束时，重新收集了260只标记个体（它们总共被观察到1017次），并检查是否感染吸虫。在19种感染组合中发现了6种吸虫，包括未感染、单感染、双感染和三感染的蜗牛。我们知道，在海滩高处和沙洲上发现的大多数蜗牛都感染了钩腺妇科吸虫（Gynaecotyla adunca）。据推测，这种宿主行为改变是一种寄生虫适应性，以增强尾蚴向半陆生下一宿主的传播。此处报告的观察结果支持这一假设，并揭示了钩腺妇科吸虫对过时泥螺行为造成的一些复杂性。未感染或感染其他寄生虫的个体没有表现出独特的活动模式，但感染钩腺妇科吸虫的个体多次进入上岸栖息地。这些活动的时间安排使得宿主寄生虫主要在夜间低潮时留在高海拔处暴露在外。由于许多蜗牛是多重感染，所提供的数据支持这样一种观点，即腹足类种群有可能被用作研究寄生虫物种之间生态和进化相互作用本质的系统。
