Gérard C, Théron A
Laboratoire de Biologie Animale, UMR 5555 CNRS Centre de Biologie et d'Ecologie tropicale et méditerranéenne. Université. 52, Av. de Villeneuve, 66860 Perpignan Cedex France Fax: (33) 4 68 66 22 81; e-mail:
Oecologia. 1997 Nov;112(4):447-452. doi: 10.1007/s004420050331.
Snail hosts of different ages constitute different resource environments for larval trematodes because each individual has a particular energy budget and energy allocation pattern at the time of infection. Effects of monomiracidial trematode infections on shell growth, body dry weight and reproductive effort of the snail host were compared between controls and infected juvenile and adult snails during the prepatent and patent periods. The results demonstrate phenotypic plasticity in the host response. There is an age/size-specific effect characterized by limitation of growth rate when snails are infected as juveniles and reduction of reproductive effort when snails are infected as adults, and a time-specific effect with early enhancement of growth rate and reproductive effort for infected juvenile and adult snails respectively during prepatency, before reduction and cessation during patency. The parasite is considered as a generalist in its energy exploitation strategy of the snail host, but taking into account the differential host responses observed relative to the host age, the possibility of a host preference for juvenile or adult snails is discussed.
不同年龄的蜗牛宿主为幼虫吸虫构成了不同的资源环境，因为每个个体在感染时都有特定的能量预算和能量分配模式。在潜伏期和发病期，比较了单尾蚴吸虫感染对对照蜗牛以及感染的幼年和成年蜗牛宿主的壳生长、身体干重和繁殖力的影响。结果表明宿主反应具有表型可塑性。存在年龄/大小特异性效应，其特征为幼年蜗牛感染时生长速率受限，成年蜗牛感染时繁殖力降低；还存在时间特异性效应，即在潜伏期，感染的幼年和成年蜗牛的生长速率和繁殖力分别早期增强，之后在发病期降低并停止。该寄生虫在对蜗牛宿主的能量利用策略上被认为是一种泛化种，但考虑到观察到的相对于宿主年龄的不同宿主反应，讨论了寄生虫对幼年或成年蜗牛宿主存在偏好的可能性。
