Mouritsen K N
Department of Marine Ecology, Institute of Biological Sciences, University of Aarhus, Finlandsgade 14, 8200 Aarhus N, Denmark.
J Helminthol. 2002 Dec;76(4):341-7. doi: 10.1079/JOH2002136.
The effects of environmental factors and exudates from the amphipod Corophium volutator on the emergence of Maritrema subdolum cercariae (Digenea: Microphallidae) from the snail Hydrobia ulvae were investigated in the laboratory. Increasing the temperature (15 to 25 degrees C) caused an overall 11-fold increase in emergence rate under varying salinities (24 to 36 per thousand). The effect of salinity depended on the experimental temperature. Emergence increased with increasing salinity at higher temperatures, but decreased with increasing salinity at 15 degrees C. Whereas the different levels of salinity had no effect, increasing the temperature significantly reduced the life span of cercariae. In comparison with complete darkness, light caused a two-fold increase in emergence, whereas an increment of the water pressure from 1.0 to 1.3 ATM (corresponding to 0 and 3 m of depth) left the shedding rate unaffected. Unidentified exudates from the second intermediate host, C. volutator, significantly depressed the cercarial emergence rate. The main transmission window of M. subdolum seems to occur during low water in tidal pools where light levels are high and solar radiation rapidly elevates the water temperature, as well as salinity through evaporation. The consequence of such a transmission strategy is discussed in relation to the impact of M. subdolum on the population dynamics of the second intermediate host.
在实验室中研究了环境因素和双壳纲动物卷钩虾（Corophium volutator）的分泌物对来自滨螺（Hydrobia ulvae）的亚氏微睾吸虫尾蚴（复殖目：微睾科）逸出的影响。在不同盐度（千分之24至36）下，升高温度（15至25摄氏度）使逸出率总体增加了11倍。盐度的影响取决于实验温度。在较高温度下，逸出率随盐度升高而增加，但在15摄氏度时随盐度升高而降低。不同盐度水平没有影响，但升高温度显著缩短了尾蚴的寿命。与完全黑暗相比，光照使逸出率增加了两倍，而水压从1.0个标准大气压增加到1.3个标准大气压（相当于深度从0米增加到3米）对逸出率没有影响。第二中间宿主卷钩虾的不明分泌物显著降低了尾蚴逸出率。亚氏微睾吸虫的主要传播窗口似乎出现在潮池中水位较低的时候，此时光照水平高，太阳辐射通过蒸发迅速提高水温以及盐度。结合亚氏微睾吸虫对第二中间宿主种群动态的影响，讨论了这种传播策略的后果。
