Dissertation: The Effect of Parasitism and Predation on the Spatial and Temporal Distributions of a Freshwater Snail

9509286种活生生的寄生虫可以极大地影响宿主的行为。这种行为变化有时会增加寄生虫被传播到另一宿主的可能性，从而使其受益。初步研究表明，吸虫寄生虫Microphallus sp.引起淡水蜗牛Potamopyrgus antipodarum的显著行为变化。这项研究将在实验上确定这种行为变化是寄生虫的副产品，还是寄生虫的一种适应性策略，以增加受感染的蜗牛被生命周期中的最终宿主鸭子吃掉的可能性。这些想法将通过确定食物剥夺对受感染和未受感染蜗牛行为的影响，以及确定水禽和不能作为寄生虫最终宿主的捕食者将受感染蜗牛从种群中移除的比率来检验。这项研究将第一次开始研究宿主和非宿主捕食者在塑造宿主-寄生虫关系方面的相互作用。这些类型的研究很重要，因为寄生虫在人群中传播的模型通常假设传播是随机事件。然而，情况显然并非如此。由于许多蜗牛的吸虫寄生虫也会作为最终宿主感染人类和家畜，了解这种寄生虫如何影响中间宿主的行为可能会导致更好的控制措施。

9509286 Lively Parasites can dramatically influence the behavior of their hosts. Such behavioral changes can sometimes benefit the parasite by increasing its probability of being transmitted to another host. Preliminary studies have demonstrated that a trematode parasite, Microphallus sp., causes of significant behavioral change in the freshwater snail, Potamopyrgus antipodarum. This research will experimentally determine if the behavioral change is simply a byproduct of parasitism, or if it is an adaptive strategy on the part of the parasite to increase the likelihood that infected snails are eaten by the final host in the life cycle, ducks. These ideas will be tested by determining the effect of food deprivation on the behavior of infected and uninfected snails, as well as determining the removal rates of infected snails from the population by waterfowl and predators that cannot serve as final hosts for the parasite. This study will be the first to begin to examine the interaction of host and non-host predators in shaping host-parasite relationships. These types of studies are important because models of parasite spread in populations usually assume that transmission is a random event. However, this clearly is not the case. Since many trematode parasites of snails also infect humans and domestic livestock as a final host, an understanding how the parasite affects the behavior of intermediate hosts may lead to better control measures.