扩散决定了宿主-寄生虫组合的空间动力学,特别是在入侵和疾病流行期间。寄生的风险可能会产生分散的动机,但是感染预计会降低传播能力,这可能会改变宿主对生物应激源的扩散反应,包括人口密度。我们测量了半水生昆虫(Notonectaundulata)在水生生物群落中的传播,在该生物群落中,我们操纵了外寄生的Hydrachnidia螨和感染的物种的存在。我们发现寄生风险会增加寄主扩散的倾向。使用飞行分析,我们确定寄生虫感染会降低宿主的扩散能力。最后,我们使用标记释放-再捕获研究来研究寄生虫风险和寄生虫感染对宿主传播的联合影响,空间结构人口。我们发现寄生风险降低了扩散概率,消除了正的密度依赖性扩散,并增加了分散距离。感染对自然种群的传播没有影响。我们的结果表明,寄生虫可以增加和减少其宿主的运动速度,根据生态环境,并且可以改变宿主对其他生物应激源的扩散反应。未来的研究应该考虑寄生虫对景观连通性的双重影响的后果,人口持久性,和宿主-寄生虫共同进化。
Dispersal determines the spatial dynamics of host-parasite assemblages, particularly during invasions and disease epidemics. The risk of parasitism may create an incentive for dispersal, but infection is expected to reduce dispersal ability, which may alter the host\'s dispersal response to biotic stressors, including population density. We measured the dispersal of a semiaquatic insect (Notonecta undulata) in aquatic mesocosms in which we manipulated the presence of ectoparasitic Hydrachnidia mites and infected conspecifics. We found that parasitism risk increases host dispersal propensity. Using a flight assay, we determined that parasite infection reduces host dispersal ability. Finally, we used a mark-release-recapture study to investigate the joint effects of both parasitism risk and parasite infection on host dispersal in a natural, spatially structured population. We found that parasitism risk reduced dispersal probability, eliminated positive density-dependent dispersal, and increased dispersal distance. Infection had no effect on dispersal in the natural population. Our results show that parasites can both increase and decrease the movement rates of their hosts, depending on the ecological context, and can alter the host\'s dispersal response to other biotic stressors. Future studies should consider the consequences of this double-headed impact of parasites for landscape connectivity, population persistence, and host-parasite coevolution.