Data from: Evidence for parasite-mediated selection during short-lasting toxic algal blooms

Parasites play a role in the control of transient algal blooms, but it is not known whether parasite-mediated selection results in coevolution of the host and the parasites over this short time span. We investigated the presence of coevolution between the toxic dinoflagellate Alexandrium minutum and two naturally occurring endoparasites during blooms lasting a month in two river estuaries, using cross-inoculation experiments across time and space. Higher parasite abundance was associated with a large daily reduction in relative A. minutum abundances, demonstrating strong parasite-mediated selection. There was genetic variability in infectivity in both parasite species, and in resistance in the host. We found no evidence for coevolution in one estuary; however, in the other estuary, we found high genetic diversity in the two parasite species, fluctuations in infectivity and suggestion that the two parasites are well adapted to their host, as in ‘Red Queen’ dynamics. Thus, coevolution is possible over the short time span of a bloom, but geographically variable, and may feedback on community dynamics.

寄生虫在暂时性藻华的调控过程中发挥着重要作用，但目前尚不清楚在如此短暂的时间尺度内，寄生虫介导的选择是否会引发宿主与寄生虫的协同进化。本研究针对两个河口为期一个月的藻华事件，采用跨时空交叉接种实验，探究有毒甲藻（toxic dinoflagellate）微小亚历山大藻（Alexandrium minutum）与两种天然存在的内寄生虫之间是否存在协同进化。研究结果显示，寄生虫丰度越高，微小亚历山大藻的相对丰度每日降幅越大，这表明寄生虫介导的选择作用极强。两种寄生虫的感染性以及宿主的抗性均存在遗传变异。我们在其中一个河口未发现协同进化的证据；但在另一个河口，两种寄生虫均表现出较高的遗传多样性，其感染性存在波动，且存在迹象表明这两种寄生虫已如「红皇后」动态（Red Queen dynamics）所述，充分适应了其宿主。由此可见，在藻华的短暂时间尺度内，协同进化是可能发生的，但存在地理异质性，且可能对群落动态产生反馈效应。