1. In considering the evolutionary dynamics of host–parasite interactions, it is usually assumed that
host populations are able to evolve rapidly under selection from various parasitic pressures. This has
been shown for endoparasites, but for ectoparasites and/or epibionts, in general, less strong effects
are expected on their hosts.
2. We show that the exposure of Daphnia magna clones (of a different origin) to lake sediment from
the Danish Lake Ring, containing dormant eggs of the epizoic rotifer Brachionus rubens, results in
infections that are associated with increased mortality in Daphnia.
3. Using a resurrection ecology approach, we reconstructed evolutionary change in the Lake Ring
D. magna population in response to B. rubens infections. We observed interclonal variation in resistance
to B. rubens in this Daphnia population, as well as changes over time in resistance to rotifers.
4. Both sediment exposure and time period from which Lake Ring clones were isolated affected
important life-history parameters, suggesting that evolution (upon exposure to Brachionus) not only
affected resistance to Brachionus, but also other traits in Lake Ring Daphnia.
5. Additionally, there were complex effects of a joint exposure of D. magna to rotifers and the indirect
effect of fish predation: exposure to fish kairomones resulted in an increased allocation of energy to
early reproduction and Daphnia performance. Further, fish kairomones apparently increased B. rubens