Host–parasite ‘Red Queen’ dynamics archived in pond sediment

Abstract

Antagonistic interactions between hosts and parasites are a key structuring force in natural populations, driving coevolution. However, direct empirical evidence of long-term host-parasite coevolution, in particular 'Red Queen' dynamics--in which antagonistic biotic interactions such as host-parasite interactions can lead to reciprocal evolutionary dynamics--is rare, and current data, although consistent with theories of antagonistic coevolution, do not reveal the temporal dynamics of the process. Dormant stages of both the water flea Daphnia and its microparasites are conserved in lake sediments, providing an archive of past gene pools. Here we use this fact to reconstruct rapid coevolutionary dynamics in a natural setting and show that the parasite rapidly adapts to its host over a period of only a few years. A coevolutionary model based on negative frequency-dependent selection, and designed to mimic essential aspects of our host-parasite system, corroborated these experimental results. In line with the idea of continuing host-parasite coevolution, temporal variation in parasite infectivity changed little over time. In contrast, from the moment the parasite was first found in the sediments, we observed a steady increase in virulence over time, associated with higher fitness of the parasite.

Evolution of transgenerational immunity in invertebrates

“…Finally, our predictions may have implications for when dispersal happens across time rather than across space, as is the case in species that produce dormant stages. Dormancy may favour the evolution of conditional investment in immunity: dormant offspring are often expected to be exposed to maladapted pathogens [59,60] and may require lower investment in immunity than their non-dormant counterparts.…”

Host compatibility rather than vector–host-encounter rate determines the host range of avian Plasmodium parasites

“…Indeed, host range expansions also depend on the compatibility of novel hosts toward those parasites, and will not proceed if new host-parasite combinations are incompatible. Traits that influence host compatibility, and its constituent properties of host susceptibility, parasite infectivity, and the virulence of infection, evolve over time [68,69]. In the West Indies, the same suite of avian hosts and malaria parasites assemble into different patterns of relationships across island replicates [27,28,41], and there is some evidence that these differences can arise over short time periods [42].…”

Resistance to a bacterial parasite in the crustacean Daphnia magna shows Mendelian segregation with dominance

“…With evidence for genotypic interactions, fast acting selection (Little and Ebert, 2000) and frequency-dependent selection in natural populations (Decaestecker et al, 2007) this host-parasite system has become one of the prime models for antagonistic co-evolution. However, genetics underlying the genotype-genotype interactions are unknown.…”