Data from: Dispersal in a patchy landscape reveals contrasting determinants of infection in a wild avian malaria system

1. Understanding exactly when, where and how hosts become infected with
parasites is critical to understanding host-parasite coevolution. However,
for host-parasite systems in which hosts or parasites are mobile (for
example vector-borne diseases), the spatial location of infection, and the
relative importance of parasite exposure at successive host life-history
stages, are often uncertain. 2. Here, using a six-year longitudinal
dataset from a spatially referenced population of blue tits, we test the
extent to which infection by avian malaria parasites is determined by
conditions experienced at natal or breeding sites, as well as by postnatal
dispersal between the two. 3. We show that the location and timing of
infection differs markedly between two sympatric malaria parasite species.
For one species (P. circumflexum), our analyses indicate that infection
occurs after birds have settled on breeding territories, and because the
distribution of this parasite is temporally stable, hosts could in
principle alter their exposure and potentially avoid infection through
postnatal dispersal. Conversely, the spatial distribution of another
parasite species (P. relictum) is unpredictable, and infection probability
is positively associated with postnatal dispersal distance, potentially
indicating that infection occurs during this major dispersal event. 4.
These findings suggest that hosts in this population may be subject to
divergent selection pressures from these two parasites, potentially acting
at different life-history stages. Because this implies parasite
species-specific predictions for many coevolutionary processes, they also
illustrate the complexity of predicting such processes in multi-parasite
systems.