A unified evolutionary framework for understanding parasite infection and host migratory behaviour

Does malaria infection increase the risk of predation-related mortality during bird migration?

The migratory culling hypothesis posits that infected individuals are less likely to survive long-distance migration due to physiological and behavioral effects, but this lacks empirical evidence. Here, we tested this hypothesis by sampling 357 passerines from 11 species during their autumn migration to wintering grounds in two different areas, i) at a stopover in southern Spain, and ii) in the Canary Islands, where they were drifted and preyed upon by Eleonora's falcons while en route to the southern Sahara. Molecular detection of infections by Plasmodium, Haemoproteus, and Leucocytozoon was conducted on bird samples. A higher prevalence of both Plasmodium and Haemoproteus was observed in birds preyed upon by falcons. While a complete understanding of the mechanistic effects of haemosporidian infections on migration performance needs experimental validation, our approach suggests that infection reduces migration success by increasing mortality due to route deviations and/or predation.

Dispersal evolution and eco-evolutionary dynamics in antagonistic species interactions

Dispersal evolution modifies diverse spatial processes, such as range expansions or biological invasions of single species, but we are currently lacking a realistic vision for metacommunities. Focusing on antagonistic species interactions, we review existing theory of dispersal evolution between natural enemies, and explain how this might be relevant for classic themes in host-parasite evolutionary ecology, namely virulence evolution or local adaptation. Specifically, we highlight the importance of considering the simultaneous (co)evolution of dispersal and interaction traits. Linking such multi-trait evolution with reciprocal demographic and epidemiological feedbacks might change basic predictions about coevolutionary processes and spatial dynamics of interacting species. Future challenges concern the integration of system-specific disease ecology or spatial modifiers, such as spatial network structure or environmental heterogeneity.

Does bird life-history influence the prevalence of ticks? A citizen science study in North East Spain

After mosquitoes, ticks are among the most important vector of pathogens of concern for animal and public health, but unless mosquitoes ticks remain attached to their hosts for long time periods providing an opportunity to analyse their role in the dispersal and dynamics of different zoonotic pathogens. Given their interest in public health it is important to understand which factors affect their incidence in different hosts and to stablish effective surveillance programs to determine the risk of transmission and spill-over of zoonotic pathogens. Taking benefit of a large network of volunteer ornithologists, we analysed the life-history traits associated to the presence of ticks using information of 620,609 individuals of 231 avian species. Bird phylogeny, locality and year explained a large amount of variance in tick prevalence. Non-colonial species non breeding in grasslands and non-spending the non-breeding season as gregarious groups or isolated individuals (e.g. thrushes, quails and finches) had the higher prevalence of ticks and appear as good candidates for zoonosis surveillance programs based on the analyses of ticks collected from wild birds. Ringers underestimated tick prevalence but can be considered as an important source of information of ticks for public and animal health surveillance programs if properly trained for the detection and collection of the different tick development phases.