Browsing by Author "Tveraa, Torkild"
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- Breeding failure induces large scale prospecting movements in the black-legged kittiwakePublication . Ponchon, Aurore; Chambert, Thierry; Lobato, Elisa; Tveraa, Torkild; Grémillet, David; Boulinier, ThierryBefore making dispersal decisions, many species are known to gather social information by prospecting potential future breeding sites, especially when they have failed breeding. So far, the role of current breeding performance on the occurrence of prospecting movements has mainly been studied at limited spatial scales, because of diffi- culties in tracking free-ranging, fast-moving individuals between distant breeding patches. Little information is thus available on individual behaviour and the spatial extent of prospecting movements in response to breeding failure. To address this issue, black-legged kittiwakes which breeding success was manipulated were tracked with GPS at the end of incubation in two Norwegian colonies. Crucially, and as predicted, prospecting visits to other breeding colonies were recorded in 33% of artificially-failed breeders, but never in successful ones. They occurred at large (40 km) as well as local spatial scales (1 km). Time-budgets of successful and failed breeders differed significantly in terms of trip duration, but also foraging, resting and nesting propensities. These results provide important elements to assess trade-offs between prospecting and other activities. They show that a substantial proportion of failed breeders prospect as early as within a week after failure at the egg stage and suggest that these individuals assess their options of future reproduction by prospecting alternative areas, although dispersal decisions may also involve more complex behavioural processes. Because they link breeding colonies situated tens of kilometres apart, prospecting movements may have critical implications for the dynamics of subdivided populations.
- Migration, prospecting, dispersal? What host movement matters for infectious agent circulation?Publication . Boulinier, Thierry; Kada, Sarah; Ponchon, Aurore; Dupraz, Marlène; Dietrich, Muriel; Gamble, Amandine; Bourret, Vincent; Duriez, Olivier; Bazire, Romain; Tornos, Jérémy; Tveraa, Torkild; Chambert, Thierry; Garnier, Romain; McCoy, Karen D.Spatial disease ecology is emerging as a new field that requires the integration of complementary approaches to address how the distribution and movements of hosts and parasites may condition the dynamics of their interactions. In this context, migration, the seasonal movement of animals to different zones of their distribution, is assumed to play a key role in the broad scale circulation of parasites and pathogens. Nevertheless, migration is not the only type of host movement that can influence the spatial ecology, evolution, and epidemiology of infectious diseases. Dispersal, the movement of individuals between the location where they were born or bred to a location where they breed, has attracted attention as another important type of movement for the spatial dynamics of infectious diseases. Host dispersal has notably been identified as a key factor for the evolution of host-parasite interactions as it implies gene flow among local host populations and thus can alter patterns of coevolution with infectious agents across spatial scales. However, not all movements between host populations lead to dispersal per se. One type of host movement that has been neglected, but that may also play a role in parasite spread is prospecting, i.e., movements targeted at selecting and securing new habitat for future breeding. Prospecting movements, which have been studied in detail in certain social species, could result in the dispersal of infectious agents among different host populations without necessarily involving host dispersal. In this article, we outline how these various types of host movements might influence the circulation of infectious disease agents and discuss methodological approaches that could be used to assess their importance. We specifically focus on examples from work on colonial seabirds, ticks, and tick-borne infectious agents. These are convenient biological models because they are strongly spatially structured and involve relatively simple communities of interacting species. Overall, this review emphasizes that explicit consideration of the behavioral and population ecology of hosts and parasites is required to disentangle the relative roles of different types of movement for the spread of infectious diseases.