Showing papers by "Etienne Danchin published in 1999"

The use of conspecific reproductive success for breeding habitat selection in a non-colonial, hole-nesting species, the collared flycatcher

Abstract: Summary 1. Breeding habitat quality strongly affects fitness. Therefore, individuals are likely to select their breeding habitat after gathering information on quality of potential breeding patches. In the study reported in this paper, we investigated whether local reproductive success of conspecifics in a patch (patch reproductive success, PRS) could be used to assess habitat quality and make dispersal decisions in a non colonial, hole-nesting, passerine bird, the collared flycatcher (Ficedula albicollis). 2. Assumptions for such a breeding habitat selection mechanism were met: the habitat patches were of different quality, as measured by PRS, with relative quality varying between years, and PRS was autocorrelated in time. 3. As in many other species, breeding dispersal was related in both sexes to individual reproductive success before dispersal: unsuccessful individuals were more likely to disperse than successful ones. 4. Additively, PRS influenced both breeding and natal dispersal. This effect depended on sex. Dispersal was negatively related to PRS in females, and positively in males with low competitive ability (juvenile and unsuccessful adult males). 5. Breeding dispersal was positively related to flycatcher density in males, but negatively in females. Moreover, when included in the analyses, laying date of the previous breeding attempt (which should be correlated with competitive ability) replaced the effect of PRS in adult males. 6. The observed patterns can be explained by PRS (or another variable correlated with PRS) being used to assess different components of habitat quality in each sex, in relation to intraspecific competition pressure. We suggest that males of low competitive ability may either use PRS to assess the level of expected intraspecific competition the following year, and choose to disperse from high PRS woodlands, or be forced to disperse when PRS is high because of strong competition. Females might use PRS to assess the expected reproductive output if breeding in the patch the following year.

Dispersal and distribution of the tick Ixodes uriae within and among seabird host populations: the need for a population genetic approach.

Abstract: The aim of this study was to characterize the spatial distribution of the tick Ixodes uriae within and among populations of its seabird hosts and to consider the potential insight that could be gained by a population genetic approach to the issue of dispersal of this tick. Analyses of data collected around the Avalon Peninsula, Newfoundland, indicated that both the prevalence and mean abundance of ticks varied significantly among sample locations. Whereas ticks were found on all 4 host species examined (Rissa tridactyla, Uria aalge, Alca torda, Fratercula arctica), infestation prevalence and mean abundance differed among the species. On R. tridactyla, ticks were significantly aggregated at the among-nest scale and nestling infestation was spatially autocorrelated. Conversely, ticks were not aggregated among chicks within nests. These results enabled us to make a priori predictions regarding tick dispersal and host specificity and suggest there may be spatial structure of Ixodes uriae populations at both macro- and microgeographic scales. Investigating the population genetic structure of ticks within and among populations of hosts with different breeding biologies should provide direct insight into the metapopulation dynamics of such a spatially structured system.