Natal dispersers pay a lifetime cost to increased reproductive effort in a wild bird population.
Natal dispersal is assumed to be costly. Such costs can be difficult to detect, and fitness consequences of dispersal are therefore poorly known. Because of lower phenotypic quality and/or familiarity with the environment, natal dispersers may be less buffered against a sudden increase in reproductive effort. Consequently, reproductive costs associated with natal dispersal may mostly be detected in harsh breeding conditions. We tested this prediction by comparing lifetime reproductive success between natal dispersers and non-dispersers in a patchy population of collared flycatchers (Ficedula albicollis) when they reared either a non-manipulated brood or an experimentally increased or decreased brood. Natal dispersers achieved lower lifetime reproductive success than non-dispersers only under more stressful breeding conditions (i.e. when brood size was experimentally increased). This was mostly due to a lower number of recruits produced in the year of the increase. Our results suggest a cost associated with natal dispersal paid immediately after an increase in reproductive effort and not subsequently compensated for through increased survival or future offspring recruitment. Natal dispersers adjusted their breeding investment when reproductive effort is as predicted but seemed unable to efficiently face a sudden increase in effort, which could affect the influence of environmental predictability on dispersal evolution.
UMR 5558, Laboratoire de Biométrie et Biologie Évolutive, CNRS, Université de Lyon, F69000, Lyon; Université Lyon 1, 18 Boulevard du 11 Novembre 1918, F69622 Villeurbanne, France germainmarion.univ@gmail.com.|Department of Animal Ecology, Evolutionary Biology Centre (EBC), Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden.|Université de Lyon, Université Lyon 2, 69000 Lyon, France.
Marion
http://orcid.org/0000-0001-5563-3655
M
Germain
Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 75007 Uppsala, Sweden.
Tomas
T
Pärt
Department of Animal Ecology, Evolutionary Biology Centre (EBC), Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden.
Lars
L
Gustafsson
UMR 5558, Laboratoire de Biométrie et Biologie Évolutive, CNRS, Université de Lyon, F69000, Lyon; Université Lyon 1, 18 Boulevard du 11 Novembre 1918, F69622 Villeurbanne, France.
Blandine
B
Doligez
D063147:Animal Distribution; D000818:Animals; D004777:Environment; D011157:Population Dynamics; D012098:Reproduction; D020308:Songbirds / Q000502:physiology*
brood size manipulation; dispersal cost; natal dispersal; reproductive effort; reproductive success; return rate