Settling down of seasonal migrants promotes bird diversification.
How seasonal migration originated and impacted diversification in birds remains largely unknown. Although migratory behaviour is likely to affect bird diversification, previous studies have not detected any effect. Here, we infer ancestral migratory behaviour and the effect of seasonal migration on speciation and extinction dynamics using a complete bird tree of life. Our analyses infer that sedentary behaviour is ancestral, and that migratory behaviour evolved independently multiple times during the evolutionary history of birds. Speciation of a sedentary species into two sedentary daughter species is more frequent than speciation of a migratory species into two migratory daughter species. However, migratory species often diversify by generating a sedentary daughter species in addition to the ancestral migratory one. This leads to an overall higher migratory speciation rate. Migratory species also experience lower extinction rates. Hence, although migratory species represent a minority (18.5%) of all extant birds, they have a higher net diversification rate than sedentary species. These results suggest that the evolution of seasonal migration in birds has facilitated diversification through the divergence of migratory subpopulations that become sedentary, and illustrate asymmetrical diversification as a mechanism by which diversification rates are decoupled from species richness.
Centre de Mathématiques Appliquées (Ecole Polytechnique), CNRS, , UMR 7641 Route de Saclay, 91128 Palaiseau, France, Muséum National d'Histoire Naturelle, UMR 7204 MNHN-CNRS-UPMC, Centre d'Ecologie et des Sciences de la Conservation, , CP51, 55 rue Buffon, 75005 Paris, France, Institut de Biologie de l'École Normale Supérieure, CNRS UMR 8197, École Normale Supérieure, , 46 rue d'Ulm, 75005 Paris, Department of Life Sciences, Imperial College London, , Silwood Park Campus, Ascot SL5 7PY, UK, Department of Life Sciences, Natural History Museum, , Cromwell Road, London SW7 5BD, UK.
Jonathan
J
Rolland
Frédéric
F
Jiguet
Knud Andreas
KA
Jønsson
Fabien L
FL
Condamine
Hélène
H
Morlon
D025041:Animal Migration; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D001717:Birds / Q000502:physiology*; D012621:Seasons
ancestral character reconstruction; behavioural evolution; extinction rate; speciation rate