Unexpected diversity in socially synchronized rhythms of shorebirds.

Martin Bulla (1) , Mihai Valcu (1) , Adriaan M. Dokter (2) , Alexei G. Dondua , András Kosztolányi (3, 4) , Anne L. Rutten (1, 5) , Barbara Helm (6) , Brett K. Sandercock (7) , Bruce Casler , Bruno J. Ens (8) , Caleb S. Spiegel (9) , Chris J. Hassell (10) , Clemens Küpper (11) , Clive Minton (12) , Daniel Burgas (13, 14) , David B. Lank (15) , David C. Payer (16) , Egor Y. Loktionov (17) , Erica Nol (18) , Eunbi Kwon (19) , Fletcher Smith (20) , H. River Gates (21, 22, 23) , Hana Vitnerová (24) , Hanna Prüter (25) , James A. Johnson (22) , James J.H. St Clair (26, 27) , Jean-François Lamarre (28) , Jennie Rausch (29) , Jeroen Reneerkens (30) , Jesse R. Conklin (30) , Joanna Burger (31) , Joe Liebezeit (32) , Joël Bêty (28) , Jonathan T. Coleman (33) , Jordi Figuerola (34) , Jos C.E.W. Hooijmeijer (30) , José A. Alves (35, 36) , Joseph A.M. Smith (37) , Karel Weidinger (38) , Kari Koivula (39) , Ken Gosbell (12) , Klaus-Michael Exo (40) , Larry Niles (41) , Laura Koloski (42) , Laura Mckinnon (43) , Libor Praus (38) , Marcel Klaassen (44) , Marie-Andrée Giroux (45, 46, 47) , Martin Sládeček (48) , Megan L. Boldenow (49) , Michael I. Goldstein (50) , Miroslav Šálek (48) , Nathan Senner (30, 51) , Nelli Rönkä (39) , Nicolas Lecomte (47) , Olivier Gilg (52) , Orsolya Vincze (4, 53) , Oscar W. Johnson (54) , Paul A. Smith (55) , Paul F. Woodard (29) , Pavel S. Tomkovich (56) , Phil F. Battley (57) , Rebecca Bentzen (58) , Richard B. Lanctot (22) , Ron Porter (59) , Sarah T. Saalfeld (22) , Scott Freeman (60) , Stephen C. Brown (23) , Stephen Yezerinac (61) , Tamás Székely (62) , Tomás Montalvo (63) , Theunis Piersma (30, 64) , Vanessa Loverti (65) , Veli-Matti Pakanen (39) , Wim Tijsen , Bart Kempenaers (1)

1 Department of Behavioural Ecology and Evolutionary Genetics
2 Computational Geo-Ecology
3 Department of Ecology
4 MTA-DE ‘Lendület’ Behavioural Ecology Research Group
5 Apiloa GmbH
6 Institute of Biodiversity, Animal Health and Comparative Medicine
7 Division of Biology
8 Coastal Ecology Team
9 Division of Migratory Birds - Northeast Region
10 Global Flyway Network
11 Institute of Zoology
12 Australasian Wader Studies Group
13 Department of Forest Sciences [Helsinki]
14 JYU - Department of Biological and Environmental Science [Jyväskylä Univ]
15 Department of Biological Sciences [Burnaby]
16 National Park Service
17 State Lab for Photon Energetics
18 Biology Department
19 Department of Fish and Wildlife Conservation
20 Center for Conservation Biology
21 Pacifica Ecological Services
22 Migratory Bird Management
23 Shorebird Recovery Program
24 Faculty of Science
25 Department of Wildlife Diseases
26 Department of Biology and Biochemistry
27 Centre for Evolutionary Biology
28 Departement de Biologie, Chimie et Géographie
29 Canadian Wildlife Service
30 Chair in Global Flyway Ecology - Conservation Ecology Group
31 Division of Life Sciences
32 Audubon Society of Portland
33 Queensland Wader Study Group
34 EBD - Estación Biológica de Doñana
35 South Iceland Research Centre
36 CESAM
37 LJ Niles Associates
38 Department of Zoology and Laboratory of Ornithology, Faculty of Science
39 Department of Ecology
40 Institute of Avian Research
41 LJ Niles Associates
42 Environmental and Life Sciences
43 Bilingual Biology Program
44 Centre for Integrative Ecology
45 Canada Research in Northern Biodiversity
46 CEN - Centre d'Etudes Nordiques
47 Canada Research in Polar and Boreal Ecology
48 Faculty of Environmental Sciences
49 Department of Biology and Wildlife
50 Alaska Coastal Rainforest Center
51 Cornell University [New York]
52 BGS - Biogéosciences [UMR 6282]
53 Evolutionary Ecology Group
54 Department of Ecology
55 Wildlife Research Division
56 Zoological Museum
57 Ecology Group
58 Arctic Beringia Program
59 Delaware Bay Shorebird Project
60 Arctic National Wildlife Refuge
61 Fieldday Consulting
62 Milner Centre for Evolution
63 Servei de Vigilància i Control de Plagues Urbanes
64 NIOZ - Royal Netherlands Institute for Sea Research
65 Migratory Bird and Habitat Program

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent's incubation bout varied from 1-19 h, whereas period length-the time in which a parent's probability to incubate cycles once between its highest and lowest value-varied from 6-43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light-dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.

Domaines: Biodiversité et Ecologie; Biodiversité

Martin Bulla, Mihai Valcu, Adriaan M. Dokter, Alexei G. Dondua, András Kosztolányi, et al.. Unexpected diversity in socially synchronized rhythms of shorebirds.. Nature, 2016, 540 (7631), pp.109-113. ⟨10.1038/nature20563⟩. ⟨hal-01419661⟩