Unexpected diversity in socially synchronized rhythms of shorebirds

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