Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Social Jet Lag (Social Jet Lag: Avian Solutions to Misalignment between Circadian Clocks and Social Cues)

Teaser

Organisms and their cells exhibit alternating phases of activity and inactivity that are regulated by internal ~24h (circadian) clocks. These clocks synchronize to natural changes in day-light, but likely also to other factors including the activity of the social group...

Summary

Organisms and their cells exhibit alternating phases of activity and inactivity that are regulated by internal ~24h (circadian) clocks. These clocks synchronize to natural changes in day-light, but likely also to other factors including the activity of the social group. Although the molecular mechanisms behind such clocks have been extensively investigated, we understand little about circadian rhythmicity in a social context. Here, we investigate how individual shorebirds cope with misalignment between their circadian clock and social time (“social jet lag”) – a phenomenon studied in only few species (mainly humans and other mammals). The SocialJetLag project has three main objectives and implications. First, SocialJetLag is testing the applicability of a new method for general research in birds. The method quantifies rhythms in circadian clock genes and hence will allow minimally invasive bio-rhythm sampling in the future. Second, SocialJetLag is quantifying internal rhythms in a vertebrate that lives in an inter-tidal zone and under the 24h day-night for 10 month of the year and breeds under the continuous day-light of the Arctic. Internal rhythms of organisms facing such complex environmental cues are so far unknown, but key to generalize current findings from invertebrates. Finally, SocialJetLag is investigating how individuals cope with social jet lag and synchronize to the timing of their group – an important topic in the field of ‘time research’.

Work performed

- experimental animals caught
- molecular clock method tested
- all animals sampled for molecular clocks
- all animals screened for internal clocks (behavioural essays)
- all animals screened for personality and basal metabolic rate
- subset of animals tested for social synchronization
- issues with molecular clock method - currently being re-solved
- data curated and cleaned
- analyses under way
- we find individual differences in strength and period of behavioural rhythms
- synchronized activity among members of the social groups, albeit the resulting activity pattern may be arrhythmic

Final results

a) Our study reveals internal rhythms in a hihger-vertebrate that lives in an environment with complex timing cues (an inter-tidal zone, 24h day-night, and social group for 10 month of the year and continuous day-light and behavioural synchronization with the partner at the Arctic breeding grounds). Such information is crucial for our understanding of biological clocks and their role in the complex natural environments.
b) The study elucidates how individuals change their behavioural rhythms when exposed to con-specifics and hence shows the amount of social jet lag, as well as toward which rhythm the group of individuals synchronizes. Such findings are of great interest because data on social synchronization are scarce and usually limited to species living in less complex environments.
c) The adoption of the circadian clock gene method for birds will allow minimally invasive bio-rhythm sampling across wide animal taxa and thus allow addressing broader research questions related to biorhythms and internal clocks and testing whether current findings are species specific or a general phenomenon.

Website & more info

More info: https://github.com/MartinBulla/SocialJetLag.