Beschrijving
Diel rhythms are driven by genetic and environmental components mediated by the circadian clock. Although individuals show to some extent repeatable timing (i.e. chronotype), there is ample variation of diel timing observed within and between individuals. Here, we investigated various environmental factors, including timing of the social partner, that could explain day-to-day variation within individuals. Synchronisation with the social partner could increase breeding success during chick provisioning, and decrease extrapair paternity opportunities for females during the fertile period if timing were consistent across the breeding stages. Therefore, we investigated fitness consequences of between-individual variation. We first assessed the magnitude of between- and within-individual variation in the timing of nest visits during chick provisioning by great tits (Parus major). We monitored nest visits of males and females in 37 broods in two seasons. Next, we explored the responsiveness of the diel timing to environmental variables, specifically comparing abiotic and social factors. The onset of nest visits varied significantly within the breeding season, with rainfall and the diel timing of the breeding partner but not with night temperature. By contrast, offset was generally more variable within individuals and less variation was explained by the environmental variables. Both males and females delayed their activity offset with the progressing season and females also had a later onset with increasing daytime rainfall. Further, the reproductive output and extrapair paternity were independent of parental chronotypes and their synchronisation within pairs. It is possible that consistency of chronotypes is less important for reproductive success than the ability to plastically respond to changing environmental conditions. Thus, the next step could be to investigate potential individual differences in plasticity which could be even linked to specific chronotypes. Chronotype-specific plasticity could help to assess potential differences in fitness which might be crucial information to predict species’ adaptability to unpredictable environments.| Periode | 05 nov. 2024 |
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| Mate van erkenning | Internationaal |