Individual Differences of Female Chronotypes and their Fitness Consequences in Wild Great Tits Parus major

Activity: Talk or presentationAcademic


Diel timing is thought to be adaptive, where consistent chronotypes facilitate the anticipation of predictable events such as sunrise. Interestingly, between and within individual variation in chronotypes is considerably high with some individuals being earlier or later chronotypes compared to their conspecifics. For Great Tit males, earliness seems beneficial during mating while little is known about fitness consequences for females. Here, we assess fitness consequences for female chronotypes in Great Tits during three breeding seasons in a Dutch island population. We recorded nest temperature using loggers during incubation and early chick provisioning, and extracted activity onsets relative to the conspecifics to obtain mean chronotypes off 150 females. Those were correlated to fitness parameters from brood monitoring data. Our data indicates that the number of hatchlings and the attempt for a second brood depends on female chronotype, but the effects vary between breeding seasons. However, these chronotypes neither obtained more fledglings nor better offspring conditions. These results suggest that chronotype can influence incubation success and multiple-brooding depending on the environmental conditions in the particular year. Further research might investigate survival and life-time reproductive success to explore fluctuations in selection pressures and potential differences in pace-of-life between different chronotypes.
Period30 Mar 2023