Individual variation in age-dependent reproduction: fast explorers live fast but senesce young?
Dingemanse, Niels et al. (2019), Individual variation in age-dependent reproduction: fast explorers live fast but senesce young?, Dryad, Dataset, https://doi.org/10.5061/dryad.12jm63xss
1. Adaptive integration of life history and behaviour is expected to result in variation in the pace-of-life. Previous work focused on whether “risky” phenotypes live-fast-but-die-young, but reported conflicting support. We posit that individuals exhibiting risky phenotypes may alternatively invest heavily in early-life reproduction but consequently suffer greater reproductive senescence.
2. We used a 7-year longitudinal dataset with >1200 breeding records of >800 female great tits assayed annually for exploratory behaviour to test whether within-individual age-dependency of reproduction varied with exploratory behaviour. We controlled for biasing effects of selective (dis)appearance and within-individual behavioural plasticity.
3. Slower and faster explorers produced moderate-sized clutches when young; faster explorers subsequently showed an increase in clutch size that diminished with age (with moderate support for declines when old), whereas slower explorers produced moderate-sized clutches throughout their lives. There was some evidence that the same pattern characterized annual fledgling success, if so, unpredictable environmental effects diluted personality-related differences in this down-stream reproductive trait.
4. Support for age-related selective appearance was apparent, but only when failing to appreciate within-individual plasticity in reproduction and behaviour.
5. Our study identifies within-individual age-dependent reproduction, and reproductive senescence, as key components of life history strategies that vary between individuals differing in risky behaviour. Future research should thus incorporate age-dependent reproduction in pace-of-life studies.
Bird identity – individual-specific unique identifier
Plot identity – nest box plot-specific unique identifier (12 levels)
Brood identity – brood-specific unique identifier associated with each nest attempt
Year identity (2010-2016)
Female body mass (in .1 grams) at catching during focal breeding attempt
Exploration score – total number of hops among cage locations; test during focal breeding attempt. Detailed by Araya-Ajoy et al. (2016).
Clutch size – total number of eggs produced during focal breeding attempt
Number of fledglings produced during focal breeding attempt; 0 = no fledglings (“failed”)
Average fledgling mass at nestling age 14
Predation risk treatment
0 = unmanipulated (all years except 2013 and 2014)
1 = blackbird treatment (“control”); 2 = sparrow-hawk treatement (“manipulated”)
Detailed in Abbey-Lee & Dingemanse (2019)
Age in calendar years. 0 = age in the year following birth.
Minimum age over all the records of the focal individual
Maximum age over all the records of the focal individual
1 = ringed as nestling in our populations
0 = all other birds
1 = not recorded for two years following last observation in the dataset
0 = all other birds
Brood size manipulation. For details see Nicolaus et al. (2015).
0 = unmanipulated
1 = reduced (3 nestlings removed)
2 = control (nestling swaps applied without changing brood size)
3 = enlarged (3 nestlings added)
Missing values (applicable to multiple variables listed above).
Abbey-Lee, R.N. & Dingemanse, N.J. (2019) Adaptive individual variation in phenological responses to perceived predation levels. Nature Communications, 10, 1601.
Araya-Ajoy, Y.G., Kuhn, S., Mathot, K.J., Mouchet, A., Mutzel, A., Nicolaus, M., Wijmenga, J.J., Kempenaers, B. & Dingemanse, N.J. (2016) Sources of (co)variation in alternative siring routes available to male great tits (Parus major). Evolution, 70, 2308-2321.
Nicolaus, M., Mathot, K.J., Araya-Ajoy, Y.G., Mutzel, A., Wijmenga, J.J., Kempenaers, B. & Dingemanse, N.J. (2015) Does coping style predict optimization: an experimental test in a wild passerine bird. Proceedings of the Royal Society B-Biological Sciences, 282, 20142405.