A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Cyclic variation in seasonal recruitment and the evolution of the seasonal decline in Ural owl clutch size
Tekijät: Brommer JE, Pietiainen H, Kokko H
Kustantaja: ROYAL SOC
Julkaisuvuosi: 2002
Lehti:: Proceedings of the Royal Society B: Biological Sciences
Tietokannassa oleva lehden nimi: PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
Lehden akronyymi: P ROY SOC B-BIOL SCI
Vuosikerta: 269
Numero: 1491
Aloitussivu: 647
Lopetussivu: 654
Sivujen määrä: 8
ISSN: 0962-8452
DOI: https://doi.org/10.1098/rspb.2001.1929
Tiivistelmä
Plastic life-history traits can be viewed as adaptive responses to environmental conditions, described by a reaction norm. In birds, the decline in clutch size with advancing laying date has been viewed as a reaction norm in response to the parent's own (somatic or local environmental) condition and the seasonal decline in its offspring's reproductive value. Theory predicts that differences in the seasonal recruitment are mirrored in the seasonal decrease in clutch size. We tested this prediction in the Ural owl. The owl's main prey, voles, show a cycle of low, increase and peak phases. Recruitment probability had a humped distribution in both increase and peak phases. Average recruitment probability was two to three times higher in the increase phase and declined faster in the latter part of the season when compared with the peak phase. Clutch size decreased twice as steep in the peak (0.1 eggs day(-1)) as in the increase phase (0.05 eggs day(-1)). This result appears to refute theoretical predictions of seasonal clutch size declines. However, a re-examination of current theory shows that the predictions of modelling are less robust to details of seasonal condition accumulation in birds than originally thought. The observed pattern can be predicted, assuming specifically shaped seasonal increases in condition across individuals.
Plastic life-history traits can be viewed as adaptive responses to environmental conditions, described by a reaction norm. In birds, the decline in clutch size with advancing laying date has been viewed as a reaction norm in response to the parent's own (somatic or local environmental) condition and the seasonal decline in its offspring's reproductive value. Theory predicts that differences in the seasonal recruitment are mirrored in the seasonal decrease in clutch size. We tested this prediction in the Ural owl. The owl's main prey, voles, show a cycle of low, increase and peak phases. Recruitment probability had a humped distribution in both increase and peak phases. Average recruitment probability was two to three times higher in the increase phase and declined faster in the latter part of the season when compared with the peak phase. Clutch size decreased twice as steep in the peak (0.1 eggs day(-1)) as in the increase phase (0.05 eggs day(-1)). This result appears to refute theoretical predictions of seasonal clutch size declines. However, a re-examination of current theory shows that the predictions of modelling are less robust to details of seasonal condition accumulation in birds than originally thought. The observed pattern can be predicted, assuming specifically shaped seasonal increases in condition across individuals.
Turun yliopiston Tutkimustietojärjestelmän portaali