Increasing temperature, not mean temperature, is a cue for avian timing of reproduction

TY - JOUR

T1 - Increasing temperature, not mean temperature, is a cue for avian timing of reproduction

AU - Schaper, S.V.

AU - Dawson, A.

AU - Sharp, P.

AU - Gienapp, P.

AU - Caro, S.P.

AU - Visser, M.E.

N1 - Reporting year: 2012 Metis note: 5103; WAG; AnE

PY - 2012

Y1 - 2012

N2 - Timing of reproduction in temperate-zone birds is strongly correlated with spring temperature, with an earlier onset of breeding in warmer years. Females adjust their timing of egg laying between years to be synchronized with local food sources and thereby optimize reproductive output. However, climate change currently disrupts the link between predictive environmental cues and spring phenology. To investigate direct effects of temperature on the decision to lay and its genetic basis, we used pairs of great tits (Parus major) with known ancestry and exposed them to simulated spring scenarios in climate-controlled aviaries. In each of three years, we exposed birds to different patterns of changing temperature. We varied the timing of a temperature change, the daily temperature amplitude, and the onset and speed of a seasonal temperature rise. We show that females fine-tune their laying in response to a seasonal increase in temperature, whereas mean temperature and daily temperature variation alone do not affect laying dates. Luteinizing hormone concentrations and gonadal growth in early spring were not influenced by temperature or temperature rise, possibly posing a constraint to an advancement of breeding. Similarities between sisters in their laying dates indicate genetic variation in cue sensitivity. These results refine our understanding of how changes in spring climate might affect the mismatch in avian timing and thereby population viability.

AB - Timing of reproduction in temperate-zone birds is strongly correlated with spring temperature, with an earlier onset of breeding in warmer years. Females adjust their timing of egg laying between years to be synchronized with local food sources and thereby optimize reproductive output. However, climate change currently disrupts the link between predictive environmental cues and spring phenology. To investigate direct effects of temperature on the decision to lay and its genetic basis, we used pairs of great tits (Parus major) with known ancestry and exposed them to simulated spring scenarios in climate-controlled aviaries. In each of three years, we exposed birds to different patterns of changing temperature. We varied the timing of a temperature change, the daily temperature amplitude, and the onset and speed of a seasonal temperature rise. We show that females fine-tune their laying in response to a seasonal increase in temperature, whereas mean temperature and daily temperature variation alone do not affect laying dates. Luteinizing hormone concentrations and gonadal growth in early spring were not influenced by temperature or temperature rise, possibly posing a constraint to an advancement of breeding. Similarities between sisters in their laying dates indicate genetic variation in cue sensitivity. These results refine our understanding of how changes in spring climate might affect the mismatch in avian timing and thereby population viability.

KW - international

U2 - 10.1086/663675

DO - 10.1086/663675

M3 - Article

SN - 0003-0147

VL - 179

SP - E55-E69

JO - American Naturalist

JF - American Naturalist

IS - 2

ER -