Why breeding time has not responded to selection for earlier breeding in a songbird population

TY - JOUR

T1 - Why breeding time has not responded to selection for earlier breeding in a songbird population

AU - Gienapp, P.

AU - Postma, E.

AU - Visser, M.E.

N1 - Reporting year: 2006 Metis note: 3967; CTE; PVD ; NPCC ; AnE; file:///L:/Endnotedatabases/NIOOPUB/pdfs/Pdfs2006/Gienapp_ea_3967.pdf

PY - 2006

Y1 - 2006

N2 - A crucial assumption underlying the breeders' equation is that selection acts directly on the trait of interest, and not on an unmeasured environmental factor which affects both fitness and the trait. Such an environmentally induced covariance between a trait and fitness has been repeatedly proposed as an explanation for the lack of response to selection on avian breeding time. We tested this hypothesis using a long-term dataset from a Dutch great tit (Parus major) population. Although there was strong selection for earlier breeding in this population, egg-laying dates have changed only marginally over the last decades. Using a so-called animal model, we quantified the additive genetic variance in breeding time and predicted breeding values for females. Subsequently, we compared selection at the phenotypic and genetic levels for two fitness components, fecundity and adult survival. We found no evidence for an environmentally caused covariance between breeding time and fitness or counteracting selection on the different fitness components. Consequently, breeding time should respond to selection but the expected response to selection was too small to be detected.

AB - A crucial assumption underlying the breeders' equation is that selection acts directly on the trait of interest, and not on an unmeasured environmental factor which affects both fitness and the trait. Such an environmentally induced covariance between a trait and fitness has been repeatedly proposed as an explanation for the lack of response to selection on avian breeding time. We tested this hypothesis using a long-term dataset from a Dutch great tit (Parus major) population. Although there was strong selection for earlier breeding in this population, egg-laying dates have changed only marginally over the last decades. Using a so-called animal model, we quantified the additive genetic variance in breeding time and predicted breeding values for females. Subsequently, we compared selection at the phenotypic and genetic levels for two fitness components, fecundity and adult survival. We found no evidence for an environmentally caused covariance between breeding time and fitness or counteracting selection on the different fitness components. Consequently, breeding time should respond to selection but the expected response to selection was too small to be detected.

KW - NIOO/PG/NPCC

U2 - 10.1554/06-235.1

DO - 10.1554/06-235.1

M3 - Article

SN - 0014-3820

VL - 60

SP - 2381

EP - 2388

JO - Evolution

JF - Evolution

IS - 11

ER -