Phenotypic selection on morphology at independence in the Chinstrap penguin Pygoscelis antarctica

• Published in: Journal of Evolutionary Biology
• Main Authors: Moreno, Eulalia, Barbosa, Andrés, León, A. de, Fargallo, Juan A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Society of Evolutionary Biology 1999
• Subjects: Flipper length; Growth; Heritability; Penguins; Selection; Deception Island; Moreno; Antarc*; Antarctica; Antártida; Chinstrap penguin; Pygoscelis antarctica
• Online Access: http://hdl.handle.net/10261/9045; https://doi.org/10.1046/j.1420-9101.1999.00032.x

Phenotypic selection on morphology at independence in the Chinstrap penguin Pygoscelis antarctica Moreno, Barbosa, León & Fargallo 1 Museo Nacional de Ciencias Naturales-CSIC, J. Gutierrez Abascal 2, E-28006 Madrid, Spain Correspondence to: Juan Moreno Copyright 1999 Blackwell Science Ltd KEYWORDS flipper length • growth • heritability • penguins • selection ABSTRACT Every year, shortly after the emancipation of chicks at our study colony (Deception Island, South Shetlands), hundreds of carcasses of presumably starved Chinstrap penguin Pygoscelis antarctica chicks are washed on the shore. In 1997 we measured the flippers of fresh carcasses and compared their lengths with those of live chicks about to become independent. There was a highly significant difference of 6.5 mm between both distributions, which suggests strong directional phenotypic selection on skeletal size operating through its association with body reserves at independence. Given that heritabilities of flipper length and body weight measured on 36 families are 0.73(± 0.32) and 0.075(± 0.081), and that both characters show a genetic correlation of 0.44(± 0.14), we can expect an evolutionary response to this selection episode. Assuming that the target of selection is weight at emancipation (heavier chicks carry proportionally larger reserves), and that flipper length changes as a consequence of its genetic correlation with weight, we can predict a response of 1.32–2.87 mm or 0.23–0.51 standard deviation units for flipper length. This substantial evolutionary response may be countered by other selective pressures affecting other life stages of these birds. Selection on reserve storage capacity at independence may affect morphological traits also in other species Our study was supported by grants ANT91-1264 and ANT94-0036 from the Spanish C.I.C.Y.T. (Programa Nacional de Investigación en la Antártida) Peer reviewed