Natural selection on body size traits in a long-lived species, the snow-petrel.

• Main Author: Barbraud, Christophe
• Other Authors: Centre d'Études Biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2000
• Subjects: survival; body size; heritability; natural selection; Pagodroma nivea; reproductive success; snow petrel; Nivea; Snow Petrel; Snow Petrels
• Online Access: https://hal.science/hal-00211869

International audience I consider the possibility of selection favouring large body size in a population of snow petrels (Pagodroma nivea), a long-lived seabird species. I measured natural selection on body size traits in a population from 1987 to 1998. There was evidence of selection on body size associated with fecundity and survival. Directional selection on bill length and stabilizing selection on tarsus length associated with reproductive success were detected among males. Selection associated with survival favoured males with longer bills. However, selection was weak in all cases. No evidence of selection acting on female body size traits was detected. Offspring±parents regression suggested that bill length and tarsus length were heritable. Although I was able to identify the targets of selection in this population, I could not demonstrate the ecological implications of both tarsus length and bill length variation. The selection on male, but not on female, body size traits suggests factors such as intrasexual competition for nests and/or mates rather than factors such as feeding ef®ciency as mechanisms of selection on bill size.