Fitness consequences of egg-size variation in the lesser snow goose

摘要: We investigated the relationship between eggsize variation and (a) egg hatching success, (b) chick survival to fledging recruitment, (c) adult female survival, over 12 years in lesser snow goose (Anser caerulescens caerulescens). By comparing means variances of size for successful unsuccessful eggs, our aim was assess relative fitness eggs different sizes determine type selection operating on this species. As both reproductive success vary with age we controlled effects age. Egg-size is very marked population, varying by up 52% successfully. However, there no post-hatching goslings or either within broods, pooling across years. Egg varied significantly clutches only 2 33 individual year comparisons. First-laid surviving onset incubation, successfully, were average larger than but probably due confounding age-specific sequence-specific survival. Variance differed 3 24, 0 21, comparisons pre- respectively. therefore found little evidence a egg-size offspring fitness, strong directional, normalising diversifying size, goose. In addition, weak support hypothesis that maintained temporal pressure (sensu Ankney Bisset 1973). It likely represents pleiotropic expression alleles affecting more general physiological metabolic processes. While does not rule out existence direct suggest their contribution heritable small.