The effect of packing constraints on optimal investment in offspring

摘要: Problem: In some taxa, females retain their entire clutch internally and face a packing constraint, which may lead to correlation between egg size total allocation (egg × size). Hypotheses: species with constraints (e.g. turtles copepods), linear measures of will be negatively correlated reproductive allocation, but volume positively allocation. By contrast, in without passerine birds), the correlations, if present, can either positive or negative. However, both same direction. Data: Egg length, width, volume, body turtles, copepods North American bird species. Methods: We calculated independent contrasts separately for each taxonomic group, using composite phylogenies ignoring branch lengths. used Smith Fretwell’s (1974) optimality model size. modified it by assuming investment individual offspring. Conclusions: The data agreed hypotheses. Suppose that increases rapidly Then, optimal offspring greatly.