Lack's Clutch Size Hypothesis: An Examination of the Evidence Using Meta-Analysis

摘要: Meta-analysis is a method ecologists may find useful for quantitatively re- viewing and systematically examining results from large number of studies on subject which there conflicting evidence. I used meta-analysis to integrate 42 independent brood-enlargement tested Lack's hypothesis that clutch size in birds has evolved toward produces the most surviving offspring. Cumulative evidence did not support hypothesis. Significantly (two-tailed P = .016) more fledg- lings were produced enlarged broods than normal-sized broods, indicating parents could raise young they had eggs. The standardized treatment effect brood enlargement across all was mean (? 1 SE) increase 0.55 (+0.22) standard de- viations produced. This result does appear be affected by publishing bias unlikely reversed inclusion additional studies. also examined differences methodology species studied as possible confounding factors explanations results. Longer with altricial likely show food limitation. Latitude date study, degree enlargement, validity annual adult survival affect