The relationship between parental age and reproductive effort in the California gull (Larus californicus)

摘要: Reproductive effort was compared among California gulls ranging in age from 3 to 18 years old. Results indicated that reproductive increased with parental age. Older parents (11–18 old) invested more foraging and defense of offspring than did younger (<10 old), so over a greater period time. Increases the efficiency parenting could not be demonstrated. Increased levels effort, therefore, appeared main factor responsible for age-related increases breeding success. The higher old were associated mortality. Thus, data support prediction cost-benefit system risk mortality vs gain operates this population. Higher can increase an individual's success; however, it also likelihood will die. Therefore, young parent, high risks involved current production would too costly (in terms loss future success) justify benefit output. Parents achieve highest maximizing life-time output by increasing as cost diminishes. Data testing relationship between demonstrate existence variation investment. They concept value proposed Fisher (1930) has validity framework which supports much our theory on life history evolution.