LIPOFUSCIN ACCUMULATION - EFFECTS OF INDIVIDUAL VARIATION AND SELECTIVE MORTALITY ON POPULATION AVERAGES

A method for evaluating the effects of individual variation and selective mortality on population life span patterns of age-specific biological parameters is tested using mortality and lipofuscin accumulation data from housefly populations. It is shown that unusual features of the experimental population life span pattern of lipofuscin accumulation in houseflies, namely, a leveling off and possible decrease in population averages at older ages, may be a result of individual variation in the housefly population which leads to selective mortality of houseflies. This result leads to the expectation that many of the unexplained features observed in the population life span patterns of age-specific biological parameters may be due to individual variation which exists in all populations and the resultant selective mortality. © 1979.