Effect of adult cohort density on age-specific mortality in Drosophila melanogaster.
Mortality rates decelerate at older ages in experimental populations of Drosophila. It is unclear whether this reflects a real slow-down in the aging process, or an artifact of declining density. Mortality was studied in age-synchronized cohorts of four inbred lines at three initial densities that varied 10-fold. A total of 70,000 flies of both sexes were studied. There were large line x density, line, and sex effects, but no systematic relationship between density and life span was detected. Mortality curves level off at older ages in 23 out of 24 sex-genotype combinations, irrespective of initial cohort density. Density has only second-order effects on the pattern of oldest-old mortality over the range of densities studied here. The dramatic departure from Gompertz-type mortality dynamics at older ages is not an artifact of declining density in Drosophila.
Khazaeli
A A
AA
Department of Ecology, Evolution, and Behavior, University of Minnesota, USA.
Xiu
L
L
Curtsinger
J W
JW
D000375:Aging / Q000502:physiology*; D000818:Animals; D015331:Cohort Studies; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D005260:Female; D005838:Genotype; D008136:Longevity; D008297:Male; D008954:Models, Biological; D012727:Sex Characteristics