Comparative demography of isogenic populations of Caenorhabditis elegans.

Demographic characteristics of the bacterial-feeding nematode Caenorhabditis elegans were determined in two long-lived mutant strains, TJ1052 (age-1), CB4876 (clk-1), and a wild-type strain, N2. Within each strain, there was little correlation between longevity and reproduction for individuals that lived longer than 10days. Long-lived mutant strains produced fewer eggs than the wild type. Mean total life spans were 13.2days for the wild type, 21.9days for age-1, and 15.8days for clk-1; maximum life spans were 24days for the wild type, 47days for age-1, and 32days for clk-1. Differences in total life span resulted primarily from longer post-reproductive survival. The mean post-reproductive life spans were longer than the wild type by 183% in age-1 and 60% in clk-1. We conclude that (i) post-reproductive survival is not correlated with egg production within isogenic populations of C. elegans, and (ii) the relationship between reproduction and longevity differs among isogenic populations with specific longevity genes.