Newborn sailfin mollies were raised from 4 populations in aquaria under all possible combinations of 2 temperatures, 3 salinities, and 2 food levels. Males were much less susceptible than females to temperature variation and were generally less plastic than females in terms of all 3 traits. Members of both sexes matured at larger sizes and at later ages in less saline and in cooler environments. Males from different populations exhibited different average ages and sizes at maturity, but females did not. The strongest sources of interdemic variation are genetic differences in males and differences in postmaturation growth and survivorship in females. -from Authors
