Effect of nutrient availability on rover (for^R) and sitter (for^s) fitness.

Rovers were more fit (expressed as the proportion surviving to pupation) than sitters when reared on low-nutrient food. Fitness was higher and the genotypes were indistinguishable when reared on the high-nutrient food. Dark bars represent low-nutrient conditions and open bars represent high-nutrient conditions. Values represent the mean ± s.e.m., n = 20 replicate trials per genotype, per food type.