Comparison of Mating Behavior and Offspring Production Success of the Guppy, Poecilia reticulata, Stocked Under Different Operational Sex Ratios

Abstract

Experiments were conducted to record mating behavior (Experiment 1) and offspring production (Experiment 2) in the guppy, Poecilia reticulata, stocked under different operational sex ratios. Male and female guppies were stocked in aquaria (Experiment 1) and in concrete tanks (Experiment 2) at sex ratios (male:female) of 2:1 (Treatment 1), 1:1 (Treatment 2), and 1:2 (Treatment 3). Courtship displays were significantly less in Treatment 3 (P < 0.05). Sneak copulation was highest in Treatment 1 (P < 0.05). Time spent by the focal female on feeding was highest in Treatment 3 and lowest in Treatment 1 (P < 0.05). Offspring production per female, initial weight of offspring, and growth values recorded for the adult female fish were highest in Treatment 3 (P < 0.05). Weight and survival rate of offspring produced from each experiment was highest in Treatment 3 (P < 0.05). Treatment 3 appeared to be the most viable in terms of both quality and quantity of offspring produced. The results indicate a female biased sex ratio (adult male:female, 1:2) to be more effective than a male biased or an evenly matched sex ratio for enhanced offspring production in the guppy.