Brood loss has effects on the operational sex ratio (OSR) of Dendrobates pumilio. OSR is the proportion of males to females capable of mating. There is usually a higher percentage of males in the mating pool because females spend more time on parental duties. There are factors that influence OSR, such as available food and nesting locations, environmental temperature, and the number of deaths for one sex being higher than for the other. Losing a clutch should also affect OSR. If a brood is lost, the parent should re-enter the mating pool more quickly, changing the ratio. Heik Prohl studied how the OSR is affected when D. pumilio loses a brood. The time males spend on parenting consists only of moistening the eggs. Females take their time choosing mates and spend more time caring for their young. Females carry their tadpoles to water them and feed them unfertilized eggs. Females do not mate during this period, which keeps them out of the breeding pool for a long time.D. pumilio was studied at the Hitoy Cerere Biological Station in Costa Rica f...