The theory of OSR hypothesizes that the operational sex ratio affects the mating competition of males and females in a population.
[6] The OSR is closely linked to the "potential rate of reproduction" of the two sexes;[1] that is, how fast they each could reproduce in ideal circumstances.
Usually variation in potential reproductive rates creates bias in the OSR and this in turn will affect the strength of selection.
This, in turn, affects how long reproductive cycles will be in both males and females.
This pushes the population towards a female biased OSR and vice versa.
[9] As aforementioned, another major factor that influences OSR is potential rate of reproduction (PRR).
However, if nutrients is low, less males will be ready to reproduce, causing the population to have a female biased OSR.