Demographic stochasticity and allee effects in populations' with two sexes

We model the effects of stochastic fluctuations in sex ratio on the demographic stochasticity in populations with two sexes. Two different mating systems, purely polygamous and purely monogamous, are considered. For both systems, the fluctuation in sex ratio adds a large component to the demographic variance. For long-lived species, there will be a large temporal autocorrelation in the sex ratio that affects the components of the demographic variance. For monogamous mating systems, the fluctuations in sex ratio may also cause an Allee effect. These effects need to be taken into account when modeling two-sex populations without explicitly using separate counts of males and females, but only the total population size.