The False Problem of the Maintenance of Sex (Review of the Original Approach)

Abstract

We analyze here the keys of the original approach about the twofold cost: the return to the asexuality starting with a mutant female, with the same reproductive capacity than a sexual one, and with double genetic-reproductive success. We propose a new approach in which 1) all individuals in a population have regulatory mechanisms of reproductive mode, and when such change occurs, it happens in all its population at the same time; 2) after a change of reproductive mode in the population there can be variations in average offspring per female, according to the environmental quality; and 3) the genetic-reproductive success of the males and its unequal paternity success are accounted for. Results: The most advantageous reproductive strategy depends on the demographic situation of the population and the degree of the unequal paternity success of males. For harem values observed in nature and in populations with moderate growth rate, stable or decreasing population, the sexual strategy is advantageous. If the population growth rate is high, the asexual strategy is advantageous. In species subject to high demographic fluctuations the best strategy depends on the ability to predict the time of occurrence of the population bottleneck: if predictable, the best strategy is the alternation of generations, if not, permanent parthenogenesis.