In evolutionary biology variation in the mating is an issue of concern. Polyandry greatly suffers the consequences of these changes (Travers, et al.). This type of mating is both advantageous and disadvantageous in terms of costs. Several studies enforce monandry in polyandrous species.  Monandry is a mating pattern where a female has a single mate at a time. On the other hand, polyandry is the mating pattern where a female has many males at a time. No particular study has been carried out to determine how variations in polyandry are maintained between genotypes, individuals, species and populations.

In polyandry variation in genetics is maintained by selection or selectively neutral. Polyandry is beneficial to the offspring who interbreed (Travers, et al.). In a population where there is no colonization mating between species of the same ancestor is common but this lessens when new species that start colonizing the ecology arrive. This is a population where there are species with different ancestors polyandrous benefits the offspring because the mating is among half-siblings rather than full siblings.

In several species, female mating with more than one male is common (Travers, et al.).  Polyandry has negative implications which include sexual conflicts, competition for a mate, as well choice of a mate. It also leads to waste of energy, time, and accelerated risks of spreading diseases and predation, as well as death in extreme cases a female,  does not have the chance to choose a suitable mate but rather mates with any species. This type of mating, however, has several advantages which include paternal care in the future.

The offspring live together and benefit from the diversity in genes (Travers, et al.). Additionally, polyandry helps the female to have the species with genes that are compatible with the female genome. There is also a rise in the diversity of the offspring who live together because a female who has several mates will have offspring from different males.  If the offspring mate then it will be between half-siblings so there will be a decreased number of pure inbreeding.

A study carried out on Drosophila pseudoobscura showed that there exists a difference between and within specific populations (Travers, et al.). Isofemale lines were used to find out the populations that have high or low polyandry levels. For seven generations there were no changes which mean that stability was maintained. Additionally, there was no balancing in the selection, and there was no distinction between high and low polyandry genotypes. Through comparison between the ancestral females and the evolved ones, there were no effects of the polyandry. There is an absence of differentiating selection even in populations with significant differences. This is a disadvantage because it creates doubt on whether polyandry is useful in creating mental fitness or not.