Polygynandry

Polygynandry is a mating system in which both males and females have multiple mating partners during a breeding season. In sexually reproducing diploid animals, different mating strategies are employed by males and females because the cost of gamete production is a lot lower for males than it is for females. The different mating tactics employed by males and females are thought to be the outcome of reproductive conflicts both ecologically and socially. Reproductive conflicts in animal societies may arise because individuals are not genetically identical and they have different optimal strategies for maximizing their fitness; and often times it is found that reproductive conflicts generally arise due to dominance hierarchy in which all or a major part of reproduction is monopolized by only one individual (wasp). In the Polistes carolina, the dominant queen amongst female wasps is determined by whoever arrives at the nest first rather than the largest foundress, who is expected to be the best at fighting (wasp). In a study of Prunella collaris, the close proximity and sharing of ranges on the mountain tops of the French Pyrenees led to a polygynandrous mating system, where two to four males would mate with a range of two to four females within the same vicinity. Polygynandry is another way to describe a multi-male and multi-female polygamous mating system. When females have multiple mating partners, it is known as polyandry and when males have multiple mating partners, it is known as polygyny; and each sex has their benefits in being promiscuous. Females, especially those with genetically ‘inferior’ social partners, have the chance to increase the genetic quality of their offspring. While males are able to fertilize the eggs of many other mates. Essentially the ideal mating behavior for males is to be promiscuous rather than monogamous—when they only have one mating partner because this leads to multiple offspring and these males monopolize their female partners by physically preventing them from copulating with other males. On the other hand, females benefit through polyandry as they have more sired offspring.

Often times females mate voluntarily with more than one male. Mating with several males reduces the risk of females having unfertilized eggs because one male may not have enough sperm to fertilize all her eggs. In dark-eyed juncos, a female mates with more than one male because often times, her social partner is of low genetic quality than other potential sperm donors. The females voluntarily mate with other males besides their mate because she sees the potential to improve her offspring viability and sexual attractiveness. Females may also mate with several males for genetic benefits such as genetic diversity among her offspring due to the variety of sperm available to her. In song birds, extra-pair matings occur because females are able to sneak away from their home territories to solicit to other males. When female song birds seek extra-male partners, they sexually select males with colorful plumage more elaborate than those of their social partner. Studies show that female song birds that have less plumage partners most actively seek extra-pair matings, furthermore males with the most developed traits—such as longer tails or brighter plumage survive better. Thus, when female song birds have multiple mating partners, they are increasing the genetic quality of their offspring.

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