Science has shown this with birds, and now with fruit flies: The girls who play the field leave a more impressive legacy of children when they exit the game of life. Promiscuity pays.
This simple experiment set female flies up in three lifestyles.
The first group of ladies each had access to a male for only as long as it took them to mate.
The second group were married off for life to a single male.
The third group were presented with an intriguing new stranger every day of their life.
The one-night stand girls laid the fewest eggs, and raised the fewest children.
The mated-for-life girls laid many more eggs, but many of them didn’t hatch, or died in childhood.
The promiscuous flies found the sweet spot. They laid fewer eggs than the mated-for-life girls, but a higher percentage of their eggs went on to mature into healthy adults.
Why? How? We’re just beginning to get hints that a GREAT DEAL OF MATING happens after the sperm are dumped off. The deed is far from done. The female reproductive system — presumably in all species — is an active judge of sperm quality. Some animals can reject the entire deposit. Others can store one deposit as a backup, then continue to shop around. How flies sort through their options — and how humans do, as well — is still a mystery.
But increasingly, we understand why promiscuity is some (sic) common. In the race to produce the most, best children, it’s a winning strategy.
I can’t remember where I read it, but the statistic said that 25% of babies are not from the acknowledged mate/father in nearly all animals, especially birds and mammals.
Relevant article: Female Promiscuity to the Max: Cheating Cheetah