SALT LAKE CITY – Researchers at the University of Utah conducted a study which indicates that, for mice at least, sexy can be dangerous.
Researcher Joey Cauceglia said when a female mouse has to compete socially for mates in a promiscuous environment, she will have sons that produce a scent more seductive to other mice.
"The more protein concentration in the urine the more attractive they are,” he said.
Mice use a protein in sexual interaction called major urinary protein, or “MUPS.” It is transported into the urine, and the mice then mark their territories.
"The more you can mark, the more attractive you are,” Cauceglia said.
Researchers took the offspring of mice in a promiscuous environment, which researchers called "barn ancestry", and compared them to the offspring of mice living in a more domesticated, monogamous setting.
Wayne Potts is a biology professor at the University of Utah, and he said they took the two groups and put them in a natural setting where they could compete for mates.
“Males that had a barn ancestry had 30 percent higher reproduction, and it was all due to their ability to attract mates during extra pair matings,” he said.
But that increased attractiveness comes at a cost, researchers said, as the "sexier" mice are more likely to die earlier than their more domestic counterparts.
“So it’s like a live fast die young sort of mentality,” Cauceglia said. “But it seems to work when you look at pure reproductive success. Despite dying young, the barn ancestry mice had increased reproductive success.”
Potts said the parent mice were able to pre-adapt their sons to have higher reproductive success depending on what they experienced in their adult life. Potts also said the findings suggest this kind of machinery could be present in other mammals, including humans.
Researchers said the effect only transfers to sons and not daughters. They said the increased likelihood of an early death comes from the extra energy used to produce the pheromones. They said a mouse making those pheromones invests as much energy as ten male peacocks do to produce the colorful tails peacocks use to attract mates.
