09.09.2019: Sexual experience is widely thought to provide important advantages when competing for mates, but surprisingly no benefits could be found from learning for male mice. This finding is the main result of a study conducted on house mice by Vetmeduni Vienna, and it shows how experience is not necessary for successful performance of mating behaviors that are critical for Darwinian fitness.

In a recent study published in Scientific Reports, researchers from Vetmeduni Vienna examined whether sexually experienced house mice males (Mus musculus musculus) have a higher mating and reproductive success than their virgin counterparts. The surprising finding: contrary to previous assumptions, sexual experience does not confer a reproductive advantage for male mice.

Postdoctoral researcher Kerstin E. Thonhauser at the Institute of Laboratory Animal Science, Vetmeduni Vienna says, “Female social preference is not a reliable indicator for male mating or reproductive success. The preference for a mating partner is therefore of only limited use in explaining partner selection. Our results show how even complex behaviours such as courtship and mating can be fully functional without learning or experience – even in mammalian species.”

Virgin males as sexually successful as experienced males

In the study conducted at the Konrad Lorenz Institute of Ethology, the researchers conducted an experiment with wild-derived mice in which they allowed females to choose between two males that differed in their previous sexual experience. Males had been previously manipulated so that they either were both sexually experienced, both virgins, or one was sexually experienced and one was a virgin. This design allowed the researchers to simultaneously test female mating preferences for male sexual experience and female multiple-male mating behaviour for infanticide avoidance as virgin males are known to be infanticidal.

Complex sexual behaviour fully functional even without experience

The researchers recorded females’ preference and mating behaviours and conducted genetic paternity analyses and found no evidence that sexual experience increased male mating or reproductive success. “Virgin males mated as often and sired as many offspring as their sexually experienced competitors. Additionally, females always copulated with both males regardless of their sexual experience,” says Thonhauser. An interesting detail is that male reproductive success was predicted by mating order but, unexpectedly, males that copulated first sired fewer offspring.

Completely new findings on the sexual behaviour of vertebrates

Previous studies have shown that the ability to learn from experience can improve Darwinian fitness and survival, but few studies have tested whether sexual experience enhances reproductive success. Sexual experience can affect mating and reproductive success by altering male behaviour, female preferences, or both. Sexual experience may improve males’ ability to court and persuade potential mates, or to out-compete rivals, as several studies on invertebrates have shown. Comparable studies with vertebrate species have been lacking, however. Based on the new findings, the study authors suggest that future research on vertebrates should take into account that female social preferences are not a reliable indicator of mate choice and that sexual experience might benefit males only under conditions where males must directly compete for females.

The article “Sexual experience has no effect on male mating or reproductive success in house mice” by Kerstin E. Thonhauser, Alexandra Raffetzeder and Dustin J. Penn was published in Scientific Reports.