The more the merrier: Promiscuity in mice is a matter of free choice

Aug 30, 2013
Choosing the perfect male depends on many factors. Credit: Kerstin Thonhauser/Vetmeduni Vienna

(Phys.org) —In many species, females frequently mate with more than one male. Researchers at the University of Veterinary Medicine in Vienna (Vetmeduni Vienna) aimed to find out why. In experiments on wild house mice, they discovered that females mate with multiple males when they have the opportunity to choose their mates freely. Sexual coercion by males could be ruled out as a factor. The results were published in the journal Behavioral Ecology and Sociobiology.

We know from earlier studies that mice can derive genetic benefits when females mate with multiple males, but until recently, the conditions under which females will voluntarily mate with multiple males were not clear. Kerstin Thonhauser and her colleagues from the Konrad Lorenz Institute of Ethology of the Vetmeduni Vienna conducted a series of experiments in which female wild-derived (Mus musculus) could mate freely with one or two males while not in danger of sexual coercion by a male. The results provide evidence for the avoidance explanation. Males that have a chance of reproducing with a female are unlikely to kill her young. Virgin males are known to be more likely to kill their , so females tend to mate with multiple virgin males to reduce the danger of infanticide. When exposed to more experienced males, however, less promiscuity was observed. It is uncertain how the females can tell whether a male is experienced or not, but it seems likely that they can detect differences in the males´ scent markings.

Scent marking as a quality indicator

The scientists discovered that females were more likely to mate with multiple males when they produced very similar levels of scent markings. Females mate with a single male when they are able to detect a significant difference in the males' scent. Thus it appears that another factor which influences ' mating decisions is whether they can perceive a difference in the quality of the males.

Correlation between paternity and litter size

Litters sired by more than one male were larger than single-sired litters, however only when there was intense competition among males. "Our results shed some new light on questions about the sexual behaviour of mice, but we still don´t have all the answers", says lead author Kerstin Thonhauser. "We need further studies to understand why litters are larger when there is intense competition between males. Another interesting question that has remained unresolved so far is how multiple paternity affects the fitness of the young."

Explore further: Danish museum discovers unique gift from Charles Darwin

More information: Thonhauser, K. et al. Why do female mice mate with multiple males? Behavioral Ecology and Sociobiology, dx.doi.org/10.1007/s00265-013-1604-8

Related Stories

Reversal of the black widow myth

May 06, 2013

The Black Widow spider gets its name from the popular belief that female spiders eat their male suitors after mating. However, a new study has shown that the tendency to consume a potential mate is also true of some types ...

Female cowbirds prefer less intense male courtship displays

May 03, 2012

In most species, females prefer the most intense courtship display males can muster, but a new study finds that female cowbirds actually prefer less intense displays. The full results are published May 2 in the open access ...

Recommended for you

Danish museum discovers unique gift from Charles Darwin

12 hours ago

The Natural History Museum of Denmark recently discovered a unique gift from one of the greatest-ever scientists. In 1854, Charles Darwin – father of the theory of evolution – sent a gift to his Danish ...

Top ten reptiles and amphibians benefitting from zoos

14 hours ago

A frog that does not croak, the largest living lizard, and a tortoise that can live up to 100 years are just some of the species staving off extinction thanks to the help of zoos, according to a new report.

User comments : 0