Polygamous Mice Have More Fertile Children
In a study of mice, for male mice at least, the more partners they have, the more fertile their offspring are, researchers in Australia found.
Dr. Renee Firman at the Centre for Evolutionary Biology at the University of Western Australia and colleagues used mice to show sperm from rival males compete to fertilize females and over several generations, polygamy can select for mice who produce more sperm -- with stronger motility -- than monogamous males.
After 12 generations of competitive selection -- polygamous -- or relaxed selection -- monogamous -- female mice were mated twice, in succession, with males from both groups.
More litters were fathered by the polygamous males, the study says.
"Polygamous males retained their advantage regardless of whether they were mated first or second, demonstrating that the increased fitness applies to both offensive and defensive competition," the study says.
"The selection procedure had no obvious effect on male size or behavior, nor did it affect female fertility."
Source; Science News
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