Hermaphroditic plants have genetic advantage in areas where extinctions are frequent

In one of the first studies to empirically compare the reproductive success of hermaphrodites and male and female populations, biologists from the University of Oxford make use of the rare and extreme sexual diversity displayed in a species of European weed to test the hypothesis that hermaphrodites have been selected in regions with frequent extinction and re-colonization.

“[We used] the general theory for the genetics of populations, which tells us that repeated bouts of extinction and re-colonization should reduce genetic diversity within populations and increase genetic differentiation between populations,” explain the authors in a forthcoming article in American Naturalist.

Given the ability to colonize new populations alone, hermaphrodites have an advantage over males and females where colonization is frequent. As expected, diversity was low and differentiation high in hermaphrodite populations of the Mercurialis annua. In contrast, populations that contained males were more diverse and less differentiated from one another.