The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they cannot successfully produce offspring. What can you infer from this information?

Postzygotic isolation

Explanation:

In the given information of edible frog both male and female hybrids exist, but when they mate among themselves, they cannot successfully produce offspring which defines that postzygotic isolation exists between the two frog species

Postzygotic isolation prevents the formation of fertile offspringBefore the postzygotic isolation can happen, there must be an offspring born from a male and female of two different speciesThis means there were no prezygotic isolations, such as the fitting together of the sex organs or incompatibility of the gametes or differences in mating rituals or locations, that kept the species in reproductive isolation    The offspring of two different species known as a hybrid is not always viableSometimes, they will self-abort before being born and other times, they will be sickly or weak as they develop