Methods of Reproduction on the Planet Osaka

Osakar sexuality involves only one zex; female, and reproduction is parthenogenesis<br />http://en.wikipedia.org/wiki/Parthenogenesis<br /><br />would all reproduction on the planet be this method? or would this method be an adaption to the disappearance of males from the gene pool in just the osakar?<br /><br />in the absense of males (killed off by a virus maybe) mother nature found a way to perpetuate the osakar.<br /><br />Perhaps its not the only method of reproduction but it is alson not unique with many varieties of higher animals using it