English: Schematic representation of cyclic parthenogenesis in the cladoceran Daphnia magna (water flea). In this reproductive system, individuals can alternate between sexual and parthenogenetic reproduction. When reproducing parthenogenetically, diploid asexual embryos fully develop in the brood chamber of mature female daphnias, and are then directly released in the environment. Sexual reproduction requires the parthenogenetic (clonal) production of males that then mate with adult females to fertilize one to two haploid eggs that are encapsulated in a hard shell and can undergo a resting phase known as diapause.