Fig. 5
From: Daphnia as a versatile model system in ecology and evolution
Life cycle of Daphnia. Adult females produce mostly asexual eggs, which develop directly inside their brood chamber (cycle: parthenogenetic reproduction). Mostly daughters hatch from these eggs. Occasionally, asexual eggs develop into males (sons). Some of the adult females in the population may switch to sexual reproduction and produce haploid eggs, which need fertilization by males (outer cycle: sexual reproduction). The female will eventually drop the fertilized eggs in an egg case made from her carapace (brown structure on top left; resting stage = ephippium). The ephippium will sink to the bottom of the water body, where it undergoes diapause. After diapause, one or two sexual offspring will hatch from it and develop into females. Conceptualization by D. Ebert and D. Vizoso. Drawing by D. Vizoso (available on Wikimedia)