Daphnia is parthenogenetic most of the year, producing unfertilized eggs that develop into females. Towards the end of seasonal population peaks, in a mechanism not well understood, parthenogenetic females produce parthenogenetic males and sexual females. The sexual females and males copulate and produce a small number of resilient eggs. These eggs can overwinter, withstand drying and freezing, etc., and will hatch when conditions permit. Consequently, the eggs aid the organism in dispersal between bodies of water and allow the species to endure in ephemeral habitats.