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Daphnia - An icon of fecundity but not sexuality.
Daphnia, a mm-long crustacean organism living in lakes and ponds, is prolific. A single female can produce dozens of eggs each day when feeding and temperature conditions are good. The female, however, usually does this without the aid of a male, as most species are parthenogenic--that is females simply reproduce identical copies (clones) of themselves without sexual reproduction. When times are tough, however, the females produce males, mating ensues, and a resting egg (ephippium) is produced.