Water Fleas, Matriarchy, and a Parasite Named Like a German Sausage

Cladocerans, commonly known as water fleas, dominate the planktonic crustacean population in freshwater environments, with the genus Daphnia being perhaps the most abundant. In marine environments, cladocerans are less diverse and limited mostly to warm, stable zones of the water column. Their presence is linked to periods of water column stability, as they are believed to be sensitive to turbulence. Cladocerans reproduce parthenogenetically during favorable conditions, with females producing clones of themselves. In adverse situations, males appear, fertilizing females that produce resting eggs called ephippia, which remain dormant until favorable conditions return. Parthenogenesis is not exclusive to cladocerans and occurs in various organisms, with some cases linked to the parasitic bacterium Wolbachia. Wolbachia, known for its diverse effects on host reproduction, has practical applications in controlling pest organisms.