The lifecycle
In
spring cladoceran populations consist of only parthenogenetic
females which hatched from resting eggs or were released from parthenogenetic
females surviving over the winter. As spring temperatures increase the
parthenogenetic females become reproductively active. Parthenogenesis
allows a rapid increase in population size over a short period of time
when environmental conditions are favourable.
Males are found only found in early summer if the water body is seasonal but more commonly they are recorded in autumn. After mating a fertilised resting egg is produced and enclosed in an ephippium by the ephippial female where it can survives desiccation and freezing.
TAXONOMY | MORPHOLOGY | ECOLOGY