A parthenogenetic life cycle in a population of Canthocamptus Staphylinus (Copepoda,Harpacticoida)

The harpacticoid copepod Canthocamptus staphylinus (Jurine) was shown to reproduce parthenogenetically in an oligotrophic Finnish lake. The population was univoltine with peaks of egg production in winter and early spring. Young from both peaks became adults in spring and aestivated as cysts. Laboratory experiments suggested that either high temperature (12 °C or more) or long days will inhibit egg production, but that both factors together are needed to induce encystment. Embryonic survival was low, on the average only 60%. The population was limited by low food levels in winter, and it is suggested that food shortage prevents the species from colonizing the profundal zone of oligotrophic lakes.