Coexistence with similar life cycles in two species of freshwater copepods (Crustacea)

摘要

Two species of freshwater cyclopoid copepods,Cyclops scutiferSars andMesocyclops leuckarti(Claus), with different ecological requirements, coexist in three humic ponds near the timberline in boreal forests in south-central Norway. The life cycle in both species is basically regulated by complete depletion of oxygen during the long winter. There is a short period of reproduction in spring followed by a rapid development during summer and autumn to advanced instars, capable of diapause when oxygen depletion starts in early winter. Both species have an exclusive 1-yr cycle.