Morphological variation and population dynamics of Bosmina (E.) longicornis kessleri Uljanin (Crustacea: Anomopoda: Bosminidae) in the Bukovec Reservoir (S.E. Slovakia)

Bosmina (Eubosmina) longicornis kessleri and B. (Bosmina) longirostris are minor components among the crustacean zooplankton in the pelagial of Bukovec Reservoir. B. (E.) l. kessleri is a recent colonist in the Carpathian region and was first found in the Bukovec reservoir in 1986. The present study gives some information about the niche occupied by B. (E.) l. kessleri in the zooplankton community; the seasonal abundance of zooplankton and phenotypic variability (cyclomorphosis) of B. (E.) l. kessleri are also examined.