Author(s):

Ankita Thakur and DK Kocher

Abstract: The freshwater cladoceran, Daphnia magna is of great importance being used as a key model in ecological, developmental and ecotoxicological studies. D. magna were collected from village ponds (Punjab), identified and then cultured under laboratory conditions. Biological characteristics like developmental period of juvenile instars or pre-adult instars, number of egg clutch/brood, body size of juveniles and adult were studied. Female D. magna showed the capacity to carry clutch of 5-10 eggs in her brood chamber. Adult female was found to produce clutch of eggs every 3-5 day during her life span. Before achieving adult size they undergoes 5-6 moltings i.e. gradually increases in their size. The developmental period from 1^st juvenile instar till the emergence of adult varied from 6-8 days in case of females. Whereas it took 4-6 days to convert juvenile instar into adult in case of male Daphnia. Females attain their sexual maturity within 6-10 days. Life cycle i.e. from egg to adult was completed within 9-11 days. Overall life span of single D. magna was 30-45 days under ideal laboratory conditions.

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