Variations in life history characteristics ofDaphnia pulex fed different algal species.

Groups of individualDaphnia pulex were fed one of three algae (Pediastrum duplex, Chlamydomonas monadina, orMelosira ambigua) from age one day until death and their reproductive characteristics were monitored.Daphnia which were fedMelosira matured later, lived longer and produced more but smaller broods thanDaphnia which were fedPediastrum orChlamydomonas. R values did not differ among the groups but the fertility pattern was variable which is suggested to be of adaptive significance resulting from fluctuations of different food quality algae.