The costs of parental care in Galilee St Peter’s fish, Sarotherodon galilaeus

Theoretical arguments concerning the evolution of parental care depend on the relative costs of caring to the two sexes. In this study experimental manipulations of parental care were used to compare the costs of care between the sexes in the biparental St Peter’s fish. For both males and females parental care had costs to growth and increased the number of days until the next reproductive cycle. In females, care also decreased subsequent fecundity, as expected from an observed positive correlation between female fecundity and body weight. The results provide strong evidence for high costs of care for females and distinguish between two components of the costs of reproduction: the costs of gamete production and the costs of care.