BROOD AGE AND PARENTAL DEFENSE IN THE CONVICT CICHLID, CICHLASOMA-NIGROFASCIATUM (PISCES, CICHLIDAE)

Most tests of the influence of offspring age on parental defensive behaviour have not controlled for repeated presentation of model predators. It is not clear therefore, whether a parent's defensive behaviour is affected by offspring age or by experience with the model. In this study, these variables were separated by varying the number of times a model predator was presented. The model predator was presented to tank-held parental convict cichlids, Cichlasoma nigrofasciatum, at three developmental brood stages: egg, wriggler and fry. The results show that the number of model presentations had no effect on parental defence. However, parental effort of both parents increased with offspring age. These results support the age-investment hypothesis and suggest that the number of previous model presentations may not influence brood defence in this species. Except in time spent with the brood, males and females did not differ in their response to the manipulations. © 1991.