Freshwater cichlid Crenicara punctulata is a protogynous sequential hermaphrodite

Several papers have suggested that the Freshwater Cichlid Crenicara punctul ata is capable of protogynous sex change. These studies provide behavioral data and descriptive details of external morphology but lark information ab out gonadal histology, which is essential for definitive evidence of sequen tial hermaphroditism. Therefore, this study was designed to determine wheth er C, punctulata is a sequential hermaphrodite. The present study included a behavioral experiment, an isolation: transformation experiment, as well a s a detailed analysis of gonadal structure. The behavioral experiment estab lished social hierarchies in four groups of juvenile female C. punctulata. The hypothesis that the dominant female in each group would be the only ind ividual to develop male secondary sexual characteristics in that group was verified. The isolation experiment tested the hypothesis that female C. pun ctulata would change sex without the presence of conspecifics. After social isolation, females that were previously dominant among a group of females in a male harem developed male secondary sexual characteristics. Histologic al analysis revealed that these individuals possessed testes, whereas all d ominant females examined possessed mature ovaries. The results from behavio ral, isolation, and histological portions of this project strongly suggest that C. punctulata is a protogynous sequential hermaphrodite, at least in c aptivity.