Evolutionary transitions in parental care in cichlid ®sh

Cichlid ¢shes (Cichlidae) are well suited for testing theories of the evolution of vertebrate parental care. These freshwater teleost ¢sh provide parental care for their o¡spring, display many di¡erent forms of care and have interspeci¢c variation in which sex stays with the young. Here, we assemble the ¢rst family-wide composite phylogeny based on morphological and molecular studies, and trace two sets of character evolution: form of care (substrate guarding and mouthbrooding), and sex of care-giver (biparental, female-only, and male-only). Mouthbrooding has evolved from ancestral substrate guarding with 10^14 transitions and 0^3 reversals. The data support hypothesized transitions in the sex of caregiver, with uniparental female care having arisen from biparental care 21^30 times with 0^10 reversals. There is also evidence that male-only care evolved once from biparental care. These transitions in parental care characters are the most numerous reported for any family of vertebrates and, to our knowledge, provide the ¢rst quantitative support for models of parental care evolution in ¢sh.