Evolutionary transitions in parental care in cichlid fish

Cichlid fishes (Cichlidae) are well suited for testing theories of the evol ution of vertebrate parental care. These freshwater teleost fish provide pa rental care for their offspring, display many different forms of care and h ave interspecific variation in which sex slays with the young. Here, we ass emble the first 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 subst rate guarding with 10-14 transitions and 0-3 reversals. The data support hy pothesized transitions in the sex of caregiver, with uniparental female car e 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. Th ese transitions in parental care characters are the most numerous reported for any family of vertebrates and, to our knowledge, provide the first quan titative support for models of parental care evolution in fish.