Parental Care in Cichlid Fishes

" Cichlid fishes are champion caregivers that protect, clean, aerate, and sometimes even feed their young. This tropical fish family’s extensive species radiation combined with great diversity in care habits make cichlids immensely useful models for studying the evolution of parental care. In this chapter, we review the diverse ways that care is provided (~1/3 of species guard young on the ground and 2/3 mouthbrood) and the variation in sex of the caregiver (42% of species have biparental care, 58% show the derived state of female-only care). Substrate guarding, the ancestral form of care, is especially common among New World cichlids. In contrast, mouthbrooding, dominates in African clades. We also describe two forms of expanded (allo) care: (1) brood mixing where parents care for non-descendant young; and (2) cooperative breeding with joint care by an entire social group. Such cooperative breeding, arguably one of the most socially complex breeding systems, has arisen at least 5X among cichlids, all within a single clade, the Lamprologines of Lake Tanganyika. Using one well-studied cooperative species, Neolamprologus pulcher, as an example, we review the various possible explanations for the evolution of cooperative care. We conclude by discussing some exciting future directions for the study of parental care in cichlids "