Comment on 'Biparental mucus feeding: a unique example of parental care in an Amazonian cichlid'

摘要

Buckley and colleagues (Buckley et al., 2010) describe parental care in discus cichlids of the genus Symphysodon, demonstrate that immunoglobulin is present in the mucus secreted by breeding discus, and propose that discus might be an interesting novel model system for studies of mammal-like parental care. Hildemann (Hildemann, 1959) appears to have been the first to describe parental care in discus, providing detailed analyses of the behaviours re-visited by Buckley and colleagues (Buckley et al., 2010). Parental investment is provided after fertilization of the eggs not just in discus but in all cichlids (ca. 1600 species), and many other families of fish (for reviews, see Blumer, 1979; Breder and Rosen, 1966; Gross and Sargent, 1985). In fact, parental care is exhibited in around 22% of teleost fish, and in 72% of non-teleost fish (Sargent and Gross, 1993). Sargent and Gross also review the literature and the proposed models that investigate the cost of reproduction and the parent–offspring conflict within fish (Sargent and Gross, 1993), citing early examples, just after the publication of Robert Trivers’ theory (Carlisle, 1982; Presley, 1976; Trivers, 1974).