Cuckoo catfish (Synodontis multipunctatus) have a cunning reproductive strategy. Rather than expend the energy required to care for eggs themselves, they sneak their developing offspring into the mouths of cichlids, who raise them as their own.
Familiarity with the catfish may help the cichlids avoid being their unwilling babysitters. Radim Blažek and colleagues report last week (May 2) in Science Advances that cichlids that coevolved with the parasitic catfish rejected the eggs more often than cichlids that hadn’t. Even though the behavior led to the savvy cichlids sometimes rejecting their own eggs, they still were more successful in raising their own offspring than cichlids who accepted the catfish eggs were.
R. Blažek et al., “Success of cuckoo catfish brood parasitism reflects coevolutionary history and individual experience of their cichlid hosts,” Science Advances, doi:10.1126/sciadv.aar4380, 2018.