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Abstract

The cuckoo catfish (Synodontis multipunctatus) from Lake Tanganyika in Africa parasitizes mouth-brooding cichlid fishes (catfish eggs get picked up and incubated in the mouths of cichlid females, where the catfish young feed on cichlid eggs). I examined the impact of parasitism by the cuckoo catfish on an allopatric (not naturally co-occurring) mouthbrooding cichlid, the red zebra (Maylandia estherae) relative to that of a previously characterized sympatric (naturally co-occurring with the parasite) host species (Ctenochromis horei). The red zebra was parasitized significantly more than the sympatric C. horei, which suggests that the sympatric host has evolved strategies to minimize cuckoo catfish parasitism. Early development of the red zebra did not differ significantly from that of the C. horei, indicating no early developmental adaptations to deter the catfish young from eating the host young. While the courtship behaviors of C. horei were also similar to that of the red zebra, C. horei was clearly more aggressive, which may be an adaptation to avoid brood parasitism. I also examined levels of parasitism between the red zebra and a closely related, also sympatric albino zebra cichlid (Maylandia zebra). Due possibly to its lower visual acuity, the albino zebra morph was parasitized significantly more than the red zebra. Lastly, the catfish was found not to parasitize hosts at random, but to prefer to parasitize female cichlids of an intermediate size.