Synodontis catfish are not the only cuckoo spawners in the Rift Lakes, according to a study published in a recent issue of the journal Copeia.
American ichthyologists Jay Stauffer and William Loftus report for the first time brood parasitism (cuckoo spawning) carried out by the clariid catfish Bathyclarias nyasensis (known locally as Bombe) using the large bagrid catfish Bagrus meridionalis (known locally as Kampango) as the host.
The Kampango is a substrate-spawning catfish that practices biparental care. Female Kampango feed their young trophic (unfertilised) eggs while the male gathers macroinvertebrates from nearby sand habitats and carries them by mouth back to the young in the nest.
Consequently, the young Kampango gather around the vent of the female to feed when she is in the nest and around the gill openings of the male (where the macroinvertebrates are discharged) when he is in the nest.
The authors observed 14 Kampango nests while scuba diving in Lake Malawi and found four of these broods to be composed entirely, or almost entirely of young Bombe. The young Bombe fed exactly like young Kampango, gathering around the vent of the female when she was in the nest, and around the gill openings of the male when he was in the nest.
The prevalence of the parasitised broods led the authors to hypothesise that the Bombe most likely laid their eggs over spawning Kampango, and that the Bombe young hatch first and devour the Kampango eggs and larvae, leaving only the Bombe to be raised by the Kampango. This scenario is identical to well-known case of brood parasitism carried out by Synodontis multipunctatus on cichlid hosts in Lake Tanganyika.
For more information, see the paper: Stauffer, JR Jr and WF Loftus (2010) Brood parasitism of a bagrid catfish (Bagrus meridionalis) by a clariid catfish (Bathyclarias nyasensis) in Lake Malawi. Copeia 2010, pp. 71–74.