Brazilian scientists have discovered that some cichlids follow potamotrygonid stingrays to opportunistically feed on the invertebrates flushed out by the foraging activity of the rays.
Publishing the results of their study in a recent issue of the journal Neotropical Ichthyology, Domingos Garrone-Neto and Ivan Sazima record this association while making in situ observations of the fishes at two sites in the upper Paraná River drainage.
The authors found that the foraging activities of the stingrays Potamotrygon falkneri and P. motoro, attract four cichlid species (Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi, and Geophagus proximus) to follow them.
The authors describe the association as “…a ray stirring the unconsolidated (loose) substrate to uncover small invertebrates such as insect larvae, crabs, and snails.
This activity stirs the substrate particles and discrete sediment clouds are formed near the foraging ray. These clouds apparently catch the attention of nearby cichlids that approach the ray and feed on small preys and other food types exposed this way.”
This is yet another case of a nuclear-follower association, which has been reported for a number of South American freshwater fishes.
The nuclear-follower association is an interspecific interaction defined by the presence of a nuclear species that promotes a disturbance during foraging and a follower species that feeds on the items exposed or flushed out by the former.
For more information, see the paper: Garrone-Neto, D and I Sazima (2009) The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays. Neotropical Ichthyology 7, pp. 499–501.