Two intertidal fish species use visual association learning to track the status of food patches in a radial maze.
We tested fifteen-spined sticklebacks, Spinachia spinachia, and corkwing wrasse, Crenilabrus melops, for their ability to associate visual spatial cues with food sources in a radial maze and so to track renewal frequencies and productivity. When all locations contained food or were empty, subjects displayed win-shift or lose-shift behaviour by avoiding recently visited locations; this behaviour therefore appeared to be a basic trait. Both species readily learned food-cue associations, although with less efficiency as the diversity of cues increased. They used this information to distinguish food sources renewed within and between daily foraging bouts from those that remained empty. Moreover, both species distinguished between renewable food sources differing in productivity, preferentially visiting those containing more food. Reversal of cue roles caused an immediate decline in foraging efficiency, followed by rapid recovery as new food-cue associations were learned. Evidently, therefore, subjects tracked the status of potential food sources by continued sampling and could switch from win-shift to win-stay behaviour, when preferred locations were persistently revisited, as appropriate. The formation of food-cue associations, together with sampling and flexible use of win-shift and win-stay behaviour, would enable these rocky intertidal fish species to exploit patchily distributed food sources whose status changes during the tidal cycle. Copyright 2000 The Association for the Study of Animal Behaviour.
Hughes
RN
School of Biological Sciences, University of Wales, Bangor
Blight
CM