Preying at the edge of the sea: the nemertine Tetrastemma melanocephalum and its amphipod prey on high intertidal sandflats

摘要: In the European Wadden Sea, nemertine Tetrastemma melanocephalumoccurs together with its prey, amphipod Corophium arenarium, in upper intertidal zone. T. melanocephalumleaves sediment when tide has receded and captures C. arenarium U-shaped burrow. Highest abundances of melanocephalumon surface were found on summer evenings, 2–4 h after high tide, just a thin film water was left flats. Laboratory Y-maze experiments indicated that gradients substances produced by this play role tracking prey. field, melanocephalum appeared significantly higher numbers experimental density patches arenarium. The turn is able to recognize nemertine. aquarium experiments, more amphipods escaped from into column predator present. both prey showed mobility drifting tidal waters. Benthic abundance maxima arenariumusually did not coincide spatially. It assumed nemertines avoid flats dry out quickly leaving too little time for capture. dig sediment, but lives burrows Nereis diversicolor. polychaete inversely related presenting dilemma melanocephalum: spatial overlap food accommodation rather small.