Impact of the nemertean Lineus viridis on its polychaete prey on an intertidal sandflat

Interactions of the predator Lineus viridis (O. F. Muller 1774) with infaunal polychaetes were investigated in the German Wadden Sea. L. viridis is the dominant heteronemertean in this intertidal area with a mean abundance of 14 individuals per square meter. Predator enclosure experiments in the field revealed that L. viridis preyed on predatory polychaetes. The preferred prey species was Nereis diversicolor; others were Anaitides maculata. Nephtys hombergii and Harmothoe sarsi. These results were supported by a series of feeding experiments in the laboratory. The rate of consumption was estimated by laboratory and field experiments. The feeding rate of Lineus viridis was estimated by laboratory enclosure experiments to 5.6 g ashfree dry weight (AFDW) per square meter annually.