Our research combines three main topics: (i) Chemotactic responses of herbivore protists; (ii) dimethylated sulfur compounds (DMSCs) and their role as infochemicals and (iii) microzooplankton selective predation. The research line investigates the three concepts but above all, tries to disclose how they associate. The cycling and ecophysiological functions of DMSCs are explored within the frame of chemotaxis as a driver of protist grazing.