Data for predator-induced defense decreases growth rate and photoprotective capacity in a nitrogen-limited dinoflagellate

Many phytoplankton produce defensive toxins with grazer deterrent effects when exposed to grazers. While the benefits are obvious, the costs of toxin production remain elusive. However, there must be costs, otherwise, all phytoplankton would be equally defended, and the search for and quantification of defense costs has been a long-standing research topic. Our experiment demonstrate both a direct growth penalty and - for the first time – an indirect photoprotection cost of gazer-induced toxin production in a dinoflagellate, and we suggest possible mechanisms for the costs. Toxin-producing cells benefit lower grazing risk at the cost of reduced growth and protection against damaging light.