The genus Scenedesmus can forms defensive colonies under predation pressure. The adaptive benefits of colony formation for Scenedesmus have been investigated in many studies. However, no direct evidence about the cost accompanying with the benefit is detected. On June 16, 2017, Dr. Yuan Huang gave us a talk about the costs and trade-offs of grazer-induced defense in Scenedesmus. She studied the grazer-induced defense and the growth of Scenedesmus under different environment stress, such as nutrient-deplete, competition and pollution. Her studies provide evidence supporting the existence of costs and trade-offs of inducible defense in Scenedesmus.