Alarm Response of Diadema antillarum.

Diadema antillarum possesses a sensitive escape response to juices of crushed conspecific sea urchins. Stimulation usually results in urchins moving rapidly downcurrent. Strong species specificity of the response suggests that it is an adaptation to reduce predation. Diadema antillarum also responds with a running response to contact with Cassis tuberosa, a known predator.