Crown-of-Thorns Starfish recognizes communication molecules from peers

The Crown-of-Thorns starfish were left in an aquatic Y-shaped maze overnight (on top). In one of the smaller branches (bottom left on the left-hand tank and bottom right on the right-hand tank) scientists added water collected around starfish aggregations from inside an aquarium, suspecting they communicate through water-borne signals to gather in huge populations during spawning events. The COTS can be seen moving towards these specific locations, suggesting the animal reacts to molecules induced by another COTS.