Cnidocyte mechanoreceptors are tuned to the movements of swimming prey by chemoreceptors

Cnidocytcs, the stinging cells of cnidarians, discharge nematocysts in response to physical contact accompanied by the stimulation of specific chemoreceptors. Cnidocytes in fishing tentacles of a sea anemone are now found to discharge nematocysts preferentially into targets vibrating at 30, 55, and 65 to 75 hertz. Moreover, in the presence of submicromolar concentrations of known chemosensitizers, such as N-acetylated sugars and mucin, these optima shift to 5, 15, 30, and 40 hertz, frequencies that correspond to the movements of swimming prey. Hence, chemoreceptors for these substances tune cnidocyte mechanoreceptors to frequencies that match the movements of the prey.