Nitric oxide and the control of firefly flashing

Bioluminescent flashing is essential for firefly reproduction, yet the spec ific molecular mechanisms that control Light production are not well unders tood. We report that Light production by fireflies can be stimulated by nit ric oxide (NO) gas in the presence of oxygen and that NO scavengers block b ioluminescence induced by the neurotransmitter octopamine, NO synthase is r obustly expressed in the firefly Lantern in cells interposed between nerve endings and the light-producing photocytes, These results suggest that NO s ynthesis is a key determinant of flash control in fireflies.