Photic Inhibition of Brain Stimulated Firefly Flashes

A study of the effects of photic stimulation on the ability to induce flash luminescence in the female Photuris firefly by electrical brain stimulation was made. Pulses of light delivered to the eye of the firefly aie not only able to inhibit spontaneous flashing but also reduce the ability of electrical biain stimuli to induce firefly flashes. Inhibition by photic pulses is most effective when the pulses are delivered approximately 300–400 msec prior to brain stimulation. Only flashes of biain stimulus—flash onset latency greater than 120 msec can be inhibited in this fashion, while driven flashes of 90 msec were immune from the inhibitory effect. It is suggested that the inhibilory effects of photic stimulation provide some physiological explaintion of the male-female response latency found in the courting fireflies.