[The effect of optical radiation on the migration of third stage larvae of Oesophagostomum quadrispinulatum out of feces].

The influence of optical radiation on the emigration of third stage larvae out of faeces was investigated by exposing faeces containing infective larvae of Oesophagostomum quadrispinulatum to broad-band radiation of a sun-simulating wavelength spectrum corresponding to a sunny day, a cloudy day, dawn, and a full-moon night, as well as to monochromatic radiation of different wavelength spectrum at dawn and to complete darkness. It was demonstrated that third stage larvae of O. quadrispinulatum were able to differentiate between daylight and darkness responding to different irradiances with very high emigration rates at irradiances corresponding to dawn, and significantly lower emigration rates corresponding to full-moon light, and darkness as well as a cloudy and sunny day. Infective larvae reacted to monochromatic radiation of different wave-length spectrum at dawn and showed significantly higher emigration rates at the violet, green, yellow, and red light wavelength compared to darkness.