Abstract: The responses of Chrysopa pallens Ramber to light stimuli with different intensities were investigated by means of electroretinogram (ERG) technique and behaviour measurement. The results were as follows: (1) The white light with given intensity (Log I=4.5~0.0) could evoke the ERG responses of the compound eyes of C. pallens after 2 h dark-adaption. A linear increase in ERG value occurred with the increase of the light intensity, and no plateau end was seen in the strongest intensity, which revealed that C. pallens owned almost the same photosensitivity within the test range of light intensity and was able to perceive stronger light. (2) Obvious phototactic responses in behavior upon given light stimuli that were stronger than Log I=4.0 were also observed, and the stronger the light intensity, the higher the percentage of behaviour response, especially in the range of stronger intensity (Log I=1.5~0.0). However, their photophobism was rather lower or irregular, with the maximum of 4.5%. It is so concluded that both the perception to light and subsequently phototaxis behavior of C. pallens depend on the light intensity obviously, there is no visible photophobism response in any case, and the response of primal receptor cell potential is accordant with the phototactic behavior in a certain range of light intensity, indicating that light intensity plays a subtle role during the light perception and succeeding phototaxis.

Key words: Chrysopa pallens, light intensity, white light, electroretinogram (ERG), phototactic behavior