Studies On Mechanism Of Photosensitivity And Phototaxis Of Green Lacewing(Neuroptera: Chrysopidae)

The mechanism of photosensitivity and phototaxis was studied with optical andelectrophysiological method. The results are as follows:1 among three kinds of Chysopa peral. of the compound eyes show little daily change in Chrysopa sinica Tjedar .The model and color of psesudpopupil show significant daily change in Chrysopa septempzhbybimctata Wesmacl and Chrysopa formosa Brauer, color and diameter of the psesudpopupil of the compound eyes in Chrysopa septempunctata Wesmacl make rapid change at noon, afternoon ,night are similar ,but make little change in the morning and the next morning. Diameter of psesudpopupil of compound eyes is the biggest in the afternoon, which of Chrysopa formosa Brauer, is the biggest at noon. The phenomenon of eye glow is generally thought to be caused by reflecting layer as the tapetum lucidum.2 The spectral and intensity response from the compound eye of green lacewing were investigated by using ERGs extracellular recording method. The result show that the monochromatic light stimuli with the different wavelength within U.V. and most of visible region, coving the range of wavelength from 340-360nm can induce ERG reactions with different amplitude, according to the size of ERGs amplitude (perk-perk value), there are three or four perks in their spectral sensitivity curves. There are three perks between Chrysopa sinica Tjedar and Chrysopa septempunctata Wesmacl The major perk appears at 562nm(yellow-green), the second 524nm and the third 460nm(blue).There are four perks in range of 340-605nm.They are most sensitive to wavelength of 524nm,the second 562nmand also sensitive to 460-420.The result suggested the presence of three typesreceptors at least in the compound eye of Chrysopa sinica Tjedar and Chrysopa50septempunctata Wesmacl, but four type receptor in Chrysopaformosa Brauer.3 The intensity make effect on ERGs value .The result indicate that the stronger the luminance, the higher the ERG value in a certain intensity range of monochromatic and white light stimuli,but the rate of improvement make creeping until the extent to intensity. The whole curve appears near S shape curve which revealed that the compound eyes of green lacewinng have strong adapting ability to light stimuli.4 Relation of the dark-adapted time and ERG value indicates that time of day eyes turning to night eyes is not similar in different kind of species. The turn of compound eye from day eyes to night eyes need about 120min in Chrysopa sinica Tjedar,, but is not accord to in different unit the other two species.The compound eye complete turning in 60-90min,few need 120min.The compound eyes of Chrysopa formosa Brauer need about 60min.The result show that the rate of pigment movement are different in different species or different unit of the same species.5 ERG consist of 4 parts in the compound eyes of green lacewing -on light reaction, positive pontential, long negative pontential and off light reaction, their size and shape can be influenced by wavelength , light-intensity and stimulation time.