Abstract:The western flower thrip, Frankliniella occidentalis (Pergande), is one of the most serious pests causing adverse effects on global crop production. Since 2003, F. occidentalis has been affecting the crop fields of several provinces in China. The selectivity of F. occidentalis on colors has been reported to have significant differences. In the present paper, the phototaxis behavior of F. occidentalis(Pergande) in response to spectral sensitivity and light intensity were investigated. The results were as follows: (1) The spectral sensitivity response of phototaxis at 14 monochromatic light selected within the range of 340-605 nm occurred in a curve with multiple peaks. The primary peak within the range of 498-524 nm (blue-green) is the highest response rate of phototaxis (20.31%); the secondary peak at 380 nm (violet) is the highest response rate of phototaxis (19.06%); and the rest of the peaks at 440 nm (blue) is the highest response rate of phototaxis (18.44%). (2) The spectral sensitivity response of photophobism at 14 monochromatic light selected within the range of 340-605 nm occurred in a curve with two peaks: a peak at 440 nm (blue) is the highest response rate of photophobism (17.19%), and another peak at 340 nm (ultra-violet) is the highest response rate of photophobism (15.63%). (3) The same wavelengths of light intensity appeared in different intensities in different phototactic response rates. In the white light and monochromatic light at 380 and 524 nm, the response rate of phototaxis is increasing together with the relative intensity of light; the relative intensity of light appeared as curves with increasing L-shaped peaks, which is the maximum response rate in log0.0. At 498 nm, two peaks appeared in log4.5 and log0.0 with the sharp having multiple peaks. At 440 nm, the response rate of phototaxis is slowly increasing together with the relative intensity of light, and the shape was
near a straight line displaying the maximum response rate in log0.0. The response rate could be detected at the lowest intensity and not at the summit of the strongest intensity. (4) The same wavelength appeared in different light intensities in different response rates. Two peaks of photophobism behavior appeared at 340 and 440 nm, respectively. The monochromatic light at 440 nm with light intensity and maximum response rate in log0.0 had a slowly increasing response rate and relatively flat linear response curve. The monochromatic light at 340 nm with light intensity and maximum response rate in log1.0 had photophobism response rate changes with a response curve that displayed more moderate fluctuations in line. Therefore, both the spectrum and intensity of light stimulus gave rise to the phototaxis of F. occidentalis (Pergande). However, light intensity seems to have played a more important role than the spectrum, but the effect level may also have been involved with the wavelengths. The phototactic behavior of its spectrum exerted a great influence away from light, particularly on the light intensity of the larger phototactic behavior, the effect of light intensity, and the wavelength of other the factors.