Study On The Influence Factor Of Phototaxis And Feeding Behavior Of Propylea Japonica (Thunberg)

The influence factor of phototaxis and photophobism behavior of the dominant predatory enemies-Propylea japonica (Thunberg) was investigated by behavior measure. And analysis of the impact of their feeding behavior by spectra and colors, the main results were as follows:1. Both the spectrum and intensity of light stimulus gave rise to the phototaxis of P. japonica, it seemed to play a more important role that the light intensity than spectrum, but the effect level was also involved with wavelengths. There was not significant photophobism response to light for the ladybird, the behavior probably derived from phototaxis or partly due to random movements. The effect of sex to response to the spectral sensitivity and intensity was not significant.The spectral sensitivity response at 14 monochromatic light selected through 340 nm to 605 nm occurred in curve with multiple peaks, the primary peak in 340 nm (ultra-violet) was the highest response rate of phototaxis (21%), the secondary in 524 nm (green), and the rest in 400~440 nm and 483 nm in order; The response rate of phototaxis was increasing as the relative intensity of light, it was showed as curves with inverse "L" shape in white light and the monochromatic light of 483 nm, as an upward ladder at 524 nm and a near straight line at 340 nm. However, the response rate could be detected at the lowest intensity and not arrived to the summit at the strongest yet. Moreover, a broader range of light intensity could be perceived by the ladybird compound eye. Light intensity has a strong sense of self-regulating and light capabilities, and its light intensity phototaxis sexual stimulation and light-dependent type.2. The feeding rate of Propylea japonica (Thunberg) adult in the 12 h and a certain period were all increase in the role of varying degrees after stimulation of 6 species monochromatic lights ( 340, 420, 483, 524, 583, 605 nm). The effect of sex to their feeding behavior was certain effect.After stimulation of monochromatic lights, the order of the amounts of feeding was: 340 nm (82.37) > 524 nm (78.4) > 605 nm (77.1) > 483 nm (75) > 420 nm (74.04) > white (72.15) > 583 nm (60.45), it was drop only at yellow zone (583 nm). The ladybird's feeding rate curves after monochromatic light stimulation in 1~12 h were all reduced with time, but different at 2, 5, 9 h. The feeding rate curves declined in 1~3 h (340, 420, 483, 524, 605 nm), increased in5~8 h (340, 420, 483, 524 nm) or lowered (583, 605 nm), and increased in 9 h (483, 524, 605 nm). It shows that the feeding rate increased significantly in specific time after stimulation of monochromatic lights.3. Compared with the black, under the four kinds of background colours (red, yellow, green, blue), the trend rate of Propylea japonica (Thunberg) adult to different color were reduced when shielded. The amounts of feeding of aphids increased only under the red, decreased in varying degrees the rests in 4 h, the feeding-time response curves in 1~4 h was increased or decreased. Gender affected the colour trend rate, but has no effect on their feeding rate.When prey is not shielded, the orders of colour trend rate was: yellow (83.3%) > red (79.2%) = green (79.2%) > Blue (62.5%), in which the female trend green (91.7%) and the male trend yellow(91.7%). The orders when prey shelter was: red (58.3%) > yellow (50%) = green (50%) > Blue (12.5%), in which the female trend green and the male trend control. When shelter or not, the female trend green, both sexes tend to blue the lowest.Under four kinds (Red, yellow, green, blue) and black background, the order of the amounts of feeding was: red (41.15) > control (40.32) > yellow (39.99) > Blue (39.98) > Green (32.51). The feeding rate curves between 1~4 h was different. the control line was oblique type, It was the "S" type under red, yellow and green, the last "L"-type under blue; compared with the control, its feeding rate were lower in 1~2 h and higher in 3~4 h under red, yellow and blue, it was all lower in1~4 h under green. It shows that their feeding rate has different changes under four colors, the feeding rate was the minimum to green which also was the body colour of the prey.This innovation is confirmed both the spectrum and intensity of light stimulus gave rise to the phototaxis of P. japonica, it seemed to play a more important role that the light intensity than spectrum, but the effect level was also involved with wavelengths. At the same time, confirmed the monochromatic light and colour stimulation were efficient to P. japonica's feeding trends and the success of a certain impact. These findings reveal the intrinsic link between the source of the characteristics of light and the provision of a scientific reference of phototaxis in lady beetles or insects, but also provided a new thinking and approaches for natural enemies's protection and sustainable use to control pests of agriculture and forestry.