Influence of light and mechanical stimuli on behavior of locust

Abstract: The mechanical techniques for nontoxic control of locust are developing rapidly in order to inhibit pesticide endangerment. Photoelectric trapping technique based on photoelectric inducing effect and slipping collection mechanism has exhibited an attracting trapping effect for nontoxic control of locust, and this technique is developed toward an integrated technique of optoelectronic-mechanical trapping machine. In the present study, we investigated the influence of light and mechanical stimuli on the behavior of locust in order to improve the photoelectric induction efficiency. The induction rate and induction efficiency of locusts were tested using LED light and homemade behavior reaction experimental device. 3 to 5 locusts were used as testing materials. The locusts were collected in the same rearing environment to reduce variance. The LED light source was arranged in an array at the wavelength of 465 nm. Light intensity was measured by illuminance meters and set by variable resistors. The experimental chamber had four channels distributed by 90° .A glass rod was placed on the top of the chamber for continuously touching the locust body or image stimulating the movement of the locust. The reaction of locust was recorded by the image collecting device which can measure the position changes and the moving speed of the locust. For keeping the state of the compound eyes consistent, the locusts were adapted in dark before testing for an hour. There were 4 stimulation treatments in our study: 1) movement behavior text with inducing light source; 2) movement behavior text with motion image stimuli; 3) movement behavior text with touch stimuli; 4) movement behavior text with coupling effect of light source and the mechanical stimuli. The results showed that the locust exhibited different behaviors by different factors stimulation. Two biological reacting behaviors were found with the different stimuli: the behavior of direction selectivity and the different motion sensitivity and adaptability. Mechanical stimuli had obvious effect on movement activity, but had no effect on movement direction selectivity of locusts. Locusts randomly moved into the various reaction channels, the induced efficiency was about 20%. Light had significant effect on the movement direction selectivity, but had no effect on movement activity. Locusts slowly moved to the channel with light, and the number of locust in channel 1 was much higher than that in other channels. Light stimuli had a stimulation inducing rate by 71.5%, which was higher than that of other treatments. Light source stimuli in combination with mechanical stimuli had an effect on both movement direction selectivity and continuous movement activity of locusts. The inducing efficiency improved by combining the light and mechanical stimuli had over 70% inducing rate. The relation was discussed on the outside stimulus response of the nerve and the movement behavior. Locust behavior is at least the superimposed results of anatomical structures and sensory nerve pathway. The complexity of locust behavior cannot be explained by its anatomical and electrophysiological mechanisms. The actual living environment of locusts was much different with the experimental condition, thus the accuracy of locust movement behavior was impacted by many factors.