To provide theoretical support for study of locust phototactic vision nature,the locust phototactic physiology and visual spectrum effects were investigated by stimulating the visual system using light from an AvaSpec fiber-optic spectrometer and Flir thermal imaging system.When light stimulated the locust visual system,the biological photoelectric transformation effect of the visual system caused by photon energy,presented with the higher physiological temperature on the forehead,as tested by the Flir thermal system.After stimulation with light,the different absorption degrees of the vision system on the spectral photons,as tested by the AvaSpec spectrometer,showed that the phototactic response to light had the simultaneous requirements of lighting intensity and time.The absorbing differences of spectral photons by the vision system demonstrated the absorption selectivity under light stimulation,as exhibited by the sensitive absorption of spectral energy at 430 nm,545 nm and 615 nm.Moreover,the higher forehead temperature increment indicated and induced the stronger physiology activity which was the reason that causing the good phototactic response degree of locusts with 30 min light stimulation,and the adaption time was about 60 min.Therefore,only when the visual reaction effect was stimulated to absorb sensitive spectral energy and generate the physiological exciting response could cause the phototactic behavior.
The slippery trapping plate in swarm locust control is a method of realizing resource utilization of locust and avoiding pesticide residues in the entironment. Some slippery plates with different material composition or surface characteristic were investigated through the sliding tests of locust on slippery plates, and sliding rubbing behaviors of locusts on the plate were observed by means of CCD video monitoring system. Poor sliding character of silicate glass to locust was verified, which is in accordance with the adhesive effect generated by secretion of locust feet pads on the smooth surface. And also, PVC plastic plate presents a poor sliding character to locusts, because the soft surface of PVC can permit claws of locust feet to engender mechanical interlock on the surface. The zinc plate shows a considerable slippery ratio for locusts because of the appropriate surface characteristic and material property. Photoelectric stimulation for resting locust can promote the movement of locust. Accordingly, the contact form of locust feet and abdomen on slippery plates is changed and contact area is reduced severely, so the sliding effect of locust on slippery plates is strengthened effectively. These results supply a suitable theoretical foundation for manufacturing locust slippery trapping plates and trapping units, and indicate the important role of photoelectric stimulating factors in biotribology.
