Attractiveness of four wavelengths of LED light: UV (385 nm), violet (405 nm), blue (450 nm), and red (660 nm) for seven species of natural enemies

Abstract

Recently, the positive phototaxis exhibited by natural enemies such as Nesidiocoris tenuis (Hemiptera: Miridae) and Orius sauteri (Hemiptera: Anthocoridae) has been explored to enhance pest control efficiency in agriculture, mainly in Korea and Japan. Here, we evaluated the responses of seven natural enemies: Aphidius colemani, Asobara japonica (Hymenoptera: Braconidae), Chrysoperla carnea (Neuroptera: Chrysopidae), Harmonia axyridis, Illeis koebelei (Coleoptera: Coccinellidae), Nabis stenoferus (Hemiptera: Nabidae), and O. minutus (Hemiptera: Anthocoridae), to different wavelengths of LED light (i.e., 385, 405, 450, and 660 nm) to clarify the potential of phototaxis for behavioral manipulation of natural enemies. Also, we assessed how mating status and gender affected the responses of A. colemani and O. minutus using a video tracking system, EthoVision® XT. Overall, wavelengths of 385 and 405 nm were highly attractive to natural enemies, except for C. carnea and N. stenoferus. Unmated females of A. colemani moved greater distances than mated ones, the latter remaining significantly longer in the zone illuminated with UV light compared to the zone illuminated with white light. Adult O. minutus of both sexes remained longer under UV light than under white light. Therefore, the use of UV or near-UV lighting should serve to increase the retention time of natural enemies near light sources and might be useful to retain these and other natural enemies in specific agricultural contexts for better control of pests.