The photokinesis of oriental fruit flies,Bactrocera dorsalis,to LED lights of various wavelengths

The oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), is an invasive pest of orchards around the world, particularly in Asian countries such as China. Light traps offer a potential means for pest monitoring and management. This study aimed to evaluate the sensitivity of the fly to light and investigate the impact of monochromatic light in the sensitivity spectrum on B. dorsalis. Six light wavelengths in LEDs – green (522 nm), yellow (596 nm), blue (450 nm), red (633 nm), purple (440 nm), and white (compound light) – were adapted to test responses of 5‐, 10‐, and 20‐day‐old B. dorsalis adults kept in laboratory conditions. We also tested the effects of green and red lights on pupal development and adults’ life activities. The results indicated a phototaxis preference rank in B. dorsalis adults to monochromatic LEDs with, in decreasing order, green, yellow, purple, blue, and red. Moreover, positive phototaxis significantly increased with age. Male adults are more sensitive than female adults to test lights, mainly at the age of 10 and 20 days. Emergence rates of pupae exposed to 12 and 24 h green light daily were 42 and 67%, respectively, whereas controls held in red light emerged at 33 and 37%, respectively. Furthermore, body weight, female fecundity, and mortality of B. dorsalis in night‐time exposure of green light (from 21:00 to 09:00 hours; during daytime flies were illuminated by white LED light) were significantly higher than in red‐light test groups and dark controls. In conclusion, B. dorsalis displayed preference toward green light, and fly age and gender seemed to significantly impact the phototactic behavior. Green LED light exposure during nighttime remarkably improved the emergence rates of B. dorsalis, and it enhanced growth, development, and ovipositing peak period, but decreased adult lifespan. This research lays a foundation for the development of new trap models, e.g., with green sticky cards or green light, for monitoring and control of B. dorsalis in the field.