Abstract: 【Aim】 To study the repellent effects of menthol on the oviposition of several common Drosophila species, and to evaluate the toxic effect of menthol through the survival rate and developmental duration of offspring and the mortality rate of adult Drosophila.【Methods】 The oviposition selection of Drosophila was assessed by using the two-choice apparatus under the action of 0.05%, 0.1% and 0.2% menthol. The double dye food preference experiment was used to detect the effects of menthol on the feeding behavior of Drosophila. The effects of menthol on the location of D. melanogaster was tested by oviposition apparatus. The effects of menthol on the oviposition selection of D. melanogaster were investigated by using dark conditions, removal of antennae and forelegs, and Orco² mutant test. The effects of menthol on the survival rate and developmental duration of D. melanogaster offspring were investigated. The effects of menthol on the lifespan, running speed and climbing speed of adult D. melanogaster were detected. The reactive oxygen species (ROS) level in the gut of D. melanogaster adults fed with 1% menthol for 3 d was evaluated by dihydroethidium (DHE) fluorescence staining technique.【Results】Menthol repelled the oviposition of female adults of Drosophila, and the oviposition indexes of D. melanogaster were -0.42, -0.58 and -0.98 under the treatment of 0.05%, 0.1% and 0.2% menthol, respectively. The female adults of D. suzukii, D. yakuba and D. pseudoobscura also showed oviposition avoidance response to menthol in the same way as those of D. melanogaster. D. melanogaster and D. suzukii adults significantly rejected the medium containing menthol during the feeding process. D. melanogaster adults showed obvious positioning avoidance to the medium containing menthol, and the position indexes of D. melanogaster under the treatment of 0.05%, 0.1% and 0.2% menthol were -0.32, -0.44 and -0.84, respectively. All concentrations of menthol still showed significant oviposition repellency to the female adults of D. melanogaster in dark environment and with foreleg removed, but under the condition of removing the antennae of D. melanogaster adults, the oviposition repellency of menthol was significantly reduced, and the oviposition indexes under the treatment of 0.05%, 0.1% and 0.2% menthol were -0.04, -0.06 and -0.26, respectively. Menthol still had oviposition repellent effect on Orco² mutants. In the treatment group with 1% menthol, the time to puparium formation and time to adult eclosion were significantly extended by 0.74 and 0.73 d, respectively, and the survival rates dropped significantly by 63.2% and 91.3%, respectively, as compared to those in the control group. With the increase of menthol concentration, the survival rate of D. melanogaster adults decreased, and their running speed and climbing speed were decreased significantly, i.e. mentol decreased the fitness of the parent D. melanogaster. Treatment with 1% menthol dramatically enhanced the ROS level in the gut of D. melanogaster adults at 3 d after treatment.【Conclusion】Menthol mediates the oviposition avoidance response through olfactory in Drosophila species, and reduces the fitness and survival rate of offspring and parents.

Key words:  Drosophila, menthol, oviposition avoidance, olfactory system, developmental duration, survival rate