Lethal effect of blue light on the developmental stages of the urban mosquito, Culex pipiens form molestus (Diptera: Culicidae)

We previously reported that short-wavelength visible light (blue light: 400–500 nm) has a lethal effect on various insect species and that the most toxic wavelength to the pupae of the hygiene pest, the mosquito, Culex pipiens form molestus Forskål (Diptera: Culicidae), is 417 nm. However, previous reports on Drosophila melanogaster Meigen (Diptera: Drosophilidae), and Galerucella grisescens (Joannis) (Coleoptera: Chrysomelidae) demonstrated that the most harmful wavelengths of blue light differed among different developmental stages. The most toxic wavelengths to the developmental stages of C. pipiens f. molestus, besides the pupal stage, remain unclear. We investigated the lethal effect of various wavelengths of the blue-light spectrum on the eggs, larvae, and adults of C. pipiens f. molestus using light-emitting diodes (LEDs). Blue light irradiation had a lethal effect on all life stages tested. Furthermore, our results reaffirmed the results of previous studies, where 417 nm light had a strong effect on all life stages. To our knowledge, this is the first report of an insect species where the most effective wavelength does not vary among developmental stages. In addition, our findings indicate that ~ 420 nm is the most promising wavelength to control C. pipiens f. molestus populations using blue-light irradiation.