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Lethal effects of short-wavelength visible light on insects.

Hori M, Shibuya K, Sato M, Saito Y - Sci Rep (2014)

Bottom Line: We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs).Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species.For some animals, such as insects, blue light is more harmful than UV light.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.

ABSTRACT
We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

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Emission spectra of LED lighting units used for the experiments.
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f4: Emission spectra of LED lighting units used for the experiments.

Mentions: LED lighting units (IS-mini®, ISL-150 × 150 Series; CCS Inc., Kyoto, Japan; light emission surface: 150 × 150 mm; 360 LEDs were equally arranged on a panel; LED type: φ 3-mm plastic mould) with power supply units (ISC-201-2; CCS Inc.) were used for UV and visible light radiation. Insects were irradiated with LED light in a multi-room incubator (LH-30CCFL-8CT; Nippon Medical & Chemical Instruments Co., Ltd., Osaka, Japan). The emission spectrum was measured using a high-resolution spectrometer (HSU-100S; Asahi Spectra Co., Ltd., Tokyo, Japan; numerical aperture of the fibre: 0.2) Comparison of the emission spectra used in the experiments is shown in Fig. 4. The number of photons (photons·m−2·s−1) was measured using the spectrometer in a dark room and was adjusted using the power-supply unit. The distance between the light source and the spectrometer sensor during measurements was approximately the same as that between the insects and light source in the incubator. Because the insects were irradiated through a glass lid, polystyrene lid, or glass plate, the same lid or plate was placed between the light source and sensor during measurement. The distances between the lid or plate and the light source during measurements were approximately the same as those in the incubator. Insect containers were placed directly under the light source during irradiation. We confirmed that the upper surfaces of the containers were irradiated homogeneously by measuring the numbers of photons. In addition, we assumed that temperature changes caused by the light source would not affect survival of the insects because LED light emits little heat. To check this assumption, we measured the temperature inside the containers using a button-type temperature logger (3650, Hioki E. E. Co., Ueda, Japan), of the insects and in the media except for water (filter paper, culture medium, bottom of dish) using a radiation thermometer (IR-302, Custom Co., Tokyo, Japan). We measured water temperature using a digital thermometer (TP-100MR, Thermo-port Co., Iruma, Japan). Temperatures that showed lethal effects in several light treatments were measured in each experiment and under DD and LD (16L:8D photoperiod) conditions. The temperature data are summarized in Supplementary Tables 5 and 6.


Lethal effects of short-wavelength visible light on insects.

Hori M, Shibuya K, Sato M, Saito Y - Sci Rep (2014)

Emission spectra of LED lighting units used for the experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260232&req=5

f4: Emission spectra of LED lighting units used for the experiments.
Mentions: LED lighting units (IS-mini®, ISL-150 × 150 Series; CCS Inc., Kyoto, Japan; light emission surface: 150 × 150 mm; 360 LEDs were equally arranged on a panel; LED type: φ 3-mm plastic mould) with power supply units (ISC-201-2; CCS Inc.) were used for UV and visible light radiation. Insects were irradiated with LED light in a multi-room incubator (LH-30CCFL-8CT; Nippon Medical & Chemical Instruments Co., Ltd., Osaka, Japan). The emission spectrum was measured using a high-resolution spectrometer (HSU-100S; Asahi Spectra Co., Ltd., Tokyo, Japan; numerical aperture of the fibre: 0.2) Comparison of the emission spectra used in the experiments is shown in Fig. 4. The number of photons (photons·m−2·s−1) was measured using the spectrometer in a dark room and was adjusted using the power-supply unit. The distance between the light source and the spectrometer sensor during measurements was approximately the same as that between the insects and light source in the incubator. Because the insects were irradiated through a glass lid, polystyrene lid, or glass plate, the same lid or plate was placed between the light source and sensor during measurement. The distances between the lid or plate and the light source during measurements were approximately the same as those in the incubator. Insect containers were placed directly under the light source during irradiation. We confirmed that the upper surfaces of the containers were irradiated homogeneously by measuring the numbers of photons. In addition, we assumed that temperature changes caused by the light source would not affect survival of the insects because LED light emits little heat. To check this assumption, we measured the temperature inside the containers using a button-type temperature logger (3650, Hioki E. E. Co., Ueda, Japan), of the insects and in the media except for water (filter paper, culture medium, bottom of dish) using a radiation thermometer (IR-302, Custom Co., Tokyo, Japan). We measured water temperature using a digital thermometer (TP-100MR, Thermo-port Co., Iruma, Japan). Temperatures that showed lethal effects in several light treatments were measured in each experiment and under DD and LD (16L:8D photoperiod) conditions. The temperature data are summarized in Supplementary Tables 5 and 6.

Bottom Line: We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs).Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species.For some animals, such as insects, blue light is more harmful than UV light.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.

ABSTRACT
We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

Show MeSH
Related in: MedlinePlus