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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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Effects of irradiation with 467-nm blue light on eggs, larvae, and adults of Drosophila melanogaster.(a) Dose–response relationships for lethal effects of irradiation with LED light on eggs. “0” photons represents the 24-h dark condition. Data are means ± standard error (SE). (b) Relationship between light dose and developmental stage at which mortality occurred. Developmental stages of larvae and pupae were classified according to Bainbridge and Bownes (1981)19. L1 and L2 are third-instar larvae, P1–P4 are prepupae, and P5–P15 are phanerocephalic pupae. No irradiated flies died during the P5–P9 developmental stages. Data are mean values. Mortality (mean ± SE) of flies that could not emerge is indicated by the black line. (c) Dose–response relationships for effects of irradiation with LED light on adult longevity. “0” photons represents the 24-h dark condition. Data are means ± SE. Different lowercase letters above bars indicate significant differences (Steel–Dwass test, P < 0.05). (d) Dose–response relationships for the effects of irradiation with LED light on fecundity. DD indicates the 24-h dark condition. Inset numbers (1.0, 5.0, and 10.0 × 1018) indicate light dose in photons·m−2·s−1. Data are mean values.
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f2: Effects of irradiation with 467-nm blue light on eggs, larvae, and adults of Drosophila melanogaster.(a) Dose–response relationships for lethal effects of irradiation with LED light on eggs. “0” photons represents the 24-h dark condition. Data are means ± standard error (SE). (b) Relationship between light dose and developmental stage at which mortality occurred. Developmental stages of larvae and pupae were classified according to Bainbridge and Bownes (1981)19. L1 and L2 are third-instar larvae, P1–P4 are prepupae, and P5–P15 are phanerocephalic pupae. No irradiated flies died during the P5–P9 developmental stages. Data are mean values. Mortality (mean ± SE) of flies that could not emerge is indicated by the black line. (c) Dose–response relationships for effects of irradiation with LED light on adult longevity. “0” photons represents the 24-h dark condition. Data are means ± SE. Different lowercase letters above bars indicate significant differences (Steel–Dwass test, P < 0.05). (d) Dose–response relationships for the effects of irradiation with LED light on fecundity. DD indicates the 24-h dark condition. Inset numbers (1.0, 5.0, and 10.0 × 1018) indicate light dose in photons·m−2·s−1. Data are mean values.

Mentions: Irradiation with a wavelength of 467 nm had the strongest lethal effect on Drosophila pupae, although this wavelength was also lethal to other developmental stages. The mortality rate of eggs increased with increasing numbers of photons (Fig. 2a); the majority of eggs died after 48-h irradiation at ≥5.0 × 1018 photons·m−2·s−1, whereas most eggs hatched under dark conditions. Irradiation with a wavelength of 467 nm for 24 h was lethal to final-instar larvae (L1–L2)19 and showed a dose–response relationship (Fig. 2b). Most flies died before adult emergence after irradiation at 7.0 × 1018 photons·m−2·s−1. Flies died during earlier developmental stages as the number of photons increased. Forty percent and 27% of flies died during the larval stage following irradiation at 12.0 × 1018 and 10.0 × 1018 photons·m−2·s−1, respectively. Using these same irradiation levels, more than 90% of flies died during the larval or prepupal stages (L1–P4). With irradiation at 7.0 × 1018 photons·m−2·s−1, the flies that died before adult emergence were almost evenly divided among the flies that died during the larval or prepupal stages (L1–P4) and those that died during the pupal stage (P5–P15). Interestingly, none of the irradiated flies died during the developmental stages of P5–P9. Adult longevity decreased significantly as the number of photons increased (Fig. 2c, Supplementary Table 2). In contrast, the longevity of adult flies maintained under dark conditions was approximately 60 d. Irradiation with a wavelength of 467 nm affected fly fecundity (Fig. 2d); the mean number of eggs deposited by surviving females decreased with increasing numbers of photons. These results show that irradiation with blue light has a lethal effect on the pupal stage of Drosophila, and also on other developmental stages of this insect—including the adult stage, which is typically considered tolerant of light irradiation.


Lethal effects of short-wavelength visible light on insects.

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

Effects of irradiation with 467-nm blue light on eggs, larvae, and adults of Drosophila melanogaster.(a) Dose–response relationships for lethal effects of irradiation with LED light on eggs. “0” photons represents the 24-h dark condition. Data are means ± standard error (SE). (b) Relationship between light dose and developmental stage at which mortality occurred. Developmental stages of larvae and pupae were classified according to Bainbridge and Bownes (1981)19. L1 and L2 are third-instar larvae, P1–P4 are prepupae, and P5–P15 are phanerocephalic pupae. No irradiated flies died during the P5–P9 developmental stages. Data are mean values. Mortality (mean ± SE) of flies that could not emerge is indicated by the black line. (c) Dose–response relationships for effects of irradiation with LED light on adult longevity. “0” photons represents the 24-h dark condition. Data are means ± SE. Different lowercase letters above bars indicate significant differences (Steel–Dwass test, P < 0.05). (d) Dose–response relationships for the effects of irradiation with LED light on fecundity. DD indicates the 24-h dark condition. Inset numbers (1.0, 5.0, and 10.0 × 1018) indicate light dose in photons·m−2·s−1. Data are mean values.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Effects of irradiation with 467-nm blue light on eggs, larvae, and adults of Drosophila melanogaster.(a) Dose–response relationships for lethal effects of irradiation with LED light on eggs. “0” photons represents the 24-h dark condition. Data are means ± standard error (SE). (b) Relationship between light dose and developmental stage at which mortality occurred. Developmental stages of larvae and pupae were classified according to Bainbridge and Bownes (1981)19. L1 and L2 are third-instar larvae, P1–P4 are prepupae, and P5–P15 are phanerocephalic pupae. No irradiated flies died during the P5–P9 developmental stages. Data are mean values. Mortality (mean ± SE) of flies that could not emerge is indicated by the black line. (c) Dose–response relationships for effects of irradiation with LED light on adult longevity. “0” photons represents the 24-h dark condition. Data are means ± SE. Different lowercase letters above bars indicate significant differences (Steel–Dwass test, P < 0.05). (d) Dose–response relationships for the effects of irradiation with LED light on fecundity. DD indicates the 24-h dark condition. Inset numbers (1.0, 5.0, and 10.0 × 1018) indicate light dose in photons·m−2·s−1. Data are mean values.
Mentions: Irradiation with a wavelength of 467 nm had the strongest lethal effect on Drosophila pupae, although this wavelength was also lethal to other developmental stages. The mortality rate of eggs increased with increasing numbers of photons (Fig. 2a); the majority of eggs died after 48-h irradiation at ≥5.0 × 1018 photons·m−2·s−1, whereas most eggs hatched under dark conditions. Irradiation with a wavelength of 467 nm for 24 h was lethal to final-instar larvae (L1–L2)19 and showed a dose–response relationship (Fig. 2b). Most flies died before adult emergence after irradiation at 7.0 × 1018 photons·m−2·s−1. Flies died during earlier developmental stages as the number of photons increased. Forty percent and 27% of flies died during the larval stage following irradiation at 12.0 × 1018 and 10.0 × 1018 photons·m−2·s−1, respectively. Using these same irradiation levels, more than 90% of flies died during the larval or prepupal stages (L1–P4). With irradiation at 7.0 × 1018 photons·m−2·s−1, the flies that died before adult emergence were almost evenly divided among the flies that died during the larval or prepupal stages (L1–P4) and those that died during the pupal stage (P5–P15). Interestingly, none of the irradiated flies died during the developmental stages of P5–P9. Adult longevity decreased significantly as the number of photons increased (Fig. 2c, Supplementary Table 2). In contrast, the longevity of adult flies maintained under dark conditions was approximately 60 d. Irradiation with a wavelength of 467 nm affected fly fecundity (Fig. 2d); the mean number of eggs deposited by surviving females decreased with increasing numbers of photons. These results show that irradiation with blue light has a lethal effect on the pupal stage of Drosophila, and also on other developmental stages of this insect—including the adult stage, which is typically considered tolerant of light irradiation.

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