Kivelä Linnea, Elgert Christina, Lehtonen Topi K, Candolin Ulrika
Organismal and Evolutionary Biology, University of Helsinki, PO Box 65, 00014, Helsinki, Finland.
Tvärminne Zoological Station, University of Helsinki, J.A. Palménin Tie 260, 10900, Hanko, Finland.
Oecologia. 2025 Jul 12;207(8):133. doi: 10.1007/s00442-025-05768-3.
Light pollution is a widespread threat to dark-adapted species. Attraction to artificial light can have severe, even fatal, consequences with population level repercussions, especially for nocturnal insects. Since most insects are particularly drawn to short-wavelength light, the recent switch to LEDs with a greater emission in the blue range has exacerbated the problem. One potential mitigation measure is to adjust light spectra toward longer wavelengths. However, the effectiveness of this measure may vary among species that differ in their spectral sensitivities. In glow-worms (Lampyris noctiluca), nocturnal beetles with presumably declining abundance, especially blue and white artificial light hamper males' search of yellowish-green glowing females. Here, we assessed whether easing the search by switching to longer wavelengths impacts males' phototactic behavior. We recorded the movements of males in an arena illuminated at one end by either white, yellow, red, or no artificial light. Males displayed positive phototaxis toward yellow and red light, and negative phototaxis toward white light, with the latter also being associated with reduced activity. Therefore, males' attraction to longer wavelengths that resemble the female glow could be an evolutionary trap in human-modified environments with artificial lights of that color range. These results show that different wavelengths can influence disparate behaviors even within a single species and adjustment of outdoor lighting systems, by filtering out the blue part of the spectrum, has limited capacity to solve the light pollution problem.
光污染是对适应黑暗环境的物种的一种广泛威胁。对人造光的吸引可能会产生严重甚至致命的后果，并对种群水平产生影响，尤其是对夜间活动的昆虫。由于大多数昆虫特别容易被短波长光吸引，最近向蓝光范围内发射更强的发光二极管（LED）的转变加剧了这一问题。一种潜在的缓解措施是将光谱调整为更长的波长。然而，这一措施的有效性可能因物种的光谱敏感度不同而有所差异。在萤火虫（欧洲萤火虫）中，这种夜间甲虫的数量可能在下降，尤其是蓝色和白色的人造光会妨碍雄性寻找发出黄绿色光的雌性。在这里，我们评估了通过切换到更长波长来简化寻找过程是否会影响雄性的趋光行为。我们记录了雄性在一个一端被白色、黄色、红色或无人工光照亮的场地中的运动。雄性对黄色和红色光表现出正向趋光性，对白色光表现出负向趋光性，后者还与活动减少有关。因此，在具有该颜色范围人造光的人类改造环境中，雄性对类似雌性发光的更长波长的吸引力可能是一种进化陷阱。这些结果表明，即使在单一物种内，不同波长也会影响不同的行为，并且通过滤除光谱中的蓝色部分来调整户外照明系统，解决光污染问题的能力有限。
