Data from: The evolution of adult light emission color in North American fireflies

Firefly species (Lampyridae) vary in the color of their adult bioluminescence. It has been hypothesized that color is selected to enhance detection by conspecifics. One mechanism to improve visibility of the signal is to increase contrast against ambient light. High contrast implies that fireflies active early in the evening will emit yellower luminescence to contrast against ambient light reflected from green vegetation, especially in habitats with high vegetation cover. Another mechanism to improve visibility is to use reflection off the background to enhance the light signal. Reflectance predicts that sedentary females will produce greener light to maximize reflection off the green vegetation on which they signal. To test these predictions, we recorded over 7500 light emission spectra and determined peak emission wavelength for 675 males, representing 24 species, at 57 field sites across the Eastern United States. We found support for both hypotheses: males active early in more vegetated habitats produced yellower flashes in comparison to later-active males with greener flashes. Further, in 2 of the 8 species with female data, female light emissions were significantly greener as compared to males.萤科（Lampyridae）各萤火虫物种的成虫生物发光颜色存在差异。已有假说提出，其发光颜色经自然选择演化，以提升同种个体对信号的探测效率。提升信号可视性的机制之一，是增强信号与环境光之间的对比度：高对比度意味着，在傍晚活动较早的萤火虫，其发出的光会更偏黄，以便与绿色植被反射的环境光形成对比，在植被覆盖度较高的生境中这一效应尤为显著。另一种提升信号可视性的机制，则是利用背景反射来增强光信号。基于反射效应的假说预测：静息的雌虫会发出更偏绿的光，以最大化其求偶所处绿色植被的反射效率。为验证上述两项假说，研究团队在美国东部57个野外调查点，记录了超过7500条发光光谱，并测定了代表24个物种的675只雄虫的发光峰值波长。研究结果为两项假说均提供了支持：相较于活动时间较晚、发出偏绿光脉冲的雄虫，在植被更茂密的生境中活动较早的雄虫，其发光脉冲更偏黄。此外，在获取了雌虫数据的8个物种中，有2个物种的雌虫发光显著比雄虫更偏绿。