See and be seen: Understanding trade-offs in bioluminescent signalling and how it is affected by artificial lighting at night

几乎所有的动物都对光环境很敏感。它们利用光来实现各种功能，包括激发它们的生物节律和视觉。因此，环境中光照水平的任何变化都可能对动物产生巨大的后果，改变活动周期并影响视力。即使动物能够迅速适应环境的如此深刻的变化，它们仍然可能招致严重的成本，因为它们不能完全补偿。例如，在以前黑暗的环境中出现明亮的光线可能会扰乱动物的活动和睡眠模式。人类通过在夜间引入人工照明，极大地改变了环境中的光照制度(艾伦)，这种照明现在存在于地球上的大片地区。最流行的艾伦形式是道路照明，随着道路网络的扩大而激增。地球夜间的卫星图像证明了地球大部分地区道路照明的程度。事实上，最新的LED路灯意味着Alan比以往任何时候都更便宜、更节能，推动了广泛的采用。这些LED灯比以往任何时候都更亮、更白，与他们取代的橙色钠灯有很大不同。然而，艾伦的存在会扰乱夜间活动的动物，可能会把它们转移到更黑暗的避难所。此外，白天活动的动物可能会将它们的活动延长到晚上，这给夜间活动的物种带来了额外的压力。虽然艾伦影响动物的活动模式是显而易见的，但人们对它们的行为和生理改变的机制以及对种群的更大规模的影响知之甚少。我们的目的是了解艾伦如何在行为、生理和种群水平上影响动物。我们将用萤火虫作为指示物种，俗称“矿井中的金丝雀”。我们对指示物种的选择是由它们独特的交配行为决定的，在这种交配行为中，不会飞的雌性发光虫在它们的腹部产生生物发光，吸引雄性，雄性飞向它们交配。我们的策略将是利用这种交配行为来量化艾伦对萤火虫的影响。我们的数据表明，这些影响很可能是严重的，因为雌性发光消耗了大量的能量，而这些能量由于成年后不进食而无法补充。我们的初步数据还显示，在人工照明的情况下，被雌性吸引的雄性要少得多，因此在艾伦的照射下发光的雌性会使用宝贵的能量，而不会带来什么好处。此外，道路上的照明可能会起到屏障的作用，阻止雄性在整个环境中分散寻找雌性，影响萤火虫种群的结构，最终影响萤火虫种群的生存。我们将使用实验室和野外实验相结合的方法，直接测试艾伦对萤火虫繁殖的影响的假说。我们将把这一点与评估萤火虫种群的遗传结构结合起来，以确定它们已经变得多么分散。然后，我们将使用统计和建模技术来绘制种群的分布、它们之间的基因流动以及艾伦在当地和更广泛的尺度上的存在。通过这样做，我们将确定艾伦对萤火虫生物学的影响的机制原因，并可能对其他夜间动物产生广泛的影响。我们还将明确测试这一假设，即艾伦已经并将继续对发光蠕虫种群产生严重影响，潜在地孤立它们并将它们赶到灭绝。通过在整个过程中与政策制定者和自然保护从业者保持密切联系(参见影响的途径)，我们的项目有可能为有关艾伦的政策以及其对野生动物的影响可以减轻的程度提供信息。

Almost all animals are sensitive to their light environment. They use light for diverse functions including entraining their biological rhythms and vision. Consequently, any alteration to light levels within the environment has potentially enormous consequences for animals, shifting activity cycles and affecting vision. Even if animals can adapt rapidly to such profound changes to their environment, they may still incur severe costs because they cannot fully compensate. For instance, the presence of bright light in formerly dark environments may disrupt the activity and sleep patterns of animals. Humans have dramatically altered the light regimes in the environment through the introduction of artificial lighting at night (ALAN), which is now present across vast areas of the planet. The most prevalent form of ALAN is road lighting, which proliferates as road networks expand. Satellite images of the Earth at night attest to the extent of road lighting across much of the planet. Indeed, the newest LED street lighting means that ALAN is cheaper and more energy efficient than ever before, promoting widespread adoption. These LED lights are brighter and whiter than ever before, quite different from the orange sodium lamps they replace. Yet the presence of ALAN disturbs nocturnal animals, potentially displacing them to darker 'refuge' habitats. Moreover, day-active animals may extend their activity into the night, creating additional pressures on nocturnal species. Although it is clear that ALAN affects the activity patterns of animals, there is little understanding of the mechanisms by which their behaviour and physiology is altered, or of larger scale effects upon populations.Our aim is to understand how ALAN affects animals at the behavioural, physiological, and population levels. We will use glow worms as an indicator species, a proverbial 'canary in the mine'. Our choice of indicator species is determined by their unique mating behaviour in which flightless female glow worms generate a bioluminescent glow in their abdomen that attracts males, which fly to them to mate. Our strategy will be to exploit this mating behaviour to quantify the effects of ALAN upon glow worms. Our data indicate that these effects are likely to be severe because female glowing consumes substantial amounts of energy that cannot be replenished because they do not feed as adults. Our preliminary data also show that far fewer males are attracted to females when they are illuminated by artificial lighting, so females glowing under ALAN use valuable energy for little benefit. Moreover, lighting along roads may act as a barrier by preventing males from dispersing through the environment to find females, affecting the structure and ultimately the survival of glow worm populations.We will use a combination of laboratory and field experiments to directly test hypotheses about the effects of ALAN upon glow worm reproduction. We will couple this with assessing the genetic structure of glow worm populations to determine how fragmented they have become already. We will then use statistical and modelling techniques to map the distribution of populations, the gene flow among them, and the presence of ALAN at both the local and broader scales. By doing so, we will identify the mechanistic cause of the effect of ALAN upon glow worm biology, with potentially broad implications for other nocturnal animals. We will also explicitly test the hypothesis that ALAN has had, and continues to have, a severe impact upon glow worm populations, potentially isolating them and driving them to extinction. By maintaining close links with policy makers and nature conservation practitioners throughout (see Pathways to Impact), our project has the potential to inform policy around ALAN and the extent to which its effects on wildlife can be mitigated.