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它们的光环境敏感。它们利用光来实现各种功能，包括引导它们的生物节律和视觉。因此，环境中光照水平的任何改变都可能对动物产生巨大的影响，改变活动周期并影响视力。即使动物能够迅速适应环境的这种深刻变化，它们仍然可能因为无法完全补偿而付出沉重的代价。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。人类通过引入夜间人工照明（ALAN），极大地改变了环境中的光环境，这种照明现在存在于地球的广大地区。ALAN最普遍的形式是道路照明，随着道路网络的扩展而激增。夜间地球的卫星图像证明了地球大部分地区的道路照明程度。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，促进了广泛的采用。这些LED灯比以往任何时候都更亮更白，与它们所取代的橙子钠灯大不相同。然而，ALAN的存在扰乱了夜间活动的动物，可能会将它们转移到更黑暗的“避难所”栖息地。此外，白天活动的动物可能会将它们的活动延长到夜间，给夜行动物带来额外的压力。尽管很明显ALAN会影响动物的活动模式，但人们对动物行为和生理改变的机制或对种群的更大规模影响知之甚少。我们的目标是了解ALAN如何影响动物行为、生理和种群水平。我们将使用萤火蠕虫作为指示物种，一个谚语中的“金丝雀在矿井”。我们对指示物种的选择是由它们独特的交配行为决定的，在这种行为中，不会飞的雌性萤火虫在腹部产生生物发光的光芒，吸引雄性萤火虫飞到它们身边交配。我们的策略是利用这种交配行为来量化ALAN对萤火蠕虫的影响。我们的数据表明，这些影响可能是严重的，因为女性发光消耗大量的能量，无法补充，因为他们不作为成年人喂养。我们的初步数据还表明，当被人工照明照亮时，很少有雄性被雌性吸引，所以在ALAN下发光的雌性使用宝贵的能量，但几乎没有好处。此外，照明沿着道路可能会作为一个障碍，阻止男性分散通过环境中找到女性，影响结构，并最终的萤火虫population.We的生存将使用实验室和现场实验相结合，直接测试的假设ALAN后萤火虫繁殖的影响。我们将结合评估萤火虫种群的遗传结构，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分布图，它们之间的基因流，以及ALAN在局部和更广泛尺度上的存在。通过这样做，我们将确定ALAN对萤火虫生物学影响的机械原因，对其他夜行动物具有潜在的广泛影响。我们还将明确测试假设，即ALAN已经并将继续对萤火虫种群产生严重影响，可能会使它们孤立并导致它们灭绝。通过与政策制定者和自然保护从业者保持密切联系（见影响途径），我们的项目有可能为ALAN的政策提供信息，并在多大程度上减轻其对野生动物的影响。

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.