Organismal and Evolutionary Biology, University of Helsinki, PO Box 65, 00014 Helsinki, Finland.
Tvärminne Zoological Station, University of Helsinki, J.A. Palméns väg 260, 10900 Hanko, Finland.
Proc Biol Sci. 2020 Jul 29;287(1931):20200806. doi: 10.1098/rspb.2020.0806. Epub 2020 Jul 15.
The amount of artificial light at night is growing worldwide, impacting the behaviour of nocturnal organisms. Yet, we know little about the consequences of these behavioural responses for individual fitness and population viability. We investigated if females of the common glow-worm -which glow in the night to attract males-mitigate negative effects of artificial light on mate attraction by adjusting the timing and location of glowing to spatial variation in light conditions. We found females do not move away from light when exposed to a gradient of artificial light, but delay or even refrain from glowing. Further, we demonstrate that this response is maladaptive, as our field study showed that staying still when exposed to artificial light from a simulated streetlight decreases mate attraction success, while moving only a short distance from the light source can markedly improve mate attraction. These results indicate that glow-worms are unable to respond to spatial variation in artificial light, which may be a factor in their global decline. Consequently, our results support the hypothesis that animals often lack adaptive behavioural responses to anthropogenic environmental changes and underlines the importance of considering behavioural responses when investigating the effects of human activities on wildlife.
夜间人工光照的数量在全球范围内不断增加，这对夜间生物的行为产生了影响。然而，我们对这些行为反应对个体适应性和种群生存能力的影响知之甚少。我们研究了普通发光虫（一种在夜间发光以吸引雄性的昆虫）的雌性个体是否通过调整发光的时间和地点来适应光照条件的空间变化，从而减轻人工光对求偶的负面影响。我们发现，当暴露在人工光的梯度下时，雌性并不会远离光源，而是会延迟甚至放弃发光。此外，我们还证明了这种反应是适应不良的，因为我们的野外研究表明，当暴露在模拟街灯的人工光下时，静止不动会降低求偶成功率，而仅仅从光源处移动很短的距离就可以显著提高求偶吸引力。这些结果表明，发光虫无法对人工光的空间变化做出反应，这可能是它们全球数量减少的一个因素。因此，我们的结果支持了这样一种假设，即动物通常缺乏对人为环境变化的适应性行为反应，这强调了在研究人类活动对野生动物的影响时，考虑行为反应的重要性。
