Artificial light at night may decrease predation risk for terrestrial insects

Artificial light at night (ALAN) is thought to be detrimental for terrestrial insect populations. Whilst there exists evidence for lower abundance under ALAN, underlying mechanisms remain unclear. One mechanism by which ALAN may contribute to insect declines may be through facilitating increased predation. We investigated this by experimentally manipulating insect-substitute abundance under differential levels of light. We used insect-containing birdfeed placed at varying distances from streetlights as a proxy for terrestrial insects, inspecting the rate of predation before and after dusk (when streetlights are respectively off and on). We found that there was a significantly greater effect of increasing distance on predation after dusk, suggesting that predation was actually reduced by greater levels of artificial light. This may occur because ALAN also increases the vulnerability of insectivores to their own predators. Implications for foraging behaviour and alternative explanations a...

夜间人工光（Artificial Light at Night, ALAN）被认为对陆地昆虫种群有害。尽管已有证据表明ALAN环境下昆虫丰度降低，但其潜在机制仍不明确。ALAN可能导致昆虫数量下降的机制之一，或许是通过促进捕食行为的增加。我们通过实验操纵不同光照水平下昆虫替代物的丰度来研究这一机制。我们将含有昆虫的鸟类饲料放置在距离路灯不同的位置，作为陆地昆虫的替代物，分别在黄昏前后（此时路灯分别处于关闭和开启状态）观察捕食率。我们发现，黄昏后距离增加对捕食率的影响显著更大，这表明更高水平的人工光实际上降低了捕食率。这可能是因为ALAN也会增加食虫动物对其自身捕食者的脆弱性。对觅食行为的启示及其他解释...