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The tendency of moths to circle streetlights has long been explained as disorientation caused by artificial light interfering with their navigation by the moon, since moths are thought to maintain a constant angle to a distant light source when flying straight. Under this theory, a nearby artificial light produces a spiralling path as the insect repeatedly corrects its angle. Recent high-speed camera studies, however, challenge this explanation, showing that moths often tilt their backs toward a light source regardless of flight direction, suggesting the behaviour may instead be a dorsal light response, an instinct to keep the brightest visible surface above them, which normally aligns with the sky. Under a nearby artificial light, this instinct malfunctions, tipping the insect off its intended course. Researchers now consider the two explanations complementary rather than mutually exclusive, since both mechanisms could plausibly operate under different conditions.