What is the leading explanation for moths circling a nearby lamp?

Answer: They tilt their backs toward the light as if it marked the sky above them

They turn their eyes toward the brightest point and fly straight at it — Simply steering straight toward the brightest point does not explain the observed circling. Three-dimensional flight tracking found insects tilting their backs toward the nearby light instead. That changes their posture and can keep turning their flight path.

They tilt their backs toward the light as if it marked the sky above them ✓ — Tilting the back toward light is the leading explanation for the circling observed near lamps. A bright sky normally helps an insect keep its back upward; a nearby lamp pulls that orientation cue sideways and makes it bank. This explains the tracked flight patterns, though insect responses to light are not all settled.

They turn toward warmth sensed by their antennae to keep their wings working — Turning toward heat is not the reflex that best explains these flight patterns. The light-orientation model produces circling, stalls and inversion by changing where an insect thinks up is. It does not need a warmth-seeking mechanism.