SEOUL — Swarms of “lovebugs” are back in South Korea, blanketing a mountain peak, entering houses and sticking to car windows. Flying attached to one another while mating, the insects, known to scientists as Plecia nearctica, are also called united bugs, double-headed bugs or honeymoon flies.

A hiker who filmed the infestation told local media the bugs at Gyeyangsan mountain were like a "thick carpet".