I've been wanting to get this correction out so might as well do it here. It's lovebug - all one word. A lovebug isn't a bug. It's a fly. Only true bugs have the "bug" as a separate word. There. Now I feel better.
Two major lovebug flights occur each year, first in late spring, then again in late summer. The spring flight occurs during late April and May, the summer during late August and September. Flights extend over periods of four to five weeks.
And yes, lovebugs do have a purpose. The larvae feed on the dead vegetation within the thatch of a grassy area. That releases the nutrients and also thins the thatch so grass pests don't have cover.
Feel bad for the guys. After mating, the male dies and is dragged around by the female and she herself only lives 3 or 4 days.