The batworms replaced the gliding slugworms when the gliding slugworms had a dilemma. The stickyglobes were all being replaced with non-floating plants, and the gliding slugworm's source of flight was disappearing. As a result, the muscles that controlled the wings got steadily more powerful, and eventually, true flight was achieved at last. This allowed them to broaden their territories, and after all the time of the twelve-winged worm dominating the skies, the batworm has finally gotten a foothold; it will even actively hunt the smaller, slower, and less powerful twelve-winged worm.
They tend to fly about in small groups of 50 or so individuals. They stay in this group as protection versus predators (safety in numbers), but feel no kinship to one another. If one dies, it does not bother them. Oddly enough, these are all brothers and sisters. When a batworm lays its eggs, it lays them in an egg sack. These eggs all hatch at almost the same time, and after they hatch, they look almost exactly like their distant ancestor, the slugworm. Their wings will fully mature and grow enough for flight about a week after being hatched. About a month after their being born, they gain the ability to mate. They will immediately do so, and then group back together once more. About every four months, they will scatter and mate again, then group together again with their siblings. As long as they live, they will stay together as a group.
This worm's sense of smell has improved greatly, so that they may find a meal, and so that they can find danger if it is near (due to flying, and their eyes pointing up, they cannot usually see oncoming danger). These creatures are extremely successful, due to their eating almost everything, and their developing a mild poison that coats the outside of their body, keeping away most predators. You can constantly see them swarming above carrion, or munching away at a tree.