Complex sentence: During their premating behavior, the males scent-mark prominent objects on their flight paths with a species-specific sex pheromone and patrol these paths in order to mate with females that come by the attraction to the pheromone.
Split into simpler sentences: During their premating behavior, the males scent-mark prominent objects on their flight paths with a species-specific sex pheromone. Then, they fly along these paths, showing patrolling behavior, in order to mate with females that come by the attraction to the pheromone.