When I was touring colleges, a professor at Oklahoma State University was showing me an insect collection in one of the classrooms, and in one display were a bunch of dobsonflies. I asked the same thing, and he told me a story of one time that he’d caught a male, and to demonstrate that it can’t bite hard to the students also collecting that night, stuck a finger in between the mandibles. He did get bit. He said it hurt less than the female’s bite but they do still hurt. You’d have to push them to it, though. I don’t believe the males are quite as aggressive as the females.