Some daddy longlegs fight during mating and others cooperate. In conflict-based mating interactions, males overcome females with force, and copulation takes 2 hours! In cooperative mating, copulation occurs within seconds, and males provide females nourishing "nuptial gifts." I currently lack a high-resolution video camera to capture fine behavioral details of these interactions that will allow me to understand why such extreme variation in mating behavior exists. This project will answer why conflict evolves from cooperation.