The plant and the insect co-evolved; that is, they developed an intimate connection with each other. This is called an obligate mutualism in which if one were to disappear, the other would follow the same path. Originally it was a relationship of exploitation, with the moth larvae feeding on the seeds of the yucca. But, eventually, the plant devised methods to take advantage of the situation and as a consequence, the moth also evolved to ensure food for its babies and preservation of its food plant.