The Dead Ones were planned from the first conception of the monster work. In considering biological rules for anything, an understanding of the processes of death is primary. The project changed a great deal however after the invention of the Bugs. As ancestor worshipers, the bodies of the dead monsters needed to retain an interest that would transcend a body on the ground, partly due to the monsters inability to make the art and monuments that surround the deaths of modern human ancestor worshipers.
The bugs provided the perfect vehicle for this idea. The bugs are in the bodies of the monsters from the time of their birth. During their lifetime the monsters secrete a chemical that suppresses the growth of the bugs. The bugs activity still is enough to create the exoskeleton of the monsters, which grows throughout their lifetime. In fact the exoskeleton is a common cause of death in aging monsters, having grown to large to allow breathing and eating. At the time of death the suppression of the bugs ceases and the bugs leave their microscopic state and move into their developing stage, becoming more Queen like the longer the host monster has been dead.
In addition to the growth of the bugs, the growth of the exoskeleton accelerates to create a hatchery of sorts for the next generation of the bugs, creating the floral quality of the bodies of the Dead Ones