Once a Machina has completed development by reaching Category 3, she enters into a growth cycle where she must adapt to new sources of stress until she can withstand the application of a new Larva to her body. Once a Larva is applied, she must again build up strength through adaptation until she can apply another one to her body. When Larvae are applied to a Machina, they can empower an existing organ, such as the penis for more forceful ejaculations or the womb to speed up Larvae production, they can form redundant organs and help the Machina improve their output or withstand damage, they can form the basis of new organs such as testicles and tentacles, or they can form the core of a new piece of equipment as outlined above. Breeder-class Machina often decide when a Machina is ready for another Larva and assist with bonding it to the Machina's body.