This is a clear example of the defoliation that caterpillars perform on passion vines. They are relentless. The cycle of butterfly egg laying, caterpillar leaf eating, butterfly hatching is vicious. The scream of the passion vine at night is chilling. All for what? Well, so, photographers can run around snapping shots, of course! In this area, the attack begins in late April or early May and extends into November. Ear protection helps with the piercing screams.