They eat and reproduce, eat and reproduce, until bang, they hit the edge of the petri dish, at which point they either drown in their own waste, starve from lack of resources, or both.
Mangiano e si riproducono, mangiano e si riproducono, finché, boom, non toccano il bordo della piastra e allora o annegano nei loro escrementi, o muoiono per mancanza di risorse.