Drosophila

Multicellular organisms depend on several hormones to regulate their growth and development. Drosophila melanogaster is a small, common house fly most people recognize as the insects that appear out of “thin air” to feast upon rotting fruit or the trash in one’s kitchen. Drosophila melanogaster exhibits complete metamorphism, where the life cycle includes an egg, larval (worm-like) form, pupa and finally emergence as a flying adult. Fruit flies can lay hundreds of eggs during their lifetime. After about a day, a larva emerges from the egg. As it grows, the maggot goes through three instars, which it develops until the pupa is formed. Inside the pupa, larval structures and tissues break down and are reabsorbed, and adult tissues start to develop until the adult fly breaks out of the anterior end of the pupa. Soon the body of the fly becomes more rounded and dark and the wings expand. After ten more hours, the flies are sexually mature and ready to produce another generation.