Scientists learn how insects ‘remodel’ their bodies between life stages

How is it that an insect can remake itself so completely that it appears to be a different creature altogether, not just once, but several times in its lifetime? Working with fruit flies, a team led by Ian and Dianne Duncan of Washington University in St. Louis found that genes whose expression is induced by pulses of steroid hormone are key to these transformations. A similar mechanism may underlie  puberty — the human analog of metamorphosis.