The buzz on fly neuronal remodeling.

Hormone-dependent rewiring of axons and dendrites is a conserved feature of nervous system development and plasticity. During metamorphosis in insects, steroid hormones (the ecdysteroids) and terpenoid hormones (the juvenile hormones) regulate extensive remodeling of the nervous system. These changes retool the nervous system for new behavioral and physiological functions that are required for the adult stage of the life cycle. In honey bees and other highly social insects, hormones also regulate behavioral changes and neuronal plasticity associated with transitions between social caste roles. This review focuses on recent work in fruit flies and honey bees that reveals hormonal and molecular mechanisms underlying metamorphic and caste-dependent neuronal remodeling, with specific emphasis on the role of Krüppel homolog 1.