The
ability to maintain metabolic
homeostasis is a key capability critical for the
survival and well-being of
animals living in constantly changing
environments. Metabolic
homeostasis depends on
neuromodulators, such as
biogenic amines,
neuropeptides, and
hormones, to signal changes in
animals' internal metabolic status and to orchestrate their
behaviors accordingly. An important example is the
regulation of
feeding behavior by conserved molecular and cellular mechanisms across the
animal kingdom. Its relatively simple
brain coupled with well-characterized
genetics and behavioral paradigms makes the
fruit fly Drosophila melanogaster an excellent model for investigating the neuromodulatory
regulation of
feeding behavior. In this
review we discuss the
neuromodulators and neural circuits that integrate the internal physiological status with external sensory
cues and modulate
feeding behavior in
adult fruit flies. Studies show that various specific aspects of
feeding behavior are subjected to unique neuromodulatory
regulation, which
permits fruit flies to maintain metabolic
homeostasis effectively.