  Aging affects almost all aspects of an organism -- its morphology, its
physiology, its behavior. Isolating which biological mechanisms are regulating
these changes, however, has proven difficult, potentially due to our inability
to characterize the full repertoire of an animal's behavior across the
lifespan. Using data from fruit flies (D. melanogaster) we measure the full
repertoire of behaviors as a function of age. We observe a sexually dimorphic
pattern of changes in the behavioral repertoire during aging. Although the
stereotypy of the behaviors and the complexity of the repertoire overall
remains relatively unchanged, we find evidence that the observed alterations in
behavior can be explained by changing the fly's overall energy budget,
suggesting potential connections between metabolism, aging, and behavior.
