Metrics details. The production of new neurons during adulthood and their subsequent integration into a mature central nervous system have been shown to occur in all vertebrate species examined to date. However, the situation in insects is less clear and, in particular, it has been reported that there is no proliferation in the Drosophila adult brain.
We report here, using clonal analysis and 5'-bromo-2'-deoxyuridine BrdU labelling, that cell proliferation does occur in the Drosophila adult brain. The majority of clones cluster on the ventrolateral side of the antennal lobes, as do the BrdU-positive cells. We have observed cell proliferation in the Drosophila adult brain.
The generation of new neurons from adult neural stem cells, and their subsequent integration into functional neural circuits in a mature central nervous system, is a widespread phenomenon across the animal kingdom. Adult neural stem cells were initially discovered by Joseph Altman as early as the s [ 1 β 3 ] for reviews, see [ 4 , 5 ] , and adult neurogenesis has since been shown to occur in all vertebrate species so far examined, including fishes [ 6 β 10 ], amphibians [ 11 , 12 ], reptiles [ 13 , 14 ], birds [ 15 ], marsupials [ 16 ], non-human primates [ 17 , 18 ], and humans [ 19 ].
While adult neural stem cells appear to be common in vertebrates, the situation in insects is much less clear.
The house cricket was the first insect in which adult neurogenesis was reported [ 20 ], followed by beetles [ 21 , 22 ], cockroaches [ 23 ] and moths [ 24 ]. However, adult neural stem cells were not found in the locust [ 21 ], the monarch butterfly [ 25 ], or the honey bee [ 26 ].
