Morphogenesis and cellular proliferation pattern in the developing antennal lobe of Drosophila melanogaster

The adult antennal lobe of Drosophila melanogaster emerges from a precursor, the larval antennal lobe. Pulse and pulse-chase labelling of dividing cells in larvae and pupae with bromodeoxyuridine confirmed previous data that some of the interneurons of the adult antennal lobe derive from a lateral neuroblast which starts to divide early in the first larval instar. However, the majority of these interneurons originate from neuroblasts that initiate mitosis at later stages, with a peak of about 10–12 pairs of dividing neuroblasts in the late third larval instar. No clustering of adult antennal lobe neurons according to their birthdates was observed. In contrast to neurons, terminal divisions of glia in the antennal lobe reach their maximum only 12 h after puparium formation.