TENS VERSUS FOUR: TWO GENERATIONS OF NEURAL PROGENITORS IN THE DEVELOPING MUSHROOM BODIES OF MUSCINA PROLAPSA HARRIS (DIPTERA, MUSCIDAE)

摘要

The neurogenesis of the mushroom body was studied in Muscina prolapsa throughout the larval and pupal development. The existence of two generations of neural progenitors was established in the mushroom bodies of insects for the first time. Each larval mushroom body has four neuroblasts, these dividing by the 1st type and generating a daughter neuroblast and a ganglion mother cell. The latter divides symmetrically and generates two cells differentiating into Kenyon cells. In the young pupae, 8-11 cells surrounding each mushroom body neuroblast and morphologically indistinguishable from ganglion mother cells grow in size and transform into secondary neuroblasts. These repeatedly divide asymmetrically into a daughter secondary neuroblast and a typical ganglion mother cell. Divisions of secondary neuroblasts continue from the 3rd to the 7th day after puparium formation. Within the 7th day, a massive dying of secondary neuroblasts occurs through apoptosis. The fate of four larval mushroom body neuroblasts remains obscure.