Fig. 1

Schematic of ovarian development in Drosophila from the embryo to the larval–pupal (LP) transition stage. The embryonic gonad consists of primordial germ cells (PGCs: blue) and somatic gonadal precursors (SGPs: red). The L2 larval ovary is composed of germ cells (GCs: blue) surrounded by intermingled cells (ICs: red). By the mid-third instar larval (ML3), terminal filament cells (TFCs: yellow) first appear and somatic swarm cells (SwCs: purple) are located dorsolaterally. During the LP transition, SwCs form a new posterior domain and the ICs adjacent to basal TFCs differentiate into cap cells (CCs: green); the TFCs are organized into 16–20 TF stacks