Growth is required for cell competition in the imaginal discs ofDrosophila melanogaster.

Imaginal wing discs from late third-instar larvae were gammairradiated to induce clones of rapidly growingMinute - cells in a background of slowly growingMinute cells and culturedin vivo for periods up to 18 days. Clones in discs cultured for 16 to 18 days did not grow significantly larger than clones in uncultured controls, indicating that competition between populations of cells having potentially different mitotic rates does not occur in imaginal discs after their growth is completed.