Drosophila spermatids are shown during an advanced stage of the morphogenetic process of "individualization." The apoptosis-like process of spermatid individualization—which separates the connections between developing spermatids-removes unneeded organelles and excess cytoplasm, thereby promoting major changes of the cytoarchitecture. This process requires cell death proteins, including apoptotic effector caspases (activated effector caspase is visualized by green staining). The tails of the individualizing spermatids are labeled with an antibody for polyglycylated axonemal tubulin (blue staining). The expelled cytoplasm and organelles are collected into a membrane-enclosed structure known as the "cystic bulge" or "waste bag" (marked by the red filament staining of the individualization complex). See Arama et al., e251.

Image Credit: This image was taken with a Zeiss confocal microscope by Eli Arama