Pif1A¹ and Pif1A¹/Df(3R)BSC478 males are sterile. However, wild-type females mated to Pif1A¹ or Pif1A¹/Df(3R)BSC478 males, as well as Pif1A¹ or Pif1A¹/Df(3R)BSC478 females mated to wild-type males, lay similar numbers of eggs as wild-type females mated to wild-type males.

Pif1A¹ males exhibit a small seminal vesicles that is empty of mature sperm, despite an apparently normal morphology of the reproductive system (including accessory gland and ejaculatory duct). Their testes show a grossly normal morphology, namely apparently normal patterns of early germ cells (nos-Gal4>UAS-CD8GFP positive cells), spermatogonia (bam-Gal4>UAS-CD8GFP positive cells) and somatic cyst stem cells (tj-Gal4>UAS-CD8GFP positive cells), apparently normal fusomes (1B1 positive cells), grossly normal 16-cell stage primary spermatocyte cyst and 64-cell onion stage spermatid cyst morphologies, apparently normal nucleus shape transition during individualization, and apparently normal elongated sperm tails. However, cystic bulges and waste bags are absent, and there are individual defects: individualization complexes are reduced in number, fail to progress and show defective actin cones (not synchronized, only a few of them move a short distance away from the nuclei and some show reversed orientation) and in 64-cell cysts there are few individualized regions, most axoneme/mitochondrial pairs are not separated by plasma membrane, cytoplasm/membranous organelles are still present and the nebenkern is small.