Mutant spermatocytes show an extreme reduction of the kl-3 Y-loop and also show a slight reduction of the kl-5 and kl-1 Y-loops compared to wild type. They show a failure of meiosis, leading to transformation of meiocytes into diploid pseudo-spermatids that initiate but fail to complete differentiation, resulting in cells which have prominent sperm tails which eventually degenerate.
lup-4HA10/lup-4HA30 males have defects in the kl-3 Y-loop and have immotile sperm.