fxDf1 (II: 2,484,339 - 2,487,244) removes nspf-1, nspf-2, and nspf-3. Him. This strain carries a knockout of the Nematode-Specific Peptide family, group F (NSPF) gene family, which localizes to sperm membranous organelles. There are no effects on spermatogenesis, male fertility, or sperm competitive ability. Hermaphrodites produce approximately 30% males. Reference: Kasimatis KR, et al. (2018) BioRxiv 290221; doi: https://doi.org/10.1101/290221.