Mutants show male sterility, with highly elongated, immobile, blebbed sperm tails, disrupted individualisation complexes and scattered spermatid nuclei. Observations suggest a primary defect in the assembly of the individualisation complex which may secondarily prevent its translocation along the spermatogenic cyst. Earlier stages of spermatogenesis also show defects, for example in nebenkern formation (multiple small nebenkerns are present onion-stage spermatids).