Males carrying l(1)dd4^S can develop to adults in favourable culture conditions. l(1)dd4^S males are infertile and are found to produce immotile sperm. Primary spermatocyte cysts from l(1)dd4^S testes often have fewer cells compared to wild-type. Some of the cells are larger than the others, whereas the morphology of both germline and somatic cells seems normal. l(1)dd4^S primary spermatocytes exhibit abnormalities in the morphology of the meiotic spindles. Measurement of the frequency of the different types of defective meiotic figure in a sample of 162 l(1)dd4^S cells indicates that approximately 38% are hemi-spindles, 7% sharp cones, and 33% biconical. 22% of this group have a morphology that suggests either apoptosis or necrosis. Cysts of early spermatids in l(1)dd4^S display fewer than 32 Nebenkerns with abnormal morphology and variable size. The abnormal meiotic divisions can result in onion stages with only 16 cells. Masses of microtubules are observed around presumably bivalent chromosomes at the onset of meiosis in l(1)dd4^S. Spindle-like structures then appear to develop, falling into three main categories on the basis of their morphology. One category includes conical structures with a radial and slightly concave microtubule array at the wider basal region, with bundles of microtubules converging to an apex. In l(1)dd4^S mutants, conical spindles usually display bundles of microtubules that extend distally from their apexes. In those instances, a constriction around the apex, together with a dark band interrupting the continuity of the microtubule 'tracks' suggests a rudimentary central spindle structure. The second category of abnormal spindle found in l(1)dd4^S primary spermatocytes during meiosis, appears as an umbrella cup-like structure with microtubules irradiating from the centre. These latter figures resemble astral arrays of microtubules or halves of normal spindles at early anaphase I in which the inter-polar microtubules are not yet visible. More rarely, 'biconical' spindles are seen. Chromatin has a scattered distribution during meiosis in l(1)dd4^S mutants. In l(1)dd4^S testes, γTub23C is not detected in any particular structure of the meiotic apparatus of dividing spermatocytes. In dividing l(1)dd4^S spermatocytes, cnn-containing bodies accumulate together in a cluster, or show an abnormal position relative to each other. These cnn-containing bodies are generally present in variable numbers (ranging from three to five) at the centre of the asters in both spindle types. In l(1)dd4^S mutant spermatocytes, bipolar spindles can form in meiosis I, but then subsequently collapse, either as a result of a failure of centrosome separation or through a collapse of a bipolar spindle shortly after centrosome separation. These spindle defects arise during or shortly after metaphase I.

l(1)dd4^S males normally die just after eclosion, but in dry cultures both males and females are viable though almost completely sterile. They show wings held up, absence of some bristles, and defects in abdominal segments. Mutant larval brains have a mitotic index approximately 6 times that of wild-type with about a quarter of these exhibiting a polyploid metaphase. In mutant mitotic cells spindles show abnormal centrosomes. Various centrosomal components show varied and abnormal organisation. The γ-tubulin localisation normally seen as the γ-tubulin ring complex is dispersed, cnn localisation remains in discrete bodies but often appears more broadly distributed than in wild-type. The normal juxtaposition of asp and γ-tubulin is no longer seen in mutant spindles and asp is now distributed in a punctate fashion. Cp190 is lost from the poles and accumulates around chromosomes.

Ordinarily dies just prior to eclosion, but in dry cultures, both males and females eclose and have good viability, but are almost completely sterile. Wings are held up, some bristles on the head and thorax (especially the scutellars) are absent. The abdomen has mutant effects similar to those of bb. Females heterozygous for l(1)dd4^S and a deficiency are almost completely lethal.