Homozygous flies are morphologically normal but are uncoordinated.

Homozygous males have spermatocytes which are devoid of asters, have aberrant spermatids and have non-motile sperm tails.

More than 90% of centrosomes are not associated with astral microtubules in spd-2^z3-5711/Df(3L)st-j7 larval brain neuroblasts. In the few cases where microtubules nucleation is seen, the astral microtubules are extremely short. Mutant metaphase cells have a variable number of centrosomes, varying from 0 to 4. Mutant telophases show regular central spindles and contractile rings. Most of the mutant neuroblasts show asymmetric cytokinesis, as occurs in wild type.

The mitotic index is increased compared to controls in spd-2^z3-5711/Df(3L)st-j7 larval brains. The frequency of anaphases and telophases (relative to all mitotic figures) is 23% in the mutant brains, compared to 37% in wild type. The frequency of hyperploid metaphases is 1.9% in the mutant brains (compared to 1% in wild type), while the frequency of polyploid metaphases is 2.7% in the mutant brains (compared to 0.2% in wild type).

spd-2^z3-5711/Df(3L)st-j7 larval brain neuroblasts either lack or have drastically reduced asters.

Centrosomes are often mislocalised in spd-2^z3-5711/Df(3L)st-j7 primary spermatocytes and do not mediate aster formation (95% of mutant prometaphases are devoid of asters, while the remaining 5% have extremely reduced asters). The time between nuclear-envelope breakdown and anaphase onset is longer in the mutant spermatocytes compared to wild type. Mutant telophases have regular central spindles and contractile rings, but are severely defective in chromosome segregation. The number of centrosomes in late-prophase mutant spermatocytes ranges from 0 to 8. 11% of centrioles in mutant spermatocyte cysts are unpaired and appear as single barrels rather than V-shaped structures.