tous^MB01614 homozygotes display a spectrum of morphological defects in the testes, including a reduction in size and irregular shape of one or both testes;

mature sperm fail to be loaded into the seminal vesicles in 14 days old adults. There fewer and more abnormal actin cones. Mitochondria are abnormally localized along the meiotic spindle; immediately after meiosis there is increased mitochondrial aggregation. Onion stage spermatids show nuclei that are enlarged and of heterogeneous size. Elongation stage spermatids show loss of mitochondrial integrity, and abnormal axonemal plasma membrane, bringing multiple axonemes and mitochondria into close proximity; axonemes frequently either fail to form or lose the ability to maintain a mitochondrial derivative, resulting in multiple axonemes sharing a mitochondrial derivative; both the mitochondrial derivatives are small; there are fewer accessory microtubules.

Compound action potentials can be evoked by sound in the antennal nerve of mutant flies, but the sound particle velocities required to elicit the response is increased compared to wild type. Nonlinear mechanical amplification is significantly reduced compared to wild type.