Cilium-specific protein with a role in cilium/flagellum formation (PubMed:21750193, PubMed:27646273). May be involved in transport of components into the growing cilium (PubMed:21750193). In germ cells and sensory neurons, plays a role with Cby in the building of the transition zone necessary for the formation of the ciliary cap and for the correct elongation of the axoneme (PubMed:27646273). Co-localizes with the pericentriolar material (PCM) protein cp190 at centrosomes in undifferentiated sensory neurons (PubMed:21750193, PubMed:27646273). Localizes to the ciliary base, including the basal body and transition zone in sensory neurons and germ cells (PubMed:21750193, PubMed:27646273). Expressed in chordotonal (Ch) neuronal precursors. Expressed in ciliated cells, like sensory neurons and spermatids. Expressed in developing and differentiating ciliated sensory neurons of both the chordotonal (Ch) mechanosensory neurons and external sensory (ES) cells. Displays reduced climbing ability and die very soon after eclosion (PubMed:21750193). Loss of protein expression leads to truncated sensory cilia formation and impaired intraflagellar transport processes (PubMed:21750193). Simultaneous knockout of Cby and dila results in lack of motor coordination and absence of cilia in chordotonal neurons where centrioles fail to build a transition zone and Cep290 and Mks1 are mis-localized. Males are sterile: aberrant microtubule extensions, lack of ciliary cap and mislocalization of Mks1 and B9d1 to the basal body result in failure of axoneme formation and lack of mature sperm; sperm cysts fail to elongate whereas the overall size of the testes is not reduced (PubMed:27646273). Belongs to the CEP131 family.