Drosophila melanogaster has been used as a model organism for understanding muscle development. Drosophila flight and jump muscles are distinct functionally and biochemically. This distinction is due to differentially expressed genes and differentially spliced mRNA transcripts. The exact mechanism of alternative splicing in somatic muscles is not well characterized. Aret was previously shown to be a transcriptional repressor, and has been implicated in splicing regulation based upon literature analysis and preliminary work. This study aims to define the regulatory role of Aret and the impact of alternative splicing on determining muscle diversification and fiber choice. We indicate the importance of Aret in determining flight muscle structure and function. Without this protein, the animal exhibits molecular and structural changes within the flight muscles. The CELF family proteins are mammalian orthologs of Aret and are involved in regulation of alternative splicing, which suggests the function is evolutionarily conserved between Drosophila and mammals. An incorrect dosage of CELF leads to cardiomyopathies and myotonic dystrophies reinforcing the functional relevance of this family of proteins and Aret