Apis mellifera is an excellent model for studying flight muscle contractile proteins due to its stereotypical behavior. Bees start adult life as flightless insects. After about three days they become flight capable. Utilizing Western blots we performed a screen in the flight muscles to determine the changes in the flight muscle contractile proteins during flight development. We found a protein isoform that is only present in bees that are able to fly. We also kept the bees at two different temperatures to understand if this protein is only regulated by chronological age. The result suggests that this isoform is not only developmentally regulated but it is also temperature dependent. This isoform is absent in leg muscles and only detected in the flight muscles by the Z-175 antibody. We also will present the profile of other muscle contractile proteins during flight development.