Dynamics of changes in apical cell area during sex comb rotation in .

Epithelia are highly dynamic tissues displaying various types of tissue rearrangements (Weliky and Oster, 1990; Taylor and Adler, 2008; Harris and Tepass, 2010; Lee , 2013; Firmino , 2016; Rupprecht , 2017). Here, we describe the dynamics of changes in apical cell area (ACA) in an epithelial system displaying tissue rearrangement resulting in sex comb rotation on the forelegs of male . The sex comb is a row of leg bristles which rotates during morphogenesis (Atallah, 2008; Atallah , 2009; Malagon, 2013). We quantified the ACA in the region proximal to the developing sex comb by tracing apical cell boundaries using in pupal first leg imaginal discs. We found that cells display intricate irregular oscillations in size as the comb rotates. However, the net changes in ACA within most of the cells studied are subtle, only 0 to +/-15%. Our current working hypothesis suggests these irregular oscillations confer flexibility during tissue rearrangement and can be an important mechanism for tissue homeostasis.