Cuticle refraction microscopy: a rapid and simple method for imaging Drosophila wing topography, an alternative readout of wing planar cell polarity.

The polarity of hairs on the adult Drosophila wing provides information about the planar cell polarity (PCP) signaling events that occur during pupal wing development. We have recently shown that PCP signaling also determines the orientation of cuticle ridges that traverse the surface of the adult wing membrane; a feature we call the wing membrane topography. Although hair polarity is uniform across the wild-type wing, ridge orientation differs between the anterior and posterior wing. Consequently, mapping wing topography can provide additional information about PCP signaling, rather than simply confirming observations of wing hair polarity. Wing membrane ridges can be imaged using scanning electron microscopy, however, significant preparation time and operator expertise are required. Here, we describe cuticle refraction microscopy, a rapid and simple light microscopy method for imaging Drosophila wing topography.