Meeting Abstract
Butterfly wing color patterns result from an arrangement of monochromatic scales containing both chemical pigments and a delicate architecture that can cause interference or diffraction of light, generating iridescent colors. The latter mechanism, structural coloration, serves essential functions such as conspecific recognition, mate choice, and communication in many species. Despite the ecological importance of this trait, little is known about the molecular mechanisms underlying the development of structural-based color patterns. The Southern Dogface butterfly, Zerene cesonia, exhibits sexually dimorphic development of ultraviolet wing reflectance. Males posses a UV patch on the forewing that results from nanoscale structures on the wing scales, which are absent in females. This dimorphism offers an excellent opportunity to explore the genetic mechanisms involved in pattern formation and cyto-structural variation. We used RNA-seq data from imaginal wing discs through late larval and pupal development to identify genes involved in the regulation of color pattering and scale structure formation. We identified clusters of co-expressed genes that correspond to the pre-pattering and structural scale differentiation stages. In the latter, we found differential expression of the doublesex gene (dsx); however, we did not find the typical splicing patterns of dsx found in other insects. We are working on the structural and functional characterization of a novel female dsx transcript, and exploring the pathways involved in pre-patterning of the male UV patch. Our results offer some of the first insights into genetic mechanisms that regulate scale structural coloration.
