Single-nucleus transcriptomics of wing sexual dimorphism and scale cell specialization in sulphur butterflies
Fig 5
Dsx and Bab control sexually dimorphic scale fates.
A. Working hypothesis for the effects of Dsx on sexually dimorphic wing traits, including cell non-autonomous patterning effects on marginal patterns, cell-autonomous requirements in the specification of spatulate vs. canonical margin scales, and female-specific repression of UV-iridescence in dorsal cover scales. B–D. Bab RNAi knockdowns on the dorsal forewing phenocopy mosaic KO effects [29]. Bab-expressing cells acquire a UVI state upon Bab perturbation, with the exception of the spatulate scales that are unaffected. This includes canonical melanic scales that acquire UV-iridescence while maintaining melanism (D, cyan arrowheads), resulting in a dark blue iridescent phenotype in the visible spectrum (panel D), as previously described in Bab mosaic KO experiments [29]. Ground scales are transformed to yellow UVI scales in each sex (e.g., in the medial region: C, white arrowheads), except in the female forewing marginal band where they convert from melanic to blue iridescent (combination of melanic and UVI features). Star: inset features yellow vein scales (UV-negative in WT and controls) that acquire a UVI fate upon Bab RNAi, indicating successful knockdown in this area. E, F. Summary of Dsx expression, Bab expression, and perturbation assays in dorsal wing surfaces. Scale bars: B = 5 mm; C, D = 100 μm.