Fig. 6

Wingless queen larvae develop wing muscle precursors, but lack flight muscles entirely. Panels on the left column (a, e, i, m, q) represent diagrams of Mef-2 expression. Mef-2 expression in larval myoblasts is shown as a localized stain in nuclei of myoblasts associated with the imaginal discs b, f, j, n, and r. Details on Mef-2 expression are given in Additional file 1: Figure S7. Inserts show forewing discs at higher magnification. Dashed lines on Mef2 expression patterns highlight the vestigial disc boundaries based on DAPI staining. Virtual sections (microCT) through the thorax (last two columns) showing the internal anatomy of a winged queen (top row) and wingless queens from all Sky Islands. c, g, k, o, and s show transverse sections and d, h, l, p, and t show sagittal sections. Longitudinal muscles are artificially colored in pink and dorso-ventral muscles in blue. Wingless queens from all Sky Islands show a complete absence of indirect flight muscles. These results show that, regardless of their origin, wingless queens do not develop the main flight muscles