Fig. 7
The variation in Exd expression pattern across Sky Islands corresponds to changes of fine details in thorax morphology of wingless queens. Panels on the left column (a, d, g, j, m) represent diagrams of Exd expression. Exd expression in winged queens b and wingless queens e, h, k, and n. Black arrowheads point to Exd expression in imaginal discs. Insets show a close-up of Exd expression in the vestigial imaginal discs. 3D X-ray microtomography thoracic morphology of a winged queen c and wingless queens from Pinals f, Catalinas i, Huachucas l, and Chiricahuas o Sky Islands. Insets show a close-up of the wing hinge region. Yellow brackets indicate vestigial forewing hinge and yellow arrowheads indicate outgrowths of the hindwing hinge. Note that the vestigial forewing hinge in f and o is prominent with two distinct outgrowths, while it is reduced in i, l with only one prominent outgrowth. The vestigial hindwing hinge is present in all populations