December 2012 Cover Image

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Cover photo: Rapidly evolving, sex-specific phenotypes of D. bipectinata (top) and D. malerkotliana (bottom). The sex combs (male-specific arrays of modified bristles on the front leg) are shown at the right, and male-specific abdominal pigmentation at the left. The enlarged, rotated sex comb of D. bipectinata was regained recently in the evolutionary history of this species following an earlier loss, violating the “Dollo's law of irreversibility.” Seher et al. (pp. 1465–1475) examine the genetic basis of this reversal. Image credit: Digitally inverted, brightfield images of dissected and mounted cuticles, by Artyom Kopp.