Gynandromorphs as indicators of modularity and evolvability in ants.

Gynandromorphs, individuals that display a mosaic of male and female tissues or cell populations, have been extensively documented in solitary and social insects for over 100 years. Yet the evolutionary significance of gynandromorphs has remained obscure. Here we describe our discovery of a gynandromorph in the hyperdiverse ant genus Pheidole whose pattern of bilateral head mosaicism occurs repeatedly across a wide range of ant species. Based on our findings, we propose that gynandromorphs and other mosaic forms may provide new insights into the modularity and evolvability of morphological traits.