Pattern induction across a homeotic boundary in the wings of Precis coenia (Hbn.) (Lepidoptera: Nymphalidae)

Abstract

We report on a series of homeotic transformations in the buckeye butterfly, Precis coenia (Lepidoptera: Nymphalidae), in which portions of the ventral hind wing were transformed and acquired the pigmentation, color pattern, and scale structure of homologous areas of the ventral fore wing. All homeotic transformations were restricted to the posterior half of the ventral hind wing. When a transformed region included the source cells responsible for inducing the large eyespot on the fore wing, a nearly complete eyespot developed that was a composite of fore wing and hind wing tissues. The dimensions and pigmentation of these eyespots show that pattern induction and integration of the development of a complex pattern element occurred across the homeotic boundary. Interaction between homeotic and non-transformed areas was also evident in the region of the distal band of the central symmetry system. Segments of the band that occurred within transformed tissues became smoothly aligned with their counterparts in the adjoining non-transformed portion of the wing. Our results show that eyespot-organizing centers from the fore wing can induce normal eyespots in hind wing tissue, and vice versa, suggesting that both fore wing and hind wing eyespots are induced by identical processes.