Research Associate Marine Biological Laboratory Woods Hole, Massachusetts
The origin of insect wings has long been debated. Central to this debate is whether wings are a novel structure on the body wall resulting from gene co-option, or evolved from an exite (outgrowth, e.g., a gill) on the leg of an ancestral crustacean. Here we report the phenotypes for the embryonic knockout of five leg patterning genes in the crustacean, Parhyale hawaiensis, and compare these to their previously published phenotypes in Drosophila and other insects. This leads to an alignment of insect and crustacean legs that suggests that two leg segments that were present in the common ancestor of insects and crustaceans were incorporated into the insect body wall, moving the proximal exite of the leg dorsally, up onto the back to later form insect wings. Our results suggest that insect wings are not novel structures, but instead evolved from existing, ancestral structures.
