What crustaceans can tell us about the evolution of insect wings and other morphologically novel structures

Acquisition of novel structures often has a profound impact on the adaptation of organisms. The wing of insects is one such example, facilitating their massive success and enabling them to become the dominant clade on this planet. However, its evolutionary origin as well as the mechanisms underpinning its evolution remain elusive. Studies in crustaceans, a wingless sister group of insects, have played a pivotal role in the wing origin debate. Three recent investigations into the genes related to insect wings and legs in crustaceans provided intriguing insights into how and where insect wings evolved. Interestingly, each study proposes a distinct mechanism as a key process underlying insect wing evolution. Here, I discuss what we can learn about the evolution of insect wings and morphological novelty in general by synthesizing the outcomes of these studies.