Exploring the origin of insect wings from an evo-devo perspective

Although insect wings are often used as an example of morphological novelty, the origin of insect wings remains a mystery and is regarded as a major conundrum in biology. Over a century of debates and observations have culminated in two prominent hypotheses on the origin of insect wings: the tergal hypothesis and the pleural hypothesis. However, despite accumulating efforts to unveil the origin of insect wings, neither hypothesis has been able to surpass the other. Recent investigations using the evolutionary developmental biology (evo-devo) approach have started shedding new light on this century-long debate. Here, we review these evo-devo studies and discuss how their findings may support a dual origin of insect wings, which could unify the two major hypotheses.