Wing polymorphism is common in various groups of insects, and has been studied extensively in various aspects. In general, there are two morphologically distinct morphs with long or short wings. The long-winged morph is normally able to fly, but the short-winged cannot. In some species, such as aphids, the flightless morph lacks wings and is called the apterous morph. Besides flight capability, the two wing morphs often display various behavioral and physiological differences. In this review, effects of environmental factors on determination of wing form, endocrine control mechanism, genetic s...
