ABSTRACT
Hormonal control of flight can occur at several levels. Hormones or neuromodulators can exert a direct effect on the Central nervous system or on the flight motor system, causing immediate modulation of flight activity. The switch from one developmental pattern to the other in wing polymorphic species has long been supposed to be under specific hormonal control. In spite of the fact that the evolution of flight was undoubtedly pivotal in the adaptive radiation and evolutionary success of insects, there are representatives in each of the major orders of Insecta that lack the ability to fly because all or part of the flight apparatus is missing or nonfunctional. In some, the entire species is flightless, while in others, a polymorphism exists in which environmental factors, genotype, or both control the alternate development of winged and wingless forms within the same species.
