Tegula (insect anatomy)
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A tegula is a small sclerite situated above the base of the costal vein in the wings of various insects such as Orthoptera, Lepidoptera, Hymenoptera, Diptera, and Auchenorrhyncha, and attached to the antero-lateral portion of the mesonotum.[1] It is densely innervated, with sensory bristles, campaniform sensilla, as well as a chordotonal organ in some species.[2]
The tegula in locusts is a model system for studying the role of feedback from mechanoreceptors during movement.[3][4][5] In locusts, the tegula directly controls flight muscles. The motor neurons that control the activation of wing elevator muscles are phase-locked to the neurons that innervate the tegula such that when the tegula is electrically stimulated the elevator muscles initiate an upstroke.[6] When the tegula is removed, locust flight is clumsy and disordered at first but most animals adapt, suggesting the use of other mechanoreceptors to control flight.[7][8][9]
The tegula system is also a model for studying the role of neuromodulation for state-dependent motor control. Neural signals from the tegula only initiate wing muscle contraction when the animal is in flight (or fictive flight) due to endogenous release of the neuromodulator octopamine.[10] This mechanism ensures that the animal does not initiate a wing stroke if the bristles are deflected by wind as the animal is walking.