Tegula (insect anatomy)

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A tegula is a small sclerite with innervated bristles 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]

Confocal images of a fruit fly wing with the neurons innervating the tegula labeled by Green Fluorescent Protein

The tegula in locusts is a model system for studying the role of feedback from mechanoreceptors during movement.[2][3][4] 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.[5] 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.[6][7][8]

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.[9] This mechanism ensures that the animal does not initiate a wing stroke if the bristles are deflected by wind as the animal is walking.

The tegula is labeled f on this chalcid. Click for an uncropped version.

ReferencesEdit

  1. ^ Fischer, Wolf and Büschges. "The locust tegula: kinematic parameters and activity pattern during the wing stroke". Journal of Experimental Biology. Retrieved 2010-08-31. CS1 maint: discouraged parameter (link)
  2. ^ Ramirez, J. M., & Pearson, K. G. (1993). Alteration of bursting properties in interneurons during locust flight. Journal of neurophysiology, 70(5), 2148-2160.
  3. ^ Pearson, K. G. and Wolf, H. Connections of hindwing tegulae with flight neurones in the locust, Locusta migratoria. J. Exp. Biol. 135:381-409, 1988
  4. ^ Wolf, H. "The Locust Tegula: significance for flight rhythm generation, wing movement control and aerodynamic force production." Journal of Experimental Biology 182.1 (1993): 229-253.
  5. ^ Wolf, H. "The Locust Tegula: significance for flight rhythm generation, wing movement control and aerodynamic force production." Journal of Experimental Biology 182.1 (1993): 229-253.
  6. ^ Recovery of the flight system following ablation of the tegulae in immature adult locusts, C Gee, R Robertson, Journal of Experimental Biology 1996 199: 1395-1403.
  7. ^ Kien, J., Altman, J.S. Connections of the locust wing tegulae with metathoracic flight motoneurons. J. Comp. Physiol. 133, 299–310 (1979). https://doi.org/10.1007/BF00661132
  8. ^ Büschges, A., & Pearson, K. G. (1991). Adaptive modifications in the flight system of the locust after the removal of wing proprioceptors. Journal of Experimental Biology, 157(1), 313-333.
  9. ^ Ramirez, J. M., & Pearson, K. G. (1991). Octopaminergic modulation of interneurons in the flight system of the locust. Journal of Neurophysiology, 66(5), 1522-1537.