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Aimed limb movements in a hemimetabolous insect are intrinsically compensated for allometric wing growth by developmental mechanisms.

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journal contribution
posted on 17.10.2019, 14:47 by Alexandra J. Patel, Thomas Matheson
For aimed limb movements to remain functional, they must be adapted to developmental changes in body morphology and sensory-motor systems. Insects use their limbs to groom the body surface or to dislodge external stimuli, but they face the particular problem of adapting these movements to step-like changes in body morphology during metamorphosis or moulting. Locusts are hemimetabolous insects in which the imaginal moult to adulthood results in a sudden and dramatic allometric growth of the wings relative to the body and the legs. We show that, despite this, hind limb scratches aimed at mechanosensory stimuli on the wings remain targeted to appropriate locations after moulting. In juveniles, the tips of the wings extend less than halfway along the abdomen, but in adults they extend well beyond the posterior end. Kinematic analyses were used to examine the scratching responses of juveniles (fifth instars) and adults to touch of anterior (wing base) and posterior (distal abdomen) targets that develop isometrically, and to wing tip targets that are anterior in juveniles but posterior in adults. Juveniles reach the (anterior) wing tip with the distal tibia of the hind leg using anterior rotation of the thoraco-coxal and coxo-trochanteral ('hip') joints and flexion of the femoro-tibial ('knee') joint. Adults, however, reach the corresponding (but now posterior) wing tip using posterior rotation of the hip and extension of the knee, reflecting a different underlying motor pattern. This change in kinematics occurs immediately after the adult moult without learning, indicating that the switch is developmentally programmed.

Funding

This work was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) studentship to A.J.P. [BBS/S/K/2004/11196], BBSRC research grant [BB/C005538/1] and BBSRC Research Development Fellowship [BB/I019065/1] to T.M. Deposited in PMC for immediate release.

History

Citation

Journal of Experimental Biology 2019 222: jeb208553

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/Biological Sciences/Neuroscience, Psychology and Behaviour

Version

VoR (Version of Record)

Published in

Journal of Experimental Biology 2019 222: jeb208553

Publisher

Company of Biologists

eissn

1477-9145

Acceptance date

23/07/2019

Copyright date

2019

Available date

17/10/2019

Publisher version

https://jeb.biologists.org/content/222/16/jeb208553

Notes

Original video recordings and tracked movement files for all trials analysed in this work are available from figshare: https://doi.org/10.25392/leicester.data.8943173.v1

Language

en

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