Created by Peter Downing – Educational Media Access and Production © 2011

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Locusts (Locusta migratoria) are ideal model

systems to study complex behaviours, such as flight

responses to objects approaching on a collision

course. Thus far, flight muscle activity, wing

kinematics and aerodynamic forces of locusts have

been recorded during collision avoidance

behaviour and measured from rigidly-tethered

locusts flying in open-loop conditions. However,

loosely-tethered flying locusts are capable of

changing orientation in response to looming stimuli

within a single wing beat, and generate avoidance

responses within a single downstroke. To better

understand neural control of flight steering, we

placed a loosely-tethered flying locust inside an

existing flight simulator, and presented visual

stimuli of objects moving along complex

trajectories.

INTRODUCTION

METHODS

RESULTS

Muscle activity and corresponding physiological changes

Acknowledgements

Funding provided by the Natural Science and Engineering Research Council

of Canada, the Canada Foundation for Innovation and the University of

Saskatchewan.

References

[1] McMillan, G. A., Loessin, V., & Gray, J. R. (2013). The Journal of

experimental biology, 216(17), 3369-3380. [2] Silva, A. C., McMillan, G. A.,

Santos, C. P., & Gray, J. R. (2015). Journal of neurophysiology, 113(1), 218-

231. [3] Santer, R. D., Simmons, P. J., & Rind, F. C. (2005). Journal of

Comparative Physiology A, 191(1), 61-73. [4] McMillan, G. A., & Gray, J. R.

(2012). Journal of neurophysiology, 108(4), 1052-1068.

SUMMARY

ACKNOWLEDGEMENTS &

REFERENCES

Locust flight muscle activity and body orientation in response to

objects moving along complex trajectoriesSinan Zhang and John R. Gray, Dept. Biology, University of Saskatchewan

Stimuli-independent EMG frequency change

Behavioural responses during collision avoidance

• Locusts generate steering behaviour

during collision avoidance, without

preference in directions

• Changes in flight direction can be

reflected by the latency between

bilateral flight muscle spikes

• Within a flow field background, wing

beat frequency decreased during object

approach.

High speed camera recordings (1028 x 1028 pixels at 225fps) revealed the trajectory of locust flight during

collision avoidance. Images from two cameras, allowed 3D tracking of the locust position. A) 3D tracking

results showing the locust generating a maintained right turn while avoiding the disc coming from left at 45°.

B) Video capture from one camera, showing positions of the locust before and during avoidance behaviour;

C) Movement in x and z planes showing the overall right turn (changes in the y plane were minor). Time

aligned with TOC (Time of collision).

Time

A) Experimental setup, including visual stimuli projection, high

speed cameras and EMG recordings

C) Muscles recorded in this

experiment: M97 (forewing 1st

basalar), M99 (forewing subalar),

and M127 (hindwing 1st basalar)

B) Visual stimuli with flow

field background and tether

Loosely tethered locusts (n=3) were placed in the

center of a rear projection dome screen. Head-on air

flow (v=3m/s) was provided to maintain straight

flight. Visual stimuli (7 cm disc travelling at 3 m/s)

were projected from different directions (left 45°,

right 45°, 0°), with a flow field background (B).

Four markers on the tether monitored 3D body

position. (C) We recorded from 6 flight muscles

known to be associated with steering.Activity of 3 bilaterally paired steering muscles were also recorded during collision avoidance. Previous

studies have shown that the timing of these muscles are associated with attempted steering manoeuvres. A)

Sample EMG recordings (Left 45° looming); B) Bilateral latency increases indicating a steering behaviour;

C) EMG spike frequency (reflecting wing beat frequency) decreased as the disc approached.

A)

B)

C)

B)

Stimulus

generation

Stimulus frame

pulses

LCD

projector

Rear projection

dome screen

Data collection

and analysis

EMG Recordings

Time (s)

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B)

C)

A)

C)

LocustLocust

Looming

stimuliLooming

stimuli

Before During

A) 3D motion tracking of a locust avoiding a disc looming

from the left at 45°. The coordinate system is right-handed:

positive x to the right, positive y down, positive z to the front

(from the locust’s perspective of view)

Locust Tether

EMG spike frequency across all three types of

looming stimuli, displaying a stimuli-independent

decreasing trend over time.

A)Left 45°; B)Right 45°; C)0°.

Front (Z)

Down (Y)

Right (X)