ROLEOFCOMPOUNDEYESANDOCELLIINSTEERINGOF
GRASSHOPPERSDURINGFLIGHT
ShashankChepurwar
RitvikSrivastava
Introduction:
Grasshoppers(familyAcrididae)areagileinsectsthatcanavoidpredatorsbyjumpingand
areabletoflyshortdistances.Withabrainofsuchsmallsize(~4mm),thesefeatsarepretty
impressive.Mostofthesebehaviorsarevisuallymediated.Grasshoppervisualsystem
consistsoftwoCompoundeyesandthreesimpleeyes(Onemedianandtwolateral)known
astheocelli.
Althoughthecompoundeyeshavebeenwidelystudied,thefunctionoftheocelliremain
enigmatic.Ithasbeenspeculatedthatocellihelpthecompoundeyesinthedetectionof
horizonandthushelpinflightstabilization.Theroleofocelliinmediatingtheresponseto
loomingstimulus(rapidlyapproachingobject)remainstobeascertained.
Weaimtobehaviorallystudythe
1) effectofhorizonrotationontetheredflyinggrasshoppersbymeasuringthe
rotationsintheyaw,pitchandrollaxes.
2) effectofaloomingstimulusontetheredflyinggrasshoppersbymeasuringthe
deviationfromflightpath.
Methodology:
Wewilltetherthegrasshoppersonaplatform(thoraxattachment)suchthattheyarefreeto
flaptheirwingsandremainattached.Atoothpicktipisgluedontotheheadofthe
grasshoppertobettertracktheheadmovement.
Thegrasshopperissubjectedtoanairflow(generatedbylowvelocityfan)fromtheforward
direction.AscreendisplaysspecificstimulusgeneratedbyusingMATLAB.
Schematic:
Acamerarecordsthemovements.Imageanalysisisusedtotrackthemovementsofthe
grasshopper.Blackacrylicpaintisusedtocoverthecompoundeyesortheocellitostudy
theeffectofspecificinputsfromtheseeyes.
Followingexperimentswillbeperformed
a) Control:OcelliandCompoundeyesintact.
b) AllOcellicoveredCompoundeyesintact.
c) AllocelliintactCompoundeyescovered.
d) Medianocellusintactlateralocelliandcompoundeyescovered.
e) Medianocellicoveredlateralocelliintactcompoundeyescovered.
Repeatthesewiththeotherstimulus(looming).
Theresultsoftheseexperimentswillbeusedtocomputationallymodelthegrasshopper
visualsystem.Thismodelcanbeusedinroboticequipmentsthatneedfastresponseand
flightstabilization.
MATLABprogramforloomingstimulus
(thisprogramcreatesanexpandingdotwhosesizeandexpansionratecanbecontrolled,
thismimicsafastapproachingobject)

clear;closeall;
colordefwhite;
e=59;
whilee>1
j=10;
f=1;
whilej>1
%Createdata
%Timedata
y=0;%Positiondata
%Drawinitialfigure
figure(1);
set(gcf,'Renderer','OpenGL');
h=plot(y(1),0,'o','MarkerSize',f,'MarkerFaceColor','black');
set(h,'EraseMode','normal');
xlim([1.5,1.5]);
ylim([1.5,1.5]);
%AnimationLoop
i=1;
whilei<=length(y)
set(h,'XData',y(i));
drawnow;
M(i)=getframe(1);
i=i+1;
end
j=j1.5;
f=f+100;
end
e=e1;
end

References:
1. CONTRIBUTIONOFCOMPOUNDEYESANDOCELLITOSTEERINGOFLOCUSTS
INFLIGHTBYCHARLESP.TAYLOR*
2. TheOcellarComponentofFlightEquilibriumControlinDragonfliesGertStange
3. SignalProcessinginaSimpleVisualSystem:TheLocustOcellarSystemandIts
SynapsesPETERJ.SIMMONS*