THE PARALLEL VISUAL WORLD OF AN INSECT

Gregor Belušič, Peter StušekUniversity of Ljubljana, Biotechnical Faculty, Department of Biology

OWL FLY – INTERESTING ANIMAL FROMTHE ASPEST OF VISION

bipartite eye

300

1.0

1.5

EEmax

0.5

0400 500 600 nm300

1.0

1.5

EEmax

0.5

0400 500 600 nm

R1.0

1.5

EEmax

0.5

0400 500 600 nm

R1.0

1.5

EEmax

0.5

0400 500 600 nm

R

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

R

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

ABSORBTION CHARACTERISTICS OFRHODOPSIN AND METARHODOPSIN

R

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

M

R

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

MMM

exclusive sensitivity in UV

triggering ofsignalling cascade

9h 12h 15h 18h

100

200

300

Wsr-1

0

6h

SKY RADIANCE VARIABILITY

radiance from clouds

VISUV

DIFFERENCE IN CONTRASTS

11E-31E-41E-51E-6

I/Imax

20

15

10

5

0

Intensity curve of a photoreceptor from the VL eye

Hill functionV

Vmax

= In

In

In

slope: n=1.25dynamic range=2 log units

0,10,01

mV

STEEP RESPONSE FUCTION OF UV RECEPTOR

narrow dinamicrange

light intensity

receptorresponse

activation ofsignallingcascade

VISUAL PIGMENT CYCLE

(protein)

(rhodopsin) (active rhodopsin)

Inactivation of metarhodopsin accomplished by arrestin (arr)

high affinitylow affinity

356 nm (30 % R)

dark

471 nm (100 % R)

PDA

POST DEPOLARISING AFTERPOTENTIAL, PDA

RELATIONS BETWEEN PDA AND ERG

0-1-2-3-4-5

0.0

0.2

0.4

0.6

0.8

1.0

rela

tive

ER

G

log (I)

ERG

PDA

CONCLUSIONS

1. The bipartite eye of owl-fly (Ascalaphus macaronius) is developed for catching the preys against the sky.

2. In order to accomplish this job the visual cells are exclusive sensitive to UV light to lover the ambiguous background of the sky and to enhance the visual contrast.

3. The visual cells operate at high light level therefore they pushed to the “edge” of sufficient arrestin content which is elevated.

4. Using UV light by just a part of the eye ot the whole eye is probbably the general strategy for the animals (dragon flies, drones, may flies...) whose life depends on cathing the preys or mates against the sky .

ABSORBTION CHARACTERISTICS OFRHODOPSIN AND METARHODOPSIN

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

RR

M

300

1.0

1.5

EEmax

0.5

0400 500 600 nm

triggers thesignalling cascade

UV

visible

PHOTOS OF THE SKY

adaptingpulse, 30s 460 nm, 30s

400 nm

395 nm

390 nm

385 nm

380 nm

16%

25%

35%

47%

55%

wavelength metarhodopsin

R

300

1.0

EEmax

0.5

0400

R

300

1.0

EEmax

0.5

0400

PDA AT DIFFERENT

BIPARTITE EYE OF ASCALAPHUS

ommatidiumommatidium

visualunite

STABILITY OF PDA

380 nm

10 mV

100 ms

PDA

FORMATION OF SUPERPOSITION IMAGES

object

superimposedpictures onrhabdome

clear cone

chrystallinecone

SUPERPOSITION OPTICS OF THE EYE

SKY IRRADIANCE

RR

M

1,0

1,5

EEmax

0,5

0400 500 600 nm

M

R

RR

M

1,0

1,5

EEmax

0,5

0400 500 600 nm

M

R

RR

M

1,0

1,5

EEmax

0,5

0400 500 600 nm

M

R

RR

M

1,0

1,5

EEmax

0,5

0400 500 600 nm

M

R

EFFECT OF FOTORECONVERSION

RR

M

3 0 0

1 ,0

1 ,5

EE m a x

0 ,5

04 0 0 5 0 0 6 0 0 n m

R

R

M a

3 0 0

1 ,0

1 ,5

EE m a x

0 ,5

04 0 0 5 0 0 6 0 0 n m

R

R

M i-A rr

3 0 0

1 ,0

1 ,5

EE m a x

0 ,5

04 0 0 5 0 0 6 0 0 n m

R i-arrR

M a

3 0 0

1 ,0

1 ,5

EE m a x

0 ,5

04 0 0 5 0 0 6 0 0 n m

A rr

activ atio n o fs ig na ling cascade

U V

b lueligh t

h

h

SKY RADIANCE

200 300 400 500 600 700 800 900 1000

rela

tive

qua

ntum

num

ber,

Qre

l

above atmosphere

wavelangth (nm)

Earth surfacethe region ofsensitivity of DF eye of L. macaronius

EFFECT OF MONOCHROMATIC LIGHT

100%40%

rhodopsin

arrestin

arrestin

metarhodopsin40%70%30%

UV