Entomology 1

Topic

Compound Eyes Of

Contents

• Receptors in Insects

• Photoreception in Insects

• Compound Eyes

• Ommatidia

• Components of OmmatidiaComponents of Ommatidia

• Photochemistry of Insect vision

• Forms of Compound Eyes

• Significance of Compound Eyes

• Color vision in SomeOrders Of Insects

• Summary

• References

Receptors in Insects

• Mechanoreceptors• Auditory receptors• Stretch receptors• Chemoreceptors• Olfactory receptors• Gustatory receptors• Thermo receptors• Photo receptors

Entomology 4

Vision is the perception of light.

Roles of vision in insects

•Photoreception in Insects

Photoreception in Insects

• Photoreceptors:1. Ocelli. 2. Stemmata3. Compound eyes

6

Dorsal ocelli

In larvae of hemimetabolous insects and in nearly all adults.

Poor perception of form. Active in orientation to a light

source.

Ref.02

7

Stemmata

In larvae of holometabolous insects Do not produce clear images Most caterpillars can discriminate some

shapes and they can orientate themselves with respect to boundaries.

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Compound Eyes:

Most adult insects have a single pair of compound eyes.

Reduced or absent in parasitic forms, many soil insects, and in some species that live in very dark places.

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Compound Eyes and ocelli

Entomology 10

Facet:

Hexagonal Components of Compound Eye.

OmmatidiaBasic unit of compound eyesVary in size and number.• Honey bee has 4900 Ommatidia in Queen,

6300 in workers and 13000 in donors.• Pomera punctatissima have only one

ommatidium in each eye. The sizes of Ommatidia vary from about

5 to 40 microns in diameter .

Ref.02

Components of OmmatidiaComponents of OmmatidiaOptical parts:

1. Corneal lens

2. Crystalline cone Sensory parts:

1. Retinula cells

2. Rhabdom A nerve axon projects

from each retinula cell. Optic nerve

(YADAV. M)Ref.01

Compound Eyes and Brain

13

Ref.0214

Photochemistry of Insect vision

• Photons are caught on the rhabdome by retinal.

• Retinal is connected to opsin, forming rhodopsin.

• On absorption of photon, retinal changes its form from bent to straight.

• When retinal changes its form, it separates from the rhodopsin and the opsin triggers a nerve cell.

• The nerve cells conduct the signal to the brain.

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Forms of Compound Eyes

1.Apposition eyes

2. Superposition eyes.

Ref.01

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Ref.0317

Significance of Compound Eyes

1. Flicker effect The compound eye is excellent at

detecting motion. As an object moves, ommatidia are

turned on and off.

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Significance of Compound Eyes

2. Distance Perception Most insects must be able to judge

distance. As in prey catching insects, in Grass

hopper’s jumping, and when they are landing.

Simultaneous stimulation of ommatidia.

Ref.01

Colors

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Significance of Compound Eyes

3. Color vision• Some insects are able to

distinguish colors• Most flower visiting insects

exhibit preferences for blue and yellow.

• Important in feeding and in court ship behavior

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3. Color vision

Bichromatic Insects. One pigment absorbs

green and yellow light (550 nm); the other absorbs blue and ultraviolet light (<480 nm). 

Trichromatic Insects. Absorption maxima at 360

nm (UV), 440 nm (blue-violet), and 588 nm (yellow)

REF 04

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Human Vision Vs. Insect Sight Colors visible to insects is higher in frequency (lower

in wave length) Violet light is the highest frequency of color humans

can detect, but many insects can see a higher frequency of light invisible to us, ultraviolet light.

Entomology 23

Ultraviolet vision

Color vision in SomeOrders Of Insects

1. Vision in Order Hymenoptera Eastern honey bee (Apis cerana). Family: Apidae The bees are red-blind. “orange, yellow, and green are the same color”

– yellow. Sensitive to UV light. They see blue colors best. Sense of polarization of visible light in the sky.

Ref.05

2. Vision in Order OdonataDragonfly(C. aenea) or Downy emerald

Family: Corduliidae

Compound eyes with wide-angle vision

Their eyes do not move.

30,000 eye ommatidia

Orange to ultraviolet (UV) light.

Able to estimate distance based on the

distance between their eyes.

Ref.06

3. Vision in Order Diptera

House flies (Musca domestica)

Family: Muscidae

The vision of the housefly is blurred

Compound apposition eyes

Can sense rapid motion approaching 200

cycles per second.

Ref.06

Vision in Mosquito

Mosquito (Culiseta longiareolata) Family: Culicidae Mosquitoes are attracted to black and to

dark colors. (Howlett 1910) Prefer the corners of a three-dimensional

target. (Brown & Bennett)

Ref.07

Beetle (Tetraopes tetrophthalmus)

Family: Cerambycidae Have infrared detection systems

for night vision, fire detection, and other functions as to sense forest fires.

Beetles have refraction superposition eyes

4. Vision in Order Coleoptera

Ref.06

5. Vision in Order Blattaria American cockroach (Periplaneta

americana), Family: Blattidae 2000 individual lenses Has receptors for UV light and green light.

Ref.08

6. Vision in Order Homoptera AphidsSuper family: Aphidoidea

Contains green, blue, and ultraviolet photoreceptors Ref.09

7. Vision in Order Lepidoptera Butterfly(Papilio rutulus) Family: Papilionidae Can See simultaneously in every direction. Trichromatic vision It can distinguish night from the day Can perceive colors in a high frequency

(from 310 nm to 700)

Ref.10

Vision in Order Lepidoptera Gipsy Moth (Lymantria dispar). Family: Lymantriidae Can see in the back of their

heads. Neural summation Have three types: blue, green,

and ultraviolet. Ultraviolet light reflection. Ref.12

Summary

Compound Eyes of Insects

1. YADAV. M, "Physiology of Insects," Discovery Publishing House New Delhi-110002, pp. 322-345

2. http://entomology.unl.edu/ent801/ent801home.html3. http://users.rcn.com/jkimball.ma.ultranet/

BiologyPages/C/CompoundEye.html4. www.cals.ncsu.edu/course/ent425/tutorial/

colorvision.html5. http://www.sewanee.edu/Chem/Chem&Art/

Detail_Pages/ColorProjects_2003/Crone6. www.eyedesignbook.com/index.html7. http://www.ent.iastate.edu/dept/research/vandyk/

hostseek.htm

References

8.http://www.sciencemag.org/cgi/content/abstract/171/3977/1254

9.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1945073/figure/pbio-0050187-g003

10. http://www.butterflyzone.org/butterfly-articles/butterfly-uv-vision.shtml

11.http://indianapublicmedia.org/amomentofscience/insect-color-vision

12.http://www.animalcorner.co.uk/insects/moths/moth.html

References

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