Compound Eyes Of

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Topic
Compound Eyes Of
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Contents

• Receptors in Insects
• Photoreception in Insects
• Compound Eyes
• Ommatidia
• Components of Ommatidia
• Photochemistry of Insect vision
• Forms of Compound Eyes
• Significance of Compound Eyes
• Color vision in SomeOrders Of Insects
• Summary
• References

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Receptors in Insects

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

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Vision is the perception of light.Roles of
vision in insects

• Photoreception in Insects

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Photoreception in Insects

• Photoreceptors1. Ocelli. 2. Stemmata3.
  Compound eyes

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Dorsal ocelli

• In larvae of hemimetabolous insects and in nearly
  all adults.
• Poor perception of form.
• Active in orientation to a light source.

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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
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Facet
Hexagonal Components of Compound Eye.
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Ommatidia

• Basic unit of compound eyes
• Vary 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 .

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Components of Ommatidia

• Optical 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)

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Compound Eyes and Brain
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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

• Apposition eyes
• 2. Superposition eyes.

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Significance of Compound Eyes

• 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 hoppers
  jumping, and when they are landing.
• Simultaneous stimulation of ommatidia.

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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
  (lt480 nm). 
• Trichromatic Insects.
• Absorption maxima at 360 nm (UV), 440 nm
  (blue-violet), and 588 nm (yellow)

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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.

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Ultraviolet vision
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Color vision in SomeOrders Of Insects
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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.

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2. Vision in Order Odonata

• Dragonfly(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.

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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.

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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)

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4. Vision in Order Coleoptera

• 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

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5. Vision in Order Blattaria

• American cockroach (Periplaneta americana),
• Family Blattidae
• 2000 individual lenses
• Has receptors for UV light and green light.

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6. Vision in Order Homoptera AphidsSuper
family Aphidoidea Contains green, blue, and
ultraviolet photoreceptors
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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)

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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.

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Summary

• Compound Eyes of Insects

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References

1. YADAV. M, "Physiology of Insects," Discovery
   Publishing House New Delhi-110002, pp. 322-345
2. http//entomology.unl.edu/ent801/ent801home.html
3. http//users.rcn.com/jkimball.ma.ultranet/BiologyP
   ages/C/CompoundEye.html
4. www.cals.ncsu.edu/course/ent425/tutorial/colorvisi
   on.html
5. http//www.sewanee.edu/Chem/ChemArt/Detail_Pages/
   ColorProjects_2003/Crone
6. www.eyedesignbook.com/index.html
7. http//www.ent.iastate.edu/dept/research/vandyk/ho
   stseek.htm

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References

• 8.http//www.sciencemag.org/cgi/content/abstract/1
  71/3977/1254
• 9.http//www.ncbi.nlm.nih.gov/pmc/articles/PMC1945
  073/figure/pbio-0050187-g003
• 10. http//www.butterflyzone.org/butterfly-article
  s/butterfly-uv-vision.shtml
• 11.http//indianapublicmedia.org/amomentofscience/
  insect-color-vision
• 12.http//www.animalcorner.co.uk/insects/moths/mot
  h.html

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Thank You Very Much
Good listeners make Good Speakers
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Dedicated To Dr. Sumera Afsheen

• .