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Insight into Insect Visual Systems: A Dive into Compound Eyes and Photoreception

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  1. Topic Compound Eyes Of Entomology

  2. 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

  3. Receptors in Insects • Mechanoreceptors • Auditory receptors • Stretch receptors • Chemoreceptors • Olfactory receptors • Gustatory receptors • Thermo receptors • Photo receptors

  4. Vision is the perception of light.Roles of vision in insects • Photoreception in Insects Entomology

  5. 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.

  8. 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.

  9. Compound Eyes and ocelli

  10. Facet: Hexagonal Components of Compound Eye. Entomology

  11. 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 . Ref.02

  12. 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) Ref.01

  13. Compound Eyes and Brain

  14. 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. Ref.02

  15. Forms of Compound Eyes • Apposition eyes • 2. Superposition eyes. Ref.01

  16. Significance of Compound Eyes • Flicker effect The compound eye is excellent at detecting motion. As an object moves, ommatidia are turned on and off. Ref.03

  17. 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

  18. Colors

  19. 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

  20. 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)

  21. 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. REF 04

  22. Ultraviolet vision Entomology

  23. Color vision in SomeOrders Of Insects

  24. 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

  25. 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. Ref.06

  26. 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

  27. 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

  28. 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 Ref.06

  29. 5. Vision in Order Blattaria American cockroach (Periplaneta americana), Family: Blattidae 2000 individual lenses Has receptorsfor UV light and green light. Ref.08

  30. 6. Vision in Order Homoptera AphidsSuper family: AphidoideaContains green, blue, and ultraviolet photoreceptors Ref.09

  31. 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

  32. 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

  33. Summary • Compound Eyes of Insects

  34. References • YADAV. M, "Physiology of Insects," Discovery Publishing House New Delhi-110002, pp. 322-345 • http://entomology.unl.edu/ent801/ent801home.html • http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CompoundEye.html • www.cals.ncsu.edu/course/ent425/tutorial/colorvision.html • http://www.sewanee.edu/Chem/Chem&Art/Detail_Pages/ColorProjects_2003/Crone • www.eyedesignbook.com/index.html • http://www.ent.iastate.edu/dept/research/vandyk/hostseek.htm

  35. 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

  36. Thank You Very Much Good listeners make Good Speakers

  37. Dedicated To Dr. Sumera Afsheen • .

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