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Light-Emitting Suckers in an octopus

Light-Emitting Suckers in an octopus. Sonke Johnsen, Elisabeth J. Balser, Edith A. Widder. Brandon Bell Biol 457 April 21, 2004. Bioluminescence. Characteristics Definition: Production of light by a chemical reaction within an organism Often found in squids and cuttlefish

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Light-Emitting Suckers in an octopus

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  1. Light-Emitting Suckers in an octopus Sonke Johnsen, Elisabeth J. Balser, Edith A. Widder Brandon BellBiol 457April 21, 2004

  2. Bioluminescence Characteristics • Definition: Production of light by a chemical reaction within an organism • Often found in squids and cuttlefish • Usually complex (lenses, mirrors, filters, etc.) • Rarely found in octopods (light organs) • Simple photophores Discovery of octopod, Stauroteuthis syrtensis, that emits blue-green light

  3. Bioluminescence in S. syrtensis • Deep-sea cirrate • Light organs found in the “suckers”, although the typical adhesive properties of suckers are not present • Upon stimulation, blue-green light is emitted • Maximum wavelength = 470nm • Dynamic characteristics:low-level continuous light or high-level discontinuous light The light organs show properties of both photophores and suckers, suggesting that they evolved from suckers

  4. Light organs are arranged in a single row that extends down the oral surface of each armThe light organs show very similar structural features to standard octopod suckers, although upon ultrastructural examination, some differences were found…

  5. Analysis of morphology Similarities: Outer collar of columnar epidermal cells surrounding the infundibulum with the acetabulum in the center. On the outer rim of the infundibulum, the cuticle forms a circle of hook-shaped denticles. The sub-acetabular ganglion supports the organ. Differences…

  6. Analysis of morphology cont. Differences: Radial, circular, and longitudinal muscles of in the infundibulum and acetabulum are greatly reduced. These muscles are generally used for the adhesive properties of octopod suckers.As expected, photocytes were found in place of these muscles to suit the function of the light organ.

  7. Function of light organs in S. syrtensis Two proposed functions1.) Communication 2.) Predation Communication: Shallow water octopods use their suckers for sexual signalling. This could suggest that the evolution of light organs in this species arose to allow sexual signalling in the deep sea, where non-luminescent visual cues are nearly impossible to detect.

  8. Function of light organs in S. syrtensis cont. Predation:The location of the suckers on the oral surface of the arms in conjunction with the common arms-spread posture exhibited by this species suggest that the light organs may be used for attracting and catching prey. Many crustaceans (a common prey to octopods) are attracted to bioluminescent food sources. The maximum wavelength produced by the light organs is approximately that of maximum light transmission in the ocean (475nm) further suggesting that communication and luring may be the functions of the light organs

  9. Evolutionary Process The light organs exhibit characteristics of both octopod suckers and photophores, suggesting that these organs are modified suckers. This process was speculated to have occurred during colonization of the deep sea from shallow water.

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