Light production Thanks to Rebekah Wilkins, Jackie O’Riley.
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Transcript of Light production Thanks to Rebekah Wilkins, Jackie O’Riley.
Light production
Thanks to Rebekah Wilkins, Jackie O’Riley
Perciformes
LophiiformesPerciformes
Light production in fishes
Who?scattered among 13 orders, 45 families (Bond Table 19-1)
mostly in teleosts, 2 families of elasmobranches
Where? mostly deep sea, 300-1,000mup to 2/3 of deep oceanic fishes produce light600-700 species of mesopelagic fishes
How?
General principle: production of light by ‘cold’ chemical reaction:
luciferase
Luciferin + O2 + ATP oxyluciferin + light
How?
1. produce luciferin – usually under neural controlmay have lens or iris to control emission of light
2. rob luciferin from dietconcentrate it in specialized areas of body
3. contain symbiotic bacteria in special structuresprobably derived from dietocclude with tissue or pigment to ‘flash’ light
Why?
1. Predation – reduces prey-seeking energy and timelures on anglerfisheson inside of mouth (Sternoptyx, Psueodscopelus)mimic lures of dragonfishes may mimic prey conspecificscookie cutter shark may appear smaller, less threatening
Anglerfish Dragonfish Sternoptyx
Why?
1. Predation – reduces prey-seeking energy and timelures on anglerfisheson inside of mouth (Sternoptyx, Psueodscopelus)mimic lures of dragonfishes may mimic prey conspecificscookie cutter shark may appear smaller, less threatening
Anglerfish Dragonfish Sternoptyx Lophiiformes Lophiiformes Stomiiformes
Why?
1. Predation – reduces prey-seeking energy and timelures on anglerfisheson inside of mouth (Sternoptyx, Psueodscopelus)mimic lures of dragonfishes may mimic prey conspecificscookie cutter shark may appear smaller, less threatening
2. Predation – see prey better‘flashlights’ under eyes, or in mouthred light of black dragonfish, not visible to prey
Why?
3. Defensecountershading on ventral surface (hatchefishes)
Stomiiformes
Counter illumination
Why?
3. Defensecountershading on ventral surface (hatchefishes)intimidation – appear larger (elongate dragonfish)confuse or startle predator – flashlight fish apparently change
position with each flash
Beryciformes
Why?
3. Defensecountershading on ventral surface (hatchefishes)intimidation – appear larger (elongate dragonfish)confuse or startle predator – flashlight fish apparently change
position with each flash
4. Communicationaggregate conspecifics (flashlight fish)
Why?
5. Sexual selection?Melanostomias male is brighter – female may select by brightness
Control:
lens or iris-like structures control light emission tissue or pigment occlusion allows ‘flashing’ cover the photophore with a membrane or rotate it inward
Shining Tubeshoulder
•Photophores on underside
•Tube on each shoulder
• Squirts bioluminescent ink at predators