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BIOLUMINESCENCE. Aequorea victoria. Melanostomias bartonbeani. Bargmannia sp. Beroe sp. Substrates and Enzymes. Luciferin General term Luciferase Present in diverse taxa Oxygenase Exaptation. Bacterial luciferin. Vargulin. Coelenterazine. Examples of fish. Bacterial luciferin.
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Substrates and Enzymes • Luciferin • General term • Luciferase • Present in diverse taxa • Oxygenase • Exaptation Bacterial luciferin Vargulin Coelenterazine
Examples of fish Bacterial luciferin Vargulin Neuronal control
Coelenterazine Chemical luminescence
INTERSPECIFIC COMMUNICATION • PREDATOR AVOIDANCE • PREY ATTRACTION • BURGLAR ALARM HYPOTHESIS
PREDATOR AVOIDANCE Acanthephyra purpurea and Gonostoma elegatum
PREDATOR AVOIDANCE Counter illumination
PREY ATTRACTION Melanocetus sp.
SIGNALER PAYOFF - + - MANIPULATION/ DECEIT SPITE RECEIVER PAYOFF + TRUE COMMUNICATION EAVESDROPPING SIGNAL DETECTION THEORY
SIGNALER PAYOFF - + - RECEIVER PAYOFF + SIGNAL DETECTION THEORY MANIPULATION/ DECEIT SPITE TRUE COMMUNICATION EAVESDROPPING
FLASH LIGHT FISH • Nocturnal Predator • Bacterial light organ • lluminates prey • functions as “bait”
10 billion bacteria / .035 fluid oz • Light emitted travels over 30 m • Brightest light produced by any living organism
= POTENTIALLY COSTLY ADAPTATION • Five genera and six species worldwide • DIFFERENT STRATEGIES • Two species raise skin flaps to control emission • Two species lack skin flaps; use organ rotation • Two species use both skin flaps and organ rotation
Skin flap down, light organ exposed Skin flap up, light organ covered
Do different species differ in their ability to manipulate/ deceive predators???
EXPERIMENTAL DESIGN • Large scale aquaria experiments • Two treatments for each species • -control mechanism intact • -control mechanism removed • Common, visually stimulated, nocturnal reef predator
EXPECTED RESULTS + PREDATOR - PREDATOR CONTROL INTERMEDIATE BOTH ROTATE SKIN + - + - + - LOW CONTROL HIGH CONTROL SURVIVABILITY
SIGNALER PAYOFF - + - RECEIVER PAYOFF + SIGNAL DETECTION THEORY MANIPULATION/ DECEIT SPITE TRUE COMMUNICATION EAVESDROPPING
Intraspecific Communication • Schooling • Communication • Mating Oneiroides sp.
Is bioluminescence used for mate selection? Euprymna scolopes Vibrio fischeri
Light organ of E. scolopes • silver colored reflector • shutter mechanism • transparent lens • yellow filter
Influence on mate selection? • Light organ quality may signify fitness (survivorship) • Under sexual selection? • Hypothesis: Variation in light organ characteristics will influence mate selection in E. scolopes
Experimental design part 1 • Test for variation in light organ characteristics: • size and shape of light organ • size and shape of reflector tissue • Wavelength of light emitted • Intensity of light emitted
Experimental design part 2 • Capture male and female E. scolopes • Measure wavelength (l) & intensity (I) • Assign males to categories of l & I • Group 1 female w/ multiple males that differ in l & I (control for other features) • Record mating pairs • Repeat using other females
Expected results There will be a statistically significant correlation between # mating events and category of l and/or I .
Malacosteus niger The ultimate eavesdropper
Physiology experiment • How is light signal perceived? • Conversion of wavelength not perfect • Excites visual pigments • Different detection than naturally emitted blue light? • Monitor nerve impulse • Sensory processing centers • differences in activity?