FISH 310 Lecture Notes - Lecture 17: Mantis Shrimp, Arthropod Eye, Crustacean
10 Jun 2018
School
Department
Course
Professor
Crustacean senses
Mechanoreception
Touch, "sound", proprioception (the ability to know what you limbs are
doing without looking at them)
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Hair-peg organs
Detect currents as slow as 3mm/second
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Hair Fan Organs - low frequency vibrations
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Statocysts
What tell the animal its orientation
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Chemoreception
Smell
Aesthetascs
Can sense very small concentrations of fish
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Located on the first pair of antennae
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Taste
Branched setae on dactyls, mouthparts
100x higher threshold for response than aesthetascs
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Photoreception
Vision
Compound eye
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Thousands of separate units-ommatidia
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11 types of compound eyes known
Crustacea have 10
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Stomatopod Vision
Humans: 3 color receptors
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Mantis Shrimp: 10-11, plus 6 filters for at least 16 types
6 in the 300-400 nm range
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Color and polarized light in center part
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Binocular and Trinocular Vision
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Muscles
Apdodems: internal extensions of exoskeleton used for muscle attachment
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Arthropod: innate fiber orientation
2x force per volume
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Tradeoff: human forearm: ~140 degrees of motion
Crab: ~70degrees
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Feeding
Filter
Acorn Barnacles
Active Feeding
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Wide distribution
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Gooseneck Barnacles
Passive filtering
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Limited Distribution
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Deposit
Downturned claws
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Scavenging
Ghost Crab
Sensitive to smells of decompostiion
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"sand flea" amphipods - primarily decomposing algae
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Herbivory
Land Crabs: Important in nutrient cycling
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Predation
Large claw for crusing mollusks
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Small claw for scraping; fine manipulation
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Maxillipeds for filter feeding
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Hepatopancreas
Functions as
Small intestine
Dead-end tubules
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Huge surface area for absorption
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Liver
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Pancreas
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Produces hemocyanin
Blood pigment that carries oxygen
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Energy reserve
Lipids
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Hindgut
Chitin-lined
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Evolutionary arms race
Crustaceans vs. mollusks
Predation pressure much greater in tropics
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Ornamentation much more common
Indo-Pacific 20-35% of shells
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Other parts of the world they are much simpler (colder waters)
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Defensive Strategies
Frills
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Narrow Apertures
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Thickened lip of aperture
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Cowries, olives, smooth, slippery shell hard to handle
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Freshwater and Terrestrial
Shells thin…
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Symbiosis
Mutualism
Both gain from relationship
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Commensalism
One gains, one neutral
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Parasitism
One gains, one negatively affeted
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Lecture 17: Arthropoda II
Friday, May 4, 2018
11:30 AM
