FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES When you are hungry what do you do? 1.Dig out wallet/open...
-
Upload
bernard-jenkins -
Category
Documents
-
view
213 -
download
0
Transcript of FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES When you are hungry what do you do? 1.Dig out wallet/open...
FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES
When you are hungry what do you do?
1. Dig out wallet/open fridge2. Decide what you want/can eat3. Capture Food Item4. Cook Food Item5. Consume Food Item6. Digest7. Repeat
FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES
When a herp is hungry what does it do?
1. Dig out wallet/open fridge—Wild Food Has Cost2. Decide what you want/can eat—Limitations of Cost3. Capture Food Item—Often the major cost4. Cook Food Item5. Consume Food Item—Not as easy as it sounds6. Digest—another big cost7. Repeat—When and how much8. Hope Nobody Eats You—A REALLY BIG COST9. Hope Dinner Doesn’t Bite You Back—PARASITES
FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES
What do amphibians and reptiles eat?
FEEDING ECOLOGY OF AMPHIBIANS AND REPTILES
What do amphibians and reptiles eat?
Salamanders: Mostly Inverts
Frogs: Animals
Tadpoles: Filter feed, algae, larger foods
Caecilians: Animals
Snakes: Mostly vertebrates, some Inverts
Lizards: Mostly insects, Some vertebrates
Tuatara: Inverts
Iguaninae: Herbivores
WHY ARE THERE SO FEW HERBIVOROUS HERPS
Challenges of Herbivory: Very low energetic value May not be an option for small animals
Gut FloraRotting in the Gut—Cold Temperatures
Successful Herbivores: Iguanas, 2 Other LizardsTadpoles (Are Algae Plants?)
FINDING SOMETHING TO EAT
•Active Predators vs Sit and Wait
•Risks of Both•Predation•Energy Gained/Lost•Your Defense
•Chemical Responses
•Coevolved Prey
•Phylogenetic Effects
Specializations for Feeding
Suction Feeding
1. Only Works in Water2. Primitive: How Most Bony Fish Eat3. Difficult to Do Without Gill Slits
Specializations for Feeding
Suction Feeding:Primitive Form of Larval and Paedomorphic Salamanders
Figs 11-1a, 11-2
Specializations for Feeding
Suction Feeding:Modification in Tadpoles
Fig11-10, 11-6, 11-7. 11-8
Specializations for Feeding
Suction Feeding:Challenge of Life Without Gills
Water flow is now 2 directional.How is this a problem?
Figs 11-1b
Now suction gives the predator a brief advantage, or at least reduces the “bow push.”
Snapping turtles only overcome the disadvantage of moving their head forward.
11-13
TONGUE FLICKING
Found in Mutiple Groups•Salamanders•Frogs•Iguanid Lizards•Tuatara•Chamaelion
In this mode of attack a sticky tongue •comes out of the mouth•“grabs” food item•pulls food into mouth
TONGUE FLICKING: How Does it Work
Salamanders
Hyobranchia contract forcing tongue forward.Similar to a kid with a mouth full of water.
Y YFig 11-21, 11-19, 11-18
TONGUE FLICKING: How Does it Work
Frogs
Muscle in front of moth contracts pulls tongue forward.Similar to a sling shot.
Fig 11-22
TONGUE FLICKING: How Does it Work
Chamelions
Hyobatrachium acts as a lever, pushes rod out, muscle at tipsquezes. Similar to a siege engine.
Fig 11-2311-24
TONGUE FLICKING: How Does it Work
Lizards
Lever pushes a rod. Chamelions modified this approach
I love these crunchy on the
outside chewy in the middle
ALL JOKING ASIDE, WHAT DOES THIS PATTERNSUGGEST ABOUT MODIFICATION OF THE
TONGUE AS A PREY CAPTURE MECHANISM?
Power Biters
•Some reptiles are specialized for powerful snapping.
•Skull is akinetic
•Turtles •No teeth•Keratinous beak•Large temporal notch
•Crocodiles•Short depressor mandibulae•Massive pterygoids, powerful adductor•Narrow Jaw Specialists•Wide Jaw Generalists•Alligators routinely eat large turtles
Fig 11-5
Kinetic Skulls
•Skulls of Snakes and Lizards are highly flexible
•Allows changed in skull morphology
•Tight Fits
•“Disarticulation” of snake jaws•Mandibles connected by cartilage•Unilateral Feeding•Extreme versatility
Figs 11-29b11-3611-38
•African egg eating snakes•Large gapes•Vertebral specializations
•Hinged Teeth•Mostly skink eaters
•Pit Organs •Heat sensitive•Role in defense•Widely placed phylogenetically•Evolved to stay cool (ISU Work)
•Constriction•Specialization for killing Prey•Secondarily redeveloped in colubrids
ODD Snake Specializations
Figs 11-3711-3611-35Imager11-43
Envenomation
•Poison--delivered orally
•Venom is injected
•Three families of snakes + 1 of lizards
•Colubridae (broadly defined)
•Elapidae (cobras and kin)
•Viviparidae
•Prey restrain, digestion, and defense
11-3111-40Figs 11-41
Why Aren’t More Animals Cannibals?
•Benefits •Everything you need•Eliminate Competition
•Costs•Reproduction does you no good if you eat the results•Great way to get parasites•Prions (mad cow disease)•When should you be a cannibal?
•Steve Lima’s Work
•Being prey is game over
•Predation does more than kill 1 individual
•Trade-offs of short vs long term fitness•When to hunt, When to watch•When to call, When to hide•Temperature Performance•Safe Habitat
•Protection•Cryptic Behavior/Appearance•Be dangerous•Look dangerous (Batsman Mimicry)•Look and be dangerous (Mullein Mimicry)
How Do You Avoid Getting Eaten
Figs 15-8, 15-19e
SPEAKING OF EATING HERPSASSIMILATION EFFICIENCY SUGGESTS WE SHOULD DO SO
What besides assimilation efficiency should we consider?Does agriculture pay any attention to assimilation efficiency?
Fig 1-7