Predation Flashcards
What is the major difference between predation and parasitism
Predation is where the predator kills and consumes its prey for energy
Parasitism usually only harms its prey and only sometimes ends in death
What is the red queen hypothesis
Populations must constantly adapt in order to persist against ever-evolving opposing organisms (competitors, predators) within a changing l, dynamic environment
Define coevolution
Is the arms race between predator and prey, it is the interaction of two or more species affect the evolutionary/ adaptive trajectory of all
What is a search image
Any cue that a predator may use to identify prey, usually visual but can also be chemical, auditory, vibrational etc. Signals a predator may be alert to
Predators can be divided into two general groups that describe how they hunt. What are they?
Ambush (passive waiting for prey)
Stalker (going and finding prey through both solitary and cooperative
When is cooperation between predators favoured? When is it for prey?
Predators: when the per capita gain of energy (food) is greater than in solitary
Prey: when the per capita predation risk is lower than when in solitary
All potential prey species l, such as abalone discussed in class are constantly challenged between the trade-off and of predation risk energy acquisition. Explain
Maximizing forage rate almost always comes with the cost of increasing predation risk. The abalone that’s it exposed to food rich currents or the musk ox that remain in small groups are at risk of increased predation
Isolation from predators means isolation from food but these two priorities must be balanced
What are the two fundamental assumptions of optimal foraging theory
Foraging behaviour has a genetic basis and so can be altered via natural selection
Fitness covaries with foraging efficiency
Why are the two assumption of optimal foraging theory necessary for the theory to work
- if there was no genetic basis to foraging behaviour there would be no way for the population to adapt and evolve. Behaviour fixed or randomly changing
- more successful foragers have more offspring. If they didn’t there would be no pay off for being better forager. If no differential reproduction, the population would not be able to adapt to changing conditions
Energetic analysis shows the Ei-hi =10 and E-(s+h) = 15. Should the predator add new prey item i to its diet
No because the energy gained with the new item is less then the energy gained by staying with the old diet and it’s greater search time
If travel times between food patches increases, should a forager stay in an average patch a longer or shorter time
Longer
Differentiate between Batesian and mullerian mimicry
Mullerian mimics use a shared common colour patter to warm potential predators of unpalatable or poisonous properties
Batesian mimics take advantage of the warning colour patterns but they themselves are not unpalatable or poisonous
Herbivors
Grazers: eat plants on the ground
Browser: woody plants above ground
Granivore: eats grains
Frugivore: eats fruits
Predator adaptations
Detection capture consumption of prey
What kind of adaptations expect in herbivors v carn
Herb: adaptations to overcome plant defences
Carn: adaptations to overcome animal defences
Avoiding detection/ capture
Countershading, eye and egg spots, autotomize( lose a limb)
Predator swamping
Large number of prey to swamp the predators
The closer the hatching date is to the peak date the greater the success of hatching
Optimal foraging theory
Optimizing the ratio of energy down in pursuit of food vs energy gained by consuming food
Energy maximizes: Hugh energetic cost for foraging bees
Time maximizes: foraging time is limited ground squirrel
Optimal diet model (max benefit)
Optimizing what you eat
Specialist vs generalist
Spec: high energy searching to high trop eff
Gen: low energy searching but low trop eff
Optimal solution E-h or E-(s+h)
Optimal food patch use
Travel to new food patch is costly and energy is not gained during this period
How long to stay in a foraging patch based on time to next one
Optimal foraging determinants
Energy max: handling and search
Time max: search time
Community level effects of predator
Functional: is behavioural response
Numerical: is a demographic response
Density dependent
Any char that varies according to the change in pop density
These reflect comp, predation, diseases
Density independent
Any char that does not vary as pop density changes
Weather, temp
