Fundamentals of PREDATOR-PREY Interactions Flashcards
Fundamental building block from which
increasingly complex food chains and food
webs may be constructed
Consumer-resource Link
the consumption of
one living organism by another
PREDATION
3 variety forms of Predation
- Herbivores
- Carnivores
- Omnivores
Consume plant or algal
tissue
Herbivores
Consume animal tissue
Carnivores
Consume plant or
animal tissue
Omnivores
Herbivores that are
exceptions because they kill
their “prey”, functioning as
true predators
Seed eaters (Granivores)
HERBIVORES which includes __________ and
___________ generally consume only a part of an
individual plant, which may harm the plant
but does not usually kill it.
✓Grazers
✓Browsers
It consumes nutrients from another organism, its
host, resulting in a decrease in fitness to the host.
Parasites
Several
species of wasp, is the best example of this which immobilize — but do
not kill — a host by stinging it. The female
then carries the host to a burrow, where
she lays eggs within the host’s body. After
the larvae hatch, they consume the living
tissues of the host, eventually killing it.
Parasitoids
It influences the fitness of both predators and prey.
Predation
Simplest mathematical model which describes the
interactions of predator and prey populations.
LOTKA-VOLTERRA MODEL
The following are assumptions of what?
- There is no food shortage for
the prey population. - The amount of food supplied
to the prey is directly related
to the size of the prey
population. - The rate of change of the
population is directly
proportional to its size. - The environment is constant
and genetic adaptation is not
assumed to be negligible. - Predators will never stop
eating.
LOTKA-VOLTERRA MODEL
What LOTKA-VOLTERRA equation is this?
Sx
____ = ax - Bxy
St
Prey equation
What LOTKA-VOLTERRA equation is this?
Sy
____ = Sxy - ¥y
St
Predator equation
Is the number of prey consumed per predator per unit time.
Feeding Rate
He classified predator functional responses into three basic types.
Holling (1959)
It is the relationship between prey density and predator feeding rate.
Predator’s Functional Response
A predator’s functional response assumes that:
• predator’s feeding rate increases linearly with prey density.
Type I functional response
A predator’s functional response assumes that:
• predators are not limited by handling time
Type I functional response
• Most common type of functional response
Type II functional response
A predator’s functional response that:
• Includes the constraint of handling time
Type II functional response
A predator’s functional response assumes that:
• Predator’s feeding rate accelerates over an initial increase in prey density but then
decelerates at higher prey densities.
Type III functional response
Is the difference between the
proportion of that prey type in a
predator’s diet compared with the
proportion of that prey type present
in the environment.
PREDATOR PREFERENCE
What are the 3 FACTORS AFFECTING PREDATOR PREFERENCE?
- The probability that a prey
item will be encountered. - The probability that an
encountered prey item will
be attacked. - The probability that an
attacked prey item will be
successfully captured and
eaten.
A factor that affect predator preferences that has something to do with the following:
- Prey size and reactive
distance - Prey and predator activity
patterns - Prey crypsis
✓ The probability that a prey item will be encountered
Why do predators choose to go after
some prey types and ignore others?
All else being equal, predators
should prefer to eat the most
profitable prey
A factor that affect predator preferences that has something to do with the following:
- Prey size
- Prey mobility and escape
behaviour - Prey defense
Probability that an attacked prey will be consumed
A predator defense where a prey organisms possess
colors and patterns that allow them to
blend into the background in their
environment.
Cryptic Coloring
A theory where all else being equal, predators should perfect to eat the most profitable prey
Optimal Foraging Theory
➢ Characteristics that evolved in prey
to avoid being detected, selected,
and captured by the predator
Predator Defense
How do these defenses deter a
predator?
*4 possible answer
• Foul-smelling secretions repel
predators
• Arthropods sequester toxic
plant compounds
• Venomous animals produce
their own toxins
• Alarm pheromones signal
other individuals in the same
or related species to flee
• An animal displays a visible
patch of color when disturbed that
vanishes when it is at rest.
•This
may distract and disorient the predator or
may be a signal to promote group cohesion
and raise alarm when a predator is present
Flashing Colors
is used by animals that
are toxic or have chemical defenses. These
are bold colors with patterns warning
predators that the animal is unpalatable or
painful
Warning Coloration
Is the imitation or resemblance of
one species by another species in order to
achieve a benefit.
Mimicry
2 types of mimicry
✓ Batesian mimicry
✓ Mullerian mimicry
is external or superficial
protection against attack by predators,
formed as part of the body (rather than the
behavioural use of protective external
objects), usually through the hardening of
body tissues, outgrowths or secretions.
Protective Armor
Is an ecological theory used to predict animal distribution based on resource availability and
competition for those resources
IDEAL FREE DISTRIBUTION
4 NON-CONSUMPTIVE EFFECTS OF PREDATORS
- Habitat use and habitat shifts
- Life history evolution
- Activity level
- Morphological changes
NON-CONSUMPTIVE EFFECTS OF PREDATORS
Examples:
• mouse that hides in the grass as a hawk flies overhead
• vertical migration by some zooplankton. In the open water
of lakes and oceans, zooplankton that feed on algae show
a pronounced daily migration cycle, spending the daylight
hours in the dark, cold depths and migrating to warm
surface waters at dusk, then returning to the depths at
dawn.
- Habitat use and habitat shifts
NON-CONSUMPTIVE EFFECTS OF PREDATORS
• earlier maturity/metamorphosis
Example: Trout (predator) on Mayfly, Baetis
• Bobbi Peckarsky and colleagues noted that mayflies from
streams containing trout emerged earlier and at much
smaller adult sizes than conspecifics found in streams
without trout.
- Life history evolution
NON-CONSUMPTIVE EFFECTS OF PREDATORS
Examples:
• Individuals often feed or travel in groups as a
means of reducing predation risks
• Alarm-calling species of sentinels; bluish-slate
antshrikes (Thamnomanes schistogynus) and
dusky-throated antshrikes (Thamnomanes
ardesiacus)
- Activity levels and vigilance
NON-CONSUMPTIVE EFFECTS OF
PREDATORS
• include changes in toxicity, color, body
shape, shell hardness, and the presence
of spines
Example: Divergence in body shape of
crucian carp
• The shift in body form allowed most of the carp to
escape being eaten by their pike predators
• However, expression of the deep- bodied form
resulted in about a 30% increase in energy expended
when swimming compared with the shallow-bodied,
more fusiform shape
- Morphology
