predation, foraging Flashcards
2 critical behavioral components of survival are?
finding food (feeding)
avoiding predators (foraging)
what are the 2 basic appraoches to study foraging and predation?
- evolutionary game theory
models dynamics of interactions by assessing strategies based on what others are doing, and then determines which strategies are more likely to evolve - optimality theory
predict best way an animal should behave, in terms of maximising fitness benefits and reducing fitness costs
what is the evolutionary stable strategy
the optimal solution
a single strategy in a population that cannot be overtaken by another strategy that is initially rare
hawk-dove game definition
this game establishes a payoff scheme and advantage depends on the ____ and the _______ of hawks and doves in the population.
individuals are in competition over food, and can choose either hawk or dove strategy
- hawk - win all or lose all
- dove - retreat if attacked, share if other is cooperative
payoffs; frequency
active vs passive group defense
active group defense - mobbing and vigilance
passive group defense - living in groups, safety in numbers
cost of mobbing: nest boxes with mobbing calls around them lose ____ eggs to _____.
more; pine martens
costs of alarm calling (vigilance) - fork-tailed drongos in South Africa _____ alarm calls of other birds. These fake calls scare the foraging birds away and the drongos and feed better.
mimic
dilution effect hypothesis
forming groups make it more difficult for any individuals to be depredated compared to being alone
moving as a group reduces possbility of being depredated because the crowd of moving prey targets confuses the predator and disrupts ability to single out individual - what’s this effect called?
confusion effect hypothesis
what is the selfish herd hypothesis
individuals in a group actively try to reduce own risk of depredation by positioning themselves so other group members are between them and approaching predators
butterflies drink fluids high in sodium and nitrogen in groups for the ______ effect hypothesis.
dilution
which animal uses both dilution and confusion effect hypotheses to avoid predation?
european starlings (sturnus vulgaris)
___________ animals will take fitness loss when exploited as predator shield while ___ individuals benefit. when social animals pair up, they are equally likely to share benefit.
solitary; social
what is cryptic coloration known as?
camouflage
camouflage is also known as ________ _____________. it _________ the animal to the ____ they normally utilise/rest at.
cryptic coloration; matches; substrate
in peppered moth (biston betularia), melanic phenotype is darker/lighter than the peppered phenotype.
in polluted woodland due to industrialisation, which moth survived better?
darker
melanic
which animal has aposematic coloration? how and why?
monarch butterflies. bright colors serves as warning signals that the butterflies are chemically defended and toxic due to milkweeds they consumed as caterpillars which also possess aposematic coloration.
blister beetles have this noxious chemical in their blood that defends them from predators. they can mat for hours atop flowers with no threats at all. what is this chemical?
cantharidin
mammals heavily defended usually have smaller/larger brain size, perhaps a _________ trade-off in costs.
metabolic-developmental
what are the 2 kinds of mimicry?
- batesian mimicry - non toxic animal mimics a toxic one
- Müllerian mimicry - noxious species converge to look like each other
mimicry is an ___________ defence, signalling to predators that they are dangerous and pls avoid.
adapted
red on yellow, ___________; red on black, __________
kills a fellow; the venom lack
which is poisonous and which is a mimic?
scarlet kingsnake
eastern coral snake
poisonous - eastern coral snake (red on yellow)
mimic - scarlet kingsnake (red on black)
if the snake has a ____ tail, it is likely deadly. the __ snake prolly is a bartesian mimic.
red; red-headed reed snake
tephritid fly mimics the aggressive leg-waving of jumping spiders in 2 ways. what are they? what are they trying to trick? what hypothesis are they working with?
wing coloration
behavioural pattern
approaching jumping spiders to retreat
signal deception hypothesis
what is signal deception hypothesis?
prey species appearance/behavior causes predator to retreat/escape
Thomson’s gazelles use conspicuous pronking display when being pursued by cheetahs. This is called _______, whereby the gazelle springs on 4 legs, repeatedly ________, during which its legs are held in a ____ position. It also ___ its tail which displays their ________.
stotting; bouncing; stiff; flicks; white rump patch
what are the 5 hypotheses explaining stotting (incl. rejected ones)?
- antiambush hypothesis - stot to look for predators lying in ambush in the tall grass
- alarm signal hypothesis
- confusion effect hypothesis - stot in groups to confuse predators
- social cohesion hypothesis - stot to attract conspecifics to join them
- attack deterrence hypothesis - deter predators by signalling strength and vigor
what are conspecifics?
members of same species
why is the antiambush hypothesis on stotting rejected?
gazelles stot in short grass too, where visibility of predators in ambush is excellent
gazelles often stot alone. this rejects which 2 of the 5 hypotheses on stotting?
- alarm signal
- confusion effect
why is the social cohesion hypothesis on stotting rejected?
gazelles dont display rump to other gazelles
which of the 5 hypotheses on stotting is accepted?
attack deterrence hypothesis - deter predators by signalling strength and vigor
what does the anolis lizard do when faced with snakes?
which hypothesis supports this?
push-ups
attack deterrence hypothesis
average covey size ok bobwhites is?
11 individuals
optimality theory adaptations have greater _________ than ________.
benefit-to-cost ratios; alternatives
what does the optimal foraging theory state?
foraging decisions should maximise survival and fitness benefits, as measured in weighing costs and benefits of a given behavior
what is the marginal value theorem on foraging?
an animal should leave a patch when the rate of food intake in that patch drops below the average rate for the habitat
name 3 animals which are central based foragers?
ants
birds
bees
a lab sudy in zebra finches tested if optimal feeding improved _________ fitness. seeds were given to the birds with ________ shell protection, varying how much ______ was needed to feed.
individuals with higher net calorie gains reproduced ________ and has ________ offspring.
reproductive; differing; work’
earlier; more
depending on level of predator threat, dugongs switch between 2 types of foraging. what are they? which one yields more nutrition per time spent feeding?
cropping - strip leaves from tall sea grass
excavation - uproots sea grass to access rhizomes (more nutrients)
in food patches where tiger sharks are common, dugongs ____ rather than __________ in foraging, so that they can better _______ the area.
crop; excavate; scan
foraging decisions are often based on _________ pressure.
predation
what is the landscape of fear?
spatially localised elicitation of fear in prey due to local predation threat
a community study looked at 3 prey species and all predators in zambia.
all 3 prey species were more vigilant in the areas predators used most over the long-term, as compared to when actually closest in time and space to the nearest predator.
this shows what?
prey are responding to landscape of fear, an area of expected predation
the adaptive function of competing behavioural strategies is also known as…
frequency-dependent selection
what is negative frequency-dependent selection?
as behavioural strategy becomes rarer, the genotype with that strategy begins to have higher fitness
the rarer one lives
what is positive frequency-dependent selection?
as behavioural strategy becomes rarer, the genotype with that strategy begins to have lower fitness
the rarer one dies
which one, positive or negative frequency-dependent selection, will keep strategies in equilibrium?
negative frequency-dependent selection - as behavioural strategy becomes rarer, the genotype with that strategy begins to have higher fitness
ruddy turnstones are birds with multiple feeding strategies, also known as _________ strategy.
they will use appropriate strategy given the _______.
conditional
conditions
