Animal Behavior Exam 2

antipredator adaptations

behavioral, morphological, and other adaptations of prey that help them against predators

predation sequence

prey encounter, prey detection, pursuit, capture, handling, and consumption

alarm signal hypothesis

alert others to communicate predation risk to conspecifics

social cohesion hypothesis

gazelles stot to attract conspecifics to join

confusion effect hypothesis

when multiple gazelle stot to confuse the predator and deter it from singling one individual out

attack deterrence hypothesis

gazelles stot to signal that they are good at escaping

blending in

avoids detection through camouflage

camouflage

a prey color pattern that reduces predator detection

crypsis

having a similar color to the background

disruptive coloration

contrast patterns break up an animal’s feature or outline

masquerade

resemblance of an organism to an inedible object (trying to look like something else)

industrial melanism

peppered moths were light in color until a dark form of them spread quickly in polluted areas of the countryside

active camouflage

camouflage that can change to match the enviornment

(octopus in seconds, chameleon in minutes, artic fox is seasonally)

developmentally plastic

color slowly change as they grow

peppered moth caterpillar

caterpillars choose the twig color that matches their own color and they don’t need to see to show the choice bias

how do peppered moth caterpillars sense color

they exhibit proteins that are related to visual sensitivities and have extraocular photoreceptors: visual ability from non-eye tissues

standing out

to avoid pursuit (using aposematism)

• can also be done by playing dead

• diverting attention away from lethal body parts (decoy/dazzle coloration)

aposematism

prey uses a warning signal (bright color pattern) to warn predators of its toxicity or unpalatability

predator learning

predators learn to associate certain colors with toxins and the more common a color is, the more likely the predator has been educated to avoid you

mullerian mimicry

two or more toxic species resemble each other to share the cost of educating predators (mutualism)

• both are toxic but try to teach predators that what they look like means that they are toxic

Batesian mimicry

a non-toxic species resembling a toxic species, and can lead to predators NOT avoiding a warning color (exploitation)

• one is toxic while the other isn’t (trying to look like the toxic one)

honest signal

when a signal accurately reflects the ability/condition/quality of the signaler

passive social defense

dilution effect

confusion effect

selfish herd

active social defense

mobbing

sentinels and alarm calls

cooperative social defense

H1 Dilution effect

being in groups make it less likely for any one individual to be targeted

• predation risk for individual prey is lower

• predator success rate per attempt is the same

• (decreases the probaility of an individual being targeted)

H2 Confusion effect

moving groups make predator harder to single out and go after an individual (high contrast color patterns can enhance the confusion effects)

• predation risk for individual prey is lower

• predator success rate per attempt is lower

• (decreases the predator’s ability to successfully capture an individual)

H3 Selfish Herd

individuals in a group reduce predation risks by putting others in between themselves and the predator

• moving towards a neighbor reduces the chance of benig the one selected by the predator

• animals in the center are less vulnerable, so dominant individuals jockey for that safe position

Mobbing

mobbing behavior reduces predation success

sentinels and alarm calls

sentinels watch for predators while the other members feed, and produce alarm calls to warn them if predator is being spotted

• different alarm calls can signal predator proximity, predator type, and threat level of predators

• they do it to increase inclusive fitness and when the cost is lower

costs for sentinels and alarm calls

sentinels can’t feed

they are in a position that is more vulnerable to predators

alarm calls can attract predators

foraging behavior

methods by which an animal acquires sources of energy and nutrients

foraging steps

encounter

detect/recognize

(herbivore) decision or (predator) the predation sequence

Stay vs Move

ideal free distribution

proposed that if all individuals choose patches based on payoffs, they will eventually distribute themselves among the patches based on resource distribution

optimal foraging theory

costs and benefits are associated with different foraging decisions, and animals should choose the optimal strategy for highest net benefit (benefit-cost)

• assumes that costs and benefits do NOT change with what other individuals are doing

evolutionary game theory

further assumes that costs and benefits ARE primarily determined by what others are doing

• natural selection favors behaviors that lead to the highest fitness

• the fitness of a behavior depends on what the other individuals are doing

law of diminishing returns

it becomes harder and harder to find food as time goes on

negative frequency dependent selection

relative fitness of a phenotype increases as it becomes rarer in the population

• the more common a behavioral strategy is in a population, the less benefit it has

predator-prey arms race

efficiency of predator foraging depends on how well your food (prey) can elude you

landscape of fear

the spatial distribution of where prey forage is shaped by the predation risk they perceive

• this influence both prey foraging and predator foraging

acoustic camouflage

specialized scales on wings and body that absorb ultrasound, or by producing “clicks” to mess with echolocation

acoustic decoy

divert attack to non-lethal body parts

aggressive mimicry

instead of chasing after prey, predator mimicking profitable signals (food or mates) to lure prey towards its

animal trade-offs

animals make trade-offs between finding food and avoiding predators

when there are predators around, animals often change when and where they forage

waggle dance

used to communicate the location of valuable resources to their hive mates

• will move towards the sun as the reference to communicate

• will move in the “up” direction as the reference when performed inside

• direction of waggle= direction of food

• length of waggle= distance of food

round dance

when food source is close to the hive (50m) the bee executes a round dance

dance variation

• long distance foragers: need to communicate very different ranges (10m, 100m, 1000m)

• short distance foragers: need to communicate distance resolution better (10m, 15m, 20m)

animal signals

• honest signaling: beneficial for both sender and receiver

• deceitful signaling: sender benefit at the cost of the reciever

• eavesdropping: receiver pick up cues that the “sender” had no intension of sending

ritualized aggression

a graded series of signaling displays that convey increasing agonistic intent before escalating to physical fight (risky and energetically costly)

production cost

if signal requires energy to produce, low quality or low condition individuals cannot afford to produce it

badge of status

siganl that revealed dominance status or fighting ability of an individual

• not expensive to produce but expensive to maintain

• cheaters suffer social costs that outweight any benefits of cheating

aggressive mimicry

predators use deceitful signals to exploit communication systems/innate behaviors of another species

H1 preexisting trait

provided information about the individual which evolved to become signals

H2 preexisting sensory bias

detected certain features were better than others, which the sender signal adapted to

preexisting trait hypothesis

there were preexisting traits that provide informaiton about the individual, which late evolve to become signals

preexisting sensory bias hypothesis

senders adapted to preexisting sensory biases in recievers

territoriality

the monopolization of space by an individual, pair, or group

territory

a defended area where an individual, pair, or group monopolize resources

home range

non-defended area where an individual, pair, or group spend their time

benefits of territoriality

resource monopolization

more offspring

costs of territoriality

time and energy spent defending territory

risk of injury and predation

cost of elevated testosterone

prior residence effect

when there is a fight, territorial resident usually wins, and intruders usually retreat quickly

asymmetry in RHP

territory residents overall have better contest ability than the intruders

resource holding potential (RHP)

a measure of an animal’s capacity to win a fight against an opponent

• fighting ability

payoff asymmetry

territory residents have a higher benefit if they win, so they have higher motivation to fight than the intruders

• the longer a resident defend a territory, the higher investment they put into defending it

• motivation

experience asymmetry

territory residents are more likely to have won a previous contest than the intruder, making them more likely to win the next one

• past contest experiences

winner effect

increased probability of an individual winning the next contest when it won the previous contest

loser effect

decreased probability of an individual winning the next contest when it lost the previous contest

dispersal

movement from one area to another (one-way)

migration

periodic movement to and from areas of interest (round trip)

active dispersal

animals use their own locomotive ability to move from one area to another (birds flying)

passive dispersal

animals rely on external forces like wind or water to help them move

(wind pollination, marine larvae)

diel vertical migration (DVM)

daily vertical migration of zooplanktons and other small marine animals

• night: migrate up to forage the phytoplankton on the epipelagic layer

• day: migrate down to hide from larger fish predators

dispersal cost

risk during movement

• increased movement rate and being in an unfamiliar area can result in greater risk of death

dispersal benefits

• animals only move when the potential benefits in a new patch outwighs the cost of traveling

• prevents inbreeding depression

inbreeding depression

decreased fitness of inbreeding

(increase in the chance of delterious recessive alleles becoming homozygotes)

sex-biased dispersal

in many species, one sex disperse much father, which can further reduce inbreeding

migration cost

• very energetically demanding for animals and many require extra energy reserves (fat) for migration season

• mortality risk during migration is often high

strategies to reduce migration costs

• temporary atrophy of reproductive organs

• increase in muscle/metabolism efficiency

• migrating in a route that has stops to allow for additional foraging

• flying in formation

migration benefits

• allows animals to take advantages of temporally variable resources at different locations

temperate habitat

summers have longer days, allowing more plant and insect growth and longer foraging hours

tropical habitat

winters are milder and have more food and shelters

bottom-up forces

resource availability drives migration pattern

top-down forces

predation risks dirves migration patterns