Animal Behavior Exam 2

Dr. Anderson SMSU

Mobbing

anti-predator adaptation, often to protect offspring. Collectively harass or attack 

What are the costs and benefits of mobbing

Cost: excessive use of energy, possible injury, goal could not be successful

Benefit: cooperation towards a similar goal, could get more food, could protect home better

Many people think that an adaptation is a trait that improves the survival chances, when would a survival-enhancing attribute (like mobbing) be selected against?

When there is a low stakes environment (no need to do that) 

For mobbing to have adaptive value the benefits must ___ the cost

outweigh

Convergent evolution

independent acquisition of similar traits in 2+ distantly related species

Similarities not due to common ancestry but to similar environmental pressure

Divergent evolution

differences between closely related species due to different selection pressures

Types of social defenses

Mobbing

Yelling

The dilution effect

Group vigilance

Hypotheses explaining passive group defense

Dilution effect

Confusion effect

Selfish herd

Dilution effect hypothesis

group life reduces risk that a particular individual will be preyed on

Confusion effect hypothesis

predators less able to single out/attack an individual

Selfish herd hypothesis

individuals can “hide” behind others to avoid predators, dominant individuals will be pushing for the middle of the pack

Game theory

fitness value of one individual depends on how its behavior interacts with that of others

Crypsis

resembling environmental features or inedible object

What is the benefit of crypsis?

Energetically cheap

What are the costs of crypsis?

Must select the correct background

Must spend time finding background

Spent a lot of time immobile

Operant conditioning

learning based on trial and error, where an action becomes more frequent if rewarded

Secondary lines of defense

Thanatosis

Sudden reveal of color followed by crypsis

Dematic display

Thanatosis

death feigning

Dematic display

startle display

What is the difference between Dematic displays and aposematism?

Aposematism is a genuine warning not to do something while dimitic is fake, nothing bad will happen to the predator

Aposematism

honest warning/signals often using color

Types of mimicry

Batesian mimicry

Mullerian mimicry

Batesian mimicry

aposematic inedible model has an edible mimic

Mullerian mimicry

model and mimic distasteful and exhibit warning coloration

What’s the problem for batesian models?

Mimics presence dilutes signal, predators may fail to learn association between real and fake

Mimic should be rarer than the model otherwise it’s counterintuitive

Optimality theory

assumes adaptation has greater benefit to cost ratio than alternative

What’s the difference between optimality theory and game theory?

Game theory is dependent on the actions of others whereas optimality theory is about what gives the highest benefit with the lowest cost regardless of what others are doing

What are the implications of size selective predation?

Efficient foraging, maximize caloric benefit in relation to time spent

Why might an animal choose a less than optimal prey item?

If other trade offs exist (like greater predation risk)

Landscapes of fear

spatially explicit elicitation of predation fear due to environmental cues

Preferred habitat

the habitat where breeding success is highest

Why might animals select an inferior habitat?

Less competition

What explains why individuals in a lesser preferred habitat achieve similar reproductive success?

If there is less competition then there’s more food, nest sites, mates, etc.

Ideal free distribution theory

uses fitness gains to explain why individuals distribute themselves among several patches

Animals will settle where fitness is maximized even if the habitat is inferior

Territoriality

readiness to defend an area (typically seen in males)

What is the benefit of territoriality?

Access to resources without interference

What is the cost of territoriality?

Losers forces to sub-prime habitats 

Time and energy 

Why (and when) would animals NOT be territorial?

Costs outweigh benefits

Aggressiveness is often adjusted (during non-breeding seasons and when resources aren’t limited)

Prime territory “winners” gain ___

Reproductive success

Why might a challenger give up quickly?

Arbitrary resolution hypothesis

Resource holding potential hypothesis

Payoff asymmetry hypothesis

Arbitrary resolution hypothesis

the residents always win rule based on residency not superiority

Resource holding potential hypothesis

residents have physical edge

Payoff asymmetry hypothesis

residents are familiar with and value their territories more than rivals

Is there evidence to support the arbitrary resolution hypothesis?

No, there was a study that suggested it, but upon retesting, it failed

Why do territory owners spend less time and energy chasing away neighbors than unfamiliar intruders?

The “Dear Enemy Effect”

Dear enemy effect

battles between neighbors are less intense once boundaries established (saves time and energy)

Why might animals disperse? Costs and benefits

Costs: Energy, time, predation risk

Benefit: reduces inbreeding, moving from away from competitors, better territory

Migration

seasonal cycle of departures and returns

What might cause migration?

weather, food, nest sites

What are the costs of migration?

risk of death

fuel

must gain and store weight

Why migrate?

exploit resources

long days

increase food

high quality breeding sites

reduce energy expenditure from surviving winter

How do animals know where to migrate?

thermotaxis

follow others

internal magnetic compass

landmarks

sun/moon/stars

Intraspecific

communication within a species

What is an example of intraspecific communication?

bee dancing

Interspecific

communication between 2+ species

Communication channels

how messages are relayed

Examples of communication channels

visual

auditory

chemical

tactile

electrical

surface vibration

Requirements for communication systems

signaler benefits from providing signal

receiver benefits from responding

How do female spotted hyenas greet each other?

Submissive female allows dominant female to sniff her pseudopenis

How did the pseudopenis evolve? What is the Developmental pathway?

increase androgens in females

What are the hypotheses for the adaptive value to the greeting “ceremony” of hyenas?

by product hypothesis

submission hypothesis

social bonding hypothesis

By-product hypothesis

pseudopenis itself not adaptive, but is a by product of other positive traits like large size, aggression, competition, rank

Submission hypothesis

subordinate females often 1st to display

Social bonding hypothesis

promotes formation of cooperation within clan

Hypothesis for the evolution of the pseudopenis

extra androgen hypothesis

Extra androgen hypothesis

increased levels of male hormones in females while in utero, embryo in contact with testosterone causing the clitoris to become enlarge

Round dance

a dance that indicates food sources

Waggle Dance

food more than 50m away, the longer the waggle the more distant the food, the angle of the waggle indicates what angle to fly in reference to the sun

Sensory exploitation

signal activates a preexisting sensory mechanism already present in receiver (usually female)

What is the panda principle?

panda thumbs are really modified wrist bones. Evolution will find a way to be as lazy as possible without dying

Other examples of “the panda principle”

Laryngeal nerve of giraffes

Lizards losing their tail

Humans have a nerve in the eye that cause blind spots

Sharks have to keep move in order to breath

Wales have hind leg bones

What’s the adaptive value of non-violent threat displays?

No one has to get hurt as long as dominant and submissive individuals accept their place

Honest signal hypothesis

signal conveying true info about the signaler’s quality

Who benefits from honest signaling?

the receiver and sender

Why do animals respond to wrong/deceptive signals?

novel environment theory and net benefit theory

Novel environment theory

current environment different from one where behavior evolved, not enough time for specied to adapt or human modifications of environment

Net benefit theory

illegitimate signalers reduce fitness but do not eliminate net fitness benefit of communication system

Illegitimate signalers

sends signal to deceive others, reducing their fitness

Illegitimate receivers

listen in on individuals that lose fitness by sending message to wrong target

Which sex is the “choosy” sex?

females

Why is it typical for males to do the courting and females do the choosing?

females invest more energy into offspring

Why do investments differ between the sexes when it comes to offspring?

anisogamy

Anisogamy

fusion of 2 dissimilar gametes, the egg is big and few, the sperm are small and many

Fecundity

reproductive capacity

Females aren’t limited in sperm, but by ___

Fecundity

What limits a male’s fitness?

Access to females

Why is parental care less common in males? Why might males opt to mate with more than one female?

females know the child is theirs so care increases odds of survival of offspring, males have uncertain paternity so he doesn’t want to take care of a child that might not be his

Operational sex ratio

the ratio of males to females capable of reproducing at a given time

What leads to a male biased operational sex ratio?

slower rate of reproduction by females

What is sexual selection?

differential repoductive success resulting from competition for mates

Intrasexual selection

sexual selection between same sex (males displaying different traits)

Intersexual selection

sexual selection between different sexes (females choosing)

Which sex has stronger sexual selection?

males

Why do males have stronger sexual selection?

males need to be appealing to females, females will get a male if she wants one

What drives sexual selection?

competition, the male with better traits will mate

What might a better bower signal to a female?

quality of genes, territory, and mental capacity of the male

What are the benefits of female choice?

preferential mating

direct benefits (food, nest site)

indirect benefits (offspring quality)

What is the typical OSR?

male biased, males fight each other for mates

What happens when OSR is less male biased?

cooperative care of offspring, weaker sexual selection

What happens when OSR is reversed?

There are more females ready to mate than males

males provide most care to offspring

females evolve traits for fighting/attracting males