Animal behavior final

Dr. Underwoods animal behavior final Kutztown University fall 2025

What is migration?

non-random directional movement that is predictable over time

-animal continues movement until suitable resources are encountered

Why and how do Wood Thrush birds migrate?

-breeds in Eastern PA/ US during summer

-leaves to escape winter

-spends 8 months in central america

-goes back north to escape competition for food and nest sites, exploit seasonal abundance of food in north, longer days for foraging= better reproductive success

What are the costs of bird migration?

-lots of energy, especially with storms; greater risk of death

-predation

-collisions with windows, lighthouses, towers…

What are neotropical migratory birds?

breed in northern temperate areas and winter in central/ south america

What are the benefits of the north in the summer and the south in the winter in terms of migration?

North- breed in summer

• more food

• less nest predation

• less territory competition

• better reproductive success

South- winter

• reliable food

• stable climate

• higher winter survival

What are the benefits of being a permanent northern bird? (Black-capped chickadee)

• access to resources

• no migration

• earlier nesting

  • higher reproductive success

What are the costs of being a permanent northern temperate bird? (Black-capped chickadee)

• lower winter survival

What are the benefits of being a permanent tropical bird? (Golden-Hooded Tanger)

• higher survival

• access to resources

• no migration

What are the costs of being a permanent tropical bird? (Golden-Hooded Tanger)

• high nest predation

• high competition for territories

How and why do Green Sea Turtles migrate?

• Feed in waters off Brazil

  • More food + energy

• migrate 1800km to Ascention islands to East

  • isolated beaches

  • few predators

  • reproduce and nest here

How and why do Gray Whales migrate?

• one of the longest mammal migrations

• feed in waters off of Alaska

  • more food + energy

• Migrate 10,000km to Mexico

  • calve in warm coastal waters

  • less predators

How and why do Monarch Butterflies migrate?

• Breed in US and Canada

  • more food for caterpillars; milkweed

• Migrate 4,000km to Mexico

  • mtns to 10,000ft

  • overwinter in fir trees

  • shelter, prevent freezing, but not too hot

  • reduce metabolism- low energy use

• Come back to TX/ Louisiana in spring to lay eggs

  • next gen comes back up north

How is climate change affecting Monarch Butterflies?

• some now overwintering in southern US

• going to higher elevations

• 80% reduction in our population

• 99% reduction in Cali/ western groups

Who are usually the choosers in mating?

females

who are the competitors in mating?

males

What is fighting/ aggression in securing copulations?

males fight steryotyped contests

-ex: fencing with antlers/ horns, head butting

Mates with larger body size and/ or weapon wins

Con: injury

what is dominance hierarchy in securing copulations?

dominant males inhibit subordinate males from mating

-aggressive threats

-disrupting mating

dominant has most copulations

-subordinate males mate our of sight of dominant males (surreptitious)

Are low ranking males condemned to celibacy?

no, just need to use alternate mating tactics

-male mating strategy is contingent upon competitive ability

High- large body size → compete for dominance

Low- small body → use “sneaker” strategy

What are alternative mating strategies/ benefits for large males?

-male body size and call intensity related to mating success

-large males with loud calls succeed in attracting females

What are alternative mating strategies for small males? (sneaker strategy)

adopt satellite behavior- intercepting females as they approach calling males (sneaker strategy)

intrasexual selection

what is mate guarding in terms of ensuring sperm success and what animal does it?

Amphipod- phylum Arthropoda, subphylum crustacea

Crustaceans mate for a short time after molting and do not store sperm

-male grabs female before mating

-rejects female if already mated

-if accepted, holds until she molts and sperm is transferred

-after mating, male carries female to prevent other copulations. Guards female longer if other males are present

What is sperm competition in terms of ensuring sperm success?

competition to fertilize eggs from more than 1 male mating with a female

-influenced by health of sperm, # of sperm, order of mating

what is sperm precedence?

timing of copulation relative to other males will determine success in fertilizing eggs

First male advantage

Last male advantage

sperm comp. favors males with adaptations to increase fertilization success

First male advantage

1st male to mate fertilizes most eggs

Last male advantage

last male to mate fertilizes more eggs

what is higher ejaculate volume in sperm competition?

testes size correlates with # sperm

-higher sperm= higher probability of fertilization

Gorillas: female rarely mates with >1 male

-smaller testes

Chimps: Female regularly mates with >1 male

-larger testes

what is frequent copulation in sperm competition?

dominant male guard (cant read word in notes? &) copulates frequently (Bighorn sheep)

-if subordinate chimp copulates, dominant male engages in “retaliatory copulations”

-copulate with that female even more than before

-may displace sperm by volume and sperm from last mating more likely to be successful (last mate advantage)

what is sperm displacement in sperm competition?

(penis of damselflies has backward hairs)

-scoop out sperm of previous males

engage in behaviors to stimulate female to eject previous male sperm

ex: dunnocks

what are repellents in preventing further mating?

male transfers anti-aphrodisiac pheromone with sperm

-female repulsive to future males

parasitoid wasps use scent to find offspring

what is a copulatory plug in preventing further mating?

thick secretion that blocks female reproductive tract

-rodents, snakes/ lizards, marsupials, bats, some primates

Possible functions:

-prevent mating, ensure sperm retained

-sperm transport; gradually released

-scent mark

common garden spider- very effective

what is sexual interference in preventing further mating?

< fitness of rival male by reducing mating success

salamanders produce sperm packet that is deposited on bottom of pond (spermatophore)

-female picks up and transfers to cloaca

spermatophore transfer interference

-rival male gets between courting of male/ female

-rival male deposits spermatophore to get female to pick it up

what is pseudo female behavior in sexual interference?

act like female to get rival to release spermatophore

what is infanticide in sexual interference?

kills competitors offspring

-outside male usurps resident male of a troop

kill offspring

bring female back to estrous (reproductive condition) so new male can mate

only kill unrelated offspring

(langur monkeys)

what are the direct benefits of female choice of a mate in intersexual selection?

material benefits

1.) sufficient sperm

2.) resources- food, nest

3.) parental care

what are the indirect benefits of female choice of a mate in intersexual selection?

benefit offspring

1.) good genes

2.) compatible genes

what is an example of female choice for sufficient sperm? (sato and goshima 2007)

store crabs

compared female preference for unmated vs previously mated (4x) males

-depleted sperm b/c previous mating

female prefers unmated- higher sperm

-chemical cues

important b/c female can choose from distance to avoid being caught/ held by male

what are nuptial gifts as resources in female choice of mate?

male provides nutrition/ resource

gift can:

> male mating success (balloon flies)

> number or fitness of offspring

ex: katydid- large spermatophore gives nutrients for female for eggs

arctiid moth male gives alkaloids from plants in spermatophore

australian red back spider lets female eat him, copulate 2x as long, fertilize more eggs →female less likely to mate

what are territories as resources in female mate selection?

(house wren)

secondary cavity rester- doesn’t build cavity for nest

males often defend >1 nest site

-nest limited supply

added nest boxes to territories (Eckerle and thompsoon 2006)

female preferred > nests

predation high, female can move to new site

what is parental care as a resource in female mate choice?

females prefer brighter red males (house finch)

put into captivity, controlled carotenoids in diet (red pigment)

must forage on food with high carotenoids while mating

bright red foragers indicates parental ability and red males fed chicks most food

what are good genes as an indirect benefit of female mating selection?

assess indicators of good genes

does tail symmetry affect mate choice? (moeller 1990-1992)

-female prefers long symmetrical tails

male barn swallow tail influenced by mite load

good genes for parasite resistance- healthier, better preening ability

whats an example of good genes in female mate choice for the American pronghorn?

male has harem of females (group of females the male defends for exclusive mating access)

-male provides no resources or care

why do females join?

-females prefer males who maintain “zone of tranquility”= area free from intruding rival males

-indicates male physical health/ vigor

mating success for males depends on # females in harem

what is compatible genes in reference to female mate choice?

offspring fitness may depend on fitness bt/wn male/ female genes

Major histocompatibility complex genes (MHC)

-important for immune response

-male house mice prefer diff MHC genes

-via odor cues/ chemical access to compatibility

why do animals choose compatible genes in terms of avoiding inbreeding?

1.) too much homozygosity

higher risk of genetic disorders (recessive) or lethal recessive alleles

2.) increase offspring resistance to disease with heterozygosity

what are indicator mechanisms?

traits indicate good genes

wha is runaway selection?

traits with no real benefits

-females prefer traits that can be passed over time

-male offspring more likely to have trait, pref/ trait linked

-increases selection for trait that may result in exaggeration of trait beyond natural benefits

-irish elk- massive antlers (extinct)

what is sensory bias?

traits that stimulate existing bias in female sensory system

-female prefers traits in males b/c linked to prior bias of females sensory system

Satin Bowerbird

color of females food used by males

-likes blue, males collect blue objects

tested foraging preference in females, they preferred blue food

what is the handicap principle?

-females prefer males that reduce survival- will have good genes

-male can survive despite handicap, female prefers male with largest handicap

ex: female peacocks prefer long tails/ eyespots

-foxes prey on males with lowest mating success

-male with long tail/ their offspring had higher success

-had better genes despite handicap

whats an example of runaway selection with sandflies?

-females choose mate over vertebrate host

-males with most matings called attractive, but didnt survive better; female didnt lay more eggs

-attractive male offspring had higher mating success but no actual better genes in particular

what is cryptic choice?

choice after copulation

cant see choice

female mates with >1 male, chooses which sperm fertilizes egg

males produce spermatophore

-tested males with diff quality by manipulating food access

-female chooses based on nutritional status

-manipulated female ability to control sperm (males mated with dead female)

more transfer in alive females for fed males. female controls sperm transfer

what is parental care?

parental investment

-expenditure on parents that increase offspring survival but decreases ability to invest in other offspring

-costly to parents and siblings; especially mothers

ex: desert spider- lets offspring feed on body

=matrophy

what is the cost of producing sons according to the Finland human pedigree data from the 17-1800s?

looked at offspring born after elder brothers

-survival is the same, decreased lifetime reproductive success

female cannot invest as much in next offspring

why do animals invest so much in sons?

males have higher reproductive potential

-can mate many times= many offspring

-females can only have certain number of offspring at a given time

what is the pattern of parental investment?

parents act to maximize lifetime reproductive success

-not each reproductive event

how do males and females decide patterns of reproductive investment?

1.) how much to invest in reproduction vs own growth/ survival

2.) how to allocate resources to offspring

-creates conflict between parents, parents/ offspring, and siblings

what is scrabble competition in sibling rivalry?

fighting to compete for parental resources

ex: domestic piglet fights for treats

-largest retains possession of food

-smallest fights for position- uses teeth as weapons (canines and 3rd incisors)

-if displaced, may not survive

what is siblicide?

killing sibling to obtain more parental resources

-more common in birds

ex: herons, pelicans, raptors

Why allow siblicide?

pelicans lay 2 eggs but almost always raise 1

insurance in case of:

-egg infertile/ doesnt develop

-food supply is unpredictable. If food is abundant more offspring than normal can be raised.

what are patterns of care in vertebrates?

Almost no care: amphibians, reptiles, fish

Mostly parental care: mammals, crocodilians, birds

Mammals- females provide most care, internal gestation + suckling of young

Birds- mostly biparental, require amount of food that one parent cannot provide

what are parental allocation of resources?

often males and females treated equally

Exceptions:

-brown songlarks- males are larger to attract more mates and have more reproductive success

-females feed offspring

-male nestlings grow faster and heavier, fed more/ higher quality food

males have higher reproductive potential, parents invest more

how does longevity/ reproductive strategy influence resource parental allocation?

birds tested by making feeding young more costly

-can trim parents wing or attach weight

-long-lived seabirds= dont incur costs- feed chicks less

-short-lived songbirds= feed chicks same- incur costs

short lived birds current brood of offspring makes up a larger percent of their lifetime reproductive success than long-lived birds

what is certainty of parentage in parental allocation of resources? with examples

males are less certain of parentage

bluegills- large fish will defend a nest/ care for offspring= parentals

small bluegills wont defend nest- sneaker strategy

Ex: parental nesting males exposed to sneaker males. Sneaker held in a container so it couldnt fertilize eggs

-parentals provided less care to eggs when sneaker present, but no difference in care of fry after hatching

-males can identify own offspring by chemical scent

social monogamy

birds- 90% monogamous

-10% genetically monogamous

most seek out extra pair copulations (EPC)

-no pair bond

What are the male benefits and costs of extra pair copulations?

benefit: higher reproductive success

costs: energy/ time

-cuckoldry- female has other male’s offspring

what are the female benefits and costs of extra pair copulations?

benefits: all eggs fertilized, higher quality genes, genetic diversity, resources

costs: reduced parental care

whats the example of extra pair copulations with purple martins?

old males produce avg 4.5 chicks with own mate and 3.6 chicks through EPC

What is polygamy?

pair bonds with >1 individual

whats the difference between polygyny and polyandry?

1.) polygyny- male has >1 female mate

2.) polyandry- female has >1 male mate (rarer)

describe polygyny

less or no parental care

more competition for resources

Why accept?

a.) polygyny threshold hypothesis

-female chooses a mated male IF quality of resources offsets cost

GREATER success as 2nd degree female on HIGH quality territory than monogamous female on LOW quality territory

whats an example of polygyny threshold hypothesis with the red winged black bird?

-if quality equal, female chooses unmated male

-if mated male territory is superior, female chose mated male

-females have more offspring in polygamous matings (graph on handout)

wha is the polygyny threshold?

point where there is no difference in reproductive success (PT on graph)

higher quality territory/ benefits must be greater than threshold for female to choose polygyny

what is the sexy son hypothesis?

-good genes for offspring offset polygyny

-produce sexy sons to have many grandchildren

pied flycatcher

-followed reproduction success of sons of females that chose monogamy and polygyny

found NO DIFFERENCE in reproductive success of sexy sons, no support for hypothesis

what is female defense in polygyny?

male defends female

when females are gregarious (live in groups)

-cooperate to hunt/ detect predators

-specific birthing grounds

ex: elephant seals

what is resource defense in polygyny?

males defend resources needed to reproduce: nests, food

-common in marshes/ grasslands

-bc resources are unevenly distributed/ clumped/ patchy

ex: marsh when

-male mating success related to vegetation cover

-54% cover= unmated (worse habitat)

-80%= monogamous

95%= polygamous (best habitat)

what is Lec polygyny?

males defend symbolic territories with no resources

occur in Leks (happens in birds/ bugs- midges)

-Lek= mating areas w/ those territories

-common in grouse and pheasants

-10% of dominant males get copulations, usually largest, defend central most territory

why did Lec polygyny evolve? in the male perspective

attract females, safer from predators,

hot spot hypothesis= locate Lek where > likely to encounter females

“hot shot hypothesis”= subordinate males will raise mating success by being near highly successful males

(sneaker males)

why did Lec polygyny evolve? in the female perspective

groups of females

safer from predators

avoid harassment from males

large group of males to choose from/ facilitates mate choice

what are the male/ female perspectives of polyandry?

Male perspec:

male has lowest reproduction sucess

-cant ensure paternity

-limit access to females= limit reproductive success

Female perspective:

-maximise reproductive success

only works if she gets male care/ monopolozes male parental care

what is altruism?

reducing your fitness for benefit of others

what is kin selection?

reducing your fitness for benefit of offspring

are alarm calls costly?

yes but only for terrestrial predators, not arial

what is reciprocal altruism?

does not always involve kin

actor incurs some cost helping recipient who returns favor later

selected for if net fitness go into altruist when favor returned

not dependent on kin

diff types- grooming, sharing food, alarm calls in groups, mixed spp with birds

what are the dependent factors of reciprocal altruism?

1.) high probability for repayment

2.) altruist and recipient recognize each other

-social spp. in groups

-indiv spp that live long

3.) benefit to recip > actor

what is an example of reciprocal altruism in vampire bats?

live 18 years in small stable groups

-feed on mammal blood- cows/ horses often

-1 meal sustains 48 hrs

-unsuccessful 1/3 nights of foraging; need sharing

likely that bats recognize each other; high prob of repayment

how do vampire bats share food in reciprocal altruism?

-needy bat starts licking fur of nearby successful bat

-needy licks successful bats lips

-actor regurgitates food

¼ of blood meal

recip- 12 hours of E

more beneficial to recip than cost to actor

how do vampire bats choose who to share food with?

recognize them- mates or relatives

greater opportunity for reciprocation the longer they know each other

in graph- r= coefficient of relatedness 0-1

kin share but not necessary

what is brood parasatism?

bird lays eggs in other bird’s nest and leave all care of offspring to foster parent/ host

what is a facultative brood parasite?

sometimes lays eggs in other nests, usually conspecific, ducks

what is an obligate brood parasite?

always a parasite, never builds own nest

rare- 1%

can lay more eggs than typical nesting bird

studied the most

what are some examples of an obligate brood parasite?

Common Cuckoo bird (host specialist)

brown headed cowbird (host generalist)

what is a host specialist?

only lays eggs in nest of 1 species/ a couple in an area

what is a host generalist in obligate brood parasites?

lays eggs in several spp nests

brown headed cowbird

what are the costs of parasitism for victims of cuckoo birds?

-paratatizes little song birds

-eats/ removes egg from host

-when hatches- push other eggs out

-needs more food (4x)/ space bc of size

-sometimes hatch together and throws out host’s chick

-host never raises own offspring

-total loss but rare (<5% get parasitized)

what are the costs of parasitism for victims of cowbirds?

-don’t evict hosts chicks, can throw an egg

-evolved to hatch before hosts chicks

-not total loss/ lower cost but reduce offspring for host

-cowbirds abundant- high freq.

multiple parasitism: multiple cowbird eggs in nest, they compete with eachother still

how do birds protect themselves from cuckoos and cowbirds?

1.) nest defense

2.) egg burial and nest desertion

3.) egg ejection

what is nest defense in brood parasite hosts?

can recognize eggs, cover nest. can still be attacked later

what is egg burial and nest desertion in brood parasite hosts?

build new nest on top of old nest BUT cowbird can keep coming back and laying eggs on top of new nests

-can leave nest BUT cowbird can find new nest

what is egg ejection in brood parasite hosts?

-pull out foreign egg, needs to be able to recognize

-if cowbird or cuckoo comes back, will do it again

what is cuckoo egg mimicry?

cuckoo will match look of hosts eggs

evolutionary arms race

-series of adaptations and counter adaptations between parasite/ host spp

-can also be with predator/ prey

what is a mating system?

social bond between males and females for reproduction

male and females at odds

what are the male and female restraints for reproductive success?

Male:

-access to females

-greater success by mating with more females

Female:

-parental care

-higher quality sperm/ good genes

-resources: food, nest sites

each try to maximize own success