Behavioural Ecology --- Study for Final

1. Causation (mechanism)

how is the trait produced?

3. Function (adaptation)

how does the behavior help fitness?

4. Evolutionary history (phylogeny)

how did the behavior evolve?

behavioral ecology

the study of the ecological and evolutionary adaptations for animal behavior
*optimal behavior will maximize fitness*

why is [behavioral ecology] important? (4 steps)

[behavior -> maximize fitness] -> population growth -> relevant conservation

definition of behaviour

the way an organism responds to its environment and to other species

environment includes...

- physical stuff (eg. food supply)
- conspecifics
- other species

Niko Tinbergen's 4 Questions

1. causation
2. development
3. adaptive function
4. evolutionary history

Ethology

the study of behavior in animals' natural environment

2. Development (ontogeny)

how does the behaviour change with age / what early experiences are needed to display the behaviour?

behaviors promote survival by...

-seek mates
-seek food
-seek shelter
-avoid predators

behavior is based on...

- sensory feedback (external trigger)
- coordination and control of animals physiology
**bridge between internal and external processes

Proximate

-HOW it works
-causation (mechanisms)
-ontogeny (development)

Ultimate

-WHY it happens
- adaptive significance
- evolutionary history

adaptation

changes brought about by selection that improve survival and/or reproductive success

for selection to occur...

-individuals must show variation in population
-some variation must be heritable
-competition is inevitable outcome

3 things to remember about genes in behavior

- molecular paths btwn genes + behavior are COMPLEX
- genes influence behavior AND behavior influences gene expression
- genes are NOT the only answer (genotype AND environment)

ethogram

a catalog of all of the behaviors an animal exhibits in its natural environment
- qualitative decr. --> quantitative data

1st step in methods of beh. eco.

Research question / Model system

2nd step

Test Hypotheses
(observations, experiments, comparisons, theoretical approach)

3rd step

Collect Data

4th, 5th, 6th step

4. analyze data
5. interpret results
6. communicate findings

Reproductive Success (RS)

the number of offspring an individual produces per year/breeding event; an individual's genetic contribution to the next generation

Lifetime Reproductive Success (LRS)

the number of offspring produced throughout the lifespan of an individual
can be difficult to measure in long-lived species

Fitness Proxies

indirect measures of fitness, may not be accurate alone
ex. body health, territory quality, social rank

optimality models

predict which decisions an animal should make in order to maximize its fitness in a specific environment

examples of optimality model uses

- carrying a load (parental investment)
- reproductive decisions (when dad stays/goes)
- prey choice (specialize/generalize?)

Charnov's Optimal Diet Model

predicts how a predator should choose between an array of prey types of different profitabilities

internal state matters

starvation = major currency
hungry animals take more risks

life history

schedule of an individual's life including all behavior and physical adaptations

darwinian demon

hypothetical ideal organism matures at birth, starts to reproduce immediately, is immortal and gives birth to infinitely many offspring

extrinsic factors (cause of life history variation)

imposed from outside (ecology and phylogeny)

intrinsic factors (cause life history variation)

tradeoffs among traits, phylogeny,

tradeoffs: current vs future reproduction

survival (future reproduction) vs fecundity (current reproduction)

semelparity

when organisms reproduce only once during their life

iteroparity

when organisms reproduce multiple times during their life

optimal clutch size

ideal number of offspring that yields the greatest fitness

general patterns in life history

1. variation in one trait = variation in another trait ("slow-fast continuum")
2. life history varies w/habitat/environment condition

slow-fast continuum

variation in one trait correlates to variation in another trait

patterns w/ environmental conditions

-food supply: springtime vs wintertime
-large climate variation: winter mortality

Red Queen Evolution

Never-ending arms race where each organism has to keep evolving just to stay in the same relative place

Crypsis (prey tactic)

camouflage that makes prey difficult to see

apostatic selection (prey tactic)

negative frequency dependent selection

Mullerian mimicry

two or more unpalatable species resemble each other

Batesian mimicry

a harmless species mimics a harmful one

search image (predator tactic)

search for most common prey -> rarer morphs become more common -> evolution for prey polymorph

Apostatic selection (predator tactic)

-Predators focus on more common color morphs
-Promotes polymorphism because rarer morphs are more likely to survive

aposematism

warning colorations that advertise defenses

aggressive mimicry

angler fish, alligator snapping turtle

The cuckoo/host egg arms race

-no rejection -> egg rejection evolves -> egg mimicry evolves -> accept most cuckoo eggs

focal sampling

used to select a particular member who will be observed at any given time

scan sampling

at preselected times the observer rapidly scans each member of a group so that the entire group is observed within a relatively short period

Game Theory

-use of mathematical models to represent complex decision making
-the best strategy for given conditions
-depends on others' behaviour(s)
-moves and countermoves

co-evolutionary

how one's strategy co-evolves with other strategies within population, NOT among different species

Evolutionary Stable Strategy (ESS)

a strategy that, if adopted by a population, cannot be trumped by another strategy because it yields the highest fitness

Prisoner's Dilemma

a particular "game" between two captured prisoners that illustrates why cooperation is difficult to maintain even when it is mutually beneficial

ideal free habitat

individuals are free to make a choice and will distribute according to rewards per individual

Despotic Distribution

Holding a territory that comes with substantial benefits

Economic Defendability Model

territorial behavior should be favored by selection when the benefits outweigh the costs

producer

An organism that can make its own food OR finds food independently

scrounger

uses information from others to find food

Personality

consistent differences among individuals
ex. "shy" indivs scrounge more often and spend less time foraging

alternative mating strategies

Different mating behaviors and morphologies that are maintained as a stable polymorphism by negative frequency-dependent selection.

morphological specialization

polymorphisms differing among males
ex. male dung beetles w/ horns vs without horns

endocrine system

a chemical communication network --> influences many aspects of animal behavior

ductless glands

produce hormones that they release into the blood or lymph

neurohormones

hormone secretion direct to blood via neurons

protein hormones

-small peptides or larger proteins
-water (blood) soluble
-can be stored

steroid hormones

-like testoterone + estrogen
-only fat soluble
-cannot be stored - releases immediately

transmission

elicitation of a behavioral response

dilution

safety in numbers
individual reduction in attack risk through grouping

predator swamping

an anti-predator strategy where there are so many individuals that preds have to limit their prey consumption

communal defense

Groups of prey actively defending themselves:
ex: Black-headed gulls will mob crows who come to eat eggs or chicks

vigilance

reduced as group size increases

optimal group size

the size that results in the largest relative benefit

sexual selection

when individuals select mates based on heritable traits
"result of differential mating success"

natural selection

heritable variation of fitness

Intra-sexual selection

competition between members of the same sex for access to mates of opposite sex

Inter-sexual selection

individuals of one sex CHARM indivs of opposite sex
"female choice"

Anisogamy

gamete dimorphism
-zygote survival depends on zygote size
-egg > sperm

why do males usually fight for females?

-anisogamy
-eggs larger w/ more resources, less #s, greater indiv RS
-sperm smaller w/less resources, more #s, less indiv RS
-ultimately, sperm are desperate for eggs

Polyandry

One female, several males.

evidence that sexual selection exists

-sexual size dimorphism: armaments
-female mate choice: ornaments

sexual conflict

-forced copulation
-mate guarding
-frequent copulation
-traumatic insemination

Chase-away sexual selection

evolution of a male character is neutralized by the evolution of a female character, which results in the in the evolution of an even more exaggerated male character.

parental investment

any behavioural/physiological contribution by a parent in an offspring that increases survival/fitness of offspring at a cost to the parent's ability to invest in other offspring

fitness-enhancing hypothesis

an initial benefit to offspring/parents when it was evolved

constraints hypothesis

moms forced to remain bc the embryo is internal

coefficient of relatedness

The fraction of genes that, on average, are shared by two individuals.

intra-brood conflict

offspring demands more than siblings bc its own r=1 (vs r=0.5 for siblings)

inter-brood conflict

current brood demands more than future brood

siblicide

killing your siblings so you don't have to compete with them

Facultative

only under certain circumstances

Obligate

a necessity

brood parasites

when a mama bird lays eggs in other species' nest so she doesn't have to raise them

mating system

how mates are acquired

monogamy

1 male, 1 female
permanent/sequential

polygyny

One male, several females

polyandry

1 female, several males

promiscuity

many males, many females
~free love~