Behavioural Ecology

Question 1

Four questions

Answer 1

Proximate cause: how a behaviour occurs (morphological and physiological mechanisms)
- mechanism: what stimulus causes the behaviour?
- ontogeny: how does an individuals reaction or response to the stimulus change over its lifetime?

Ultimate cause: why a behaviour occurs/why natural selection has favoured a behaviour
- adaptive value: what about the behaviour increases an individual’s fitness (helps it survive and reproduce)?
- phylogeny: what is the evolutionary history of the behaviour?

Question 2

Behaviour

Answer 2

Action (stimulus-response) that alters the relationship between an organism and its environment
- stimulus may be external ( e.g. vervet monkey alarm)
- stimulus may be internal (hunger pains)

Question 3

Innate behaviour

Answer 3

• inherited or inborn
• inflexible (i.e. not affected by learning or environmental conditions)
• stimulus triggers response automatically
• do not need be to taught these behaviours

Question 4

Instinctual behaviour

Answer 4

• inborn/inherited
• inflexible (independent of environmental conditions)
• more complex than innate
• e.g. wildebeest calves stand ad walk immediately after birth

Question 5

Condition dependent behaviour

Answer 5

flexible in response to environmental conditions/change response to environmental cue (i.e. spiny lobsters hide more when there are more predators)
- cost benefit analysis in behaviour (energetic, risk, & opportunity cost)

Question 6

Learned behaviour

Answer 6

Changes in response to learning; learning is a change in behaviour that results from a specific experience in the life of an individual (e.g. grizzly bears teach clubs to fish)

Question 7

Behaviour type matrix

Answer 7

Learnability (down) and condition dependence (right)

Question 8

Genetic predisposition

Answer 8

A genetic characteristic which influences the possible phenotypic development of an individual organism within a species/population under the influence of environmental conditions

• rover allele (high population density)
• sitter allele (low population density/resource abundant; expends less energy)

Question 9

Foraging behaviour

Answer 9

Depends on distance travelled
- min. cost of finding/ingesting food and risk of predation
- max. usebale energy then in
- farther away increases risk of predation

Question 10

Darwinian fitness

Answer 10

Measure of the reproductive success (contribution to the next generation); has 3 components:

1. Survival or mortality selection
2. Mating success or sexual selection
3. Family size or fecundity selection

Question 11

Sexual dimorphism

Answer 11

Refers to phenotypic difference between males and females; in many cases dimorphisms cannot be explained by viability selection (selection of individual organisms who can survive until able to reproduce)

Question 12

Sexual selection

Answer 12

Differential reproductive success resulting from differential abilities to find a mate; undergo different selective pressures

Question 13

Parental investment

Answer 13

The energy, time, and resources devoted to mating, gestating, and caring for offspring; parental investment usually much greater for females; eggs are expensive and sperm is cheap

Question 14

Daily energetic investment in gametes (m vs. f)

Answer 14

• daily female egg productions requires 3x the energy needed for daily basal metabolism
• daily male sperm production requires 4/1000 of the energy needed for daily basal metabolism
• eggs require more energy than sperm

Question 15

Asymmetric limits on reproductive potential

Answer 15

Males have much greater variance in reproductive success than females (can produce an infinite quantity of sperm); but success is limited by the number of mates they can obtain

• male reproductive success diminishes with age; females does not

Question 16

Intrasexual selection

Answer 16

Interactions between members of the same sex

Question 17

Intersexual selection

Answer 17

Interactions between members of opposite sexes

Question 18

“Male-male” competition: combat

Answer 18

• Intrasexual section is male-male combat can favour morphological traits (i.e. large body size, armour, antlers etc.)
• the greater the potential for reproductive success (variance) the greater the competition for mates
• when reproductive variance is greater for females, it will favour competitive traits

Question 19

“Male-male” competition: infanticide

Answer 19

Male kills off other males young since nursing females are not able to breed

Question 20

Estrus

Answer 20

Recurring period of sexual receptivity

Question 21

Cues for mating

Answer 21

Males and females synchronize; reproduction synchronizes with food availability and predation risk

Seasonal cues: Day length triggers hormonal change in spring; phonology: study of seasonal timings in life cycle events

Social cues

Question 22

Synchronizing

Answer 22

• widest selection of possible mates
• timed to coincide with abundance of resources
• timed to coincide with favourable weather
• cues result in resources when they’re most available

Question 23

Female choice

Answer 23

Females have opportunity to choose which mate they want to mate with (will pick male that has the traits she is looking for)
- most fit; passes on to offspring
- mating calls, colours etc. proves how they acquired resources

Question 24

HOW female chooses (female choice)

Answer 24

• good genes hypothesis: male ability to pass on genes that will increase survival/reproductive success of her offspring
• sexy sons hypothesis: male whose genes will produce male offspring with best chance of reproductive success
• sometimes random

Question 25

Polygyny

Answer 25

Males mating with 2 or more females

Question 26

Polyandry

Answer 26

Females mating with 2 or more males; males contribute significantly to parental care

Question 27

Classic polyandry

Answer 27

Female has multiple males in the brood that each tend their own clutch

Question 28

Cooperative polyandry

Answer 28

All males contribute to the parental care of a single clutch; some may not be his offspring but some are so he cares for them all

Question 29

Diel migration

Answer 29

Move between 2 geographic regions daily (day and night); trade off between predator avoidance and food

Question 30

Seasonal migration

Answer 30

Rainy vs. dry season; summer vs. winter

Question 31

Navigation (migration)

Answer 31

- Piloting: familiar landmarks memorized - compass orientationL ability to identify direction N,E,S,W (i.e. sun/stars, magnetic field, currents) - true navigation: ability to locate a specific place on Earth’s surface

Question 32

Why migrate? (risks & benefit)

Answer 32

RISKS: - energy expenditure - predation risk - time not reproducing BENEFITS: - exploit temporarily available resources (food) - access habitat only seasonally accessible - avoid cyclic hazards (e.g. mosquitos and caribou) - take advantage of different habitat during different life cycle stages

Question 33

Migration

Answer 33

The intentional, directional often cyclic movement of a population between two regions, usually associated with a cyclic change in the environment

Question 34

Dispersal

Answer 34

The movement of individuals in a population, typically from the area of birth to a new location (one way trip)

Question 35

Communication

Answer 35

A social process in which a signal from one individual modifies the behaviour of another individual - the stimulus is a signal and evokes a response in another individual; no response means no communication

Question 36

Mimicry

Answer 36

Mimic colouration of another species to avoid predation; lying only works when it’s uncommon (i.e. lures)

Question 37

Mimic males

Answer 37

Why aren’t all males mimics? Frequency-dependent selection. - the mimic male will be more successful; will pass on genes and have offspring; but becomes too common then less effective (back-and-forth)

Question 38

Altruism

Answer 38

Behaviour with a direct fitness cost to he individual carrying out the behaviour and a direct fitness benefit to the recipient (i.e. self-sacrifice); is rare i.e. alarm calls (ground squirrels), worker casts (protect queen bee), food sharing (wild dogs)

Question 39

Kin selection

Answer 39

Pass down your genetic info by producing offspring or by helping your relatives produce more offspring - if benefits of altruistic behaviour are high, the benefits are dispersed to close relatives who likely also possess the trait for altruism - if costs are low, alleles associated with altruistic behaviour will be favoured by natural selection

Question 40

Hamilton’s Rule

Answer 40

If Br>C, then altruism is favoured by natural selection (look at example pg. 143) B = the fitness benefit to the beneficiary r = the coefficient of relatedness C = the fitness cost to the actor

Question 41

Hamilton’s rule: direct fitness

Answer 41

Derived from your own offspring (your own specific contribution to the next generation)

Question 42

Hamilton’s rule: indirect fitness

Answer 42

Derived from helping relatives have more offspring than they could otherwise (contribution to relatives) - affected by kin selection - helping individuals in family increases chances of passing on genetics

Question 43

Inclusive fitness

Answer 43

Direct + indirect fitness

Question 44

Calculating coefficients of relatedness

Answer 44

rBC = sum of(rBA X rAC) (A, B, C are subscripts) a) half siblings: r = 1/4 b) full siblings: r = 1/2 c) cousins: r = 1/8 (0.125)

Question 45

Reciprocal altruism

Answer 45

An exchange of fitness benefit that are separated over time; not necessarily due to relatedness (may receive help in the fitter from non-kin)

Question 46

Haploid

Answer 46

haploid male develops from unfertilized egg (no father but has grandfather); diploid female develops from mating of haploid female and diploid male - diploid sisters: r = 0.75 - relatedness of diploid females to offspring: r = 0.5