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Behavioral Ecology summary 2023- BHE30306
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Behavioral Ecology summary 2023- BHE30306→ Tinbergen's 4 Question Framework
▪ A fundamental framework that explains and describes any animal behavior, the
underlying principle of behavioral ecology
▪ Two proximate (why) and two ultimate (how)
What is Tinbergen's 4 Questions?
Causation: cause of a behavior, internal/external stimuli
Ontogeny: changes throughout development
Function: adaptiveness of behaviors
Evolution: evolution of behaviors
❖ Natural Selection
• The process by which organisms that are better adapted to their environment tend
to survive and produce more offspring
• The evolution behind traits, adaptations and behaviours (the engine of biodiversity)
• both reproduction and survival ~ reproduction is required to transmit genes
between generations but you need to survive to reproduce
Five Requirements to Natural Selection
1. Variability: individuals with differing morphologies, traits are encoded by genes
2. Heritability: traits can be inherited
3. Competition: some traits being more successful than others
4. Differential survival of traits: balance between survival and reproduction
5. Adaptations to the environment: the engine of adaptations
Behavioral Ecology, genetic terms
genetic code that influences alleles and therefore behavior (alleles coding for
behavior)
Adaptations
Behaviors are associated with costs and benefits, adaptive traits have high benefits and
low costs, if they increase fitness they will be represented in future generations
, (Maladaptive - high cost, low benefit)
the process by which the success of a population is determined by the genes or traits
that are passed on
Selection for behaviors that result in B/C > 1
→ Fitness-
The overall ability to impart its genotype to the next generation, determined by genes
that encode for certain traits, includes viability (survival) and fecundity (reproduction)
High fitness - ability to obtain and allocate resources efficiently to offspring
Relative Fitness
❖ quantified as the average # of surviving offspring of a genome compared with
the average # of surviving offspring of a competing genome, an absolute
measure of fitness
❖ Fitness of an individual relative to another, it involves the competition for
resources and selective will act on individuals with the highest fitness relative to
the population
Levels of Selection
➢ Group: pressures that lead to group adaptations and altruistic traits, acting for the good
of the species
➢ Individual: pressure that led to individual adaptations and selfish traits
Genes
the unit of natural selection, organisms are vehicles that genes use to propagate
themselves
Approaches to Behavioral Ecology
1. Comparative approach: collecting data from nature for comparisons
and to derive patterns and
2. Experimental approach: manipulating variables to determine cause
and effect
3. Theoretical approach: mathematical modelling, the foundation for
which all knowledge is constructed
Survival of the Fittest
, survival as a function of heritable phenotypic traits that influence viability and
competitiveness between individuals
*Organisms better adapted to their environment will be more successful
Success - measured as the number of viable offspring an individual produces, traits that
increase success will evolve (i.e., love)
Sexual Selection
➢ Targets traits that increase the chances of mating success
➢ Occurs when individuals differ in their ability to compete for or attract mates
➢ The differential reproductive success as a function of phenotypic variants that
enhance mating success
The Selfish Gene Theory
genes act as units that encode for specific traits, genes will compete with each
other and want to be represented in future generations
Competition and individuality at the level of genes
Cooperation
with genetic relatives: kin selection theory and grandmother theory
with non-genetic relatives: reciprocal altrisum theory
Animal Competitions
Individuals competing for limited resources, two main forms
1. Scramble competition: resource is assessable to all competitors
2. Contests: fighting/aggressive behaviour to access resources
Contests
a form of competition, involves displays and escalations (costly and rare), the outcome
is influenced by the strategy selected
determine the unequal distribution of resources and fitness (the animal that obtains the
resource has a higher fitness), drives both NS and SS
Frequency-dependent Selection
, evolutionary process by which the fitness of a phenotype or genotype depends on the
phenotype or genotype of the population, individual strategy will depend on population
strategy
Evolutionary Stable Strategy (ESS)
a behavioural strategy that cannot be replaced by a different strategy through NS, if all
members of the population adopt this strategy there is no better alternative strategy
Game Theory
the study of strategies and decision making, individual decision depends on what the
population does
The Hawk-Dove Game
a pure strategy, results in ESS: a population of both hawks and doves where they both have
equal fitness
Hawk: aggressive, fight/injure opponent
Dove: pacifist, displays
Considerations
1. Resource value (V)
2. Cost of wound (W)
3. Time spent displaying (T)
Information Gathering
May occur prior to a fight, individuals gather information about costs and benefits, not
apparent in the hawk-dove game
Dilemma to Behavioural Ecology
looking at animal behaviour in societies but societies must have some means of cooperation (ie
helping behaviours)
Hamilton
explained advantages to helping relatives/kin, formalized inclusive fitness
rB -C >0 the allele will become fixed
Inclusive Fitness
direct + indirect fitness
Direct: alleles passed through offspring
indirect: alleles passed on through related kin
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