Animal Behaviour
BHE-20303
Wageningen University and Research
,Introduction to Animal Behaviour (Chapter 1 & 3)
Behaviour: The internally coordinated responses of whole living organisms to external and/or
internal stimuli.
Alternative hypotheses: Only one of a series of hypotheses could explain something.
Non-mutually exclusive hypotheses: Multiple hypotheses could explain something.
Adaptation: A trait associated with successful survival or reproduction on which natural selection
acts.
Levels of analysis; Tinbergen’s 4 questions (integrative approach):
- Proximate: Immediate causes of behaviour
o Development: How genetic-developmental mechanisms influence the assembly of an
animal and its internal components.
o Mechanism: How neural-hormonal mechanisms that develop in an animal during its
lifetime control what an animal can do behaviourally.
- Ultimate: Evolutionary causes of behaviour
o Evolution: The evolutionary history of a behavioural trait as affected by descent with
modification from ancestral species.
o Function: The adaptive value of a behavioural trait as affected by the process of
evolution by natural selection.
Divergent evolution: Shared ancestry, different behaviour.
Convergent evolution: Distinct ancestry, share behaviour similar selection pressures.
Interactive theory of development: It is the interaction between genes and the environment that
leads to production and evolution of behaviour.
Forward genetic approach: Identify genes responsible for a phenotype by examining gene activity.
Reverse genetics: Determine which phenotype arises as a result of a particular gene sequence
(manipulate genes).
Some changes in behaviour are result of changing the activity of one or more key genes. Theses
probably lead to epigenetic modifications (modifications on DNA without changing the sequence;
including histone modification and DNA methylation) changing gene expression.
Adaptive mechanisms
Imprinting: A form of learning in which individuals exposed to certain key stimuli early in life form an
association with an object or individual and may later attempt to mate with similar objects.
Operant conditioning: A form of learning based on trial and error, in which an action (operant)
becomes more frequently performed if it is rewarded.
Developmental plasticity: The ability to respond to environmental cues through the adjustment of
genotypic expression during early development.
Polyphenism: The occurrence within a species of two or more alternative phenotypes whose
differences are induced by key differences in the environments experienced by individuals.
Behavioural polymorphism: When behavioural phenotypes become relatively more influenced by
genetic factors than by the environment.
2
,Selection favours investment in the mechanisms underlying learning only when there is
environmental unpredictability that has reproductive relevance for individuals.
It is not necessarily the genetic mutations that generate behavioural variation (genomes exhibit
considerable behavioural information redundancy). Many animals develop more or less normally,
despite defective genes or deficient rearing environments because of developmental homeostasis. It
reduces variation around a mean value for a phenotype (which is an adaptive feature of behavioural
development).
Alternative proximate hypotheses for how early life conditions influence fitness later in life:
- Developmental constraint hypothesis:
Individuals born in low quality environment experience reduced fitness later in life.
- Predictive adaptive response hypothesis:
Individuals adjust their phenotype during development to match conditions later in life.
These can take place via maternal effects (phenotype is not only dependent on environment
and genotype from itself, but also from its mother). They are more likely to occur in a
relatively constant environment.
Communication (Chapter 2 & 8)
Bird vocalizations:
- Song (males, complex)
- Calls (both sexes, simple, specific function)
Acoustic communication depends on the sound transmission characteristics (how dense the
environment is) and on environmental noise. It is also important to not only look at the
communication directly near the source, but also near the receiver (the sound can be very different
at distance).
Different populations of birds often sing distinct forms of a song: dialects. Birds learn these during a
critical learning window, where social interactions enhance vocal learning and neural development.
The high vocal center nucleus (HVC) is particularly important for male song learning, and is bigger in
males of species that learn songs than in those that do not. These neural circuits of birds are
convergent with those of humans.
Non-mutually exclusive proximate hypotheses for the development of song (dialects):
- Genetic difference hypothesis:
Differences in song are the result of genetic differences.
- Acoustic stimulus hypothesis:
Differences in song are the result of differences in a bird’s acoustic environment.
- Social interaction hypothesis:
Differences in song are the result of social interactions between a young bird and its tutor.
Singing asymmetries can be in song rate, song matching, and song timing.
Ultimate hypotheses for the function of vocal learning;
- Environmental adaptation hypothesis:
Vocal learning promotes acoustic adaptations of vocal signals to the habitat.
- Recognition hypothesis:
Vocal learning allows vocal signals to become more recognizable and thereby promotes
identification of neighbours or social cohesion within groups.
- Information-sharing hypothesis:
3
, Vocal learning enables expansion of the vocal repertoire in systems where living with kin
favours greater information sharing.
- Sexual selection hypothesis:
Vocal learning enables increases in the complexity of the vocal repertoire that is used in
male-male competition or is favoured by female preference.
- Geographic matching hypothesis:
Vocal learning evolves to promote geographic variation in vocal signals, which in turn allows
assortative mating by site of origin and hence promotes local adaptations.
Sensory systems: Essential to provide animals with information to make adaptive decision (acoustic,
visual, chemical/olfactory, tactile, electric).
Communication is important to provide information and obtain information. Communication involves
signals. Signals are behavioural traits that have evolved specifically to provide information and to
provide a net benefit to the signaller and the receiver.
There are difference level of communication when it comes to the receiver:
- Signal detection (there is a signal, but you cannot place it anywhere).
- Signal discrimination (it is different from another signal, but you cannot recognize).
- Signal recognition (you recognise e.g. the meaning and signaller of the signal).
There are 2 types of signals:
- Information about the external environment (referential signalling):
o Functionally referential alarm calls: Signal represents type of predator.
o Urgency based alarm calls: Signal indicates urgency to respond/of danger.
- Information about themselves.
Alternative hypotheses how signal evolve:
- Pre-existing trait hypothesis:
Signals evolve through senders’ pre-existing traits, which are behavioural, physiological, or
morphological characteristics that already provide informative cues to receivers and can be
modified into a signal in a process called ritualization.
- Pre-existing bias hypothesis:
Signals evolve through receiver’s per-existing biases, which are biases in their sensory
systems that detect some features of the world better than others, and that can be exploited
by sender signals in a process called sensory exploitation.
Sensory drive: The fine-tuning of signals to work effectively in a particular environment.
Different forms of communication when it comes to costs and benefits:
- Receiver and sender benefit: Honest signalling.
- Only sender benefit: Deceitful signalling.
- Only receiver benefit: Eavesdropping (not real communication: individuals extra information
from others ‘interaction).
Instead of signal: cue = unintentional transfer of information.
- Both cost isn’t likely to evolve.
Honest signal: A signal that indicates the quality of the sender, facilitates decision making by a
receiver, and cannot be easily produced by the sender. It’s also hard to fake it or cheat.
Prevention of deception of honesty:
4
BHE-20303
Wageningen University and Research
,Introduction to Animal Behaviour (Chapter 1 & 3)
Behaviour: The internally coordinated responses of whole living organisms to external and/or
internal stimuli.
Alternative hypotheses: Only one of a series of hypotheses could explain something.
Non-mutually exclusive hypotheses: Multiple hypotheses could explain something.
Adaptation: A trait associated with successful survival or reproduction on which natural selection
acts.
Levels of analysis; Tinbergen’s 4 questions (integrative approach):
- Proximate: Immediate causes of behaviour
o Development: How genetic-developmental mechanisms influence the assembly of an
animal and its internal components.
o Mechanism: How neural-hormonal mechanisms that develop in an animal during its
lifetime control what an animal can do behaviourally.
- Ultimate: Evolutionary causes of behaviour
o Evolution: The evolutionary history of a behavioural trait as affected by descent with
modification from ancestral species.
o Function: The adaptive value of a behavioural trait as affected by the process of
evolution by natural selection.
Divergent evolution: Shared ancestry, different behaviour.
Convergent evolution: Distinct ancestry, share behaviour similar selection pressures.
Interactive theory of development: It is the interaction between genes and the environment that
leads to production and evolution of behaviour.
Forward genetic approach: Identify genes responsible for a phenotype by examining gene activity.
Reverse genetics: Determine which phenotype arises as a result of a particular gene sequence
(manipulate genes).
Some changes in behaviour are result of changing the activity of one or more key genes. Theses
probably lead to epigenetic modifications (modifications on DNA without changing the sequence;
including histone modification and DNA methylation) changing gene expression.
Adaptive mechanisms
Imprinting: A form of learning in which individuals exposed to certain key stimuli early in life form an
association with an object or individual and may later attempt to mate with similar objects.
Operant conditioning: A form of learning based on trial and error, in which an action (operant)
becomes more frequently performed if it is rewarded.
Developmental plasticity: The ability to respond to environmental cues through the adjustment of
genotypic expression during early development.
Polyphenism: The occurrence within a species of two or more alternative phenotypes whose
differences are induced by key differences in the environments experienced by individuals.
Behavioural polymorphism: When behavioural phenotypes become relatively more influenced by
genetic factors than by the environment.
2
,Selection favours investment in the mechanisms underlying learning only when there is
environmental unpredictability that has reproductive relevance for individuals.
It is not necessarily the genetic mutations that generate behavioural variation (genomes exhibit
considerable behavioural information redundancy). Many animals develop more or less normally,
despite defective genes or deficient rearing environments because of developmental homeostasis. It
reduces variation around a mean value for a phenotype (which is an adaptive feature of behavioural
development).
Alternative proximate hypotheses for how early life conditions influence fitness later in life:
- Developmental constraint hypothesis:
Individuals born in low quality environment experience reduced fitness later in life.
- Predictive adaptive response hypothesis:
Individuals adjust their phenotype during development to match conditions later in life.
These can take place via maternal effects (phenotype is not only dependent on environment
and genotype from itself, but also from its mother). They are more likely to occur in a
relatively constant environment.
Communication (Chapter 2 & 8)
Bird vocalizations:
- Song (males, complex)
- Calls (both sexes, simple, specific function)
Acoustic communication depends on the sound transmission characteristics (how dense the
environment is) and on environmental noise. It is also important to not only look at the
communication directly near the source, but also near the receiver (the sound can be very different
at distance).
Different populations of birds often sing distinct forms of a song: dialects. Birds learn these during a
critical learning window, where social interactions enhance vocal learning and neural development.
The high vocal center nucleus (HVC) is particularly important for male song learning, and is bigger in
males of species that learn songs than in those that do not. These neural circuits of birds are
convergent with those of humans.
Non-mutually exclusive proximate hypotheses for the development of song (dialects):
- Genetic difference hypothesis:
Differences in song are the result of genetic differences.
- Acoustic stimulus hypothesis:
Differences in song are the result of differences in a bird’s acoustic environment.
- Social interaction hypothesis:
Differences in song are the result of social interactions between a young bird and its tutor.
Singing asymmetries can be in song rate, song matching, and song timing.
Ultimate hypotheses for the function of vocal learning;
- Environmental adaptation hypothesis:
Vocal learning promotes acoustic adaptations of vocal signals to the habitat.
- Recognition hypothesis:
Vocal learning allows vocal signals to become more recognizable and thereby promotes
identification of neighbours or social cohesion within groups.
- Information-sharing hypothesis:
3
, Vocal learning enables expansion of the vocal repertoire in systems where living with kin
favours greater information sharing.
- Sexual selection hypothesis:
Vocal learning enables increases in the complexity of the vocal repertoire that is used in
male-male competition or is favoured by female preference.
- Geographic matching hypothesis:
Vocal learning evolves to promote geographic variation in vocal signals, which in turn allows
assortative mating by site of origin and hence promotes local adaptations.
Sensory systems: Essential to provide animals with information to make adaptive decision (acoustic,
visual, chemical/olfactory, tactile, electric).
Communication is important to provide information and obtain information. Communication involves
signals. Signals are behavioural traits that have evolved specifically to provide information and to
provide a net benefit to the signaller and the receiver.
There are difference level of communication when it comes to the receiver:
- Signal detection (there is a signal, but you cannot place it anywhere).
- Signal discrimination (it is different from another signal, but you cannot recognize).
- Signal recognition (you recognise e.g. the meaning and signaller of the signal).
There are 2 types of signals:
- Information about the external environment (referential signalling):
o Functionally referential alarm calls: Signal represents type of predator.
o Urgency based alarm calls: Signal indicates urgency to respond/of danger.
- Information about themselves.
Alternative hypotheses how signal evolve:
- Pre-existing trait hypothesis:
Signals evolve through senders’ pre-existing traits, which are behavioural, physiological, or
morphological characteristics that already provide informative cues to receivers and can be
modified into a signal in a process called ritualization.
- Pre-existing bias hypothesis:
Signals evolve through receiver’s per-existing biases, which are biases in their sensory
systems that detect some features of the world better than others, and that can be exploited
by sender signals in a process called sensory exploitation.
Sensory drive: The fine-tuning of signals to work effectively in a particular environment.
Different forms of communication when it comes to costs and benefits:
- Receiver and sender benefit: Honest signalling.
- Only sender benefit: Deceitful signalling.
- Only receiver benefit: Eavesdropping (not real communication: individuals extra information
from others ‘interaction).
Instead of signal: cue = unintentional transfer of information.
- Both cost isn’t likely to evolve.
Honest signal: A signal that indicates the quality of the sender, facilitates decision making by a
receiver, and cannot be easily produced by the sender. It’s also hard to fake it or cheat.
Prevention of deception of honesty:
4
