Complex animal societies
• Personalities
The concept of personality
Personality (or behavioural syndrome) = an individual’s set of
behavioural tendencies
Characterised by two main features:
1. individual behavioural consistency over time and environmental
conditions (behavioural carryover) - e.g. bold individual should be bold in
novel environment and familiar environment, in early life and later in life.
1. 2. high correlations across different behavioural traits –
boldness is mostly correlated with lack of fear and curiosity towards
novel object in environment.
For example: activity, exploration, boldness, aggressiveness, sociability
Pig example: experiment whereby pigs had to cross a space in order to
acquire food. A novel object (colander) was placed in their path. Half the
pigs did not notice novel object, half retreated upon encountering it.
Differences in personalities (bold vs shy) dictated response to the same
situation. Implications for explorations, how you deal with environment,
and how social an individual is with others of their species.
Figure (a) Behaviour measured for
three individuals in three different
environments (E1, E2 and E3).
Individual behavioural consistency is
represented by the fact that the
variation among individuals (solid
double arrow) is larger than the
variation within any individual (the
three hollow double arrows). Note
the presence of phenotypic
plasticity: the three individuals
express different behavioural phenotypes according to the environment.
(b) The three individuals vary their behavioural phenotype according to
the environment, but there is no way to predict what each of them will do
in one environment based on the information from another environment.
Furthermore, within-individual variation is as large as among-individual
variation (repeatability = 0).
The causes of personality
, Proximate causes (mechanisms)
Gene – physiology – behavioural interaction, e.g.
• different levels of circulating hormone(s) influencing a suit of
behavior - hormonal state e.g. male in courtship mode,
defending territory – testosterone levels may be very high in
order to produce this behaviour.
• pleiotropy – one gene influences several behaviour
• linkage disequilibrium – genes influencing different traits to
coevolve (in many individuals see the co-occurrence of
boldness and aggression)
Evolutionary causes (adaptive functions)
1. Life-history trade-off between growth and survival: bold & aggressive
individuals develop fast BUT may die rapidly
2. Spatial and temporal heterogeneity in the environment: selection may
favour different personalities in different environment e.g. Sparrow – bold
and shy individuals. New food – bold sparrows may have an advantage,
immediately target food. Being overly cautious disadvantageous. If
environment changes, slow/shy individuals advantageous as spend more
time calculating environmental factors. Selection may favour in certain
personalities in different environments.
Personality and parenting types
Breeding system of Eurasian penduline tit
- one parent (♀ or ♂) looks after the young (and 1/3 of the time neither
parent cares for the chick, resulting in death of offspring)
- The parent that abandons the young re-mates and re-nests with a new
partner
Sexual conflict over care, because desertion is only beneficial
for the deserting parent (reaps all the benefits with minimal
investment)
Figure: Reduced male care = positive
reproductive success (can mate with other
females). Negative impact upon female
reproductive success, who cannot mate. Vice
versa for female.
Behavioural consistency in penduline tits
- female behaviour is consistent between
different nests there are DESERTERS and
CARERS
• Personalities
The concept of personality
Personality (or behavioural syndrome) = an individual’s set of
behavioural tendencies
Characterised by two main features:
1. individual behavioural consistency over time and environmental
conditions (behavioural carryover) - e.g. bold individual should be bold in
novel environment and familiar environment, in early life and later in life.
1. 2. high correlations across different behavioural traits –
boldness is mostly correlated with lack of fear and curiosity towards
novel object in environment.
For example: activity, exploration, boldness, aggressiveness, sociability
Pig example: experiment whereby pigs had to cross a space in order to
acquire food. A novel object (colander) was placed in their path. Half the
pigs did not notice novel object, half retreated upon encountering it.
Differences in personalities (bold vs shy) dictated response to the same
situation. Implications for explorations, how you deal with environment,
and how social an individual is with others of their species.
Figure (a) Behaviour measured for
three individuals in three different
environments (E1, E2 and E3).
Individual behavioural consistency is
represented by the fact that the
variation among individuals (solid
double arrow) is larger than the
variation within any individual (the
three hollow double arrows). Note
the presence of phenotypic
plasticity: the three individuals
express different behavioural phenotypes according to the environment.
(b) The three individuals vary their behavioural phenotype according to
the environment, but there is no way to predict what each of them will do
in one environment based on the information from another environment.
Furthermore, within-individual variation is as large as among-individual
variation (repeatability = 0).
The causes of personality
, Proximate causes (mechanisms)
Gene – physiology – behavioural interaction, e.g.
• different levels of circulating hormone(s) influencing a suit of
behavior - hormonal state e.g. male in courtship mode,
defending territory – testosterone levels may be very high in
order to produce this behaviour.
• pleiotropy – one gene influences several behaviour
• linkage disequilibrium – genes influencing different traits to
coevolve (in many individuals see the co-occurrence of
boldness and aggression)
Evolutionary causes (adaptive functions)
1. Life-history trade-off between growth and survival: bold & aggressive
individuals develop fast BUT may die rapidly
2. Spatial and temporal heterogeneity in the environment: selection may
favour different personalities in different environment e.g. Sparrow – bold
and shy individuals. New food – bold sparrows may have an advantage,
immediately target food. Being overly cautious disadvantageous. If
environment changes, slow/shy individuals advantageous as spend more
time calculating environmental factors. Selection may favour in certain
personalities in different environments.
Personality and parenting types
Breeding system of Eurasian penduline tit
- one parent (♀ or ♂) looks after the young (and 1/3 of the time neither
parent cares for the chick, resulting in death of offspring)
- The parent that abandons the young re-mates and re-nests with a new
partner
Sexual conflict over care, because desertion is only beneficial
for the deserting parent (reaps all the benefits with minimal
investment)
Figure: Reduced male care = positive
reproductive success (can mate with other
females). Negative impact upon female
reproductive success, who cannot mate. Vice
versa for female.
Behavioural consistency in penduline tits
- female behaviour is consistent between
different nests there are DESERTERS and
CARERS
