How the behaviour of animals is adapted to their natural environment. By taking a behavioural ecology approach, the module integrates thinking about behaviour, ecology and evolution to understand how an animal’s behaviour is adapted. The course will focus on animal behaviour from sex to death, co...
Behavioural:
Survival: find food, compete for food avoid predators
Reproduction: find mate, compete for one, mating behaviour
Why does animal do particular behaviour?
explain the ultimate survival/reproductive value or function of the behaviour
ultimate functional explanation- why has particular behaviour evolved
other biological factors- causation (what causes behaviour), development (do offspring learn from parents),
evolutionary history (links with adaptive value)
Why does starling sing:
Territory
Mates
Warning cry
Lions in Serengeti live in prides:
Different selective expresses between male and female lions
females are synchronous in chemical cues better cub survival
oestrus males do better in groups when
leave pride
share in care for cubs
females are all related
if related males are kicked out as
group they survive bettie
high rate of copulation female infertility cubs survive better
time of ovulation concealed increased paternity uncertainty
males keep mating with female may protect cubs from males
young die when new males take abortion (chemical?) females come into oestrus quicker
over pride- infanticide males kill/evict young cub killing removes competition
from males in pride or future
disadvantage to female- female males
has used resources
advantage for male- opportunity
to produce his own offspring
Infanticide in humans
Daly and Wilson 1994
Infanticide of offspring by genetic father
Highest in young children (0-2)
5 million
Homocide by stepparent per million
Much higher in younger children (0-2)
600 million
introduction to behavioural ecology book-4th edition
, Topics in behaviour: From Sex to Death
BLGY3155
Behavioural ecology:
Behaviour
Ecology
Evolution
Adaptation:
Variation
Heritability
Competition- limited amount of resources
Natural selection - favours one carrying better gene traits
Adaptation as a result of natural selection
Genes influencing behaviour
1. Genetic mutants- irrigation-stuck marker
• Dropshila- when they mate they mate for 20 mins
• Genetic manipulation- knock out gene for this behaviour
• Behaviour gets selected out
2. Artificial selection
• Fast vs slow mating
• Manning- 1961
• Separate the ones that did longest and shortest mating
• Only mated one that did longest with longest and same for short ones
• Artificial selection
• Separate the 2 groups even further in mating time
3. Between population differences
Heritable food preferences in garter snakes
Foraging behaviour in fruit flies
Rovers- forR
• Search for food
• For codes for enzyme that is produced in brain and affects behaviour
• Good short term memory- adaptive for fast learning as they move between food patches
• Exploratory behaviour- seeking out best food resources
Sitters- forS
• Remain in 1 area to feed
• Good long term memory
(Negative) frequency dependent selection:
Advantage is influenced by how much food your taking in
Retain polymorphism
Allele is maintained
Success of rover or sitter is negatively frequency dependent
Population is dominated by sitters- individuals who are rovers will do well
Alleles of rover wills spread into the next generation until they dominate the population
Loads of fruit flies looking of food
Some will still be sitters
Find food and eat in one place- start to do better than rovers
Sitters allele starts to spread again- advantageous allele
Success is dependent on what the other population is doing
Frequency dependent fitness
Key concept
Fitness depends on adaptions to environment
, Topics in behaviour: From Sex to Death
BLGY3155
AND on fitness relative to competitors
Fitness may be frequency dependent
Behaviour and natural selection
?? to ensure survival of the species??
BUT selection acts on individuals
GROUP SELECTION (Wynne Edwards 1962)
Lion infanticide
Not good for species or the group
Selfish individuals
Talking about adaptive behaviour
Avoid animals “want” to maximise intake, spread gene
, Topics in behaviour: From Sex to Death
BLGY3155
studies:
Adaptations of female lions to infanticide by incoming males
Packer and Pusey (1982)
Introduction:
Infanticide- males kill infants of unfamiliar females
advantageous to infanticidal male
disadvantage to females
mechanisms where some females animals reduce losses to infanticide:
behaviour of females that prevents males from killing their young:
females succeed in aggressively defending their young against unfamiliar males
avoid new males by leaving the group
pregnant females show psuedoestrus and mate with new male- confuses paternity ensuring survival of infant
females minimises losses when death of offspring is inevitable:
‘bruce effect’- pregnancy is terminated by exposure to new males or their scent
minimise time and energy invested in offspring
female lions show a period of infertility and heightened sexual activity in male takeovers to reduce frequency
of offspring loss
Method:
record incidence of wounds and reproductive condition and sexual activity of females
results and discussion:
immediate resposnses:
defence of cubs:
mother vigarusly attacked infanticidal male (mothers wounded)
cooperative defence- communal rearing of cubs
avoidance of new males:
mothers accompany older cubs (1.5-2yo) to new area (nomads)
cubs (6-17mo)- remain in pride- avoid alien males
pseudo-estrus:
female lions show estrus behaviour and mate during pregnancy
estrus during pregnancy is rare- only saw 2 cases of this
spontaneous abortion:
pregnant females abort at takeover
impossible to determine is newly pregnant females abort at takeovers
effects on female reproduction and reproductive activity:
reduced fertility:
resume sexual activity, regular estrus cycles- fertility is lower
fertility is lower when cubs are lost at takeover than loss of cubs under other circumstances
lactating females that lost cubs at takeover gave birth with new male 110 days later than females
that lost cubs and mated with same male who fathered their previous litter
females that lost cubs at takeover take 6-9 oestrus cycles to become pregnant
females that lost cub under other circumstances take 1-2 oestrus cycles to become pregnant
bertram (1975)
no pregnancies were initiated until after 3.5mo
females were infertile for 102 days after takeover
they are reacting to newness of males
females become more familiar and more likely to become pregnant- females investigate male
markings
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