mini mod.: animal behaviour Flashcards
Approaches to studying behaviour-pitfalls
*Ethology –form & function
*Neuroethology –neural control of behaviour
*Behavioural ecology –behavioural adaptations & selection pressures
*Sociobiology –social behaviour
*Behavioural genetics –control of behaviour by multiple genes & modifiers of gene expression
Phsychology-perception, mental representation, learning, etc.
Anthropology -humans + human origins
PITFALLS:
Anthropomorphism - naive extrapolation from humans to animals(smiling-animals smile out of fear/aggression)
Naive soiciobiology- sexism, racism, militant atheism
definitions:
communication
signals
cues
eavesdropping+communication networks
animal senses
Communication: Passing of information from a sender to a receiver.
Signals: A feature of an animal that has evolved specifically to alter the behaviour of receivers.
Cues: Any feature that can be usedby an animal as a guide to future action.
Eavesdropping & communication networks- can be exploited by predators eg. Owl
Animal senses: Methods by which animals perceive their environment - Perception of the external world depends on sensory systems
how signals evolve
Cues revealing autonomic stimulation
Respiration
Urination/defecation-chemical marking of territories
Thermoregulation-raising hair/feathers
Pupil dilation-friendliness/arousal
Yawning-signal of aggression to primates(humans don’t fight with teeth so become physiological role)
Signals evolve to maximise transmission and minimise eavesdropping
Eg. Conspicuousness to a predator
Guppies exposed to different predators
have different colour patterns
Predators drive selection for use of “private wavelengths”
ritualised signals V cues
conspicuous- increase detect ability
Redundancy
Stereotypy
Alerting components
Ritualisation of cues revealing changes in behaviour:
Intention movements
Self protective movements
“Displacement” behaviours
signalling danger
Communication with other prey
Alert
Flee
Assemble
Attack
Communication with predator
Startle displays
Aposematism = conspicuous warning of unprofitability
Pursuit deterrence e.g. mobbing
vervet monkey
An eg. Of coding
Learned calls for specific circumstances :
‘Leopard’ -head for trees
‘Snake’ -stand + search
‘Raptor’ -look at sky
sexual selection
Sexual selection-natural selection for traits that increase reproductive success
sexual V natural selection
natural:
Variation between individuals
Variation effects survival
Variation is inherited
sexual:
Variation between individuals
Variation effects reproductive success
Variation is inherited
Anisogamy-unequal gametes
Eggs are large & expensive,
sperm are small & cheap!
*Males produce huge numbers of tiny sperm
*Females produce a relatively small number of eggs
*Females (usually) invest more in growing & caring for each offspring
Ardent males compete for choosy females!
Intra-sexual competition
MALE - MALE COMPETITION
Ardent males compete for access to females
-fighting-dangerous
-ritualised contest-roaring
-guard of females-forced mating(rape eg. Ducks)
-sperm competition-Competition for inseminations between the sperm of rival males
Inter-sexual selection
FEMALE CHOICE
Selection favours females who choose the best possible males to mate with
Benefits of choosing good quality mates:
Good resources & parenting ability
Good genes (high quality sexy parents have high quality sexy offspring)
Methods to impress females
Defeat opposition
Defend high quality territory
Provide ‘nuptial gifts’ =courtship feeding
Advertise genetic benefits of a good choice
1. Have attractive traits=runaway sexual selection
2. strategic “handicap”Conley high quality males can afford to possess(hard to escape predators-peacocks tail)
Sexual conflict
Conflict of interest between male and female
Eg. Sexual cannibalism
Eg. Infanticide
-can be over parental care
-some situations, females compete for males
Mating systems
monogamy - eg. European robin
polyagomy/polygyny - eg. marsh harrier
polyandry - eg. phalarope
polygynandry - eg. kentish plover
promiscuity - eg. aquatic warbler
Eg. Of cooperation- parental care, helping siblings
parental care:
Offspring have copies of parents genes, so helping offspring (by feeding them) is an effective way of maximising genetic contribution to future generations
Each parents contributes 50% of its genes to each offspring
helping siblings:
Siblings have coefficient 0.5 so individuals could maximise their genetic contribution to next generation by:
Helping to rear their full siblings
Rearing their own offspring
Coefficient of relatedness
= genetic similarity of 2 individuals relative to the population as a whole
= probability that 2 individuals share a gene that is identical by descent(from same ancestor)
= probability of sharing a rare allele
”Genes eye view” of selection
A gene can maximise its transmission to the next generation by:
Direct fitness-maximising the reproductive success of the individual it is in
Indirect fitness-maximise the reproductive success other individuals who share copies of that gene
inclusive fitness = direct + indirect fitness
Optimising long term fitness
Animals should maximise their lifetime inclusive fitness
Kin selections- the process by which traits are favoured due to their effects on the fitness of relatives
Hamilton rule
Identifies the conditions under which altruism will spread due to kin selection
Altruism will be favoured if:
r x B - C > 0
r = coefficient of relatedness between actor and recipient
B = benefit to recipient
C = cost to actor
Extreme altruism
Eg. Extreme altruism: suicide and sterility in the social insects
Bee stings are fatal to the worker bee = suicide
Workers rarely reproduce themselves but instead help their mother(queen) to produce offspring= sterility
Male develop from unfertilised eggs and so are haploid: all genes come from mother
Females Develop from fertilised eggs, so are diploid: half genes from mother, half from father
Eg. Naked mole rat (sabre toothed sausage)
Reproductive divisions of labour:
One reproductive female “QUEEN”
1-3 reproductive males
Reproductive suppression of “workers”
LOTS of close relations(20-300 individuals)
High coefficient of relatedness
Cooperative brood care
Overlap of generations
Cooperative foraging(sharing highly patchy foods = tubers)
Coop courtship in wild turkeys
Male turkeys form coalitions to court and defend females
One dominant male(gets all the matings)
One subordinate male(gets no matings)
Measure relatedness using micro satellite markers r=~0.5 ie. Brother-brother or father-son coalitions
Estimate benefits of cooperation by comparing reproductive success of single or dominant males
Estimate cost by comparing reproductive success of single or subordinate males
Reasons to cooperate
- Kin selection- indirect benefits to the cooperator, via benefits to close relations
- By product benefits
- Reciprocity
- Enforcement
- Deception
- By product benefits
Cooperation is the best option from a selfish perspective, but happens to help others too
Eg. Cooperative hunting increases net food intake
- reciprocity
Net benefit in the longer term
Favoured by repeated interactions between individuals
Eg. Mutual grooming, eg. Reciprocal feeding of blood meals in vampire bats
- enforcement
Cost of “defecting” are extremely high eg. Punishment in human and primate societies
- deception
Animals my cooperate “by mistake”
Manipulation of receivers by signallers
Eg. Large blue butterfly caterpillars deceiving ants
Eg. Cuckoos deceiving reed warblers
Spite – in animals
Spite - incurring cost to your own reproduction by harming others
Spite will be favoured if:
r x B - C >0. B(benefit to recipient)= negative
This can occur if r is negative (ie. If relatedness between actor and recipient is less than the population average)
Spite in animals
Most potential eg. Can be explained by longer-term direct benefits eg. Male-male fights
Real eg. Parasitoid wasps
Prisoners’ dilemma
