behaviour- tucker Flashcards
Ethology
The scientific and objective study of animal behaviour under natural conditions
Nature
Behaviourism
Rooted in psychology, stimulus and response
Nurture
What are Tinbergen’s 4 questions?
Proximate causes of behaviour:
- Mechanism- underlying causation, eg. the release of specific hormones leading to a motor response
- Ontogeny- the development history of an individual, eg. because it is learned from parents
Ultimate causes of behaviour:
- Function- impact on fitness, eg. doing something that increases its chances of food
- Phylogeny- evolutionary history of a species, eg. because other species within the family do
Lorenz
All species have a repertoire of innate, species-typical behaviours
David Lack’s robins
Highly territorial and aggressive
Males attack adult birds, not juveniles
Also attacked red feathers
The signal is the red
Little Albert
Baby given white rat
When he played with the rat, there was a loud noise
Conditioned for fear
Showed that not all behaviours are innate, some can be learned
Wynne-Edwards study
Red grouse populations
Found that a pop. that doesn’t overexploit resources will be more successful than one that does
Social behaviours have evolved to benefit the group
Ethogram
Complete inventory of all the behaviours of an organism
Behaviour sampling methods
- Ad-libitum sampling
- Qualitative
- Record individuals or groups
- Good for initial research, but has a limited data quality - Focal animal sampling
- Record either all behaviours or the occurrence of a specific behaviour
- Can reproduce more easily than ad-lib - All occurences sampling
- Measure more than one behaviour, records occurence
- Useful for recording rate, frequency - Binary sampling
- Whether a behaviour did (1) or didn’t (0) occur
- Limited use as lots of info lost by rigid categorising - Scan sampling
- Records instant activity of behaviour of all individuals in a group at set time intervals
- Useful to understand frequency of behaviours in a whole group
What do we measure
Latency- time from a specific event to the start of a behaviour
Frequency- no. of times a behaviour is displayed per unit of time
Duration- length of time that a behaviour lasts
Krebs experiment (foraging)
Experiment with great tits
Put them in a foraging box with a perch and a conveyor belt with food
Had to fly down to the food and collect it or it would be lost - this is the handling time
Changed perch distance, speed, what food was on the belt
Found that when the encounter rate was high, birds only took the biggest prey
When the encounter rate was low, they took big and small prey
Predictions using equation were correct
Caraco et al. experiment (foraging)
A few feeders drop seeds at the same time
All have the same average seeds overall, but some drop the exact same number every time and some vary
When the average seed number is high, chose the more consistent feeder
When the average seed number is low, chose the variable feeder- it is worth the risk for potential rewards
Bass + bluegill experiment (foraging)
Adult bass can’t eat adult bluegills, only juvenile
Divided pond into 2- one side had adult and juvenile bluegills, other also had bass
On both sides, adult bluegills foraged in the open
On the no-bass side, juveniles foraged in the open, but on the bass side, they stayed in the vegetation
Grew 27% slower on bass side- change foraging to avoid predation, didn’t go for optimal food source
Orb weaver spider (foraging)
Catch grasshoppers and butterflies/flies in web
Bite to kill, or wrap- wrapping takes longer and risks escape
Bite butterflies, wrap grasshoppers, as can avoid damag from them easier
Cocos finches (foraging)
Insectivores and eat nectar from flowers
Looked at their foraging in 6 hibiscus plants
Would expect there to be an optimal foraging technique that all would use, however each bird had its own individual technique- each was specialised
So the inequality is different for different individuals
Absolute fitness
The expected number of offspring that an individual will produce over the course of its lifetime
Examples of crypsis
Draco lizard on bark
Peppered moth
Crypsis behavioural experiment
Catocala cerogama and Euphyia intermediata
Superimposed on trees at different angles, flashed up to see if visible
In Catocala cerogama, better in vertical- so behaviour helps
Mimicry experiment
Snowberry fly mimics the zebra jumping spider
When encounters one, pushes wings out and does territory dance
Swapped house and snowberry fly wings
The spider only retreated when had the correct wings and dance
Also Macleay’s Spectre woooo
Predators using mimicry examples
Jumping spiders mimicing ants
Alligator snapping turtle tongues mimic worms to attract fish
Butterfly larvae smell like ant larvae- brought back and fed
Wasp pheromones confuse colony, lay eggs in butterfly larvae- mutualism b/w wasp and ants
Aposematism examples
Monarch butterfly- tastes nasty
Coral snake- can kill
Strawberry poison dart frog- poisonous
Phenotypic plasticity example
Prarie bird locust
Genetically identical raised in high and low densities
High densities = colourful (show they aren’t tasty)
Low densities = plain (hide)
Batesian mimicry
Only one is poisonous
Coral snake and milk snake
Macleays spectre and scorpions/mantids
Mullerian mimicry
2+ harmful animals evolve to look like each other
Bees and wasps
Heliconius butterflies
Lemming population control
Would expect dispersal to be reduced if not successful
Not just stoats controlling pop- in bumper years, snowy owls and arctic foxes join in
Why should we see the dying out of dispersal
Should be no disperal in temporally constant environments
Dispersers leave natal patch, go to another patch
There, they reproduce, so the population goes up
At the end of dispersing, the percentage of dispersers in the population has gone down, so should see dying out
What are the costs of dispersal?
Energetic costs- drosophila egg exp.
Investment in physiology- cricket wing/wingless morphs
Predation- voles dispersing, can’t find new hiding spot
Failure to find new habitat- butterflies and plantagos
Name for the probability that animal will disperse
Dispersal propensity
Things that contribute to decrease in dispersal propensity over time
- First individuals to colonise will be good dispersers
- Individuals that maintainthe ability to disperse tend to have lower reproductive potential
- In every generation, some good dispersers leave the patch and don’t come back
Invasion and dispersal
Selects for increased dispersal
Eg. cane toads brought to Australia to eat beetles ruining cane sugar
Poison monior lizards that eat crocodile eggs, so increased crocodile pop
What is inbreeding depression?
Reduced fitness in a population as a result of inbreeding
Recessive alleles are brought together and exposed to selection- unlikely if unrelated
4 voles were released in different patches, some related and some not- more disperal in patches with siblings
What is philopatry?
The tendency of an organism to stay in/return to an area
Eg. loggerhead turtles
Living in groups experiment
- Algorithms- found that copying more did better
But didn’t take into account competition
Best to copy when temporal variability was low
2. Rats First chose between cinnamon and cocoa Second watched and then chose Usually chose the same as the first rate chose Uneven environment, so copy
3. Goats 2 ends of a strip of grass, trough at either end First goat went, another watched Split evenly betwen the troughs Even environment, so don't need to copy
4 theories of how living in groups avoids predation
- Selfish herd theory
- Predation rate hasn’t changed, just the chance of it being you
- Common redshank- predated on by sparrowhawks more if further from the group - Predator satiation
- Predators can only eat so much
- Eg. cicadas- look at wings and shells, large groups emerging = less predated
- Birds that remember the last one are dead lol - Reduced vigilance
- Don’t need to spend as much time looking around as others are too- if one runs, everyone runs
- More time for foraging
- Goa exp. found that bigger groups = less scanning
- But have to do more foraging in a group due to competition so can’t be as vigilant- cost?? - Predator confusion
- Schools of prey in tank, 1, 6, or 20
- Introduced types of predators- all were less successful when there were larger groups
