What does selection favour?
Selections favour adaptations for avoiding predators
What is a cryptic predator avoidance technique?
An example would be camouflage, the peppered moth
What is a conspicuous means of predator avoidance?
Dendrobates (Poison dart frog) - highly colourful - usually as a warning to predators.
What is an example of a counter strategy for predation avoidance?
Some predators may develop immunities or remittances to toxins.
What anti predator Strats do some primates employ?
Grouping
What are the anti-predator benefits to grouping?
More eyes
reduced per capita diligence cost - can spend more time doing other things
Better active defence
Dilution, the selfish herd, less likely you will die if everyone runs
What is an additional benefit of grouping for consumption of nutrients?
Improved foraging - wider search swath and better patch encounter process
Better intergroup competitive ability
What are some of the costs associated with grouping?
Food comp within group
social competition - mates and what not
Disease transmission
More conspicuous to predators
What is Wranghams evolutionary model for grouping?
Resource defence
What does Resource defence postulate about sociality ?
That sociality is an adaptation to improve resource access.
Where is food most limiting?
For females who try and reduce competitor
How do females distribute themselves in space?
In relation to food
What does food dictate about female sociality
Low quality abundant food, females should be solitary
High quality scarce food, patchy females should group to harvest and defend
What is inter-group competitive ability?
The ability to outcompete other groups
What is intra-group competiton
When forming groups with kin, competition for resources can occur between different lineages in the same group
What are some predictions that should be true about resource defence?
Groups should be composed of female kin
Females should be active in resource defence
Larger groups should have greater resource access
Females in larger groups should have higher LRS
What are the contradictories in Resource defence model?
- Not all frugivorous species group
- Some folivores live in very cohesive groups
- Not clear if female in larger groups have higher LRS
What was Van Schaik model for grouping?
Predation and intra-group food comp
What does the predation theory entail?
Grouping occurs due to avoid costs related to predation risks - larger groups should be favoured
What is a cost of developing a large group?
Resource completion within the group happens
What constitutes an optimum group size?
Maximized food intake
Minimize predation risk
What are some predictions to the Predation mitigation theory?
Terrestrial group should form larger groups than arboreal species
smaller groups should suffer higher predation
Behaviour should vary with predation
What are some problems with the predation risk theory?
Hard to quantify predation risk, many small vulnerable species are solitary.
What two factors may contribute to the decision to group? What factor constrains group size?
Improved inter-group competitive ability
Predator pressure
Resource avalibiltiy
