Socioecology Flashcards
When do primates form polyspecific associations?
When there is mutual benefit to both species
What benefits are there from polyspecific association? Give 2
- Predator protection
2. Increased foraging success
Give an example of polyspecific association.
Saddleback tamarins and emperor tamarins
How can saddleback and emperor tamarins forage together without competitive exclusion occurring?
They have different foraging and locomotor styles, i.e. different ecological niches
Which parts of the canopy do a) saddleback and b)emperor tamarins forage in?
a) Understory
b) Canopy
Often insects lost by emperor tamarins are caught by the saddleback tamarins below. True or false?
True
How is the relationships between saddlebacks and emperors mutualistic?
Saddlebacks watch for predators from below, and emperors for predators from above.
Give another common polyspecific association seen in the wild.
One between (brown) capuchins squirrel monkeys
Why do capuchins and squirrel monkeys associate?
For increased foraging success and predator evasion.
How do capuchins and squirrel monkeys avoid predators?
There are more eyes and ears watching, both species respond to the other’s alarm calls and capuchins will sometimes mob predators.
Is affiliative behaviour ever observed between capuchins and squirrel monkeys?
No, in fact the caps are often mean to the squirrels
If there are scarce resources what does selection favour?
Behavioural and morphological traits that fare better in competition
Why does resource competition have more impact on females than males?
Because females have higher investment in producing offspring
When does scramble competition occur?
When a resource CANNOT be monopolised
Why can a resource not be monopolised?
Because it is dispersed over a large area
In scramble competition, does every group member have equal access to the resource?
Yes
There is a threshold to scramble competition. Why?
After a certain number of individuals access to the resource decreases
When does contest competition occur?
When a resource CAN be monopolised.
Why can a resource be monopolised?
It occurs in discrete patches so cannot be shared.
Why does contest competition occur for females?
Because the fertilisation of an egg cannot be shared.
In contest competition, who benefits most from resources?
Dominants, as they can restrict the access of subordinates to resources.
Whose reproductive success is favoured in contest competition?
Dominants
In scramble competition resources are high quality and concentrated in one place. True or false?
False, they are low quality and highly dispersed
In species with scramble competition, is there an advantage to having high rank?
No as food cannot be monopolised
Species with scramble competition have what kind of societies?
Egalitarian
Scramble competition is often for nutrient-poor food. Species with scramble competition have longer what?
Feeding times and day ranges
Although there is a threshold at which group size becomes disadvantageous in species with scramble competition, what is the advantage to having a larger group?
Predator protection (forms a trade-off with decline in energy)
How can you describe the societies of species with contest competition?
Despotic, dictatorial, unequal
Contest competition is for what kind of food?
Nutrient-rich
In species with contest competition lower ranking members have the same food intake as higher ranking. True or false?
False, their food intake is lower
What behavioural trait is selected for in species with contest competition?
Feed until sated to ensure greater share of food, i.e. shove everything into their mouths until they can’t carry any more
In species with contest competition foraging-related aggression is common. How do females cope with this?
Feed away from others
Kin cooperation is favoured in species with scramble competition. True or false?
False, it is favoured in species with contest competition. Relatives become allies in resource control.
What is the result of foraging aggression in species with contest competition?
Displacement.
In between-group contest, which groups gain access to resources?
Larger groups
Do primate societies always follow the social structure predicted by ‘food = female distribution = male distribution’?
No.
What is menarchy?
A female’s first menstrual bleed
In Western European humans, the age of menarchy has reduced from ~14 to 11. These individuals are sexually mature but they are not…?
Socially mature
Why is it thought a lowering in the age of menarchy has occurred in western civilisations?
These countries are richer and have more abundant resources
Female reproductive success is inexorably linked to what?
Foraging success
If a female has access to more resources she can do what?
Reproduce at an early age
Why is reproduction so expensive to females?
They need energy to feed themselves and the foetus during pregnancy, and still maintain enough body fat required to nurse when the infant is born
How much higher is the female’s energy requirement during lactation?
2-5 times higher.
What constitutes a ‘high quality’ diet?
Readily digestible, energy-rich food
What is a ‘growth diet’?
Diets that are not available all the time but can be used to fuel reproduction
What is a ‘fallback/subsistence food’?
Foods that are consumed when the preferred food is not available
What adaptations do folivorous primates have for eating leaves? List 3.
- Shearing molars
- Strong chewing muscles
- Elongated digestive tract to increase processing time/area
Some folivores have developed extra strong teeth and muscles, why?
To get past plant defences like shells and husks
As well as physical, plants produce chemical defences. Which chemical groups to these belong to?
Tannins and alkaloids
Are these always toxic?
No, they can be medicinal in the right dose
Young leaves are high in toxic compounds and are avoided. True or false?
False, mature leaves are toxic
Why do red colobus monkeys eat charcoal?
To neutralise plant toxins
Females and males of the same species often eat different foods. True or false?
True
Why might females and males of the same species often eat different foods? Give 2 reasons.
- To avoid inter-sexual competition
- Because they have different energy requirements
(the latter is preferred, no one is really sure)
Why do species exhibit behavioural adaptations instead of morphological? For example, why do red colobus monkeys eat charcoal to neutralise plant toxins, why don’t they just eat noon-toxic plants? Give 2 reasons.
- Because it is quicker to develop a new behavioural phenotype than a new behavioural/physiological.
- Behavioural repertoires are flexible whereas morpho/physiological constraints are not. Primates are incredibly adaptable because of their behavioural flexibility.
It can be assumed that nutritional uptake reflects the food availability and security of the environment. Therefore species living in similar environments always behave in the same way. True or false?
False, there are always exceptions, can also depend on factors like competition and predation etc.
