![Page 1: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/1.jpg)
Sociality and Social Behaviour
![Page 2: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/2.jpg)
Level of Sociality
Mating strategy
Communication System Kin Selection
Altruism
Predator Pressure
Resource Defence
Parental Care
Foraging Patterns
![Page 3: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/3.jpg)
V.C. Wynne Edwards
Animal Dispersion in Relation to Social Behaviour(1962)
![Page 4: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/4.jpg)
Reproductive restraint
Function of communal displays
Epidiectic display-allow animals to
assess their own numbers
![Page 5: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/5.jpg)
Reproductive restraint
Epidiectic display
Assessment of population size
Reproductive restraint
![Page 6: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/6.jpg)
Reproductive restraint- English Swift
Commonlylays 2 eggs perclutch
Can lay up to 5 eggs per clutch
![Page 7: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/7.jpg)
Reproductive restraint- English Swift
Wynne Edwards- Courtship displays allow census of local population
Why the restraint?
- females lay fewer eggs than they are capable
![Page 8: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/8.jpg)
Reproductive restraint- English Swift
Alternative explanation
Why the restraint?
Look at fledging success
Clutch size % fledging Mean/nest
2 82 1.64
3 45 1.35
![Page 9: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/9.jpg)
Wynne Edwards
Group Selection
- animals will behave in such a fashion as to sacrifice personal benefit for the benefit of the group (altruism)
Difficult to explain genetically
A - a gene that promotes altruism
a - a gene that promotes selfishness
A - can’t spread - contains automatic selection against itself
![Page 10: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/10.jpg)
Wynne Edwards
Difficult to explain genetically
A - a gene that promotes altruism
a - a gene that promotes selfishness
A - can’t spread - contains automatic selection against itself
p2 + 2pq + q2 = 1
Selection against any animal with’A’ = (1-s)
P2(1-s) + 2pq(1-s) + q2 = 1
![Page 11: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/11.jpg)
Wynne Edwards
Group Selection
-reproductive restraint evolves if
Benefit to group of altruism
Reproductive advantage of being selfish
![Page 12: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/12.jpg)
Group selection
Rabbits introduced to Australia - 24 in 1859
-1950 - about 1.5 billion
Control with myxoma
![Page 13: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/13.jpg)
Group selection Rabbits and Myxoma
Facts/Assumptions
1. ‘Group’ = all the viruses in one rabbit
2. ‘virulence’ = lethality = r [reproductive rate]
3. Over time - virus has become less virulent
4. Transmission is by mosquitoes- so p[infection] is proportional to the lifespan of
the rabbit
![Page 14: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/14.jpg)
Group selection Rabbits and Myxoma
Virulent form High reproduction(selfish)
Lower probability of transmission
Less virulent form
Low reproduction(altruistic)
Higher probability of transmission
![Page 15: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/15.jpg)
Group selection Rabbits and Myxoma
Group selection argument
-less virulent = restrained reproduction = individual sacrificefor group survival
-more virulent = higher indvidual success = group extinction
Individual selection argument
- high ‘r’ x low transmission < lower ‘r’ x high transmission
![Page 16: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/16.jpg)
Social BehaviourCosts and Benefits
Benefits1. Protection from physical factors - Aggregations
![Page 17: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/17.jpg)
Social BehaviourCosts and Benefits
Benefits2. Protection against predators
a. Encounter Effect Grouped animalsare more difficult to find
![Page 18: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/18.jpg)
Social BehaviourCosts and BenefitsBenefits2. Protection against predators
a. Encounter Effect
predicted
observed
Encounter rate
Colony size
![Page 19: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/19.jpg)
Social BehaviourCosts and Benefits
Benefits2. Protection against predators
b. Dilution Effect
1:9 1:1000’s
![Page 20: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/20.jpg)
How do groups form?Hamilton - Geometry for the selfish herd
Circular pond
Colony of frogs
Water snake
Colony of frogs
![Page 21: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/21.jpg)
How do groups form?
Hamilton - Geometry for the selfish herd
At same time each day,snake appears and frogsgo to side of pond
Colony of frogs
![Page 22: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/22.jpg)
How do groups form?
Hamilton - Geometry for the selfish herd
Frogs are given the opportunity to move.How???
Colony of frogs
Domain of danger
![Page 23: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/23.jpg)
How do groups form?
Hamilton - Geometry for the selfish herd
Frogs are given the opportunity to move.How???
Colony of frogs
Domain of danger
![Page 24: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/24.jpg)
Social BehaviourCosts and Benefits
Benefits3. Mate searching
![Page 25: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/25.jpg)
Social BehaviourCosts and Benefits
Benefits4. Foraging success
![Page 26: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/26.jpg)
Social BehaviourCosts and Benefits
Benefits5. Resource defense
![Page 27: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/27.jpg)
Social BehaviourCosts and Benefits
Benefits6. Division of Labour
Termite Castes
Queen
WorkerKing
Alate
Soldier
![Page 28: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/28.jpg)
Social BehaviourCosts and Benefits
Benefits7. Aiding relatives
![Page 29: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/29.jpg)
Social BehaviourCosts and Benefits
Benefits8. Modifying the environment
![Page 30: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/30.jpg)
Social BehaviourCosts and Benefits
Costs1. Increased competition
Number of aggressive acs
Colony size
![Page 31: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/31.jpg)
Social BehaviourCosts and Benefits
Costs2. Increased disease and parasite rates
Lice/ nestling
Colony size
![Page 32: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/32.jpg)
Social BehaviourCosts and Benefits
Costs3. Interference with reproduction
![Page 33: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/33.jpg)
Social Behaviour-Why behave altruistically?
W.D. Hamilton - Kin Selection
Fitness has two components
Direct - gained through personal reproduction
Indirect - gained through reproduction of related individuals
INCLUSIVE FITNESS
![Page 34: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/34.jpg)
Social Behaviour-Why behave altrustically?
Need to know the coefficient of relatedness
r = the probability that two individuals possess the same allele due to common ancestry
Parent/offspring 0.5Full siblings 0.5Half siblings 0.25Cousins 0.125[Aunt/Uncle]/[Niece/Nephew] 0.25Grandparent/grandchild 0.25
![Page 35: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/35.jpg)
Social Behaviour-Why behave altrustically?
Hamilton’s rule
Altruism will spread if
B/C > 1/r
B = benefit to recipient of altruist’s helpC = cost to altruistr = coefficient of relatedness
![Page 36: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/36.jpg)
Social Behaviour-Why behave altrustically?
Examples??
Florida Scrub Jay
![Page 37: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/37.jpg)
Social Behaviour-Why behave altrustically?
![Page 38: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/38.jpg)
Social Behaviour-Why behave altrustically?
Typical Group
Breeding Pair
Helpers
![Page 39: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/39.jpg)
Social Behaviour-Why behave altrustically?
Reproductive success - benefits to breeding pair
1.62 young /nest
2.20 young /nest
Helpers(any number)
![Page 40: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/40.jpg)
Social Behaviour-Why behave altrustically?
Reproductive success - benefits to helper
1.94 young /nest
One Helper
Helper success = 1.94 - 1.62 = 0.32 x .5 (for relatedness)
= 0.16
![Page 41: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/41.jpg)
Social Behaviour-Why behave altrustically?
Helper success = 1.94 - 1.62 = 0.32 x .5 (for relatedness)
= 0.16
From previous slide:
Novice breeder success = 1.02 / nest x 0.5 = 0.51
![Page 42: Sociality and Social Behaviour. Level of Sociality Mating strategy Communication System Kin Selection Altruism Predator Pressure Resource Defence Parental](https://reader038.vdocuments.net/reader038/viewer/2022102611/56649ce55503460f949b25b6/html5/thumbnails/42.jpg)
Social Behaviour-Why behave altrustically?
Helper success = 0.16
From previous slide:
Novice breeder success = 0.51
Why sacrifice 2/3 of your own success by being a helper?
Other costs in being a novice breeder1. Survivorship2. Being forced to marginal territories3. Greater chance of taking over home territory