Unit 8 Social Behaviour Flashcards
Social behaviours (/3)
-are trait/traits that can evolve
-cooperation**, **tolerance, and *attraction are social traits
- Social behaviours evolve just like any other set of traits
Kinds of social structures (/6)
Solitary breeding w/o parental care
Solitary breeding w/ parental care
Colonial breeding
Communal breeding
Cooperative breeding
Eusociality
Group living benefits
1 Dilution effect
2 Many eyes
3Mobbing
4 Foraging
5 Selfish Herding
6 Mate Finding
Pathogens
Disease transmission
Prairie dogs are transmitting the plague to each other
see this with flea transmission too
bigger colonies have higher density of fleas
sociality promotes the increase in pathogens
Living with dominants
Energy budget in Neolamprologuspulcher
-● sociality means you have to live with other organisms (sucks)
● Agnostic behaviours- (fighting) involves aggression
● Submissive behaviors - giving in involves submission
● more than ⅔ of this animal’s life is interacting with other
individuals via agonism or submitting (fighting or submitting)
● another problem is cuckolded
- they lose paternity in the group
– if they are in a big group, another male could actually be the eggs
Interference competition
Groove-billed anis, some dope-looking birds.
● They have social groups that share one territory and one nest, where everybody lays their eggs.
● When laying, individuals often knock previous eggs from nest. Or bury them.
● There’s a high cost to being among the first to lay in the nest.
● Bigger groups of anis have fewer young.
* They all benefit from being in a group for territory defense, but this behavior has reproductive costs.
Kind of like hiding drop shoes on a release date
Exploitation competition and the Tragedy of the Commons
- temptation to take a little extra leads to exploitation and now nobody can use the resource
Long awnser…
small village with a common area where animals are raised, the size of the commons is fixed, every family in the village can raise 5 sheep, keeps the commons the right size, creates a sustainable commons
- but of course, everyone
wants more sheep because they would benefit from having one more (e.g., extra wool, meat) - one or two families doing this
will be fine, but everyone wants to exploit the resource more so
they over exploit the resource and the commons is no longer
suitable for grazing and now it all collapses
Exploitation competition
- take the resources you want to take
e.g., pinata breaks and all the children run and take all the candy
Interference competition -
e.g., kid hits all the other kids with the pinata stick
In a Tragedy of the Commons we can think of two types of people
- cooperators and cheaters
Cooperators
are those who only put out 10 sheep to graze, who
don’t over-exploit.
Cheaters
are the 12-sheep jerks, who are
detrimental to the common good (a shared resource)
Usually slime mold looks like slime except…
But when it’s time to
reproduce, they produce “fruiting bodies” composed of a stalk and
a head, which disperses spores.
- The stalk and head are multi-cellular. Stalk cells don’t get to reproduce, only the cells in the head get to pass on their genes.
- Why do the stalks exist if they never get to reproduce? Why would they be cooperators if they lose in the end? It is an evolutionary paradox.
Competition Refraining (as a resource)
Think of the rainforest trees from class
The grow taller to get more sun, then their competition tries to match.
They keep going up and up for not reason “wasted energy”
Similar to inflation of getting plastic surgery
Competition refraining can also apply for animals
One Darwinian
dilemma…
⚫According to Darwin, selection eliminates
behaviors that reduce individuals’ reproduction
⚫ Yet ants, slime molds, and many other organisms sacrifice individual reproduction so that other individuals can gain reproductive success
2nd Darwinian dilemma
-1. Darwin says that natural selection should eliminate any behaviors that do not contribute to reproduction
a. how do these costly, helpful social behavior, evolve?
-2nd problem of understanding the evolution of these cooperative behaviors
- what prevents cheating from breaking down the social groups →
even if cheating collapses the system cheaters do benefit in the short term
- despite all this, social living is common. It must have significant benefits to counter the costs, but how are these social systems
protected from cheaters?
Three solutions to the evolution of
self-sacrifice
- Manipulation
- Cooperation
- Altruism
- Manipulation
Potential cheaters are forced not to cheat
- Cooperation
I scratch your back, you scratch mine
Self-sacrifice is only short term
Behavior is beneficial for all over the long term
a. self-sacrifice is only short term, and long term we all benefit
b. “I scratch your back, you scratch mine”
c. this makes sense - Darwin was cool with cooperation
– Self-sacrifice is only short term
– Behavior is beneficial over the long term
- Altruism
-a. true self-sacrifice in a darwinian sense
b. they sacrifice their own reproduction
c. need to understand Hamiltonian theory
– Self-sacrifice reduces individual
reproduction, is truly costly
– Evolution of altruistic behaviour is mediated
by indirect (Hamiltonian) benefits
Manipulation
- PROSOCIALITY is imposed on individuals
- in an ant colony - the queen reproduces and the workers may not be able to reproduce - so it is a form of cheating that the queen can reproduce and the others can’t
- if a worker is trying to reproduce, the other works may just grab on to them
for a long time or they kill them - this leads to counter adaptations
- it is a lot easier for adults to police offspring so this creates a power dynamic
Policing in pig-tailed macaques
Policing outside social insects is less common. It does happen in some primates like
pig-tailed macaques.
● An experiment removed the most dominant males who “policed” the population (big bois)
● With the policing efforts removed, the social network became MORE FRAGMENTED, and the group was less cohesive.
So policing can serve to unite the group socially.
Cooperation
- give you something that benefits you and is mildly inconvenient for me, and later you can do the same for me
Social behavior benefits all involved on average
-Social behavior benefits both (all) actors’ lifetime reproductive success, on average
– Consistent with Darwinism
-e.x. mutual allogrooming in wild horses
-e.x. some birds, if they are mated, will pick the bugs off the other birds
neck and then they will reciprocate
- reciprocal allogrooming
-e.x., european starlings are mobbing the bird of prey - they all get
together and chase away the predator
- we see this a lot all over lethbridge
Blue footed boobies: males show different degrees of ‘blue-ness’ in their plumage
- When comparing which ones are paired with females, it was shown
that the least successful males were those with intermediate plumage
scores. Both not-so-blue males and very-blue males were more
successful.
-* It’s because the not-so-blue males and very-blue males cooperate to steal the mates of those damn intermediate blue males. It’s cooperation because the behaviour is mutually beneficial to both kinds of males, reducing competition for both of them.
