Set 10 - Aggression

Starlings in Protective Aviaries

Gain more fat because they have to escape predation less

Great Tits Gain More Fat when

Predation is low

Red Eye Embryos drop

Immediately from vibration spacing and duration

Red Eye Embroyo Peak Hatch

Is 7th days at night

Diseases are

Tiny parasites

How many People have Aids or Died from Aids?

40 million people have AIDS and 42 million have died from it

How many people died by flu?

30 000 people in US

Malaria has killed

Half of all people every lived

Frogs are sensitive to

Snail and parasite density, will decrease in presence of parasite and in snails

Male Lions

Defend the pack from invading males killing his cubs and using the lioness for his own

Sexual Selection

Differential reproduction from heritable variation in ability to get mates

Female Gametes are

Large and limited by resources

Male Gametes are

Small, limited by access to females

Operational Sex Ratio

Number of Males ready to Mate/Number of Females Ready to Mate

Biparental Care causes

Mutual match choice and sexually selected traits

Western Grebe Courting System

• Repeat each other’s movements

• Run on the surface of the water together

• Gift each other weed from the bottom of the lake

Female Fruit Flies consider

Smell, taste and song for compatibility and quality of mate

Pied Flycatchers prefer

Brighter males that sing

Birds Sing at Dawn

• No distortion

• Mating availability

• Female fertility at its highest

As Sedge Warbles repertoire increases

Pairing time decreases

Muted Red Winged Blackbirds have

More intrusions, fights and territory losses

Direct Benefits Model

Females gain something from mate choice

Optimal Prey Size for Scorpionflies

20mm

Male Barn Swallows with Longer Tails have

Fewer parasitic mites who are better parents and fledging have more mass

Direct Benefits Model Con

Often males only contribute sperm so direct benefits less likely

Good Genes Model

Females gain by having superior offspring S

Sage Grouses

Endangered and SARA law in 2003 for protection

Cock of the Rock Birds

Bright orange and cluster to bounce competitively to attract Females

Cock of the Rock Choice

Females peck on the male’s neck to tell that they chose them and they often copy mate choice

Male Pronghorn Harem Holding Ability

Positively correlate with offspring quality

Cons of Good Gene Model

There’s no clear distinction between direct benefits and good genes, males can someone contribute parasites or STDs

MHC

Set of genes involved in immune responses with high individual variation

MHC Similarity and Pleasantness

Negative Correlation

Runaway Selection Model

Extreme male traits evolve via genetic link between male trait and female preference

Runaway Selection Assumptions

• Assumes 2 loci that has heritable variation

• Trait and preferred alleles become linked causing extreme trait

Stalked Eye Flies Experiment

Evolutionary change in eye span in males correlated with evolutionary change in preference in the females

Runaway Selection Model Con

Meta analysis shows no proof for genetic correlation between male trait’s and female preference

Banded Kokopu Fish

Have aggressive contests with fish at the top of the hierarchy get preferred access to food in the pool

Subordinate Banded Kokopu FIsh

More likely to move to new pools than dominants and got equal food amount but better growth

Male Weapons

Associated with system, males defend resource that’s spatially restricted and sometimes honest indicators

Aggression

Animals send threatening signals and/or engage in some physical combat 

Dominance Hierarchies

Rank orderings of individual based on the results of pairwise aggressive interactions

Green Woodhoopoe Birds Increase

Grooming together in their group when they enter areas where conflicts with another group is likely

Conspecific Aggression

Aggression between member of the same species

When benefits of victory outweighs fighting costs

Selection favours aggressive behaviours

Dominant Individuals and Winners have

Increased androgen levels and more likely to fight

Subordinates have higher

Glucocorticoid going into and finishing fights

Atlantic Salmon Loser

Increased cortisol and swim closer to the surface to avoid future aggression with the winner

Atlantic Salmon Colour Change

Dominant get dark vertical eye bands and subordinate get darker body colour 

Swordtail Colour Change

Dominant get red lateral stripes, and subordinates get black

Low Serotonin Levels linked to

Increased level of aggression but lower social status but depends on social or asocial environment

In fish, subordinates have

Increased serotonin levels and decrease fighting behaviour

In crustaceans, increased serotonin

Increases aggression and high social status

Hawk Dove Game

Analyzes costs and benefits between hawks and doves

Hawk

Players escalates until it’s injured or opponent cedesd

Dove

Player displays as if it’ll escalate but retreats and cedes if it esacales

Winners of Hawks and Doves

• Hawks wins against Doves

• Hawks fight costly

• Doves share the resources

Bourgeois

Individual plays hawk if it’s a territory holder but dove if it doesn’t own territory

When Male Speckled Wood Butterflies come across another male’s territory

Resident wings and intruder retreats, only a fight when males both think they’re owners of patch

War of Attrition Model

Two or more players compete for a prize by paying a cost overtime and ends when one concedes

War of Attrition Assumptions

1. Individuals choose to display aggressively for however long

2. Display behaviour costs

3. No clear cues can settle a contest

Male dung flies move patch to patch and stay time equals

Benefits of staying equals the cost of leaving

Sequential Assessment Model

Analyze fights, which individual continually assess each other in a series of bouts until they determine their odds

When opponents are more evenly matched

They should have more dangerous behaviours

Length of Acts between Nannacara Anomala Fish

Depends on the difference in weight, but the order is the same 

Winner and Loser Effect

Winner or losers more likely to win or loser/

Loser Effect associated with

Increased glucocorticoid, low testosterone (winners are opposite)

Larger Winning Copperhead Snakes get access to females but

Two time losers lose all contests to smaller opponents

Plasma Corticosterone

Increase in losers than winners, subordinate rarely challenge other males or court females where they fought

Next to Last Aggressive Interactions Affect

Current chance of winning or losing, but less effect on current outcome than wins and losses one move back in time

Bystander Effect

Observer of aggressive interaction changes its assessment of fighting abilities of those it has observed

Green Swordtail Fish Eavesdroppers more likely to

Avoid winner of contest

Eavesdroppers less likely to initiate

Aggressive behavior and win against losers that had persisted in fights or loser that escalated their aggression

Audience Effect

Individual in aggressive interaction change their behaviour in they’re watchedV

Victim Screams

Entice support from observers

In Mildly Aggressive Chimp Interactions

No difference in screams when audience was there or not

In Severe Aggression

Victim screams longer, intense with audience when only a member a rank equal or above the aggressor was there

Policing

Small number of males in a group, sometimes breaking up fights between pig tailed macaques

When Policing Males were removed

Aggressive behaviours increased and those remaining had fewer play partners and grooming partners

Reach

How quickly information flows in a group

When reach decreases in monkeys

Decrease in pro social behaviour and smaller subgroups instead of a single group

What’s the main message?

Subordinates relative growth rate increases after moving

What’s the main message?

When serotonin was given, aggressive levels increased in small lobster

What’s the main message?

Male dung flies appear to engage in wars of attrition when determining how long to stay on a patch where females may alight

What’s the main message?

Copperhead loser snakes have increased levels of plasma corticosterone compared with controls 

What’s the main message?

Fish in mirror treatment, less likely than opaque treatment to initiate interaction and escalate aggressive interaction against winners

What’s the main message?

Testosterone increases after eavesdropping on a fight in Oreochromis mossambicus

What’s the main message?

Chimpanzees in severe aggressive interactions emitted distinctive screams, and longer screams hen fights were watched by an audience that included a chimp of equal or higher rank to the aggressor

What’s the main message?

Males fight more intensely when being watched by another male