R19 Evolutionary conflict and cooperation Flashcards
What are the types of conflicts ?
Parent-offspring conflict, sibling conflicts and mate conflicts, genetic conflict
How do family conflicts arise?
investment in gametes, and offspring success vs investment in offspring (more investment increases the chance of their success)
Conflicts in families are the result of unequal investment from parents, and/or differential investment that maximises individual fitness at the expense of others (e.g., mating partner, offspring, or siblings)
In most cases, what does a male want to achieve ?
Multiple mating increases offspring quantity, they go for the quantity of mates
In most cases, what does a female want to achieve ?
increase mates doesn’t increase offspring quantity, they go for the quality of mates
What is the relatedness coefficient ?
r is the relatedness coefficient, so r=1 for offspring but r=0.5 to offspring from parents. Sibling conflicts have a r of 0.5, one sibling will get a better proportion of both parents.
larger value = more relation
Why do females want to conserve resources ?
Females want to conserve as many resources to have as many children as possible, this causes sex conflicts.
Males benefit most when females … ?
- Invest in his offspring (instead of another male’s)
- Invest in current reproduction (instead of future reproduction)
Females benefit most when … ?
- They produce offspring with the best quality of males
- Get the greatest investment from a male in their offspring
Why would a male want to damage a female ?
Males may want to damage females to stop them re-mating until the damage is healed, limits the loss of paternity
- Females lay more eggs so the male does not need to mate again
What is inter-loci sexual conflict ?
o Inter-loci sexual conflict (different loci): males develop a morphology that increases their reproductive success, this creates a selective pressure for the females to gain resistance which is on a different locus. This causes a “arms race” where a cycle of constant evolution is created, referred to as “chase away” sexual selection.
This could lead to speciation, as different male morphology and different female resistance can form
What is intra-loci sexual conflict ?
o Intra-locus sexual conflict (same loci): an allele that increases showiness will benefit the male but harm the female, sexual antagonism (SA) can be expressed as females could carry phenotype of the males’ bright colours but have no advantage and costs the organism
What is altruism and what are the different types ?
- Collective self-interest: an apparently ‘altruistic’ act benefits the individual; they can get more prey when they cooperate
- Mutual benefits: an altruistic act can be repaid later (reciprocity or ‘reciprocal altruism), like grooming behaviour or alarm calls in birds
- Group selection
o Doing good things for the group, the population is being selected not the individual
o Carrying capacity limits the group, dominant females may evict other mating females (meerkats)
o Requires a thought experiment: a mutation may occur so that the lineage of the ‘only mating female’ is disrupted. The offspring mate despite the rules
o Group selection is not an evolutionarily stable strategy (ESS) - Kin selection
o r – wright’s coefficient of relatedness – the probability that an allele present in an individual is also present, by common descent, in its relatives.
What is the value of r between you and:
siblings
parents
half siblings
aunt/uncle/niece/nephew
grandparent
first cousins by two grandparents
1
0.5
0.5
0.25
0.25
0.25
0.125
What is inclusive fitness?
the number of offspring equivalents that an individual rears, rescues or otherwise supports through its behaviour
How do we work out the inclusive fitness ?
Wi = ai - ci + rij+bij
wi = inclusive fitness of donor
i = individual
ai = direct fitness of donor
ci = effect of altruistic act on donor’s own direct fitness
rij = coefficient of relatedness between donor and recipient
j = recipient
bij = increase in fitness of recipient due to the action of donor
What happens in wi is 0?
no mate is present
What is Hamiliton’s rule ?
altruism will evolve if:
Relatedness x benefit to recipient > cost to donor
r x b > c
r x b – c > 0
what is direct and indirect fitness ?
Direct fitness is the number of offspring the individual procreates, whereas indirect fitness is defined by the number of offspring begotten by the genetic relatives of the individual.
Usually, What is the female and male seeking ?
- the females seek quality mates, the males seek multiple mates
- males produce more offspring with more mates, so they seek multiple mates for more offspring
How can we tell which sex is investing less ?
The parental investment is unequal
they mate with multiple mates
What is polyandry?
Females mate with multiple males
(other way around to the normal)
If females have less investment than males what should happen?
Males should be choosy and have a greater opportunity cost to investing in a female’s offspring.
How would mutations spread if they affect sexual selection?
- Mutations that confer a mating advantage will spread in males in this example.
How can we remove sexual conflicts ?
remove differential investment, one sex wants lots of partners, and another wants to work on the offspring.
- Ensure paternity (that the female invests in his offspring)
- Enforce monogamy (so there is no loss in mating opportunities)
What was the holland and rice experiment ?
- One population of fruit flies with sexual conflict and one with monogamy
What are the expected outcomes to a population that has the sexual conflict removed ?
No protein compound (that harm the female in fruit fly sex conflict) needed as the female wants to invest in his offspring and only his, Courtship decreases in monogamy, female survival is higher as they aren’t damaged by sexual conflict, females can put more investment into the offspring as less is needed in costly defence to the conflict leading to increase in overall reproduction.
How does sexual conflict arise?
Sexual conflict is caused by unequal investment in reproduction and differential costs to missed reproductive opportunities, and can lead to an arms race if the traits in conflict is at different loci or a tug-of-war if the trait is at the same locus. It can lower overall reproduction, but persists because it has advantages to the individuals that engage in the conflict.
Why would altruistic behaviour occur in unrelated individuals ?
Apparently altruistic behaviour in unrelated individuals can be due to self-interest or reciprocity and altruism can evolve in related individuals if the cost of the behaviour is low, the benefits are high, and/or they are more closely related.
