Lecture 26-29: Hammond Flashcards
What are some examples of social behaviour?
Parental behaviour, mating behaviour, extended families, cooperation. Interspecific interactions, predation, chance groupings are NOT SOCIAL BEHAVIOUR
Define adaptations?
Characteristics which increase reproductive fitness –> generally the outcome of selection, either natural or selective
What is the action of selection?
Doesn’t generally affect groups –> mutant in a group could go against the rest of the group and be successful. Normally acts on traits that are controlled by genes made up alleles.
What are the four types of social interactions?
Cooperation: recipient + / donor + Altruism: recipient + / donor - Selfish: - / + Spiteful: - / -
Benefits of living in groups?
Greater protection from predators Increases resources obtained, located and maintained Mating opportunities Reduced infanticide
How does group living lead to greater protection from predators?
Dilution effect- individual predation decreases Increased vigilance - many eyes hypothesis Selfish Herd - trying to get into centre of the group —> underlying drive is selfish but appears as cooperation
How does group living lead to increased obtaining, locating and maintaining resources?
Increased group size –> Increased kill size, decreased chasing in a hunt (African Hunting Dogs) Cooperation of ant queens: unrelated queens form colonies together to increase the success rate. When workers are produced they then go and forage –> queens then fight to the death for nest dominance.
How does group living lead to the creation of mating opportunities?
Lekking behaviour (Lek- display area of congregated males to attract females), males defend very small territories and females select. Male mating success correlates with display activity, aggression and lek attendance. Increases with male trait extravagance. Position in groups also dictates how successful the male will be- central males are more successful
How does group living lead to less infanticide?
Lions killing cubs - If they live in groups then lions less likely to kill cubs
What are the costs of living in groups?
Increases competition- mates and resources Increased conspicuousness to predators Increased chance of disease.
What are the four characteristics of eusocial behaviour?
Adults live in groups Cooperative care of juveniles- caring for individuals which are not their own. Division of reproduction Overlap of generations
Explain the structure of the naked mole rats groupings?
75-80 individuals living in a complex burrow with 1 queen and 1-3 breeding males, everyone else workers Workers can compete with queen to become breeding queen –> morphological change (non-reproductive state –> reproductive state) Low extrinsic mortality so can live to up to 300 years.
In what insect species is eusociality seen?
Hymenoptera (ants, some bees and wasps) Termites and cockroaches
What adaptations are often seen with eusociality?
Role specialisation: soldiers, leaf-cutters, driver ants
What is the relatedness like in eusocial insects?
High relatedness between workers because they are from the same mother - Can be a single male or multiple males but males always haploid.
What are the problems with altruism and cooperation?
Altruism: appears incompatible with natural selection Cooperation: it is possible for individuals to cheat
How does kin-selection explain altruism?
Helping individuals which share copies of the same genes. Relatedness x benefit > cost - Relatedness is higher in eusocial insects than other species, low relatedness would mean cost > benefit
What are examples of kin-selection?
Parental care- relative offspring care - If a long tailed tit fails with its nest then it will go and help relatives set up a successful nest - Fostering chicks and seeing who they go an help after —-> chicks which attempt to help will help those which they think are their parents (foster parents)
How can co-operation be explained as a by-product of a selfish act?
Multiple ant queens want to create a nest but need to cooperate to do so. —> by cooperating they are more successful and gain increased resources, but then will have to fight for the death. Group augmentation in meerkats —> helping / babysitting
Please explain reciprocity?
Helping one individual in the knowledge that they will then help them back e.g. vampire bats, humans, cleaning fish and clients
Please define enforcement:
Behaviour which rewards cooperation but will punish free riding (cheating)
What are some examples of enforcement?
Dominant female meerkat will temporarily evict pregnant subordinates and in turn this causes abortion. —> prevents a shift in power, dominant female wants all the offspring to be hers. Cleaner fish experiment
Please explain how the cleaner fish experiment demonstrates enforcement?
Cleaner fish, is likely to feed on lower benefit but lower cost food, if there is a chance of punishment or fleeing of higher value food.
What is the equation to test whether kin selection is positive?
Relatedness x Benefit > Cost
Must be >
What are the different types of social conflict which can occur between families?
Between paretns: sexual conflict
Parent offspring conflict
Sibling conflict
How do you find the optimal level of parental investment
Where there is the greatest positive difference between benefit and cost
-Resources are only limited and cannot be shared with other offspring
Why is the individual offspring selfish in cases of inter-brood and intra-brood conflict
1.0 relatedness to itself compared to 0.5 relatedness to its sibling.
Individual is selfish and wants to preserve as much as its genes as possible 1>0.5
Parent wants to invest equally as 0.5 related to both offspring
How does the cost-benefit analysis change depending on perspective
Offspring would benefit 2x as much from parental investment as a parent would because it has a relatedness to itself of 1.
Parent is only related to offspring by 0.5 so it gains half the benefit of the offspring
How do Galapagos fur seals demonstrate conflict?
Average survival of younger sibling is decreased compared to older siblings
This is due to faculatitive siblicide –> different in age of death
How do blue-footed boobies demonstrate conflict?
Older sibling begs more effectively than younger sibling (Eggs laid 4 days apart)
If food is abundant then both get food
If food is scarce then the older sibiling takes the food and the younger one starves
FACULATIVE SIBLICIDE
What is obligate siblicide?
The older sibling always kills the younger sibling
Second egg is laid as insurance
Removal of the second egg decreases reproductive success.
What is the influence of relatedness?
Loudness of begging in passerine birds increases as relatedness in the nest decreases.
This theory needs to be tested over the evolutionary spectrum.
What other factors affect how each individual gets fed in a bird brood?
Gape colour
- Colour stands out differently compared to different backgrounds.
—> Yellow gapes in darker background
—> Red gapes in lighter background
Plummage colour
- Juveniles of brighter plummage (orange) are fed more compared to darker plummage (black) in manipulation experiment
What examples are there of conflict within a colony?
Queen spreading behaviour
Male percentage (who produces males- queens or workers)
Sex ratio ( investment into males and females)
Reproductive skew ( sharing of reproduction between queens)
Caste fate (does a female become a queen or a worker)
How does a nest with a singly mated queen work?
Each worker female is 0.75 related to each other because they are each 0.5 related to the queen, and 0.25 related to male (haploid)
Only 0.25 related to brothers (half of 0.5)
Workers are 0.5 related to their offspring (males / nephews). And are 0.35 related to other workers offspring
WORKERS MORE RELATED TO NEPHEWS THAN BROTHERS
How does a nest with a multiply mated queen work?
Workers are between 0.25 and 0.5 due to the variety of males / sperm.
Still 0.25 related to brothers
Still 0.5 related to offspring
Workers <0.25 related to nephews
MULTIPLY MATED NEST, MORE RELATED TO BROTHERS THAN NEPHEWS
Why does conflict occur over male percentage?
Relatedness –> preferance
Single mated queen –> worker produced males
Multiple mated queen –> queen produced males
Queens sons preferred if queen mated 3 times or more. Workers and queens sons are equal at 2 mates.
What are the other affects of a multiple mated queen producing all of the males.
Workers police other workers to make sure they do not produce males
WORKERS POLICING BEHAVIOUR
- Other workers eat eggs
- Females ovaries do not develop
What happens if workers sons are more related than queens sons?
How do ants recognise one another?
Cuticular hydrocarbons.
What is the difference in sex ratio in single mated and multiply mated nests?
In single mated nests: 3 females : 1 male
In multiple mated nests : 1 female: 1 male
Aligned with worker kin selection intrests
–> workers are in controll of sex ratio
—-> feed the larvae and therefore in control of which sex develops.
Please describe the split sex theory
1- colonies with singly mated queens
–> should just produce workers
2- colonies headed by doubly mated queens
—> should just produce males
How are the different sex ratios produced?
Queens always lay the same sex ratio, workers control what sex ratio is produced
–> kill male larvae in single mated colonies –> skewed
BIASING CASTE FATE
Different populations lead to different skews
Give examples of species which demostrate the split sex theory
- Formica exsecta:* split sex ratio from variation in mating frequency- workers maintain sex ratio
- Leptothorax acervorum:* workers manipulate sex ratio to form the correct balance of queens and workers
How and why is punishment induced and enforced in queenless ants?
Dominance interactions- gamergates
- Manipulation experiments making weaker (less dominant) individuals appear more dominant (morphology)
- Gamergate / dominant individual smears her sting on the pretender
- This leads to immobilisation behaviour –> appendages held out by workers for 3-4 days
Which ants can produce the sting smearing response which lead to immobilisation
How do workers influence royal reproduction?
Different types of multiple queen colonies
Polygynous - multiple reproductive queens
–> low colony relatedness (UK + c. Europe)
Monogynous - single reproductive queen
–> high colony relatedness (Spain)
Workers may be aggressive to queens which do not lay eggs.
