14. Behavioural Ecology 1

Question 1

Give the basics of grassland ecology. 3

Answer 1

1. little temperature variation but high seasonal rainfall 2. relatively uniform primary producer 3. complexish foodwebs but arrnaged into clear trophic levels and energy pathways

Question 2

What is behavioural ecology? 3

Answer 2

1. Study of the evolutionary basis for animal behavior 2. Study of the roles of behavior in enabling an animal to adapt to its environment 3. Both ultimate (evolutionary and development) and proximate (physiological and neurological) factors involved in controlling behaviour and how they are affected by biotic and abiotic factors.

Question 3

What is altruism? 3

Answer 3

1. There are many situations where animals do things that appear to be primarily for the benefit of others. 2. In other words their fitness is reduced whereas another individuals fitness is increased. 3. Since natural selection works on individual fitness we would expect such behaviours to be selected against. 4. eg. bee leaving sting in human with intestines and dying for good of others

Question 4

Why is the evolution of altruism interesting? 4

Answer 4

1. Selfish behaviour should be more common. e.g. Infanticide. 2. Some apparently altruistic acts lead to personal benefit, particularly in a social context, and therefore will be selected for. • Kin selection • Reciprocal altruism

Question 5

What is infanticide? Use macaques as an example. 4

Answer 5

1. live in small groups with one male 2. males compete to take over group 3. overtaking male kills all young already in the group 4. females return to oestrous much quicker with no loss to new macaque

Question 6

Describe infanticide in brown bears and the benefits to the new male. 2

Answer 6

1. after young killed, mother returns to oestrous within 6 months, rather than years 2. males only have about 4 years before own displacement

Question 7

What is kin selection? 3

Answer 7

1. The currency of selection is the genes. 2. Kin selection works because you share genes with your kin. 3. So a trait that leads to improved fitness for your kin can be selected for.

Question 8

Describe an example of kin selection in Datana caterpillars. 3

Answer 8

1. bright warning pattern for predators 2.don’t taste nice 3. bird eats one and realises this so does not eat another

Question 9

Describe kin selection in the ground squirrel. 4

Answer 9

1. Have alarm animals that sound alarm is danger detected 2. these far more likely to be eaten by predator 3. also reduce own fitness as spend less time eating, so maybe less repro chance 4. protects the others in a closely related group

Question 10

What is reciprocal altruism? 3

Answer 10

1. In most situations it pays to be selfish. 2. However in social groups where an animal can remember an individual who did a good deed in the past and there are opportunities to return the favour, it can pay to be altruistic. 3. Relatively low cost for unrelated animals

Question 11

How do vampire bats practice reciprocal altruism? 4

Answer 11

1. Food sharing with non0-relatives 2. Well fed bat can regurgitate some meal to bat that is struggling 3. starving bats die quickly without food, so even a small amount can be helpful 4. low cost as once bat has had a good meal, does not eat for several days anyway

Question 12

What is game theory?

Answer 12

1. The exact conditions that can lead to reciprocal altruism can be explores using Game Theory. This approach was developed by maynard smith
2. The classic example is the prisoners dilemma.
3. In this case, with no knowledge or chance for future interaction both prisoners should testify. •
4. However if the prisoners will meet in the future, and know what happened last time then a tit-for-tat rule can lead to a situation where both prisoners stay silent.
5. This is an Evolutionary Stable Strategy (ESS)

Question 13

Describe cooperation in elephants. 6

Answer 13

1. Reciprocal altruism requires that the animals are smart enough to cooperate and also able to rememberwhat has occured previously.
2. Joshua M. Plotnik, Richard Lair, Wirot Suphachoksahakun, and Frans B M De Waal. Elephants know when they need a helping trunk in a cooperative task. PNAS, 2011 108:5116-5121
3. Rope runs around platform
4. food reward in centre
5. both elephants must cooperate to get food reward
6. initially no cooperation but quickly lean to work together

Question 14

What the disadvantages of group living 3

Answer 14

1. Competition for resources within group (space, food, mates) as competition strongest within own species
2. Increased levels of disease and parasites
3. Higher visibility to predators

Question 15

What are the benefits of group living? 5

Answer 15

1. Territory defense so better access to resources between groups
2. Anti-Predator strategies: defense, vigilance, dilution effects eg. if more wood pigeons are looking for predators, more likely to see one and all escape
3. Cooperation and food sharing eg. can share watches so more time for feeding etc as less time on watch
4. Shared parenting
5. Information sharing

Question 16

What is the selfish herd? 5

Answer 16

1. Geometry of the Selfish Herd (Hamilton 1971)
2. Living in a group of e.g. 100 antelope increases the frequency of predation on the group.
3. However the chance of being targeted is 1 in 100 so as long as the frequency is less than 100 times higher than for a solitary animal you are still safer in a group.
4. And in a group your chances of successfully defending yourself from a predator is higher if the group works together.
5. Also the position in the group is important: you are safer in the mid

Question 17

How are optimal group sizes reached? 4

Answer 17

1. The costs and benefits of group living depend on the size of the group. •
2. Depending on the situation there will be an optimal group size.
3. However the optimal size may be different for animals in the group and those that wish to join the group.
4. If animals in the group cannot easily evict new members then the group size will increase until it is marginally better to be in the group than not, rather than stabilising at the size that maximises within-group fitness.

Question 18

How can group size be predicted eg. in baboons? 3

Answer 18

1. Old world monkeys are a good example of a social mammal that lives in variable sized groups.

2 What evidence do we have that ecological factors affect the optimal group size?

3. ecological factors such as rainfall contribute and can help predict group size accurately

Question 19

What is adaptive story telling? 4

Answer 19

1. One of the big dangers of behavioural ecology is adaptive story telling.
2. It is easy to come up with “Just-So” stories that appear to explain the observations.
3. However you can often come up with lots of different possible explanations, and all may be false.
4. It is may be impossible to conclusively prove or disprove an adaptive scenario.