Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 3: Adaptation > Reciprocal altruism in bats > Flashcards

Reciprocal altruism in bats Flashcards

1
Q

Who conducted the initial studies on the common vampire bat?

A

Wilkinson, 1984

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the latin name for the common vampire bat?

A

Desmodus rotundus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What did Wilkinson (1984) find?

A

That bats regurgitate blood meals to save roost mates from starvation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what three ways could you describe the regurgitation behaviour of bats?

A
  1. Group selection
  2. Kin selection
  3. Reciprocal altruism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where were the experiments on D. rotundus carried out? For how long?

A

Northwest Costa Rica for 26 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which sex is philopatric in D. rotundus?

A

Females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Do females move between roosting sites?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Do males associate with females?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many roosting sites were involved in the study?

A

14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What was the population of D. rotundus estimated at? How many individuals were ID tagged?

A

Estimated at 200, 184 were tagged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How was relatedness assessed?

A

Direct observation of mothers nursing their offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When was regurgitation observed?

A

When roost mates had failed to obtain a blood meal for themselves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How did capture experiments confirm the cause of sharing?

A

In a captive group an individual was prevented from feeding. Upon release roost mates shared their blood meals with her.

The experiments were repeated after feeding; upon release no blood meals were shared.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In which age category was failure to obtain a blood meal more common? Why?

A

Younger bats, presumably due to hunting inexperience

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is group selection?

A

Where group selection acts on a group as a whole, rather than on individuals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does group selection require?

A

Cooperation of all individuals within the group to behave ‘for the good of the group’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Group selection favours populations of…

A

altruists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How many cases of blood meal sharing were observed in the experiment?

How many occurred between mother and offspring?

How many occurred between unrelated individuals that displayed close association?

A

110

77

21

19
Q

How can group selection be used to explain blood meal sharing?

A

Bats shared with unrelated individuals as it increased survivorship of the entire group as less members die of starvation

20
Q

What disproves group selection as the reason for blood meal sharing in bats?

A

Males are consistently excluded from sharing, both in the wild and in captivity (proven by Wilkinson’s captive experiment with one male in an all-female group)

21
Q

Why are males excluded from sharing?

A

As they are the dispersing sex and do not co-roost with females for prolonged periods of time, so there is no guaranteed future pay-off to the donor in sharing with a male

ALTRUISM DOES NOT PERSIST WITHOUT BENEFIT TO THE INDIVIDUAL

22
Q

Why is group selection a contentious theory? Give 2 reasons.

A
  1. Natural selection relies on random mutations with unforeseen effects in response to environmental changes. Under group selection groups systematically change their strategy.
  2. Group selection assumes individual selection is not acting on group members, when in reality each member wishes to proliferate their genes. This is why cheaters invade and can spread to fixation.
23
Q

What is kin selection?

A

The preference for relatives due to inclusive fitness (shared genes by descent)

24
Q

How can kin selection be used to explain regurgitation in bats? Refer to Hamilton’s rule.

A

77 cases between related individuals were observed. Relatedness between mother and offspring = 0.5, thus it is possible that rb > c

25
Q

Why is kin selection not responsible for regurgitation in bats? Refer to Hamilton’s rule.

A

21 cases were observed between non-related individuals, where r = 0. Thus it is likely that rb

26
Q

Why would a mother want to save her starving offspring?

A

So the offspring can go onto proliferate the mother’s genes, is actually a selfish act

27
Q

Why might 77 cases of mother-offspring regurgitation have been observed, NOT because of relatedness?

A

Because of close association and proximity; mothers and daughters roost next to each other

28
Q

If mothers roost next to younger daughters and adults, both of which they are affiliated with, why might it be more common to observe regurgitation between mother and daughter?

A

Because younger bats are inexperienced at hunting and more likely to need rescuing than adult roost mates

29
Q

What is reciprocal altruism?

A

When an individual commits a selfless act with the expectation of future payback

30
Q

What is reciprocal altruism based on?

A

Repeated interaction

31
Q

What are the three conditions required for reciprocal altruism?

A
  1. Repeated, pair-wise interaction
  2. Benefit must exceed cost
  3. Non-reciprocators can be identified and avoided
32
Q

How do we know bats have repeated pair-wise interactions, indicating reciprocal altruism?

A

They roost with the same individuals for years and can live up to 18 years old, presenting lots of opportunities for reciprocity

33
Q

How do we know benefits exceed costs, indicating reciprocal altruism?

A

After a blood meal bat weight declines exponentially due to a high metabolism and evaporative water loss. Therefore time to death is rapid. A bat that donates blood will lose less time than the recipient will gain.

34
Q

How do we know non-reciprocators are identified and not shared with, indicating reciprocal altruism?

A

Males are not shared with as they do not reciprocate blood meals

35
Q

How can males be distinguished from females?

A

They are smaller, presumably also olfactory and sonic differences

36
Q

How could we prove regurgitation is attributed to reciprocal altruism with further tests? What two things would need to be tested?

A

That conditions for reciprocal altruism are always filled:

  1. That repeated pair-wise interaction leads to RA
  2. That non-reciprocators are identified
37
Q

How would we test for repeated pairwise interactions that lead to RA?

A
  1. Wild behavioural focals
  2. Observe a new arrival at a roosting site that is not affiliated with the existing females, see how they behave towards her (wild and captive experiments)
  3. Captive studies between unrelated and related groups that are then mixed
38
Q

Explain how captive studies between unrelated and related groups that are then mixed would indicate RA.

What would we assume under RA?

A

(CONTROL) Two groups, all individuals unrelated, leave to establish close bonds, then mix. See whether individuals that already know each other associate more.

Two groups, related bats initially kept in separate groups, upon mixing see whether they share with relatives they haven’t associated with or with non-relatives they have roosted with previously.

Under RA, assume that bats associate with previous roost mates, not distant relatives

39
Q

Males are easily identified as non-reciprocators due to sexual dimorphism. How might females distinguish each other? How can this be tested?

A

Olfactory or sonic cues

Obtain a long-associated, reciprocal pair, separate them, expose each to the other’s scent or vocal recordings, see what provokes a behavioural response

40
Q

Wilkinson found that female vampire bats social groom. In what year did he find this?

A

1986

41
Q

Wilkinson, 1986:

Females bats social groom. When? Why is this important?

A

Grooming occurs before regurgitation and is correlated to regurgitation frequency.

This can be used as a way to identify non-reciprocators.

42
Q

How can experiments that focus on grooming give information about reciprocation?

A

Measure the association between grooming and regurgitation, see whether they are correlated.

Females may identify individuals to share with by grooming.

43
Q

Who looked at captive studies on just males? What happened?

A

Wilkinson, 2013:

An all-male captive group began sharing with each other after some time, supports reciprocal altruism as there is guaranteed pay-off to helping non-relatives.

Year 3: Adaptation (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions