Special reading - counter intuitive behaviour -1 - supressing subordinates in meerkats Flashcards Preview

Animal behaviour - year 2 > Special reading - counter intuitive behaviour -1 - supressing subordinates in meerkats > Flashcards

Flashcards in Special reading - counter intuitive behaviour -1 - supressing subordinates in meerkats Deck (9)
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1

who wrote the paper?

Bell et al (2014)

2

what are the hypotheses?

when dominant females successfully supress subordinate reproduction fitness of the dominants offspring increases

3

what is the aim of the paper?

to understand the evolutionary paradox of eusociality by explaining the benefits of extreme reproductive inequality within stable societies - paper hopes to understand the fitness benefits to dominant meerkats when they supress subordinates

4

how did the experiment simulate subordinate suppression?

- used contraceptive injections to prevent subordinate reproduction in a long term study
- in year 1 in six treated groups all subordinate females over 180 days old were injected (n=35)
- in 6 control groups all subordinate females (n=38) were injected with an equivalent volume of saline solution
- in year 2 - control and treatment groups were swapped and protocol repeated

5

how did they measure benefits to dominant from supressed subordinate reproduction?

- individuals were tagged for identification- meerkats were trained to step on scales and weight was measured throughout experiment (twice a week)

6

how did they observe the meerkats throughout the experiment?

visited the group twice per week: collected behavioural data, recorded group composition and weighted meerkats
- every week focal watches were done on dominant females to monitor aggression towards subordinates

7

in treated groups what were the results for how the behaviour of the dominants changed?

aggression towards subordinates decreased
dominants more tolerant of treated subordinates and less likely to evict them

8

what changed in the treated groups?

- Ratios of helper to pups increased in treated groups (less subordinate females were evicted + less kids born)
- Dominant females in treated groups captured more food per minute
- Pups born to dominant females in treated groups were heavier when they first emerged from burrows +grew faster

9

Meaning of results

- results prove that dominants are selected to suppress subordinate breeding because it reduces dominant fitness
- subordinates represent a resource, which is depleted when they attempt to breed

- Results also indicate the cost of subordinate repression behaviour for dominant females
- this is shown by dominants increased foraging success, gestational weight gain and pup emergence weight in treated groups.

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