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

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who wrote the paper?

Bell et al (2014)


what are the hypotheses?

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


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


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


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)


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


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


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


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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